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Background: Intratumor heterogeneity (ITH) is a key biological characteristic of gliomas. This study aimed to characterize ITH in adult-type diffuse gliomas and assess the feasibility of using habitat imaging based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) to preoperatively predict isocitrate dehydrogenase (IDH) genotypes and prognosis., Methods: Sixty-three adult-type diffuse gliomas with known IDH genotypes were enrolled. Volume transfer constant (K trans ) and apparent diffusion coefficient (ADC) maps were acquired from DCE-MRI and DWI, respectively. After tumor segmentation, the k-means algorithm clustered K trans and ADC image voxels to generate spatial habitats and extract quantitative image features. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were used to evaluate IDH predictive performance. Multivariable logistic regression models were constructed and validated using leave-one-out cross-validation, and the contrast-enhanced subgroup was analyzed independently. Kaplan-Meier and Cox proportional hazards regression analyses were used to investigate the relationship between tumor habitats and progression-free survival (PFS) in the two IDH groups., Results: Three habitats were identified: Habitat 1 (hypo-vasopermeability and hyper-cellularity), Habitat 2 (hypo-vasopermeability and hypo-cellularity), and Habitat 3 (hyper-vasopermeability). Compared to the IDH wild-type group, the IDH mutant group exhibited lower mean K trans values in Habitats 1 and 2 (both P < 0.001), higher volume (P < 0.05) and volume percentage (pVol, P < 0.01) of Habitat 2, and lower volume and pVol of Habitat 3 (both P < 0.001). The optimal logistic regression model for IDH prediction yielded an AUC of 0.940 (95% confidence interval [CI]: 0.880-1.000), which improved to 0.948 (95% CI: 0.890-1.000) after cross-validation. Habitat 2 contributed the most to the model, consistent with the findings in the contrast-enhanced subgroup. In IDH wild-type group, pVol of Habitat 2 was identified as a significant risk factor for PFS (high- vs. low-pVol subgroup, hazard ratio = 2.204, 95% CI: 1.061-4.580, P = 0.034), with a value below 0.26 indicating a 5-month median survival benefit., Conclusions: Habitat imaging employing DCE-MRI and DWI may facilitate the characterization of ITH in adult-type diffuse gliomas and serve as a valuable adjunct in the preoperative prediction of IDH genotypes and prognosis., Clinical Trial Number: Not applicable., Competing Interests: Declarations. Ethics approval and consent to participate: This retrospective clinical study obtained approval from the Ethics Committee of Renji Hospital, Shanghai Jiao Tong University School of Medicine (approval number: LY2023-154-B). The requirement for informed consent from patients was waived due to the retrospective nature of the study. All methods were performed in accordance with relevant guidelines and regulations. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Objective. Gold nanoparticles (GNPs) are widely used for biological research and applications. The in-vivo concentration of GNPs is usually low due to biological safety concerns, thus posing a challenge for imaging. This work investigates on optimal energy threshold selection in photon-counting detector(PCD)-based CT (PCCT) for the quantification of low-concentration GNPs. Approach. We derived the mathematical expression of the upper bound of the material decomposition error in the gold image. Comprehensive simulations were implemented for cylindrical phantom with inserts of different GNP concentrations. CT scans of this phantom were simulated with a 140 kVp x-ray beam under a realistic pre-clinical CT dose range. The PCD energy thresholds from 30 to 110 keV were enumerated for 2,3-channel PCCT and the optimal energy thresholds were determined by searching for the lowest decomposition error. Main results. The optimal energy threshold(s) to minimize the decomposition error in gold image was 44 keV for the 2-channel PCCT and{34,40}keV for the 3-channel case. Numerical results also validated the derived upper bounds of the decomposition error. Significance. This work addressed the need for selecting appropriate energy thresholds for accurate quantification of contrast agent distributions in pre-clinical PCCT. Both the analytical expression of the upper bound of material decomposition error and simulation results showed that the balanced consideration on photon counting noise levels and the numerical properties of the decomposition matrix is required in selecting the appropriate energy thresholds to achieve the most accurate material decomposition., (© 2025 Institute of Physics and Engineering in Medicine. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Background and Purpose: Lateral decubitus CT myelography (LDCTM) is one of the main studies for the detection of CSF-venous fistulas, but detection of CSF-venous fistulas is dependent on intrathecal contrast attenuation. The purpose of this investigation was to assess the tolerability and technical performance of increased intrathecal doses of myelographic contrast compared with standard doses., Materials and Methods: This is a retrospective series of 24 patients who underwent LDCTM following administration of either 10 or 20 mL of intrathecal iodinated contrast media (300 or 320 mg/mL of iodine content). Patients were scanned in the initial lateral decubitus position and then turned to the contralateral side and re-scanned in the same session. The safety and tolerability of the 20 mL dose was assessed from clinical records. The technical performance of the studies was compared between groups (10 or 20 mL) by measuring attenuation values over the lateral thecal sac at standardized levels. Both the initial scan and the scan after turning the patient to the contralateral side were assessed., Results: No moderate or severe adverse event was recorded in either group. The 20-mL group showed higher attenuation values, which were statistically greater on the second side examined compared with the standard-dose group., Conclusions: Increased volume of intrathecal contrast was well-tolerated and improved the technical performance of LDCTM in this limited series. Further assessment of the safety and impact on diagnostic yield using larger patient cohorts is warranted., (© 2025 by American Journal of Neuroradiology.)

Background: Beginning in 2006, neuroradiologists became increasingly aware of the risk of nephrogenic system fibrosis (NSF) when patients with chronic kidney disease (CKD) received gadolinium-based contrast agents (GBCAs) in conjunction with MRI scans. Radiology practices began withholding GBCAs from MRI patients with substantial CKD and instated a variety of safety measures to ensure that these individuals did not inadvertently receive GBCAs. As a result, the worldwide incidence of NSF was dramatically reduced. Since that time, a wealth of research on NSF and its etiology has found few unconfounded cases associated with those GBCAs categorized as group II agents by the American College of Radiology., Methods: In 2023 and 2024, members of the American Society of Neuroradiology (ASNR) Standards and Guidelines Committee reviewed new research evidence on GBCA safety and its relevance to current MRI contrast administration guidelines for patients with CKD. This focused on systematic reviews and meta-analyses conducted during the past 5 years. Upon consideration of this literature, recommendations for the administration of GBCAs to patients with CKD were formulated., Key Message: For neuroimaging applications, the ASNR recommends that group II GBCAs no longer be withheld in patients with CKD when these agents are medically indicated for diagnosis. Moreover, if group II GBCAs are exclusively used in an MRI practice, other safety measures, such as checking renal function or querying patients about CKD, can be discontinued., (© 2025 by American Journal of Neuroradiology.)

Background and Purpose: Even though glioblastoma (GB) and brain metastases (BM) can be differentiated using radiomics, it remains unclear if the model performance may vary based on the contrast-enhanced sequence used. Our aim was to evaluate the radiomics-based model performance for differentiation between GB and brain metastases BM using MPRAGE and volumetric interpolated breath-hold examination (VIBE) T1-contrast-enhanced sequence., Materials and Methods: T1 contrast-enhanced (T1-CE) MPRAGE and VIBE sequences acquired in 108 patients (31 GBs and 77 BM) during the same MRI session were retrospectively evaluated. After standardized image preprocessing and segmentation, radiomics features were extracted from necrotic and enhancing tumor components. Pearson correlation analysis of radiomics features from tumor subcomponents was also performed. A total of 90 machine learning pipelines were evaluated using a 5-fold cross-validation. Performance was measured by mean area under the curve (AUC)-receiver operating characteristic (ROC), log loss, and Brier scores., Results: A feature-wise comparison showed that the radiomics features between sequences were strongly correlated, with the highest correlation for shape-based features. The mean AUC across the top 10 pipelines ranged between 0.851 and 0.890 with T1-CE MPRAGE and between 0.869 and 0.907 with the T1-CE VIBE sequence. The top-performing models for the MPRAGE sequence commonly used support vector machines, while those for the VIBE sequence used either support vector machines or random forest. Common feature-reduction methods for top-performing models included linear combination filter and least absolute shrinkage and selection operator for both sequences. For the same machine learning feature-reduction pipeline, model performances were comparable (AUC-ROC difference range, -0.078-0.046)., Conclusions: Radiomics features derived from T1-CE MPRAGE and VIBE sequences are strongly correlated and may have similar overall classification performance for differentiating GB from BM., (© 2025 by American Journal of Neuroradiology.)

Background and Purpose: In ischemic stroke, leptomeningeal collaterals can provide delayed and dispersed compensatory blood flow to tissue-at-risk despite an occlusion and can impact treatment response and infarct growth. The purpose of this work is to test the hypothesis that the inclusion of this delayed and dispersed flow with an appropriately calculated local arterial input function (local-AIF) is needed to quantify the degree of collateral blood supply in tissue distal to an occlusion., Materials and Methods: Seven experiments were conducted in a preclinical middle cerebral artery occlusion model. Dynamic susceptibility contrast MRI was imaged and postprocessed to yield quantitative cerebral blood flow (qCBF) maps with both a traditionally chosen single arterial input function applied globally to the whole brain (ie, "global-AIF") and a delay and dispersion corrected AIF (ie, "local-AIF") that is sensitive to retrograde flow. Leptomeningeal collateral arterial recruitment was quantified with a pial collateral score from x-ray angiograms, and infarct growth was calculated from serially acquired diffusion-weighted MRI scans., Results: The degree of collateralization at x-ray correlated more strongly with local-AIF qCBF in the ischemic penumbra (R 2 = 0.81) than with traditional global-AIF qCBF (R 2 = 0.05). Local-AIF qCBF was negatively correlated with infarct growth (slower infarct progression with higher perfusion, R 2 = 0.79) more strongly than global-AIF qCBF (R 2 = 0.02)., Conclusions: In acute stroke, qCBF calculated with a local-AIF is more accurate for assessing tissue status and collateral supply than traditionally chosen global-AIFs. These findings support the use of a local-AIF that corrects for delayed and dispersed retrograde flow in determining quantitative tissue perfusion with collateral supply in occlusive disease., (© 2025 by American Journal of Neuroradiology.)

Contrast-enhanced computed tomography (CECT) is constantly used for delineating organs-at-risk (OARs) in radiation therapy planning. The delineated OARs are needed to transfer from CECT to non-contrast CT (NCCT) for dose calculation. Yet, the use of iodinated contrast agents (CA) in CECT and the dose calculation errors caused by the spatial misalignment between NCCT and CECT images pose risks of adverse side effects. A promising solution is synthesizing CECT images from NCCT scans, which can improve the visibility of organs and abnormalities for more effective multi-organ segmentation in NCCT images. However, existing methods neglect the difference between tissues induced by CA and lack the ability to synthesize the details of organ edges and blood vessels. To address these issues, we propose a contrast-enhanced knowledge and anatomical perception network (CKAP-Net) for NCCT-to-CECT synthesis. CKAP-Net leverages a contrast-enhanced knowledge learning network to capture both similarities and dissimilarities in domain characteristics attributable to CA. Specifically, a CA-based perceptual loss function is introduced to enhance the synthesis of CA details. Furthermore, we design a multi-scale anatomical perception transformer that utilizes multi-scale anatomical information from NCCT images, enabling the precise synthesis of tissue details. Our CKAP-Net is evaluated on a multi-center abdominal NCCT-CECT dataset, a head an neck NCCT-CECT dataset, and an NCMRI-CEMRI dataset. It achieves a MAE of 25.96 ± 2.64, a SSIM of 0.855 ± 0.017, and a PSNR of 32.60 ± 0.02 for CECT synthesis, and a DSC of 81.21 ± 4.44 for segmentation on the internal dataset. Extensive experiments demonstrate that CKAP-Net outperforms state-of-the-art CA synthesis methods and has better generalizability across different datasets., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Object: This study aimed to evaluate the relaxivity and uniformity of agarose gel phantoms added with relaxation modifiers. It is hypothesized that the modifiers could manipulate the T1 and T2 relaxations as well as the signal uniformity., Materials and Methods: Twenty agarose gel phantoms with different GdCl₃ and FeCl₃ volume fractions were prepared. The phantoms were scanned using a 3-T scanner implementing a turbo spin echo sequence to acquire T1 and T2 images. The SNR of the images were computed using Image-J software from 1, 3, and 25 regions-of-interest (ROIs) and were inverted as T1 and T2 curves., Results: With the increase in relaxation modifier content, T1 SNR increased at a faster rate at very short TR and reached saturation at TR well below 400 ms. Agarose gel phantoms containing GdCl 3 showed a higher saturation value as compared to phantoms containing FeCl 3 . For T2 SNR, differences between plots are observed at low TE. As TE gets larger, the SNR between plots is incomparable. The SNR for both groups was uniform among 1, 3, and 25 ROIs., Discussions: It can be concluded that GdCl₃ and FeCl₃ solutions can be used as effective relaxation modifiers to reduce T1 but not T2 relaxation times., Competing Interests: Declarations. Competing interests: All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript. Ethical approval: This study has been approved by the Internal Review Board of the Universiti Kebangsaan Malaysia (UKM JEP-2021-616)., (© 2024. The Author(s), under exclusive licence to European Society for Magnetic Resonance in Medicine and Biology (ESMRMB).)

Objects: To investigate the specific manifestations of neurogenic and non-neurogenic tumors involving peripheral nerves on contrast-enhanced magnetic resonance neurography (CE-MRN) and explore the potential of CE-MRN in aiding differential diagnosis., Materials and Methods: Twenty-nine patients with neurogenic tumors and 23 with non-neurogenic tumors involving peripheral nerves were enrolled in this study. Both routine MRI and CE-MRN scanning were performed on all subjects. The location, pattern of involvement, classical MRI signs, and novel CE-MRN signs of nerve involvement were evaluated and compared between the two groups. The novel CE-MRN signs included "Enhanced target sign", "Nerve effacing sign", "Nerve wrapping sign", "Nerve compressing sign", "Nerve tail sign", and morphological changes of nerves. Diagnostic confidence in identifying nerve involvement and lesion conspicuity were assessed and compared between routine MRI and CE-MRN., Results: The majority of neurogenic tumors were schwannoma (79.3 %) and involved a single nerve (75.9 %), whereas the majority of non-neurogenic tumors were malignant tumors (78.3 %) and involved multiple nerves (78.3 %) (P < 0.001). In terms of classical MRI signs, neurogenic tumors exhibited a significantly higher incidence of the "Tail sign" (75.9 % vs 13 %), "Dumbbell sign" (31 % vs 4.3 %), "Target sign" (51.7 % vs 8.7 %), and "Split fat sign" (55.2 % vs 4.3 %), while showing a lower incidence of the "Effacement of fat plane" (3.4 % vs 60.9 %) compared to non-neurogenic tumors (all p < 0.05). Regarding novel CE-MRN signs, neurogenic tumors demonstrated a significantly higher incidence of the "Enhanced target sign" (65.6 % vs 13 %) and the "Nerve tail sign" (100 % vs 13 %), while exhibiting a lower incidence of the "Nerve effacing sign" (0 % vs 52.2 %) and the "Nerve wrapping sign" (0 % vs 17.4 %) compared to non-neurogenic tumors (all p < 0.05). CE-MRN yielded significantly higher diagnostic confidence scores (2.87 ± 0.35 vs 1.75 ± 0.84), but lower lesion conspicuity scores (2.35 ± 0.71 vs 2.92 ± 0.27) compared to routine MRI (all P < 0.001)., Conclusion: CE-MRN is a valuable imaging modality for the identification of tumor-related peripheral nerve involvement, as it offers supplementary indicators and enhances diagnostic confidence., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objective: The incidence of stroke after on-pump cardiac surgery during the perioperative period can affect up to 2% of patients, and is frequently linked to carotid artery disease. Notably, in patients with significant unilateral carotid artery stenosis of 80%-99%, the risk of stroke reaches 4%. Among individuals undergoing coronary artery bypass grafting (CABG), 3% to 10% exhibit significant carotid artery stenosis. To mitigate the risk of stroke and mortality, patients can undergo either simultaneous or staged carotid endarterectomy and CABG. The aim of this study was to assess whether early postoperative complications, including stroke, following simultaneous CABG/CAE procedures, correlate with morphological attributes of carotid plaque, assessed via contrast-enhanced ultrasound., Methods: A single centre retrospective analysis was performed including 62 patients who underwent simultaneous CABG/CEA between 2019 and 2022. Our study excluded patients who underwent staged carotid endarterectomy and CABG procedures, off-pump CABG, or those necessitating urgent CABG. Our analysis focused on patients meeting elective CABG criteria, diagnosed with symptomatic triple-vessel or left main trunk coronary artery disease (CAD), alongside asymptomatic carotid stenosis (a. carotis internae) exceeding 70% or symptomatic ipsilateral carotid stenosis surpassing 50%. The extent of contralateral carotid artery stenosis was not taken into account. Prior to the CEA/CABG procedure, each patient underwent contrast-enhanced ultrasound to assess atherosclerotic lesions, which were classified using Nakamura et al.'s classification. Among the patients, 37.1% exhibited no neovascularisation within the atherosclerotic plaque, 56.5% showed insignificant neovascularisation, and 6.5% displayed notable neovascularization within the plaque. Our study aimed to establish a connection between the degree of plaque vascularisation identified through contrast-enhanced ultrasound and subsequent postoperative complications., Results: Upon evaluating postoperative complications occurring within 30 days after the surgery and the plaque morphology identified through contrast-enhanced ultrasound, a statistically significant correlation was observed between a higher grade of plaque vascularisation and the occurrence of ischaemic stroke (r = 0.329, p = .008). Monte Carlo calculations of the Chi-square test indicated a significant association between a higher grade of plaque vascularisation and the presence of peripheral artery disease (χ2 = 15.175, lls = 2, p = .003)., Conclusion: Within 30 days of surgery, a significant correlation exists between the occurrence of ischaemic stroke following carotid endarterectomy subsequent to CABG and the presence of a higher grade plaque vascularisation as identified by contrast-enhanced ultrasound., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: To evaluate the feasibility of aortoiliac CT-Angiography (CTA) using dual-source photon-counting detector (PCD)-CT with minimal iodine dose., Methods: This IRB-approved, single-center prospective study enrolled patients with indications for aortoiliac CTA from December 2022 to March 2023. All scans were performed using a first-generation dual-source PCD-CT. Images were acquired with fast pitch and full spectral capabilities (collimation 144 × 0.4 mm). The contrast protocol included a mixture of sodium chloride and iodinated contrast agent (Iopromide, total iodine dose: 9.5-9.8 g). Virtual monoenergetic images (VMIs) were reconstructed at 40, 50, 60, and 68 keV. Two blinded radiologists evaluated image quality on a 4-point scale. Attenuation was measured across eight regions in the aorta and iliac arteries, and contrast-to-noise ratio (CNR) was calculated. Statistical comparisons were performed using repeated measures ANOVA and Bonferroni post-hoc tests., Results: The final cohort consisted of 39 subjects (mean age: 69.6 ± 9.6 years; 30.8 % female). VMI at 40 keV provided significantly higher attenuation: 478 ± 114 HU, compared to 50 keV (331 ± 74 HU), 60 keV (241 ± 51 HU), and 68 keV (190 ± 48 HU) (p < 0.01). This translated in increased CNR for 40 keV reconstructions (11.8 ± 3.9), followed by 50 keV (9.1 ± 3.0), 60 keV (7.0 ± 2.3), and 68 keV (6.1 ± 1.9) (p < 0.01). Subjective image quality was rated excellent at 40 keV (4 [3,4]), though associated with highest noise (38 ± 7.4 HU, p = 0.02)., Conclusion: Aortoiliac CTA using dual-source PCD-CT at 40 keV achieved high attenuation and CNR, enabling effective imaging with only 9.8 g of iodine., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 The Author(s). Published by Elsevier B.V. All rights reserved.)

The risk of developing a severe delayed cutaneous reaction (SCAR) is very low following iodine-based contrast medium (ICM) administration and extremely low following gadolinium-based contrast agent (GBCA) administration. However, SCAR can be very severe and potentially life-threatening. It is crucial for the imaging physician to recognize danger signals: bullous skin eruption, skin erosion and detachment, mucosal involvement, systemic symptoms, and laboratory abnormalities. Patients suspected of having a SCAR should be urgently referred to a drug allergy specialist or dermatologist. To prevent recurrence, consider exploring alternative imaging modalities and avoid administering the same type of contrast medium involved: if the culprit is a ICM, avoid all ICM and if the culprit is a GBCA, avoid all GBCA. In an allergy centre with experience in SCAR evaluation a careful allergologic analysis may be performed safely several months after the patient has recovered from SCAR. However, allergologic analysis is challenging due to the lack of reliable in vitro diagnostic tests and the risks of in vivo diagnostic tests, particularly drug provocation tests., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Acquired skull base cerebrospinal fluid (CSF) leaks can result from trauma, tumors, iatrogenic causes, or may be spontaneous. Spontaneous skull base CSF leaks are likely a manifestation of underlying idiopathic intracranial hypertension. The initial assessment of rhinorrhea or otorrhea, which may be suspected owing to an acquired skull base CSF leak, requires integration of clinical assessment and biochemical confirmation of CSF. When leaks are multiple or if samples of fluid cannot be obtained for testing, then recourse to intrathecal contrast-enhanced cisternography may be necessary. We also review various other applications for diagnosis of intracranial abnormalities using contrast-enhanced cisternography., Competing Interests: Disclosure The authors have no commercial or financial conflicts of interests to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: To compare the diagnostic efficacy of the Ovarian-Adnexal Reporting and Data System (O-RADS) MRI score with that of the modified O-RADS score on the basis of a simplified contrast-enhanced (CE) MRI protocol in characterizing adnexal masses with solid tissue. The added value of clinical features was evaluated to improve the ability of the scoring system to classify adnexal masses., Methods: A total of 124 patients with 124 adnexal lesions containing solid tissue were included in this two-center retrospective study. Among them, there were 40 benign lesions (40/124, 32.3%) and 84 were malignant lesions (84/124, 67.7%). Three radiologists independently reviewed the images and assigned the O-RADS MRI score and the modified O-RADS score for each adnexal mass. Histopathology was used as the reference standard. The diagnostic efficacy of the two scoring methods was compared. Univariate and multivariate logistic regression were performed to evaluate the value of significant features in the prediction of malignant tumors., Results: The O-RADS MRI score and modified O-RADS score showed sensitivity at 100.0% (95% CI, 95.7-100.0%) and 71.4% (95% CI, 60.5-80.8%), specificity at 12.5% (95% CI, 4.2-26.8%) and 75.0% (95% CI, 58.8-87.3%), respectively. The area under the curve of the modified O-RADS score was higher than the O-RADS score (0.732 [95% CI, 0.645-0.808] vs 0.575 [95% CI, 0.483-0.663]; p < 0.001). Multivariate analysis showed that the modified O-RADS score 4b or 5 combined with patient age > 38.5 years, nullipara, maximum diameter > 40.5 mm and HE4 > 78.9 pmol/L significantly improved the diagnostic efficacy up to 0.954 (95% CI, 0.901-0.984) (p < 0.001)., Conclusion: A modified O-RADS score combined with certain clinical features can significantly improve the diagnostic efficacy in predicting malignant tumors., Competing Interests: Declarations. Conflict of interest: The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. Ethical approval: The Retrospective observational cohort study received approval from the two institutional ethics board (No. B2021324 and Y2022-007)., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Aim: To investigate the value of the LR-5, which is based on hepatobiliary phase (HBP) hypointensity, for small hepatocellular carcinoma (sHCC) using LI-RADS v2018 criteria., Materials and Methods: From January 2015 to December 2021 in institution 1, and from January 2019 to February 2022 in institution 2, 239 patients at high risk for hepatocellular carcinoma (HCC) underwent contrast-enhanced MRI. Two radiologists independently evaluated the imaging features and classified them according to LI-RADS v2018 criteria, calculating the diagnostic performance of LR-5 based on consensus data. LI-RADS-m1: HBP hypointensity was used as an additional major feature along with the LI-RADS v2018. LI-RADS-m2: HBP hypointensity replaced nonperipheral "washout" in the portal venous phase. The definition of LR-DN was nodules pathologically diagnosed as high-grade dysplastic nodules (HGDN) were recategorized as LR-DN. The diagnostic performance of LR-5 was recalculated. The diagnostic performance of the LR-5 was compared using McNemar's test., Results: Using LI-RADS v2018, LI-RADS-m1, and LI-RADS-m2 criteria for LR-5, the sensitivities were 82.67%, 86.22%, and 88.44%, the specificities were 82.00%, 66.00%, and 54.00%, and the accuracies were 82.55%, 82.55%, and 82.18%, respectively. After the addition of the LR-DN, the sensitivities of LR-5 in the above diagnostic model remained unchanged, with accuracies of 84.36%, 87.27%, and 88.36% and specificities of 92.00%, 92.00%, and 88.00%, respectively., Conclusions: HBP hypointensity may improve the sensitivity of LR-5. We attempted to propose the LR-DN, HBP hypointensity may be used as a complement to washout as an additional major feature without significantly decreasing specificity., Competing Interests: Conflict of interest The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: Contrast agents are frequently administered in computed tomography (CT) scans used for opportunistic screening of osteoporosis. The objective of this study is to compare the impact of contrast-related bone mineral density (BMD) increase between phantom-based and internal CT calibration techniques., Materials and Methods: Phantom-based and internal CT calibration techniques were used to determine trabecular BMD in 93 existing clinical CT scans of the lumbar spine of 34 subjects, scanned before and after administration of contrast agents. BMD differences between native (Nat) and contrast-enhanced scans in arterial (Art) and portal venous (PV) phases were compared among calibration methods. Three pairs of internal reference materials were investigated: blood/air, subcutaneous adipose tissue (SAT)/air and muscle tissue/air., Results: Contrast agents increased CT values of blood in the aorta and the inferior vena cava in the Art phase by 210 ± 99HU and 47 ± 35HU, respectively and in the PV phase by 110 ± 49HU and 73 ± 28HU, respectively. Effects on CT values of muscle and SAT were < 5HU in the Art phase and < 10HU in the PV phase. BMD obtained with phantom calibration increased significantly (p < 0.01) in Art and PV phases by 8.6 ± 14.7 mg/cm 3 and 14.4 ± 16.3 mg/cm 3 , respectively. If SAT/air or muscle/air were used as internal reference materials, increases in internally calibrated BMD (<12 mg/cm 3 in AT phase and < 17 mg/cm 3 in PV phase) did not significantly differ (p > 0.1 for Art and PV phases) from increases of phantom-calibrated BMD., Conclusions: Although CT values of internal reference materials increased following the administration of contrast, internal calibration was unable to mitigate the contrast-related BMD increases observed in phantom-based calibration., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Klaus Engelke reports a relationship with German Bundesministerium für Bildung und Forschung (BMBF) Project ARTEMIS − Artificial intelligence musculoskeletal disorders study (reference 01EC190B) that includes: funding grants. Klaus. Engelke is a part time employee of Clario, Inc. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper]., (Copyright © 2025 The Authors. Published by Elsevier B.V. All rights reserved.)

Objectives: Asymmetries on screening contrast-enhanced mammography (CEM) often lead to patient recall. However, in diagnostic settings, negative CEM has effectively classified these as normal or benign, questioning the need for further workup of non-enhancing asymmetries (NEAs)., Material and Methods: A computational search of all screening CEM examinations performed between December-2012 and June-2021 was conducted to identify cases reporting NEAs. Their diagnostic workup was reviewed, and the positive predictive value for cancer was statistically compared to that of enhancing asymmetries on screening CEMs., Results: During the study period, 97 cases of 106 NEAs were identified among 3,482 screening CEM exams (2.8 %). NEAs were classified as asymmetry (n = 83), focal asymmetry (n = 22), and global asymmetry (n = 1), with no cases of developing asymmetry. The mean size of NEAs was 1.0 ± 0.7 cm (range: 0.3-4.9 cm). Diagnostic workup for NEAs included additional mammographic views (AMV) (n = 63), AMV plus ultrasound (n = 30), AMV plus MRI (n = 1), and all three modalities (n = 3), leading to four biopsies. None of the NEAs were malignant on follow-up, as opposed to enhancing asymmetries (P < 0.05)., Conclusion: NEAs detected on CEM were relatively uncommon and were usually investigated with additional mammographic views and US, yielding no cancer. Ruling out malignancy based on lack of enhancement without further workup may reduce patient recall rates and improve CEMs specificity., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Maxine Jochelson’s disclosure includes a previous paid lecture for GE, whose mammograms were utilized as part of the routine clinical work in our institute, regardless of this current study. The rest of the authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article., (Copyright © 2024. Published by Elsevier B.V.)

Purpose: The aim of this study was to assess the effect of gadopiclenol versus gadobenate dimeglumine contrast-enhanced magnetic resonance imaging (MRI) on decision-making between whole-brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS) for treatment of brain metastases (BMs)., Methods: Patients with BMs underwent 2 separate MRI examinations in a double-blind crossover phase IIb comparative study between the MRI contrast agents gadopiclenol and gadobenate dimeglumine, both administered at 0.1 mmol/kg. The imaging data of a single site using identical MRI scanners and protocols were included in this post hoc analysis. Patients with 1 or more BMs in any of both MRIs were subjected to target volume delineation for treatment planning. Two radiation oncologists contoured all visible lesions and decided upon SRS or WBRT, according to the number of metastases. For each patient, SRS or WBRT treatment plans were calculated for both MRIs, considering the gross target volume (GTV) as the contrast-enhancing aspects of the tumor. Mean GTVs and volume of healthy brain exposed to 12 Gy (V 12 ), as well as Dice similarity coefficient scores, were obtained. The Spearman rank (ρ) correlation was additionally calculated for assessing linear differences. Three different expert radiation oncologists blindly rated the contrast enhancement for contouring purposes., Results: Thirteen adult patients were included. Gadopiclenol depicted additional BM as compared with gadobenate dimeglumine in 7 patients (54%). Of a total of 63 identified metastatic lesions in both MRI sets, 3 subgroups could be defined: A, 48 (24 pairs) detected equal GTVs visible in both modalities; B, 13 GTVs only visible in the gadopiclenol set (mean ± SD, 0.16 ± 0.37 cm 3 ); and C, 2 GTVs only visible in the gadobenate dimeglumine set (mean ± SD, 0.01 ± 0.01). Treatment indication was changed for 2 (15%) patients, 1 from no treatment to SRS and for 1 from SRS to WBRT. The mean GTVs and brain V 12 were comparable between both agents ( P = 0.694, P = 0.974). The mean Dice similarity coefficient was 0.70 ± 0.14 (ρ = 0.82). According to the readers, target volume definition was improved in 63.9% of cases (23 of 36 evaluations) with gadopiclenol and 22.2% with gadobenate dimeglumine (8 of 36), whereas equivalence was obtained in 13.9% (5 of 36)., Conclusions: Gadopiclenol-enhanced MRI improved BM detection and characterization, with a direct impact on radiotherapy treatment decision between WBRT and SRS. Additionally, a more exact target delineation and planning could be performed with gadopiclenol. A prospective evaluation in a larger cohort of patients is required to confirm these findings., Competing Interests: Conflicts of interest and sources of funding: Funded by Guerbet SA, Villepinte, France. G.R.S. received personal fees and grants from Carl Zeiss Meditec AG, not related to this work. F.A.G. reports financial support from Guerbet SA (travel expenses), nonfinancial support from Implacit GmbH (consulting, partnership) and Oncare GmbH, grants and personal fees from NOXXON Pharma AG, grants and personal fees from CARL ZEISS MEDITEC AG, personal fees from Bristol-Myers Squibb, personal fees from Roche Pharma AG, personal fees from MSD Sharp and Dohme GmbH, and personal fees from AstraZeneca GmbH, outside of the submitted work; in addition, F.A.G. has a patent pending (US 62/435405). M.B. received personal fees from Guerbet (consultation, related to this work), Seagen, Novartis, Boehringer-Ingelheim (paid lectures, not related), DFG, European Union, and Novartis (grants to the institution, not related). J.F., M. Eckl, F.S., A.R., L.C.S., A.F., D.K., M. Essig, and F.W. have nothing to declare., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Purpose: This study aimed to investigate the potential of radiomic features derived from dynamic contrast-enhanced MRI (DCE-MRI) in predicting Ki-67 and p16 status in head and neck squamous cell carcinoma (HNSCC)., Materials and Methods: A cohort of 124 HNSCC patients who underwent pre-surgery DCE-MRI were included and divided into training and test set (7:3), further subgroup analysis was performed for 104 cases with oral squamous cell carcinoma (OSCC). Radiomics features were extracted from DCE images. The least absolute shrinkage and selection operator (LASSO) was used for radiomics features selection, and receiver operating characteristics analysis for predictive performance assessment. The nomogram's performance was evaluated using decision curve analysis (DCA)., Results: Ten DCE-MRI features were identified to build the predictive model of HNSCC, demonstrating excellent predictive value for Ki-67 status in both the training set (AUC of 0.943) and test set (AUC of 0.801). The nomograms based on the predictive model showed good fit in the calibration curves (p > 0.05), and DCA indicated its high clinical usefulness. In subgroup analysis of OSCC, fourteen features were selected to build the predictive model for Ki-67 status with an AUC of 0.960 in training set and 0.817 in test set. No features could be included to establish a model to predict p16 status., Conclusion: The radiomics model utilizing DCE-MRI features could effectively predict Ki-67 status in HNSCC patients, offering potential for noninvasive preoperative prediction of Ki-67 status., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Purpose: Vessels encapsulating tumor clusters (VETC) was implicated in the unfavourable prognosis of hepatocellular carcinoma (HCC). While potentially valuable for noninvasive evaluation, the proposed imaging criteria of VETC require external validation. This study aimed to evaluate the performance and prognostic value of these imaging criteria via CT and gadoxetic acid-enhanced MRI., Methods: Retrospectively, we gathered study included 191 patients with a single HCC who underwent preoperative CT and gadoxetic acid-enhanced MRI at three tertiary care centers between January 2017 and May 2021. The performance of previously reported radiological feature-based criteria of VETC, including the SN (size and necrosis) score, the VETC nomogram, and Fan's model, were evaluated using the area under the curve (AUC) and compared using the DeLong method. Imaging estimated VETC stratification was assessed for its association with early recurrence., Results: Ninety-four patients (49.2%) were pathologically identified as VETC-positive HCC. No significant differences were found between CT and gadoxetic acid-enhanced MRI regarding the performance of the criteria (allP> 0.05). However, the VETC nomogram, which incorporates tumor size, necrosis, and enhancement pattern, outperformed the SN score and Fan's model (AUC: 0.825 vs. 0.716 and 0.588 at CT; 0.841 vs. 0.721 and 0.621 at gadoxetic acid-enhanced MRI, bothP< 0.001). Stratification using the VETC nomogram, validated on both CT and gadoxetic acid-enhanced MRI, was associated with early recurrence (P< 0.05)., Conclusion: This study confirmed that the radiological feature-based criteria of VETC in HCC are applicable to both CT and gadoxetic acid-enhanced MRI, with the VETC nomogram showing strong discriminatory power in identifying VETC-positive HCC and predicting early recurrence., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

Purpose: To evaluate the interest of additional pseudo-CT images to standard clinical contrast-enhanced MR images (CE-MRI) in the detection of inflammatory erosions and to differentiate them from intraosseous ganglia at the finger joints., Method: 47 prospectively included patients with suspected or diagnosed rheumatoid arthritis received a CE-MRI of the fingers. Additionally, pseudo-CT images were derived from non-contrast MRI (pCT) and from contrast-enhanced MRI data (CE-pCT) using a high-resolution gradient-echo 3D fast low-angle shot sequence (FLASH), respectively. CE-MRI, pCT, and CE-pCT images were evaluated for erosions and intraosseous ganglia at the metacarpophalangeal and proximal interphalangeal joints by two musculoskeletal radiologists. Findings were defined on CE-MRI by an experienced independent 3rd reader which served as reference standard. Diagnostic confidence (1 = worst, 4 = best) was rated for 3 different image sets (1 = CE-MRI, 2 = CE-MRI + pCT, 3 = CE-MRI + CE-pCT) and compared., Results: Reference standard revealed 44 erosions and 37 intraosseous ganglia on CE-MRI. Diagnostic confidence for CE-MRI was moderate for erosions (both readers) and intraosseous ganglia (reader 2). For the combination of CE-MRI and pCT, high confidence levels were observed for erosions for both readers (median 3 (Q1-Q3: 2.5-3) and 3 (3-3); p<.001 and p<.001) and for intraosseous ganglia for reader 2 (3 (3-3); p<.001). CE-MRI combined with CE-pCT showed very high confidence levels for both readers for erosions (4 (3-4) and 4 (4-4); p<.001 and p<.001) and for intraosseous ganglia (4 (4-4) and 4 (4-4); p<.001 and p<.001)., Conclusions: Pseudo-CT combined with CE-MRI increases the confidence in detection of inflammatory erosions at the finger joints, with CE-pCT being superior to pCT., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Stefan Sommer is an employee of Siemens Healthineers AG. All other authors have nothing to disclose]., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Cardiac MRI is the reference standard for identifying and evaluating myocardial pathologic conditions. Late gadolinium enhancement characteristics provide an excellent guide in classifying disease and triaging patients. Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is an uncommon congenital anomaly. Myocardial enhancement at cardiac MRI is often a sign of a myocardial pathologic condition, while more specifically, subendocardial enhancement is a feature expected in patients with ALCAPA. This report describes the atypical finding of mid myocardial late gadolinium enhancement in three adult patients with ALCAPA. Keywords: Mid Myocardial Enhancement, Cardiac MRI, Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery © RSNA, 2025.

Purpose: We aimed to characterize and further understand CSF circulation and outflow of rabbits. To our knowledge, there is no research on contrast material-enhanced MR cisternography (CE-MRC) with T1 and T2 mapping in the rabbit model using a clinical 3-T MR unit without a stereotaxic frame., Materials and Methods: Twenty-one rabbits were included in the study. The CE-MRC exams with T1/T2 mappings were categorized into approximate time points based on an intention-to-scan approach: precontrast, less than 4 h after contrast, 24 h after contrast, and 24 to 120 h after gadobutrol. The presence of contrast media in the head and neck structures was scored with a 3-point scale (present, score: 2; absent, score: 0; and inconsistent, score: 1). T1 and T2 estimates were directly derived by drawing regions of interest on the corresponding maps., Results: Gadobutrol accumulation was detected in the CSF near the cribriform plate and nasal areas on early-phase postcontrast images of all animals. These contrast material accumulations completely disappeared on the images obtained in postcontrast ≥ 24 h. The lowest T1 and T2 estimates in olfactory and cerebral areas were observed on early-phase images. Significant correlations were observed between the enhancement of the bladder and the medial portion of the sclera and the enhancement of inner ear structures, olfactory regions, turbinates, nasal cavities, and cranial subarachnoid spaces. The T1 and T2 estimates of the septum and olfactory bulb were generally lower than those measured in the frontal and parietal lobes on early-phase images., Discussion: Our findings, which indicate an absence of clearly visible arachnoid granulations in rabbits, support the significance of olfactory outflow and the glymphatic system as highlighted in recent literature. Glymphatic transport can be more effectively demonstrated using T1 mapping in rabbits. The anatomical and physiological differences between human and rodent central nervous systems must be considered when translating experimental results from rabbits to humans., (© 2024 John Wiley & Sons Ltd.)

Objectives: Reducing gadolinium-based contrast agents to lower costs, the environmental impact of gadolinium-containing wastewater, and patient exposure is still an unresolved issue. Published methods have never been compared. The purpose of this study was to compare the performance of 2 reimplemented state-of-the-art deep learning methods (settings A and B) and a proposed method for contrast signal extraction (setting C) to synthesize artificial T1-weighted full-dose images from corresponding noncontrast and low-dose images., Materials and Methods: In this prospective study, 213 participants received magnetic resonance imaging of the brain between August and October 2021 including low-dose (0.02 mmol/kg) and full-dose images (0.1 mmol/kg). Fifty participants were randomly set aside as test set before training (mean age ± SD, 52.6 ± 15.3 years; 30 men). Artificial and true full-dose images were compared using a reader-based study. Two readers noted all false-positive lesions and scored the overall interchangeability in regard to the clinical conclusion. Using a 5-point Likert scale (0 being the worst), they scored the contrast enhancement of each lesion and its conformity to the respective reference in the true image., Results: The average counts of false-positives per participant were 0.33 ± 0.93, 0.07 ± 0.33, and 0.05 ± 0.22 for settings A-C, respectively. Setting C showed a significantly higher proportion of scans scored as fully or mostly interchangeable (70/100) than settings A (40/100, P < 0.001) and B (57/100, P < 0.001), and generated the smallest mean enhancement reduction of scored lesions (-0.50 ± 0.55) compared with the true images (setting A: -1.10 ± 0.98; setting B: -0.91 ± 0.67, both P < 0.001). The average scores of conformity of the lesion were 1.75 ± 1.07, 2.19 ± 1.04, and 2.48 ± 0.91 for settings A-C, respectively, with significant differences among all settings (all P < 0.001)., Conclusions: The proposed method for contrast signal extraction showed significant improvements in synthesizing postcontrast images. A relevant proportion of images showing inadequate interchangeability with the reference remains at this dosage., Competing Interests: Conflicts of interest and sources of funding: R.H., T.P., E.K., D.P., A.E., A.R., and K.D. are cofounders and stakeholders of relios.vision GmbH; Z.B. and C.G. have no conflicts to declare. R.H. is funded by a research grant (BONFOR; O-194.0002.1 and O-194.0003.1) of the Medical Faculty of the University of Bonn. A.E. and T.P. are funded by the German Research Foundation under Germany's Excellence Strategy (EXC-2047/1, 390685813 and EXC-2151, 390873048)., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

The purpose of this article is to review commonly used medications in abdominal radiology including their indications, mechanisms of action, dosages, contraindications, precautions, and adverse reactions. We will clarify common inquiries and address frequently asked questions by patients and clinicians related to their use. In addition, we will explore the indications, advantages and disadvantages, dosages, and contraindications of enteric contrast agents used for CT and fluoroscopic examinations., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Purpose: This study aims to investigate the factors influencing the malignant risk of BI-RADS 4B calcification-only lesions detected on Contrast-Enhanced Mammography (CEM) and to develop a predictive model for stratifying malignant risk., Methods: A retrospective analysis was conducted on 131 calcification-only lesions of BI-RADS 4B identified on low-energy (LE) images of CEM from 125 females between March 2017 and April 2023 at three institutions. The patients were grouped as training (95 lesions) and external validation sets (36 lesions). On LE images, morphological features of the calcifications, including morphology, distribution and size, were evaluated. On recombined images, the presence and types of enhancement were assessed as qualitative variables, and the grey values from lesion areas and background were measured as quantitative variables. Multivariate logistic regression analysis was used to construct a predictive model. The discrimination of the model was assessed by the receiver operating characteristic (ROC) curve and confirmed by the external validation set., Results: Of the 131 lesions, 43 were malignant. The morphology, distribution, the presence and types of enhancement and the grey values of calcifications showed significant differences between benign and malignant lesions. The nomogram was developed based on morphology and the presence of enhancement, with areas under the ROC curve of 0.859 (95% confidence interval [CI]: 0.769, 0.949) and 0.856 (95% CI: 0.729, 0.983) in the training and external validation sets, respectively., Conclusion: On CEM, the presence of enhancement and morphology were identified as independent predictors of malignant calcifications of BI-RADS 4B. The predictive model demonstrated favorable performance., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethics approval: This is an observational study. The Research Ethics Committee has confirmed that no ethical approval is required. Consent to participate: Informed consent was obtained from all individual participants included in the study. Consent to publish: The authors affirm that human research participants provided informed consent for publication of the images in Fig. 2 and 3., (© 2024. The Author(s).)

The discontinuous peripheral enhancement is a pattern of enhancement usually attributed to typical cavernous hemangioma, that is the most common benign solid lesion of the liver. The discontinuous peripheral enhancement, however, may be encountered in many other benign and malignant focal liver lesions as an atypical presentation or evolution, and hemangiomas with discontinuous peripheral hyperenhancement on hepatic arterial phase may not always have the typical post-contrast pattern on portal venous and delayed phases. Therefore, abdominal radiologists may be challenged in their practice by lesions with discontinuous peripheral enhancement. This pictorial essay aims to review the spectrum of benign and malignant focal liver lesions that may show discontinuous peripheral enhancement. A particular point of interest is the diagnostic tree pathway that may guide the radiologists in the differential diagnosis., Competing Interests: Declarations. Conflict of interest: Roberto Cannella is an Associate Editor (Hepatobiliary) for Abdominal Radiology; support for attending meetings from Bracco and Bayer; research collaboration with Siemens Healthineers. The other authors have no competing interests., (© 2024. The Author(s).)

Purpose: To evaluate the behavior of n-butyl cyanoacrylate-Lipiodol-iopamidol at a ratio of 2:3:1 (NLI231) with and without microcoils and/or flow control in embolization of medium-sized arteries in an in vitro vascular model., Materials and Methods: A vessel model representing a common hepatic artery was prepared. Six scenarios were set for embolization, each ran three times: 1) NLI231 injected alone with flow control to 0 ml/min during and up to 5 min after embolization; 2) NLI231 injected into a mesh of microcoil of 5% density with the flow control; 3) NLI231 injected into a microcoil of 10% density with the flow control; 4) NLI231 injected alone without the flow control; 5) NLI231 injected into microcoil of 5% density without the flow control; 6) NLI231 injected into a microcoil of 10% density without the flow control. The microcoils were delivered to the embolization site, and NLI231 was injected. After 1 h of observation, distal filters were collected, and grades of migration (I = none, II = partial, III = almost all-all) were assessed for each scenario., Results: Embolization was achieved in scenarios with NLI231 and microcoils regardless of flow control (p < 0.01). NLI231 did not migrate in scenarios with microcoils and flow control (p < 0.05). NLI231 with microcoils without flow control can embolize the vessel, but partial migration occurred, and the distal distance of the NLI231 complex from the embolization site was longer (p < 0.01)., Conclusion: Combining sparse coiling with NLI231 may be feasible but is limited to use when flow control is available, or where distal embolization is permissible to some extent., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no competing interest. Ethical approval: This article does not contain any studies with human participants or animals performed by any of the authors. Institutional review board approval was not required for this study. Informed consent: For this type of study, informed consent is not required. Consent for publication: For this type of study, consent for publication is not required., (© 2024. The Author(s).)

Objective: To investigate the relationship between the rim-like enhancement pattern on pre-ablation contrast-enhanced ultrasound (CEUS) of colorectal liver metastasis (CRLM) and the therapeutic efficacy of percutaneous microwave ablation (MWA)., Methods: Patients with CRLM underwent MWA and were evaluated using CEUS before ablation in our hospital between February 2020 and February 2023 were enrolled in this retrospective study. The enhancement patterns of CRLM were assessed by two radiologists and classified as rim-like enhancement and non-rim-like enhancement patterns. The therapeutic outcomes, including cumulative intrahepatic progression rate and early intrahepatic progression rate, were followed up and analyzed., Results: Overall, 50 patients with 121 nodules were enrolled. Rim-like enhancement pattern was observed in 18 patients (18/50, 36.0%). The cumulative intrahepatic progression rate was significantly higher in the rim-like enhancement group than the rate in the non-rim-like enhancement group (p = 0.022). The early intrahepatic progression rate in the rim-like enhancement group was also significantly higher than the rate in the non-rim-like enhancement group (12/17, 70.6% vs. 6/24, 25.0%, p = 0.005). The multivariable analysis demonstrated that the rim-like enhancement pattern of CRLM was a significant risk factor associated with early intrahepatic progression after MWA (p = 0.013)., Conclusion: Rim-like enhancement pattern on pre-ablation CEUS of CRLM was associated with a higher risk of intrahepatic progression after MWA., Competing Interests: Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2024 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Purpose: To quantitatively evaluate the performance of two types of recurrent neural networks (RNNs), long short-term memory (LSTM) and gated recurrent units (GRU), using Monte Carlo dropout (MCD) to predict pharmacokinetic (PK) parameters from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data., Methods: DCE-MRI data for simulation studies were synthesized using the extended Tofts model and a population-averaged arterial input function (AIF). The ranges of PK parameters for training the RNNs were determined from data of patients with brain tumors. The effects of the number of training samples, number of hidden units, dropout rate (DR), and bolus arrival time delay and dispersion in AIF on the accuracy of the PK parameters were investigated, and the uncertainties for different DRs and peak signal-to-noise ratios (PSNRs) were quantified. For comparison, PK parameters were estimated using the nonlinear least-squares method. In the clinical studies, the PK parameter and uncertainty images were generated by applying the trained RNNs to DCE-MRI data., Results: Compared with GRU, the computational cost for training the LSTM was significantly higher. The prediction accuracy of GRU decreased with decreasing numbers of training samples and hidden units, whereas the performance of LSTM remained stable. Despite an increased computational cost, MCD reduced the prediction error at low PSNR and improved the quality of PK parameter images. The simulation results recommended using a DR of 0.25-0.5 at low PSNR and ≤ 0.25 for other PSNRs. The clinical studies recommended using a DR of 0.25 and 0.5 for LSTM and GRU, respectively., Conclusions: MCD is effective in quantifying uncertainty in PK parameter prediction from DCE-MRI data and improves their performance, particularly at low PSNR; however, at the expense of increased computational cost. This study helps deepen our understanding of RNNs with MCD and select suitable hyperparameters for creating an RNN architecture for DCE-MRI studies., (© 2024 The Author(s). Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)

Objectives: Contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) is used to definitively diagnose hepatocellular carcinoma (HCC) in patients at risk. However, the user variability associated with CEUS LI-RADS has not been validated in North American and European patients. This study aims to evaluate the inter-reader agreements of CEUS LI-RADS features for, and final categorization of, HCC in patients at risk., Methods: This retrospective multicenter clinical study used the database of a previous prospective multinational study, evaluating the accuracy of CEUS LI-RADS for HCC diagnosis in patients at risk. All cases were first evaluated by a site physician performing/supervising the CEUS examination. Randomly selected cases were re-evaluated by a blinded central reader. Final diagnosis was confirmed with the reference standard, which was a composite of imaging tests and histology. Cohen's kappa test was used to evaluate inter-reader agreement., Results: This study included 150 liver nodules and 58.0% (87/150) were confirmed as HCC, 4.7% (7/150) non-HCC malignancies, 22.7% (34/150) had no confirmed final diagnosis, and 14.7% (22/150) were nonmalignant. Inter-reader agreements were substantial for CEUS LI-RADS categorization (κ = 0.61; 95% confidence interval [CI]: 0.51-0.71) and major features assessment (ranged κ = 0.64-0.78), LR-5 (κ = 0.65; 95% CI: 0.52-0.77), and LR-M (κ = 0.67; 95% CI: 0.44-0.90), while for LR-1 and LR-2 categorization was almost perfect (κ = 0.85; 95% CI: 0.65-1.00)., Conclusion: Our study reported a substantial inter-reader agreement for overall CEUS LI-RADS categorization, especially for LR-5 and LR-M, and major imaging features of HCC, further confirming CEUS LI-RADS as a valuable and reliable tool for diagnosis of HCC., (© 2024 The Author(s). Journal of Ultrasound in Medicine published by Wiley Periodicals LLC on behalf of American Institute of Ultrasound in Medicine.)

Purpose: To investigate the added value of using contrast-enhanced magnetic resonance imaging (MRI) in conjunction with contrast-enhanced computed tomography (CT) for differentiating malignant and benign ampullary strictures., Materials and Methods: The present retrospective study included 90 patients with ampullary strictures who underwent preoperative contrast-enhanced CT and contrast-enhanced MRI at two tertiary institutions. The image sets (i.e., CT alone vs. combined CT and MRI) were evaluated by three abdominal radiologists, who used a five-point Likert scale to score their confidence for diagnosing malignancy in patients with ampullary strictures. Diagnostic accuracy was calculated using receiver-operating characteristic (ROC) curve analysis, sensitivity, specificity, and accuracy. Additionally, interobserver agreement regarding the scoring of potential malignancies of the ampullary strictures was assessed., Results: The addition of contrast-enhanced MRI to contrast-enhanced CT showed a significant improvement in predicting malignant ampullary strictures in all three observers (p = 0.007, 0.001, and 0.002) using ROC curve analysis, and a significant improvement was observed in diagnostic sensitivity and accuracy for predicting malignancy (p = 0.016 and 0.029 for observer 1; p = 0.023 and 0.010 for observer 2; and p = 0.010 and 0.011 for observer 3). The interobserver agreement for the five-point scale in determining malignancies of the ampullary strictures was 0.86 for CT alone and 0.93 for the combined set of CT and MRI., Conclusion: The addition of contrast-enhanced MRI to CT provided added value for differentiating malignant from benign ampullary strictures., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no competing interests. Ethical approval: This study was conducted in accordance with the principles of the Declaration of Helsinki. Approval was granted by the Institutional Review Board. Informed consent: The need to obtain informed consent was waived due to the retrospective study design., (© 2024. The Author(s) under exclusive licence to Japan Radiological Society.)

Objective: Differentiating hepatic epithelioid hemangioendothelioma (EHE) and angiosarcoma (AS), the two most common vascular tumors in the liver, is important due to disparities in their prognosis and treatment. We aimed to compare clinical and MRI features of the two tumors., Methods: This retrospective study included patients with pathologically-confirmed AS or EHE who underwent MRI using gadoxetate disodium between 2008 and 2023. Two radiologists independently reviewed MR images. Wilcoxon rank sum and Fisher's exact tests were used to compare clinical and imaging features. Overall survival was compared using restricted mean survival time at 3 years., Results: 32 patients with AS (18 women [56.3%]; median age, 68 years) and 38 with EHE (24 women [63.2%]; 51 years) were included. Patients with AS were generally older (81.3% ≥ 60 years; P < 0.001), had more frequent laboratory abnormalities (P ≤ 0.018), and poorer overall survival (11.2 vs. 31.8 months; P < 0.001) than those with EHE. On MRI, a large dominant mass accompanied by smaller nodules (14/32, 43.8%), often with ill-defined margins (15/32, 46.9%) was prevalent in AS; compared with nodules of similar sizes (24/38, 63.2%; P = 0.015) with well-defined margin (30/38, 78.9%; P = 0.002) in EHE. Cirrhotic appearance of the liver was more frequent in AS (62.5%, P < 0.001), along with decreased parenchymal enhancement on hepatobiliary phase (31.3%, P < 0.001) and ascites (37.5%, P = 0.010). AS frequently presented with avid enhancement of bizarrely-shaped foci, with a centrifugal enhancement pattern. In comparison, targetoid appearance was characteristic of EHE (78.9% on T2-weighted, 54.1% on diffusion-weighted, 65.8% on multiphase images) (P ≤ 0.002), with enhancement degree typically lower than that of the aorta. On hepatobiliary phase, all the AS exhibited hypointensity, while 39.5% of EHE showed targetoid appearance (P < 0.001)., Conclusion: Patients aged ≥ 60 years presenting with laboratory abnormalities, typically with a large dominant mass accompanied by smaller nodules, exhibiting avid, bizarre, and centrifugal enhancement-particularly in the cirrhotic-appearing liver-suggests the likelihood of AS over EHE., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethical approval: This single-center retrospective study was approved by the Institutional Review Board. The requirement for obtaining informed consent was waived owing to the retrospective nature of the data analysis., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: Ultrasound plays a central role in liver transplant evaluation. Acute, subacute, and chronic complications can be readily identified using grayscale and color Doppler ultrasound. Contrast-enhanced ultrasound adds a new dimension to liver transplant evaluation, depicting vascular and parenchymal processes with exquisite detail. In addition, emerging evidence suggests that contrast-enhanced ultrasound may allow for localization of biliary leak in select patients. We aimed to assess the use of multiparametric ultrasound-including grayscale, color and spectral Doppler, and contrast-enhanced ultrasound-in the setting of liver transplantation., Methods: A literature review was performed using the MEDLINE bibliographic database through the National Library of Medicine. The following terms were searched and relevant citations assessed: "abdominal ultrasound," "contrast-enhanced ultrasound," "liver transplant," and "ultrasound.", Results: Grayscale and color Doppler ultrasound represent the mainstay imaging modalities for postoperative liver transplant evaluation. The addition of contrast enhancement plays a complementary role and can provide valuable information related to the allograft vasculature, parenchyma, and biliary tree. The appropriate implementation of grayscale, color Doppler, and contrast-enhanced ultrasound can optimize sensitivity, specificity, and accuracy for the detection of liver transplantation complications, including hepatic artery stenosis, biliary leakage, and infection., Conclusion: Multimodal sonographic evaluation is essential to identify postoperative complications in liver transplant recipients. Contrast-enhanced ultrasound may be of value in challenging cases, providing excellent anatomic delineation and reducing the risk of false-positive and false-negative diagnoses. A broad familiarity with appropriate applications of both nonenhanced and contrast-enhanced ultrasound may help radiologists optimize allograft assessment and improve patient outcomes., Competing Interests: Declarations. Conflict of interest: The authors have no relevant financial or non-financial interests to disclose. The authors have no competing interests to declare that are relevant to the content of this article., (© 2024. The Author(s).)

Objectives: To evaluate the value of (dynamic) contrast-enhanced MRI for the diagnosis and follow-up of central cartilage tumors (CCT) of the proximal humerus, distal femur and proximal tibia., Materials & Methods: 97 patients (44 ± 11 years, 31men) with a CCT (histopathologically proven and/or > 2 years follow-up (5 ± 3 years)) were retrospectively/consecutively included at the Ghent University Hospital (Belgium, 2003-2021). Thickness of the enhancing rim and dynamic contrast-enhanced MRI parameters of the entire tumor were calculated. Tumor volumes were calculated to assess tumor growth. Significant differences between enchondromas, atypical cartilaginous tumors, high-grade chondrosarcomas, tumors with and without growth at follow-up were evaluated and ROC-curves were analyzed., Results: A significant difference (p = 0.015) existed in enhancing rim thickness between high-grade chondrosarcomas and other groups. A ROC-curve with an AUC of 0.89 and cut-off value of 1.2 mm had a sensitivity of 100 % and a specificity of 64 % to identify high-grade chondrosarcomas. A significant correlation was found between the relative maximal enhancement (Rel-Emax) of the whole tumor compared to muscle and the absolute growth rate (ρ = 0.75, p < 0.001). Lesions with a Rel-Emax < 1 remained stable or showed regression during follow-up (mean -0.1 ± 0.3 ml/year). Lesions with a Rel-Emax between 1 and 2 showed little growth (mean + 0.2 ± 0.2 ml/year), and lesions with a Rel-Emax > 2 had the highest growth rate (mean 0.4 ± 0.2 ml/year)., Conclusion: A thick enhancing rim > 1.2 mm has a high sensitivity to detect high-grade chondrosarcomas. The higher the Rel-Emax of the whole tumor compared to muscle, the higher the growth rate of a CCT., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: The administration of intravenous (IV) contrast media during computed tomography (CT) examinations is essential to enhance diagnostic accuracy in various clinical scenarios. Traditionally, older age is considered a risk factor for the development of post-contrast Acute Kidney Injury (PC-AKI); however, there is limited information available for the super-elderly population (aged ≥ 85). This study aims to investigate the incidence and risk factors associated with PC-AKI in individuals aged 85 and older undergoing CT scans with IV contrast., Methods: A retrospective cohort study, including all hospitalized patients aged 85 or older who underwent CT scans between the years 2005 and 2021. Patients were categorized into IV contrast and non-IV contrast groups. Baseline demographic and clinical data, along with kidney function parameters, were collected., Results: The final cohort included 7,078 patients who underwent CT scans, with 40% receiving IV contrast. The overall AKI occurrence within 72 h post-CT was 5.72%, slightly elevated in the non-IV contrast group (6.25% vs. 4.94%, p = 0.02). However, multivariate analysis revealed no significant difference between the groups (OR 1, CI 0.8-1.2, p = 0.92), even after stratifying by kidney function. A secondary analysis, using a less strict AKI definition, supported these findings. Baseline creatinine levels emerged as prominent risk factor associated with PC- AKI., Conclusion: The current study provides reassurance regarding the safety of contrast-enhanced CT scans in super-elderly patients, particularly those with baseline normal to mild kidney dysfunction. These findings may contribute to the ongoing discussion on the risk-benefit balance of contrast-enhanced CT scans in the super-elderly population., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no conflict of interest., (© 2024. The Author(s) under exclusive licence to Japan Radiological Society.)

Hepatobiliary (HB) contrast agents are increasingly valuable diagnostic tools in MRI, offering a wider range of applications as their clinical use expands. Normal hepatocytes take up HB contrast agents, which are subsequently excreted in bile. This property creates a distinct HB phase providing valuable insights into liver function and biliary anatomy. HB contrast agents can assist in diagnosing a broad spectrum of HB diseases ranging from diffuse liver disease to focal hepatic lesions and can delineate anatomic details of the biliary tree. Understanding the pharmacodynamics of HB contrast agents is paramount to their appropriate clinical application and troubleshooting. HB phase hypointensity can arise from various diffuse and focal abnormalities that may or may not be associated with biliary excretion. Hypointensity during the HB phase can be broadly grouped into diffuse hypointensity, regional hypointensity, and focal lesions for better evaluation of the underlying cause. Abnormalities may arise from hepatic parenchymal, biliary, or vascular causes, or a combination thereof in each of the broad groups. Recognition of a suboptimal hypointense HB phase is important in the evaluation of focal lesions in patients with cirrhosis of the liver and particularly in those with hepatocellular carcinoma. Furthermore, hypointensity can also suggest the aggressiveness of malignancies such as hepatocellular carcinoma or colorectal metastases, which may affect the prognosis. It is essential to consider all imaging findings relative to the clinical context and the complete set of the MRI sequences performed for diagnosis of liver abnormalities. This comprehensive approach minimizes the risk of misinterpretation or pitfalls. The authors aim to equip radiologists with key insights for accurately understanding hypointensity in the HB phase, ultimately leading to more accurate diagnoses. © RSNA, 2025 Supplemental material is available for this article.

Purpose: To evaluate the impact of the use of lean body weight (LBW)-based contrast material (CM) dose and bolus tracking technique on portal venous phase abdominal CT image quality., Materials and Methods: IRB-approved prospective study; informed consent was acquired. In the period July-November 2023, we randomly selected 105 oncologic patients scheduled for a portal venous phase abdominal CT to undergo our experimental protocol (i.e., 0.7 gI/Kg of LBW CM administration and bolus tracking on the liver). Included patients had performed a "standard" portal venous phase abdominal CT (i.e., 0.6 gI/Kg of total body weight (TBW) contrast material administration and 70 s fixed delay) on the same scanner within the previous 12 months. One reader evaluated CT images measuring liver, portal vein, kidney cortex, and spleen attenuation; values were normalized to paraspinal muscles., Results: Median administered contrast dose (350 mgI/mL CM) was 99 mL (IQR: 81-115 mL) using the experimental protocol and 110 mL (IQR: 100-120 mL) using the standard one (p < 0.0001). Median acquisition delay using the experimental protocol was 65" (IQR 59-73"). Median normalized hepatic enhancement was significantly higher using the experimental protocol (1.97, IQR: 1.83-2.47 vs. 1.86, IQR: 1.58-2.11; p < 0.0001). Median normalized portal vein enhancement was significantly higher using the experimental protocol (3.43, IQR: 2.73-4.04 vs. 2.91, IQR: 2.58-3.41; p < 0.0001). No statistically significant differences were found in the kidneys' cortex and aorta normalized enhancement (p > 0.05)., Conclusion: The combination of LBW-based CM dose administration and bolus tracking allows a significant CM dose reduction and a significant liver and portal vein enhancement increase., Clinical Relevance Statement: Lean body weight-based contrast material (CM) dose administration and bolus tracking technique in portal venous phase CT scans overcome differences in body composition and hemodynamics, improving reproducibility. It allows a significant CM dose reduction with increased liver and portal vein enhancement., Key Points: Lean body weight (LBW)-based contrast material (CM) dosing could be superior to total body weight dosing. Portal venous phase CT with a liver bolus tracking technique improved liver and spleen enhancement with a reduced contrast dose. The combination of LBW-based CM dosing and liver bolus tracking technique enables more "customized" CT examinations., Competing Interests: Compliance with ethical standards. Guarantor: The scientific guarantor of this publication is R.V. Conflict of interest: G.A.Z. is an Editor of European Radiology, they did not participate in the selection nor review processes for this article. The remaining authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. Statistics and biometry: One of the authors (V.V.) has significant statistical expertise. Moreover, no complex statistical methods were necessary for this paper. Informed consent: Written informed consent was waived by the Institutional Review Board. Ethical approval: Institutional Review Board approval was obtained. Study subjects or cohorts overlap: None of the study subjects or cohorts have been included in previously published studies. Methodology: Prospective Experimental Performed at one institution, (© 2024. The Author(s), under exclusive licence to European Society of Radiology.)

Purpose: This study aimed to identify the radiological CT findings that are significantly correlated with the outcome of conservative management with oral water-soluble contrast medium in patients presenting with Adhesive Small Bowel Obstruction (ASBO) to the Emergency Room., Methods: In this retrospective single-center study, we considered all consecutive patients admitted to the ER from February 2019 to February 2023 for ASBO with an available contrast-enhanced CT scan performed at diagnosis and treated with conservative management. The investigated CT findings were type and location of transition zone, ASBO degree, fat notch sign, beak sign, small bowel feces sign, presence of peritoneal free fluid and pneumatosis intestinalis. Radiological parameters were analyzed using univariable and multivariable logistic regression to test the significant association between the CT parameters and the target., Results: Among the 106 included patients (median age 74.5 years), conservative treatment was effective in 59 (55.7%) and failed in 47 (44.3%), needing delayed surgery. In the failure group, there was a higher prevalence of patients who had previous ASBO episodes (p = 0.03), a greater proportion of females (p = 0.04) and a longer hospital stay (p < 0.001). At multivariable analysis, two CT findings were significantly correlated with failure of conservative treatment: fat notch sign (OR = 2.95; p = 0.04) and beak sign (OR = 3.42; p = 0.04)., Conclusions: Two radiological signs correlate with failure of non-operative management in ASBO, suggesting their importance in surgical decision-making. Patients presenting with these signs are at higher risk of unsuccessful conservative treatment and may require undelayed surgical intervention., Competing Interests: Declarations. Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The Institutional Review Board approval was waived due to the retrospective nature of this study, and the absence of any procedural change from the current standard of practice. Informed consent: Informed consent was obtained from all individual participants included in the study. Consent for publication: Consent for publication was obtained for every individual person’s data included in the study. Conflict of interest: The authors have no competing interests relevant to the content of this article., (© 2024. The Author(s), under exclusive licence to American Society of Emergency Radiology (ASER).)

Background/objectives: Postoperative pancreatic fistula (POPF) is a critical complication of pancreatectomy, with a higher risk associated with the absence of pancreatic fibrosis. We investigated whether pancreatic extracellular volume fraction (ECV) calculated from preoperative contrast-enhanced computed tomography (CE-CT) images can be used to predict pancreatic fibrosis and POPF., Methods: This retrospective study included patients who underwent CE-CT before pancreatectomy. ECV map was created by subtracting unenhanced from equilibrium-phase images. We assessed the relationship between pancreatic ECV, the histopathological grade of fibrosis at the pancreatic resection margin, and the occurrence of POPF., Results: Among the 107 patients included, 66 underwent pancreaticoduodenectomy (PD) and 41 underwent distal pancreatectomy (DP). The median ECV at the pancreatic resection margin was 22.5 %. Pancreatic ECV significantly correlated with the histopathological grade of pancreatic fibrosis (ρ = 0.689; p < 0.001). In PD cases, the ECV was an independent risk factor for all-grade POPF (odds ratio, 0.852; 95 % confidence interval, 0.755-0.934), with excellent predictive capability (area under the curve, 0.912; 95 % confidence interval, 0.842-0.983). In DP cases, pancreatic thickness was the only factor associated with all-grade POPF., Conclusions: Pancreatic ECV obtained from routine CE-CT images accurately predicted the histopathological grade of pancreatic fibrosis and was an independent risk factor for POPF after PD., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest related to this article., (Copyright © 2024 IAP and EPC. Published by Elsevier B.V. All rights reserved.)

Background: There are discrepancies between guidelines of scientific societies and information of the package inserts of contrast media concerning breastfeeding following the application of a contrast agent to the mother., Objectives: The contents of different review articles reflect the opinion of scientific societies. Consequently, in clinical routine settings it is difficult to find the optimal advice for a breastfeeding woman and her baby., Methods: Therefore, the paper carefully summarized important information dealing with the topic 'breastfeeding and contrast media' from the literature. Among other things, the paper focuses on topics that are not yet taken into account in other reviews (e.g. approval for breastfeeding women, contrast agents that have been analysed in human breast milk)., Results: In this way, the review shows new aspects. It has been revealed that data concerning the amount of contrast agents in human breast milk as well as contrast medium absorption by the infants' intestine are sparse. Instead of them, a lot of speculations and incorrect conclusions do exist in the literature. Because studies are rare or missing, contrast media are not approved for breastfeeding women (off-label-use)., Conclusion: Although breastfeeding women 100% prefers a break from breastfeeding, in current decision-making processes, their preference plays a minor role. However, this should change in the future. In addition, it would be very important to inform breastfeeding women in the future about the missing data concerning 'breastfeeding and contrast media'., (© 2025 The Author(s). Fundamental & Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of Société Française de Pharmacologie et de Thérapeutique.)

Objective: Subharmonic Aided Pressure Estimation (SHAPE) is a noninvasive technique for estimating organ-level blood pressure using the strong correlation between the subharmonic signal and ambient pressure. The compressible gas core of microbubbles enables them to generate linear and nonlinear acoustic responses when exposed to ultrasound. Here, the sulfur hexafluoride (SF 6 ) gas core of SonoVue (known as Lumason in the United States), a clinical contrast agent, was exchanged with a perfluorobutane (PFB) core to investigate its effect on the SHAPE response., Methods: Excitations of 25-700 kPa peak negative pressure (PNP) and 3 MHz transmission frequency were used to study in vitro the effects of overpressure changes ranging from 5 to 25 kPa (37-186 mm Hg)., Results: Unlike SonoVue with SF 6 , at low PNPs (<400 kPa), SonoVue with a PFB gas core exhibited no subharmonic at the atmospheric pressure, but during pressurization, a stable subharmonic response (maximum of 25 dB at 100 kPa PNP and 20 kPa Overpressure) appeared. SonoVue with a PFB gas core showed an increase in subharmonics with overpressure at high PNPs (>400 kPa), which was not observed before in normal SonoVue or other lipid microbubbles. With negligible size distribution difference between these two microbubbles, these effects on subharmonic generation are likely due to the gas core, casting new light on the mechanism by which ambient overpressure affects subharmonic., Conclusion: This study may inform future SHAPE technique developments., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2024 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Contrast-enhanced mammography (CEM) is an advanced emerging imaging technique that uses iodine contrast medium to improve breast cancer detection. Understanding CEM artefacts and pitfalls is important to prevent diagnostic misinterpretation. This article aims to provide a comprehensive review of the artefacts and potential diagnostic pitfalls encountered in CEM, focusing on their characteristic imaging features and strategies to mitigate these issues., Competing Interests: Conflict of interest The authors declare no conflict of interest., (Copyright © 2024 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Introduction: Background parenchymal enhancement (BPE) refers to the physiological enhancement of breast fibroglandular tissue. This study aimed to determine the agreement of BPE evaluation between contrast enhanced mammography (CEM) and magnetic resonance imaging (MRI) and investigate potential confounders., Materials and Methods: This retrospective, IRB-approved study included women recalled from screening or with inconclusive findings on mammography and/or ultrasound, who underwent both CEM and MRI between 2018 and 2022. Imaging protocols followed international recommendations. Two breast radiology fellows assessed density and BPE on CEM and MRI using BI-RADS, evaluating the early post-contrast acquisition (EP). In addition, BPE on MRI was assessed in the late post-contrast acquisition (LP). Data on menopausal status, breast thickness, and compression force were retrieved. Univariate and multivariate analyses were used., Results: 343 patients were consecutively enrolled. Post-menopausal patients showed lower BPE levels (p < 0.001). Agreement on BPE levels between CEM and MRI in the EP was fair (R1 κ = 0.342, R2 κ = 0.383). In the LP agreement was moderate for R1 (κ = 0.432) and fair for R2 (κ 0.368). There was a significant correlation between BPE and density in CEM (R1 ρ 0.399, R2 ρ 0.441; p < 0.001). A negative correlation was found on CEM between BPE and compression force (ρ -0.100, p = 0.001). Inter-reader agreement was high with both modalities (CEM κ = 0.678, MRI-EP κ = 0.690, MRI-EP κ = 0.692)., Conclusions: The agreement of BPE assessment between MRI and CEM was fair to moderate and reproducibility among readers was high. Compression force and mammographic breast density seem to influence BPE levels in CEM., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Imaging evaluation of the gallbladder is a fundamental skill in the majority of radiology practice. Due to ease of accessibility, low cost, lack of ionizing radiation, and excellent spatial resolution, ultrasound is often the first imaging modality used to evaluate the gallbladder. In this invited article we review and update how ultrasound can evaluate common pathologies including gallbladder polyps, tumefactive sludge, adenomyomatosis, and acute cholecystitis. We also discuss the role of Doppler, microvascular flow imaging, and contrast enhanced ultrasound in the sonographic assessment of the gallbladder., Competing Interests: Declarations. Competing interest: CF: Research grant: Exact Imaging, Partner Radiologist MIC Medical Imaging, Shareholder: Mikata Health RS: None. RN: None. KV: None. DF: Research Agreements: GE HealthCare, Philips Healthcare, and Siemens Healthineers. Advisory Board: GE HealthCare, Philips Healthcare, Siemens Healthineers, and Bracco Diagnostics. Speakers Bureau: Siemens Healthineers., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: Ultrasmall silver sulfide nanoparticles (Ag 2 S-NP) have been identified as promising contrast agents for a number of modalities and in particular for dual-energy mammography. These Ag 2 S-NP have demonstrated marked advantages over clinically available agents with the ability to generate higher contrast with high biocompatibility. However, current synthesis methods for inorganic nanoparticles are low-throughput and highly time-intensive, limiting the possibility of large animal studies or eventual clinical use of this potential imaging agent., Methods: We herein report the use of a scalable silicon microfluidic system (SSMS) for the large-scale synthesis of Ag 2 S-NP. Ag 2 S-NP produced using this system were compared to bulk synthesis and a commercially available microfluidic device through characterization, contrast generation, in vivo imaging, and clearance profiles., Results: Using SSMS chips with 1 channel, 10 parallelized channels, and 256 parallelized channels, we determined that the Ag 2 S-NP produced were of similar quality as measured by core size, concentration, UV-visible spectrometry, and in vitro contrast generation. Moreover, by combining parallelized chips with increasing reagent concentration, we were able to increase output by an overall factor of 5,100. We also found that in vivo imaging contrast generation was consistent across synthesis methods and confirmed renal clearance of the ultrasmall nanoparticles. Finally, we found best-in-class clearance of the Ag 2 S-NP occurred within 24 h., Conclusions: These studies have identified a promising method for the large-scale production of Ag 2 S-NP, paving the way for eventual clinical translation., Competing Interests: Declarations. Competing interests: The authors have no relevant financial interests to disclose. Non-financial interest: an author of this manuscript, JCH, is an editor of this journal., (© 2024. The Author(s).)

This study aimed to evaluate the efficacy of the single-energy metal artifact reduction (SEMAR) algorithm in reducing metal artifacts and enhancing image quality in contrast-enhanced computed tomography (CT) for patients undergoing endovascular aneurysm repair (EVAR) with coil embolization. Thirty-eight patients (mean age 81.0 ± 6 years; 31 men, 7 women) who underwent contrast-enhanced CT following EVAR and internal iliac artery coil embolization between September 2022 and May 2023 were retrospectively analyzed. The Artifact Index (AI) quantified metallic artifacts from internal iliac artery aneurysm coils in CT images, calculated from the standard deviation of the artifact-containing region relative to a reference region. CT values of the external iliac artery at the same slice were also evaluated and compared. Two radiologists independently performed qualitative assessments of SEMAR and non-SEMAR images. SEMAR significantly reduced metal artifacts, decreasing the AI from 171.9 ± 74.5 HU to 35.8 ± 16.9 HU (p < 0.001). The mean CT values of the external iliac artery were similar for SEMAR (259.4 ± 63.7 HU) and non-SEMAR (257.1 ± 63.6 HU, indicating no significant difference. Qualitative assessment scores improved significantly with SEMAR (from 1.0 ± 0.0 to 2.5 ± 0.5; p < 0.001), enhancing visualization of internal iliac artery aneurysms. Interobserver agreement was high (κ = 0.83). The SEMAR algorithm effectively reduces metal artifacts in contrast-enhanced CT, significantly enhancing image quality without altering adjacent artery CT values. These improvements enhance the image quality of post-operative assessments in patients undergoing EVAR with coil embolization., Competing Interests: Declarations. Ethical approval: This study was conducted in accordance with the principles of the Declaration of Helsinki. Ethical approval was obtained from the Ethics Committee of Jichi Medical University Saitama Medical Center (S23-080). Consent to publish: An opt-out policy has been implemented. The opt-out document is available on the Department of Radiology’s website at the Saitama Medical Center, Jichi Medical University, and at the laboratory reception. All participants have been provided the opportunity to decline inclusion in this research. Competing interests: Financial interests: Junji Mochizuki, Osamu Manabe and Noriko Oyama-Manabe have received research funding from Canon Medical Systems. The other authors have no financial or non-financial interests to disclose., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Objectives: To measure dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) biomarker repeatability in patients with non-small cell lung cancer (NSCLC). To use these statistics to identify which individual target lesions show early biological response., Materials and Methods: A single-centre, prospective DCE-MRI study was performed between September 2015 and April 2017. Patients with NSCLC were scanned before standard-of-care radiotherapy to evaluate biomarker repeatability and two weeks into therapy to evaluate biological response. Volume transfer constant (K trans ), extravascular extracellular space volume fraction (v e ) and plasma volume fraction (v p ) were measured at each timepoint along with tumour volume. Repeatability was assessed using a within-subject coefficient of variation (wCV) and repeatability coefficient (RC). Cohort treatment effects on biomarkers were estimated using mixed-effects models. RC limits of agreement revealed which individual target lesions changed beyond that expected with biomarker daily variation., Results: Fourteen patients (mean age, 67 years +/- 12, 8 men) had 22 evaluable lesions (12 primary tumours, 8 nodal metastases, 2 distant metastases). The wCV (in 8/14 patients) was between 9.16% to 17.02% for all biomarkers except for v p , which was 42.44%. Cohort-level changes were significant for K trans and v e (p < 0.001) and tumour volume (p = 0.002). K trans and tumour volume consistently showed the greatest number of individual lesions showing biological response. In distinction, no individual lesions had a real change in v e despite the cohort-level change., Conclusion: Identifying individual early biological responders provided additional information to that derived from conventional cohort cohort-level statistics, helping to prioritise which parameters would be best taken forward into future studies., Clinical Relevance Statement: Dynamic contrast-enhanced magnetic resonance imaging biomarkers K trans and tumour volume are repeatable and detect early treatment-induced changes at both cohort and individual lesion levels, supporting their use in further evaluation of radiotherapy and targeted therapeutics., Key Points: Few literature studies report quantitative imaging biomarker precision, by measuring repeatability or reproducibility. Several DCE-MRI biomarkers of lung cancer tumour microenvironment were highly repeatable. Repeatability coefficient measurements enabled lesion-specific evaluation of early biological response to therapy, improving conventional assessment., Competing Interests: Compliance with ethical standards. Guarantor: The scientific guarantor of this publication is James O’Connor. Conflict of interest: The authors of this manuscript declare relationships with the following companies: Geoff Parker has ownership and shares interests with Bioxydyn Ltd. The remaining authors declare no conflicts of interest. Statistics and biometry: One of the authors has significant statistical expertise (Nuria Porta). Informed consent: Written informed consent was obtained from all subjects (patients) in this study. Ethical approval: Institutional Review Board approval was obtained. Study subjects or cohorts overlap: Subjects were included in a separate study ( https://pubmed.ncbi.nlm.nih.gov/31053599/ ) but the data reported here are entirely independent and do not overlap. Methodology: Prospective Experimental Performed at one institution, (© 2024. The Author(s).)

Objective: To elucidate the magnetic resonance imaging (MRI) characteristics for distinguishing solitary fibrous tumors (SFTs) from desmoid tumors (DTs)., Materials and Methods: A retrospective study of 66 consecutive patients with histopathologically proven SFT (n = 34; 13 males and 21 females; mean age, 52.0 ± 17.1 years) or DT (n = 32; 11 males and 21 females; mean age, 39.0 ± 21.3 years) was conducted. The two groups were quantitatively compared in terms of the size, signal intensity ratio (SIR), and apparent diffusion coefficient value. For qualitative analysis, the tumor location, boundary, shape, internal uniformity, predominant signal intensity, T1-weighted images (T1WI) characteristics (hyperintense area), T2-weighted images (T2WI) characteristics (hypointense area, marked hyperintense area, flow void, band sign, and yin-yang sign), and contrast-enhanced T1WI characteristics (unenhanced area and degree of enhancement) were compared between the two groups. Multiple stepwise logistic regression analyses were conducted to distinguish between the SFT and DT., Results: T1 ( P = 0.010) and T2 ( P = 0.026) SIRs were higher in SFTs than in DTs. Hyperintense areas on T1WI ( P < 0.001), marked hyperintense areas on T2WI ( P = 0.025), and flow void ( P = 0.025) were more frequently noted in SFTs. On T1WI, the solid component predominantly revealed hyperintensity in SFTs and isointensity in DTs ( P < 0.001). Indistinct tumor boundary ( P < 0.001), hypointense area on T2WI ( P < 0.001), and band sign ( P < 0.001) were more frequently observed in DTs. Multiple stepwise logistic regression analysis revealed that the hyperintense area on T1WI (odds ratio favoring SFT, 12.80, P = 0.002) and band sign (odds ratio favoring DT, 0.03; P < 0.001) were independent predictors., Conclusion: MRI characteristics can help distinguish SFT from DT. The presence of a hyperintense area relative to the skeletal muscle on T1WI in SFTs and the band sign on T2WI in DTs are important MRI features., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2025 The Korean Society of Radiology.)

Objectives: To summarize our institutional experience with contrast-enhanced mammography (CEM) exams reporting asymmetric background parenchymal enhancement (BPE)., Materials and Methods: Consecutive CEMs performed between December 2012 and July 2023 were retrospectively reviewed to identify exams reporting asymmetric BPE. Associated factors, the level of reporting certainty, BI-RADS score, diagnostic workup, and clinical outcome were summarized. BPE grades and BI-RADS were compared between initial CEM vs. immediate MRI and 6-month follow-up CEM, when indicated, using the Sign test., Results: Overall, 175/12,856 (1.4%) CEMs (140 female patients, mean age, 46 ± 8.0 years) reported asymmetric BPE. Reporting certainty was mostly high (n = 86), then moderate (n = 59) and low (n = 30). Associated factors included contralateral irradiation (n = 94), recent ipsilateral breast treatment (n = 14), and unilateral breastfeeding (n = 4). BI-RADS scores were 0 (n = 21), 1/2 (n = 75), 3 (n = 67), 4 (n = 3), and 6 (n = 1), or given for a finding other than asymmetric BPE (n = 8). Initial diagnostic-workup often included targeted-US (n = 107). Immediate MRI (n = 65) and/or 6-month CEM follow-up (n = 69) downgraded most cases, with a significant decrease in BPE grade compared to the initial CEM (p < 0.01 for both). On follow-up, two underlying cancers were diagnosed in the area of questionable asymmetric BPE., Conclusion: Apparent asymmetric BPE is most often a benign finding with an identifiable etiology. However, rarely, it may mask an underlying malignancy presenting as non-mass enhancement, thus requiring additional scrutiny., Clinical Relevance Statement: The variability in the diagnostic-workup of apparent asymmetric background parenchymal enhancement stresses the clinical challenge of this radiological finding. Further studies are required to verify these initial observations and to establish standardized management guidelines., Key Points: Apparent asymmetric background parenchymal enhancement usually represents a benign clinical correlate, though rarely it may represent malignancy. Evaluation of asymmetric background parenchymal enhancement varied considerably in the metrics that were examined. Targeted US and MRI can be useful in evaluating unexplained asymmetric background parenchymal enhancement., Competing Interests: Compliance with ethical standards. Guarantor: The scientific guarantor of this publication is Dr. Maxine Jochelson. Conflict of interest: M.J.’s disclosure includes a previously paid lecture for GE, whose mammograms were utilized as part of the routine clinical work in our institute, regardless of this current study. The rest of the authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. Statistics and biometry: One of the authors (N.N.) has significant statistical expertise. Informed consent: Written informed consent was waived by the Institutional Review Board. Ethical approval: Institutional Review Board (Memorial Sloan Kettering Cancer Center) approval was obtained. Study subjects or cohorts overlap: No overlap. Methodology: Retrospective Observational Performed at one institution, (© 2024. The Author(s), under exclusive licence to European Society of Radiology.)