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Background: Reliable, non-invasive evaluation of liver fibrosis is essential for early disease management. Computed tomography (CT)-based extracellular volume (ECV) fraction and portal venous phase enhancement rate (VP-ER) have shown potential in quantifying mild-to-moderate fibrosis. This study investigates the diagnostic performance of ECV and VP-ER in differentiating non-significant (F0–F1) from significant (F2–F3) fibrosis in biopsy-confirmed patients. Methods: Ninety-three patients (20–72 years, 56.9% male) undergoing liver biopsy and multiphasic CT scans were retrospectively enrolled. Patients with METAVIR F4 cirrhosis or incomplete imaging/pathological data were excluded. Hematocrit levels were obtained on the day of CT. ECV was calculated from differences in liver and aortic attenuation between delayed and enhanced phases, adjusted for hematocrit. VP-ER was derived as the ratio of liver attenuation in venous to portal venous phases multiplied by 100. Spearman's correlation, receiver operating characteristic (ROC) curves, and DeLong tests evaluated their performance. Multiple logistic regression assessed independent contributions of ECV and VP-ER to fibrosis status. Results: Fifty-three patients had no significant fibrosis (F0–F1) and 40 had significant fibrosis (F2–F3). ECV demonstrated a moderate correlation with fibrosis grade (r = 0.531, p < 0.0001), while VP-ER showed a weaker yet statistically significant correlation (r = 0.363, p = 0.0003). ROC analyses yielded an area under the curve (AUC) of 0.698 for ECV (cut-off = 38%) and 0.763 for VP-ER (cut-off = 71%), with no significant difference between AUCs (p = 0.358). VP-ER accurately classified 70 patients, while ECV correctly predicted 65. Logistic regression revealed significant associations for both VP-ER (OR = 1.08; p = 0.007) and ECV (OR = 1.025; p = 0.0132), achieving 72.04% classification accuracy and an overall AUC of 0.756 (95% CI: 0.688–0.863). Conclusion: ECV fraction and VP-ER demonstrated reliable, complementary capabilities for distinguishing non-significant fibrosis from significant fibrosis. Their combined use in routine multiphasic CT protocols may reduce dependence on invasive biopsy while offering robust sensitivity and specificity for early fibrosis assessment. Further studies including cirrhotic populations and larger cohorts are recommended. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the feasibility and accuracy of non-electrocardiogram (ECG)-triggered chest low-dose computed tomography (LDCT) with a kV-independent reconstruction algorithm in assessing coronary artery calcification (CAC) degree and cardiovascular disease risk in patients receiving maintenance hemodialysis (MHD). Methods: In total, 181 patients receiving MHD who needed chest CT and coronary artery calcium score (CACS) scannings sequentially underwent non-ECG-triggered, automated tube voltage selection, high-pitch chest LDCT with a kV-independent reconstruction algorithm and ECG-triggered standard CACS scannings. Then, the image quality, radiation doses, Agatston scores (ASs), and cardiac risk classifications of the two scans were compared. Results: Of the 181 patients, 89, 83, and 9 were scanned at 100, 110, and 120 kV, respectively. Excluding those scanned at 120 kV, 172 patients were enrolled. Although the ASs of non-ECG-triggered LDCT were lower than those of the standard CACS, the agreement and correlation of ASs of the two scans were excellent, and both intraclass correlation coefficients (ICCs) and Pearson's correlation coefficients were > 0.96. Cardiac risk classifications did not significantly differ between the non-ECG-triggered LDCT and standard CACS (χ2 = 3.933, P = 0.269), and the agreement was excellent (weighted kappa value = 0.936; 95% confidence interval (CI): 0.903–0.970). The effective radiation doses of standard CACS and non-ECG-triggered chest LDCT scannings were 1.34 ± 0.74 and 1.04 ± 0.35 mSv, respectively. Conclusions: The non-ECG-triggered, automated tube voltage selection, high-pitch chest LDCT protocol with a kV-independent reconstruction algorithm can obtain chest scans and ASs simultaneously and significantly reduce patients' radiation exposure. [ABSTRACT FROM AUTHOR]

Objective: Unusual clinical course Background: Pembrolizumab, a programmed cell-death protein-1 (PD-1)-targeting antibody, extends survival in cancer patients but may cause lung injury as a side effect. This immunotherapy enhances the immune system's ability to recognize and eliminate cancer cells. However, its immunomodulatory action can sometimes lead to immune-related adverse events, including lung injury. Case Report: A 40-year-old female patient, previously managed for malignant melanoma of the left gluteal region with surgery and immune checkpoint inhibitors, was transitioned to pembrolizumab for ongoing cancer treatment. Subsequently, she was referred to our department for further evaluation due to findings on chest imaging revealing multiple nodules in the bilateral lung fields. The patient exhibited neither cough, fever, nor breathlessness. Bronchoscopic examination yielded no abnormalities. Cytological assessments were negative, as were cultures for bacteria, fungi, and acid-fast bacilli. Bronchoalveolar lavage and endobronchial ultrasound-guided transbronchial needle aspiration biopsy of the right lower lobe bronchus B9a were conducted. Pathological analysis identified a combination of acute inflammatory and chronic fibrotic lesions, primarily histiocytic, leading to a diagnosis of pembrolizumab-induced lung injury. Steroid pulse therapy followed by tapering resulted in improvement of the pulmonary shadows. The patient is currently under observation without requiring steroid therapy. Conclusions: This case underscores the importance of vigilance for potential pembrolizumab-induced lung injury in patients undergoing immunotherapy for cancer treatment. Prompt recognition and appropriate management are essential for optimizing patient outcomes. Additionally, this case highlights the challenge of diagnosing lung lesions based solely on imaging, necessitating bronchoscopy with tissue sampling as a critical diagnostic tool. [ABSTRACT FROM AUTHOR]

Background: Individually tailored contrast medium (CM) may improve vascular image quality in chest computed tomography (CT). Purpose: To evaluate vascular attenuation in chest CT by comparing CM dose calculations using lean body mass (LBM) and body surface area (BSA) with a fixed-dose protocol. Material and Methods: Patients referred for contrast-enhanced chest CT were categorized as either normal, muscular, or overweight. Patients were accordingly randomized into three CM dosing protocols: fixed-dose group (n = 87), LBM group (n = 92), and BSA group (n = 93). Results: Of the patients, 94% in the fixed-dose group, 99% in the LBM group, and 98% in the BSA group achieved optimal vascular attenuation. In the overweight category, lower attenuation was demonstrated in the fixed-dose group compared to the LBM group (P = 0.032) and the BSA group (P = 0.010). In the fixed-dose group, vascular attenuation showed a negative correlation with total body weight for all body composition categories. In the LBM group, a positive correlation was observed between attenuation and total body weight in the muscular category (P = 0.041), while a negative correlation was noted for the overweight category in the BSA group (P = 0.049). Conclusion: Fixed-dose CM protocol exhibited larger variations in vascular attenuation between patients of various body weights and body compositions compared to tailored CM doses based on LBM and BSA. [ABSTRACT FROM AUTHOR]

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Abstract Objectives This study aimed to evaluate the feasibility and accuracy of non-electrocardiogram (ECG)-triggered chest low-dose computed tomography (LDCT) with a kV-independent reconstruction algorithm in assessing coronary artery calcification (CAC) degree and cardiovascular disease risk in patients receiving maintenance hemodialysis (MHD). Methods In total, 181 patients receiving MHD who needed chest CT and coronary artery calcium score (CACS) scannings sequentially underwent non-ECG-triggered, automated tube voltage selection, high-pitch chest LDCT with a kV-independent reconstruction algorithm and ECG-triggered standard CACS scannings. Then, the image quality, radiation doses, Agatston scores (ASs), and cardiac risk classifications of the two scans were compared. Results Of the 181 patients, 89, 83, and 9 were scanned at 100, 110, and 120 kV, respectively. Excluding those scanned at 120 kV, 172 patients were enrolled. Although the ASs of non-ECG-triggered LDCT were lower than those of the standard CACS, the agreement and correlation of ASs of the two scans were excellent, and both intraclass correlation coefficients (ICCs) and Pearson’s correlation coefficients were > 0.96. Cardiac risk classifications did not significantly differ between the non-ECG-triggered LDCT and standard CACS (χ2 = 3.933, P = 0.269), and the agreement was excellent (weighted kappa value = 0.936; 95% confidence interval (CI): 0.903–0.970). The effective radiation doses of standard CACS and non-ECG-triggered chest LDCT scannings were 1.34 ± 0.74 and 1.04 ± 0.35 mSv, respectively. Conclusions The non-ECG-triggered, automated tube voltage selection, high-pitch chest LDCT protocol with a kV-independent reconstruction algorithm can obtain chest scans and ASs simultaneously and significantly reduce patients’ radiation exposure.

A 61-year-old man with obstructive jaundice caused by distal bile duct cancer recurrence was admitted to our hospital. As treatment, we performed endoscopic ultrasound-guided hepaticogastrostomy and placed a self-expanding metal stent. Computed tomography was performed immediately after the procedure to ensure proper stent placement. Although repeat imaging the next day revealed that the stent on the hepaticogastrostomy route had shortened, the stent on the gastric side maintained sufficient length. However, 11 days after the procedure, the stomach-to-liver distance had increased, and the stent on the gastric side was significantly shortened. Endoscopic imaging revealed that the stent had almost migrated, and we added a fully covered self-expanding metal stent into the previous metallic stent via the hepaticogastrostomy route. The patient was discharged 19 days after the initial procedure without complications. Computed tomography performed 40 days after the hepaticogastrostomy revealed that the initial stent had migrated into the abdominal cavity, but the second stent was in an appropriate position. In conclusion, repeated monitoring by computed tomography after hepaticogastrostomy procedure may be an effective method for preventing stent migration in high-risk cases.

Objective To investigate the value of CT enterography (CTE) in the diagnosis and differential diagnosis of small intestinal tumors and tumor-like lesions. Methods A retrospective analysis was performed for the imaging data of 74 patients who underwent CTE in our hospital from January 2015 to December 2022 and were diagnosed with small intestinal tumors and tumor-like lesions based on pathological examination, and according to the nature of lesions, they were divided into malignant tumor group with 54 patients and non-malignant+tumor-like lesion group with 20 patients. The two groups were compared in terms of major axis of tumor, intestinal residual rate, and CT values during plain scan phase, arterial phase, and venous phase. Results Compared with the non-malignant+tumor-like lesion group, the malignant tumor group had significantly higher major axis of tumor and CT value during plain scan phase (Z=-3.512,-3.214,P0.05). In the malignant tumor group, compared with the patients with adenocarcinoma, the patients with lymphoma had significantly higher major axis of tumor and intestinal residual rate (Z=-3.161,-4.853,P0.05). Conclusion CTE can fully display the features of small intestinal tumor and tumor-like lesions and thus provide a basis for the diagnosis and differential diagnosis of these diseases.

Objective To explore the value of computerized tomography (CT) and magnetic resonance imaging (MRI) imaging features in differential diagnosis of giant cell tumors with prominent aneurysmal bone cysts (GABCs) in the extremities and primary aneurysmal bone cysts (PABCs). Methods In this study, the CT and MRI imaging features of 20 patients with GABCs in the extremities and 21 patients with PABCs were retrospectively analyzed, and the age and sex of patients were collected. The differences in different indicators between the two groups were compared. The diagnostic sensitivity and specificity for GABCs and PABCs were calculated based on the age, transverse/longitudinal diameter ratio of the mass, subchondral bone involvement, deep edge lobulation of the lesion, and vascular shadow around the mass. Results There were significant differences in the age and transverse/longitudinal diameter ratio of the mass between the two groups (t=-3.956,-2.985,P

Photon-counting detector computed tomography (PCD-CT) has emerged as a revolutionary technology in CT imaging. PCD-CT offers significant advancements over conventional energy-integrating detector CT, including increased spatial resolution, artefact reduction and inherent spectral imaging capabilities. In cardiac imaging, PCD-CT can offer a more accurate assessment of coronary artery disease, plaque characterisation and the in-stent lumen. Additionally, it might improve the visualisation of myocardial fibrosis through qualitative late enhancement imaging and quantitative extracellular volume measurements. The use of PCD-CT in cardiac imaging holds significant potential, positioning itself as a valuable modality that could serve as a one-stop-shop by integrating both angiography and tissue characterisation into a single examination. Despite its potential, large-scale clinical trials, standardisation of protocols and cost-effectiveness considerations are required for its broader integration into clinical practice. This narrative review provides an overview of the current literature on PCD-CT regarding the possibilities and limitations of cardiac imaging. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether switching to contrast media based on the sharing of N-(2,3-dihydroxypropyl) carbamoyl side chain reduces the recurrence of iodinated contrast media (ICM)-associated adverse drug reactions (ADRs). Materials and methods: This single-center retrospective study included 2133 consecutive patients (mean age ± SD, 56.1 ± 11.4 years; male, 1052 [49.3%]) who had a history of ICM-associated ADRs and underwent contrast-enhanced CT examinations. The per-patient and per-exam-based recurrence ADR rates were compared between cases of switching and non-switching the ICM from ICMs that caused the previous ADRs, and between cases that used ICMs with common and different carbamoyl side chains from ICMs that caused the previous ADRs. Downgrade rates (no recurrence or the occurrence of ADR less severe than index ADRs) were also compared. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) analysis were additionally performed. Results: In per-patient analysis, switching of ICM showed a lower recurrence rate (switching, 10.4% [100/965] vs. non-switching, 28.4% [332/1168]), with the adjusted odds ratio (OR) of 0.27 (95% CI: 0.21, 0.34; p < 0.001). The result was consistent in PSM (OR, 0.29 [95% CI: 0.22, 0.39]; p < 0.001), IPTW (OR, 0.28 [95% CI: 0.22, 0.36]; p < 0.001), and in per-exam analysis (5.5% vs. 13.8%; OR, 0.32 [95% CI: 0.27, 0.37]; p < 0.001). There was lower per-exam recurrence (5.0% [195/3938] vs. 7.8% [79/1017]; OR, 0.63 [95% CI: 0.47, 0.83]; p = 0.001) and higher downgrade rates (95.6% [3764/3938] vs. 93.3% [949/1017]; OR, 1.51 [95% CI: 1.12, 2.03]; p = 0.006) when using different side chain groups. Conclusion: Switching to an ICM with a different carbamoyl side chain reduced the recurrent ADRs and their severity during subsequent examinations. Clinical relevance statement: Switching to an iodinated contrast media with a different carbamoyl side chain reduced the recurrent adverse drug reactions and their severity during subsequent examinations. Key Points: Patients who experience adverse drug reactions from iodinated contrast media (ICM) may need to undergo contrast-enhanced studies again. Switching of ICM away from the ICM that caused the previous adverse drug reactions showed significantly lower recurrence rates. Compared to common side chain groups, there were significant differences in the per-exam recurrence rates and downgrade rates when using ICMs with different side chains. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the variations in the root canal morphology of mandibular third molars (M3M) using cone beam computed tomography (CBCT). Material and Methods: A total of 186 CBCT images were analyzed to assess the root and root canal morphology of M3M using Vertucci classification. Gender influence on morphology was also examined. Statistical analysis was performed using Chi-square or Fisher's exact test. Results: Most M3M exhibited two roots, followed by a single root and three roots, with no significant difference in number of roots between sexes on either side (p=0.512 and p=0.598). Three canals were most common in both sexes, but four canals were significantly more common in males on the right side. No significant sex difference was observed for the left side (p=0.245). Distal roots predominantly showed Type I canal configuration on both sides, while mesial roots exhibited Type IV on the right and Type I on the left. Conclusion: Mandibular third molars in the South Indian population had two roots and three canals, with four canals more common in males on the right. Distal root mostly exhibited Type I canal configuration, whereas mesial root varied, highlighting the importance of understanding the complexity for endodontic treatment planning.

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Introduction: According to the Portuguese clinical guidelines published in 1999, patients with traumatic brain injury and coagulopathies should remain in-hospital for 24 hours for clinical and image surveillance, despite having an admission computed tomography (CT) scan showing no intracranial lesions. Growing evidence suggests this practice is not only void of clinical relevance, but that it can also be potentially harmful for the patient. Nevertheless, up until now there is no published data concerning the economic impact of this clinical practice. Methods: A cost analysis compared retrospective data from patients admitted to our emergency department during 2022 with a hypothetical scenario in which a patient with an admission CT scan without traumatic lesions was discharged. Clinical data was also retrieved concerning the rate of a delayed intracranial bleeding on 24-hour CT scan and mortality at a six-month-period after discharge. Direct costs for the national health service were determined in terms of funding and time invested by medical teams. Results: From a sample of 440 patients, 436 remained in-hospital for a 24-hour clinical and image surveillance, of which only two (0.5%) showed a new intracranial lesion on the second CT-scan. Neither of these two patients required therapeutic measures to control bleeding and were discharged 36 hours after admission. Out of 440 patients, one patient (0.2%) died of cardiac arrest during the 24-hour surveillance period, despite having an initial normal CT scan showing no brain lesions. Our current surveillance practice directly amounted to €163 157.00, whereas the cost of our hypothetical scenario amounted to €29 480.00: a difference of €133 677.00. The application of our surveillance guideline also meant that nine emergency shifts were devoted to this task, compared to 4.6 hypothetical shifts if patients were discharged after an initial CT scan without traumatic intracranial lesions. Conclusion: In spite of apparently not adding any clinical value to our practice, our in-hospital surveillance may represent a significant financial and time-consuming burden, costing five times as much and demanding our medical teams twice as much work when compared to a scenario without clinical surveillance and 24-hour CT scans.

Background: High-quality images with minimum radiation dose are considered a challenge in Computed Tomography (CT) scans.Objective: The current study aimed to assess the efficacy of the Iterative Reconstruction in Image Space (IRIS) algorithm combined with Automatic Tube Current Modulation (ATCM) compared to Filtered Back Projection (FBP) in brain CT scans.Material and Methods: In this cross-sectional study, 200 patients underwent to brain CT scan, and images were then reconstructed using both FBP and IRIS. The CT Number (CTN), noise, and Signal-to-Noise Ratio (SNR) were computed for different tissues from CT images. The performance of two algorithms under different exposure conditions was evaluated using a water phantom. Two experienced radiologists assessed the image quality. Volume CT Dose Index (CTDIvol) and Dose Length Product (DLP) were recorded for each scan.Results: FBP reconstruction exhibited higher noise and lower SNR compared to IRIS, both with and without ATCM. Noise levels significantly increased for FBP combined with ATCM. Subjective analysis showed higher performance for IRIS without ATCM compared to other approaches. The mean CTDIvol with and without ATCM was 20.04±3.33 and 36.37±4.65 mGy, respectively. In the phantom study, the noise with IRIS remained lower than that with FBP even with a 42% dose reduction. Conclusion: IRIS algorithm can preserve the image quality when radiation dose is significantly reduced by ATCM in brain CT scan. Implementation of IRIS combined with ATCM is recommended for brain CT examinations.

Introduction: Our objective was to investigate the utility of fluorodeoxyglucose positron emission tomography‐computed tomography (FDG PET‐CT) in assessing CT Stage 1A non‐small cell lung cancer (NSCLC) in patients under consideration for curative treatment. Performing FDG PET‐CT in these patients may lead to unnecessary delays in treatment if it can be shown to provide no added value. Methods: We retrospectively reviewed 735 lesions in 653 patients from the New Zealand Te Whatu Ora Northern region lung cancer database with suspected or pathologically proven Stage 1A NSCLC on CT scan who also underwent FDG PET‐CT imaging. We determined how often FDG PET‐CT findings upstaged patients and then compared to pathological staging where available. Results: FDG PET‐CT provided an overall upstaging rate of 9.7%. Category‐specific rates were 0% in Tis, 0.9% in T1mi, 7.4% in T1a, 10% in T1b and 12% in T1c groups. The percentage of lesions upstaged on FDG PET‐CT that remained Stage 1A was 100% in T1mi, 100% in T1a, 47.1% in T1b and 40.7% in T1c groups. The P value was statistically significant at 0.004, indicating upstaging beyond Stage 1A was dependent on T category. Conclusion: Our data suggests that FDG PET‐CT is indicated for T1b and T1c lesions but is of limited utility in Tis, T1mi and T1a lesions. Adopting a more targeted approach and omitting FDG PET‐CT in patients with Tis, T1mi, and T1a lesions may benefit all patients with lung cancer by improving accessibility and treatment timelines. [ABSTRACT FROM AUTHOR]

Objective To evaluate the efficacy of dual-energy CT (DECT) water -hydroxyapatite (HAP) decomposition technique for detecting acute vertebral fractures. Methods Fifty consecutive patients who underwent both DECT and MRI of the thoracolumbar spine after trauma were retrospectively enrolled. Conventional linear-blended CT scans and corresponding water-HAP reconstructions were obtained. Four radiologists with 1, 5, 8 and 12 years of experience independently evaluated the gray-scale CT for the presence of fractures and their suspected age. The water -HAP images were then blindly assessed by the same readers to detect bone marrow edema. Findings were compared with those from fat-suppressed T2-weighted MRI as the standard. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) analyses for diagnostic performance and matched pair analyses were performed. Results Fifty-four fractures were classified as acute and 38 as chronic on MRI. The diagnostic performance of all readers in the detection of acute fractures improved from 0.76, 0.75, 0.82, and 0.84 with conventional CT alone to 0.87, 0.89, 0.92, and 0.93 in combination with water-HAP images, respectively. The diagnostic sensitivity increased from 0.83, 0.89, 0.66, and 0.71 to 0.93, 0.98, 0.79, and 0.84 whereas the specificity increased from 0.83, 0.87, 0.63, and 0.79 to 0.94, 0.94, 0.82, and 0.92, respectively. The PPV increased from 0.78, 0.81, 0.74, and 0.82 to 0.86, 0.90, 0.88, and 0.97 whereas the NPV increased from 0.76, 0.85, 0.73, and 0.81 to 0.88, 0.94, 0.91, and 0.92, respectively. The number of vertebrae rated as uncertain vertebral fracture decreased from 23, 21, 19, and 12 to 7, 5, 5, and 1, respectively. The accuracy improved significantly with the water-HAP decomposition technique (P<0.05) and the number of patients potentially referred to MRI decreased from 14, 13, 14, and 11 to 4, 3, 3, and 1, respectively. Conclusion DECT based water -HAP decomposition technique can improve the diagnostic confidence of radiologists in acute vertebral compression fractures. [ABSTRACT FROM AUTHOR]

Objective To explore the application value of double-flow method of CT angiography using a mixture of normal saline and contrast agent before injection of contrast agent to achieve differential imaging within the human body in CT pulmonary angiography (CTPA). Methods Forty patients with clinically suspected pulmonary embolism at our hospital from January 2022 to March 2024 were randomly divided into monitoring scanning control group (20) and dual-flow scanning study group (20) for CTPA using Philips 128-row spiral CT. In the control group, region of interest (ROI) was placed in the superior vena cava (SVC) with a threshold of 150 HU, 50 mL iobitridol (350 mg I/mL) and 30 mL normal saline were continuously injected. In the experimental group, ROI was placed in the pulmonary trunk (PT) with a threshold of 60 HU, 6 mL of contrast agent and 16 mL of normal saline mixture, 17 mL of contrast agent and 3 mL of normal saline mixture, and 30 mL of normal saline solution were continuously injected. The CT values of PT, pulmonary vein (PV) and SVC of the two groups were measured and the image quality was compared. Results There was no significant difference (t=-2.16, -1.168; P>0.05) between the CT values of PT (371.35±60.16) and PV (153.8±30.29) in the control group and that of the experimental group (360.1±48.09, 154.25±45.97). These numbers are the same for both groups. The SVC CT value of the study group (198.5±55.97) was significantly lower (t=-8.048, P<0.05) than that of the control group (1001.25±299.55). There was no significant difference in pulmonary artery subjective scores between the experimental group and the control group (P=0.085). The subjective score of superior vena cava artifact in the experimental group was significantly higher than that in the control group (P=0.000). Conclusion Double-flow CTPA uses less contrast agent with decreased enhancement of SVC and better PT image quality. [ABSTRACT FROM AUTHOR]

Purpose: In this cross-sectional study, we aimed to characterize how frequently the anatomy of interest (AOI) was excluded when evaluating genital pathology using the current CT pelvis protocol recommended by the American College of Radiology and evaluate how AOI exclusion affects patient management. Methods: We retrospectively reviewed medical records, using diagnosis and CPT codes, of patients admitted with genital pathology who obtained a CT scan at our institution from July 1, 2020–April 30, 2023. Baseline patient demographics were included. Data about each index CT scan (scan obtained at our institution) were recorded and assessed for exclusion of the AOI. Statistical analysis was performed to determine the rate of AOI exclusion and to compare patient management between patients with AOI excluded versus those without AOI exclusion. Results: 113 presentations for genital pathology included an index CT scan and were included for analysis. Patients were primarily men (98%) with a mean age of 53.1 years (SD 13.9). The most common diagnoses were Fournier's gangrene (35%), scrotal abscess (22%) and unspecified infection (19%). 26/113 scans (23%) did not capture the entire AOI. When the AOI was missed during the index scan, there was a higher rate of obtaining additional scans (38% vs. 21%), but a similar rate of intervention (77% vs. 63%) when compared to index scans that captured the entire AOI. 35 scans (31%) had protocol-extending instructions; index scans that captured the entire AOI were more likely to have specific protocol-extending instructions (38% vs. 8% p < 0.01). Conclusions: Creating a specific CT protocol for genital pathology could decrease the amount of inappropriate irradiation and improve AOI capture rates without relying on specific request for protocol deviation. [ABSTRACT FROM AUTHOR]

Background/Aims: Despite advances in imaging and endoscopic technology, diagnostic modalities for small bowel tumors are simultaneously performed. We investigated the discrepancy rate between each modality and predictive factors of discrepancy in patients with definite small bowel tumors. Methods: Data of patients with definite small bowel tumors who underwent both device-assisted enteroscopy (DAE) and computed tomography (CT) were retrieved from web-based enteroscopy registry database in Korea. Predictive risk factors associated with discrepancy were analyzed using logistic regression analysis. Results: Among 998 patients, 210 (21.0%) were diagnosed with small bowel tumor using DAE, in 193 patients with definite small bowel tumor, DAE and CT were performed. Of these patients, 12 (6.2%) showed discrepancy between examinations. Among 49 patients who underwent DAE and video capsule endoscopy (VCE) examination, 13 (26.5%) showed discrepancy between examinations. No significant independent risk factors were associated with concordance between DAE and CT in multivariate logistic regression analysis among the patients. In a multivariate logistic regression analysis, red blood cell transfusion was negatively associated with concordance between DAE and VCE in patients with small bowel tumor (odds ratio, 0.163; 95% confidence interval, 0.026 to 1.004; p=0.050). Conclusions: For small bowel tumors, the discrepancy rate between DAE and CT was 6.2%, and 26.5% between DAE and VCE. Despite developments in cross-sectional imaging (VCE and DAE modalities), discrepancies still exist. For small bowel bleeding that require significant transfusion while showing insignificant VCE findings, DAE should be considered as the next diagnostic approach, considering the possibility of missed small bowel tumor. [ABSTRACT FROM AUTHOR]

Purpose: This study examines the hepatic extracellular volume fraction (ECV) disparity between the left and right lobes (ECV_left and ECV_right) in patients with chronic thromboembolic pulmonary hypertension (CTEPH), its association with right heart catheterization (RHC) metrics, and with intolerance to increased pulmonary hypertension (PH)-targeted medication dosages. Methods: We retrospectively analyzed 72 CTEPH-diagnosed patients who underwent equilibrium-phase abdominal dual-energy CT (DECT) and RHC. Hepatic ECVs, derived from DECT's iodine maps using circular regions of interest in the liver and aorta, were correlated with RHC parameters via Spearman's rank correlation and lobe differences through the Wilcoxon signed-rank test. Logistic regression assessed cases with ECV_left exceeding ECV_right by > 0.05, while receiver operating characteristic curve analysis gauged ECVs' predictive power for medication intolerance. Results: Of the 72 patients (57 females; median age 69), ECV_total (0.24, IQR 0.20–0.27) moderately correlated with RHC parameters (rs = 0.28, −0.24, 0.3 for mean pulmonary arterial pressure, cardiac index [CI], and pulmonary vascular resistance index, respectively). ECV_left significantly surpassed ECV_right (0.25 vs. 0.22, p < 0.001), with a greater ECV_left by > 0.05 indicating notably lower CI (p < 0.001). In 27 patients on PH medication, ECV_left effectively predicted medication intolerance (AUC = 0.84). Conclusion: In CTEPH patients, hepatic ECV correlated with RHC metrics, where elevated left lobe ECV suggested reduced CI and potential medication intolerance. The hepatic extracellular volume fraction (ECV), measured via dual-energy CT, was notably higher in the left lobe compared to the right in patients with chronic thromboembolic pulmonary hypertension, with elevated ECV in the left lobe correlating with reduced cardiac index and intolerance to medication. [ABSTRACT FROM AUTHOR]

ABSTRACT Spontaneous non-aneurysmal aortic rupture is rare and is usually attributed to penetrating aortic ulcers, infections, tumor infiltrations, or inflammatory and collagen diseases. Chronic rupture is infrequent but extremely rare in non-aneurysmal aortas, which makes diagnosis difficult because the absence of an aneurysm can mislead the physician to rule out rupture. Here, we describe the case of an 85-year-old male, who was undergoing oncological investigation for weight loss, inappetence, and back pain. Computed tomography and magnetic resonance imaging performed 3 months before admission showed a contained pseudoaneurysm of the infrarenal aorta associated with significant aortoiliac calcification and images suggestive of peritoneal implants. The patient was referred to our oncological center and underwent abdominal computed tomography for oncological investigation and staging. The patient was urgently admitted to the intensive care unit after a critical finding of contained rupture of the infrarenal aorta during the scan. Endovascular repair was indicated, and the patient was successfully treated with implantation of an Endurant IIs 25 × 25 × 70 mm endoprosthesis. No procedural complications were observed. Postoperative course was uneventful, and the patient was discharged on the fifth postoperative day. Control computed tomography performed 1 and 6 months after surgery showed no leaks. This case emphasizes the importance of communication between the radiologists and attending physicians. As the rupture was punctual and well defined in the computed tomography and angiography images, endovascular repair with an aortic cuff was safely performed, and the procedure time was reduced.

Background/purpose: To investigate a quantitative method for assessing image quality of low dose lung computed tomography (CT) and find the lowest exposure dose providing diagnostic images. Methods: Axial volumetric lung CT acquisitions (256 slice scanner) were performed on three different sized anthropomorphic phantoms at different dose levels. The maximum steepness of sigmoid curves fitted to line density profiles was measured at lung-to-pleura interfaces. For each phantom, image sharpness was calculated as the median of 468 measurements from 39 different locations. Diagnostic image quality for the adult and paediatric phantom was rated by three radiologists using 4-point Likert scales. The image sharpness cut-off for obtaining adequate image quality was determined from qualitative ratings. Results: Adequate diagnostic image quality was reached at a median steepness of 713 HU/mm in the adult phantom with a corresponding CTDIvol of 0.14 mGy and an effective dose of 0.13 mSv at a dose level of 100 kVp and 10 mA. In the paediatric phantom diagnostic image quality was reached at a median steepness of 1139 HU/mm with a corresponding CTDIvol of 0.13 mGy and an effective dose of 0.08 mSv at a dose level of 100 kVp and 10 mA. Conclusions: Determination of image sharpness on line density profiles can be used as quantitative measure for image quality of lung CT. Sufficient-quality lung CT can be achieved at effective radiation doses of 0.13 mSv (adult phantom) and 0.08 mSv (paediatric phantom). These findings suggest that substantial dose reduction is feasible without compromising diagnostic accuracy.

Purpose: Traditional CT acquisition planning is based on scout projection images from planar anterior-posterior and lateral projections where the radiographer estimates organ locations. Alternatively, a new scout method utilizing ultra-low dose helical CT (3D Landmark Scan) offers cross-sectional imaging to identify anatomic structures in conjunction with artificial intelligence based Anatomic Landmark Detection (ALD) for automatic CT acquisition planning. The purpose of this study is to quantify changes in scan length and radiation dose of CT examinations planned using 3D Landmark Scan and ALD and performed on next generation wide volume CT versus examinations planned using traditional scout methods. We additionally aim to quantify changes in radiation dose reduction of scans planned with 3D Landmark Scan and performed on next generation wide volume CT. Methods: Single-center retrospective analysis of consecutive patients with prior CT scan of the same organ who underwent clinical CT using 3D Landmark Scan and automatic scan planning. Acquisition length and dose-length-product (DLP) were collected. Data was analyzed by paired t-tests. Results: 104 total CT examinations (48.1 % chest, 15.4 % abdomen, 36.5 % chest/abdomen/pelvis) on 61 individual consecutive patients at a single center were retrospectively analyzed. 79.8 % of scans using 3D Landmark Scan had reduction in acquisition length compared to the respective prior acquisition. Median acquisition length using 3D Landmark Scan was 26.7 mm shorter than that using traditional scout methods (p < 0.001) with a 23.3 % median total radiation dose reduction (245.6 (IQR 150.0–400.8) mGy cm vs 320.3 (IQR 184.1–547.9) mGy cm). CT dose index similarly was overall decreased for scans planned with 3D Landmark and ALD and performed on next generation CT versus traditional methods (4.85 (IQR 3.8–7) mGy vs. 6.70 (IQR 4.43–9.18) mGy, respectively, p < 0.001). Conclusion: Scout imaging using reduced dose 3D Landmark Scan images and Anatomic Landmark Detection reduces acquisition range in chest, abdomen, and chest/abdomen/pelvis CT scans. This technology, in combination with next generation wide volume CT reduces total radiation dose.

Abstract Background The application of radiomics in thoracic lymph node metastasis (LNM) of lung adenocarcinoma is increasing, but diagnostic performance of radiomics from primary tumor to predict LNM has not been systematically reviewed. Therefore, this study sought to provide a general overview regarding the methodological quality and diagnostic performance of using radiomic approaches to predict the likelihood of LNM in lung adenocarcinoma. Methods Studies were gathered from literature databases such as PubMed, Embase, the Web of Science Core Collection, and the Cochrane library. The Radiomic Quality Score (RQS) and the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) were both used to assess the quality of each study. The pooled sensitivity, specificity, and area under the curve (AUC) of the best radiomics models in the training and validation cohorts were calculated. Subgroup and meta-regression analyses were also conducted. Results Seventeen studies with 159 to 1202 patients each were enrolled between the years of 2018 to 2022, of which ten studies had sufficient data for the quantitative evaluation. The percentage of RQS was between 11.1% and 44.4% and most of the studies were considered to have a low risk of bias and few applicability concerns in QUADAS-2. Pyradiomics and logistic regression analysis were the most commonly used software and methods for radiomics feature extraction and selection, respectively. In addition, the best prediction models in seventeen studies were mainly based on radiomics features combined with non-radiomics features (semantic features and/or clinical features). The pooled sensitivity, specificity, and AUC of the training cohorts were 0.84 (95% confidence interval (CI) [0.73–0.91]), 0.88 (95% CI [0.81–0.93]), and 0.93(95% CI [0.90–0.95]), respectively. For the validation cohorts, the pooled sensitivity, specificity, and AUC were 0.89 (95% CI [0.82–0.94]), 0.86 (95% CI [0.74–0.93]) and 0.94 (95% CI [0.91–0.96]), respectively. Conclusions Radiomic features based on the primary tumor have the potential to predict preoperative LNM of lung adenocarcinoma. However, radiomics workflow needs to be standardized to better promote the applicability of radiomics. Trial registration CRD42022375712.

Abstract The goal of this experimental study was to quantify the influence of helical pitch and gantry rotation time on image quality and file size in ultrahigh-resolution photon-counting CT (UHR-PCCT). Cervical and lumbar spine, pelvis, and upper legs of two fresh-frozen cadaveric specimens were subjected to nine dose-matched UHR-PCCT scan protocols employing a collimation of 120 × 0.2 mm with varying pitch (0.3/1.0/1.2) and rotation time (0.25/0.5/1.0 s). Image quality was analyzed independently by five radiologists and further substantiated by placing normed regions of interest to record mean signal attenuation and noise. Effective mAs, CT dose index (CTDIvol), size-specific dose estimate (SSDE), scan duration, and raw data file size were compared. Regardless of anatomical region, no significant difference was ascertained for CTDIvol (p ≥ 0.204) and SSDE (p ≥ 0.240) among protocols. While exam duration differed substantially (all p ≤ 0.016), the lowest scan time was recorded for high-pitch protocols (4.3 ± 1.0 s) and the highest for low-pitch protocols (43.6 ± 15.4 s). The combination of high helical pitch and short gantry rotation times produced the lowest perceived image quality (intraclass correlation coefficient 0.866; 95% confidence interval 0.807–0.910; p

Objective To analyze the clinical and imaging features of Dyke-Davidoff-Masson syndrome (DDMS). Methods The clinical data, unenhanced CT (12) and MRI (4) of 13 patients with type I (6), II (4), and III (3), acquired (8) and congenital (5) DDMS were retrospectively analyzed. Three of the 13 patients underwent both CT and MRI. Results The clinical manifestations included epilepsy (12), hemiplegia (9), mental retardation (9), mental disorders (9), extremity atrophy (3), facial asymmetry (2), sexual dysfunction (1), and bilateral auricular malformation (1). The patients showed unilateral cerebral hemiatrophy and ipsilateral ventricle dilatation (13), ipsilateral midline structural shift (12), ipsilateral basal ganglia and cerebral peduncle atrophy (10), encephalomalacia (9), hippocampal atrophy (6), porencephaly (4), crossed cerebellar atrophy (3), bilateral cerebellar atrophy (3), corpus callosum hypoplasia (3), schizencephaly and agenesis of septum pellucidum (1). All 13 patients had varying degrees of ipsilateral compensatory cranial changes of calvarial thickening, excessive aeration of the frontal sinus and mastoid air cells. Conclusion The main clinical features of DDMS are epilepsy, hemiplegia, mental retardation and mental disorders. Unilateral cerebral hemisphere atrophy and ipsilateral compensatory cranial changes are typical imaging features. [ABSTRACT FROM AUTHOR]

Objective To evaluate the image quality of CT portal venography (CTPV) under low radiation dose conditions at 100 kVp using a second-generation dual-layer detector spectral CT (DLCT). Methods A total of 110 patients [54 men, 56 women, mean age: (57.47±15.07) years] underwent abdominal contrast-enhanced DLCT from May 2023 to March 2024. The patients were randomly divided into a control group (120 kVp, n=50) and a study group (100 kVp, n=60). The original CTPV data from the control group were reconstructed into conventional mixed-energy images (CI), while the data from the study group were reconstructed into CI and virtual monoenergetic images (VMI) at 40-80 keV intervals (10 keV steps). The CT values, standard deviation (SD), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of the main portal vein and its left and right branches were measured. Subjective image quality was assessed by two radiologists. Results The effective radiation dose (ED) for the study group [(1.92±0.21) mSv] was 52.59% lower than that of control group [(4.05±1.23) mSv]. The average CT values, SNR, and CNR of the portal vein and its branches in the 40, 50, and 60 keV VMIs of the study group were significantly higher than those in the CIs of both groups (all P<0.0001), with the highest SNR and CNR observed at 40 and 50 keV VMIs. There was no significant difference in the SNR and CNR between 40 and 50 keV VMIs (P<0.05). The SD of 40 and 50 keV VMIs in the study group was comparable to that of control (P>0.05) whereas the SD of 60-80 keV VMIs was significantly lower than that of control (P<0.05). Subjective image quality assessment showed that 50 keV VMI had the highest proportion of scores rated as 5 (best) at 75% with good interobserver agreement (all K>0.8). Conclusion Using 50 keV VMI with 100 kVp DLCT provides image quality that meets clinical diagnostic requirements while significantly reducing radiation dose compared to conventional images at 120 kVp. [ABSTRACT FROM AUTHOR]

Objective To study the feasibility of spectral CT virtual monoenergetic imaging (VMI) for one-stop coronary artery and vein examination. Methods From December 2023 to January 2024, an experimental group of 25 patients underwent coronary artery and vein CT imaging using personalized scanning protocols and a randomly selected controlled group of 25 patients underwent coronary artery CT imaging using routine scanning protocols. The conventional images of the experimental group as group B1, and the 40 keV virtual monoenergetic reconstructed images as group B2. The CT image quality of the control group (A), conventional CT (B1) and 40 keV VMI (B2) of the experimental group was evaluated quantitively including CT values, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of coronary artery branches. Subjective evaluations were completed by two experienced radiologists using a 5-point scale, and the inter-rater reliability was analyzed using the Kappa test. Group comparisons were conducted using the Mann-Whitney test. Results CT values, SNR and CNR of the left main coronary arteries [(1306.07±185.16) HU, 101.820± 38.10, 113.91±42.13], right coronary arteries [(1284.97±203.8) HU, 99.99±37.61, 112.10±41.53], left circumflex coronary arteries [(1191.88±182.83) HU, 93.01±36.10, 105.11±39.92], and left anterior descending arteries [(1202.44±185.50) HU, 88.05±33.57, 106.33±41.84] in group B2 were significantly higher (P<0.001) than that of groups A and B1. The CT values, SNR and CNR values of the coronary veins including coronary sinus, great cardiac vein, posterior intraventricular vein, anterior interventricular vein, posterior vein of the left ventricle, and left marginal vein in group B2 were also significantly higher (P<0.001) than that of group B1. The subjective image quality scores of B2 group (5, 5) were better than that of groups A and B1 with good consistency (κ>0.7). Conclusion Spectral CT VMI allows one-stop examination of the coronary arteries and veins. [ABSTRACT FROM AUTHOR]

Objective To investigate the value of dual-layer detector spectral CT in the differential diagnosis of arterial phase hyperenhancement (APHE) liver metastases and hepatocellular carcinoma (HCC). Methods Fifty-three patients with clinical or pathologically confirmed APHE liver metastasis (23) and HCC (30) from December 2021 to June 2023 were included in this retrospective study . The spectral CT parameters on the standardized virtual monoenergetic image (VMI) including tumor / liver standardized iodine no water (NINW-Ltumor to liver), tumor/liver standardized iodine density (NID-L), tumor/liver standardized Z-effective (NZeff-L), and tumor/abdominal aorta NZeff (NZeff-Atumor to aorta) were calculated. The receiver operating characteristic (ROC) curve and Cohen d were used to analyze the diagnostic effectiveness of these parameters. Results In the arterial phase, the CT values of liver on 40 keV (NCT-L40keV), 50 keV (NCT-L50keV), and 60 keV (NCT-L60keV) VMI, NINW-L, NID-L, NZeff-L and NZeff-A of APHE liver metastases were significantly less than that of HCC (P<0.05). The area under the ROC curve of NINW-L in the arterial phase was the highest at 0.752. The 0.298 threshold value of NINW -L in the arterial phase had the best differentiation between liver metastases and HCC with 63.3% sensitivity and 87.0% specificity. Conclusion NCT-L40keV, NINW-L and NID-L in the arterial phase are valuable for differentiating APHE liver metastasis from HCC. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate diagnostic performance and image quality of ultralow-dose CT (ULDCT) in diagnosing acute appendicitis with an image-based deep-learning denoising algorithm (IDLDA). Methods: This retrospective multicenter study included 180 patients (mean ± standard deviation, 29 ± 9 years; 91 female) who underwent contrast-enhanced 2-mSv CT for suspected appendicitis from February 2014 to August 2016. We simulated ULDCT from 2-mSv CT, reducing the dose by at least 50%. Then we applied an IDLDA on ULDCT to produce denoised ULDCT (D-ULDCT). Six radiologists with different experience levels (three board-certified radiologists and three residents) independently reviewed the ULDCT and D-ULDCT. They rated the likelihood of appendicitis and subjective image qualities (subjective image noise, diagnostic acceptability, and artificial sensation). One radiologist measured image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). We used the receiver operating characteristic (ROC) analyses, Wilcoxon's signed-rank tests, and paired t-tests. Results: The area under the ROC curves (AUC) for diagnosing appendicitis ranged 0.90–0.97 for ULDCT and 0.94–0.97 for D-ULDCT. The AUCs of two residents were significantly higher on D-ULDCT (AUC difference = 0.06 [95% confidence interval, 0.01–0.11; p =.022] and 0.05 [0.00–0.10; p =.046], respectively). D-ULDCT provided better subjective image noise and diagnostic acceptability to all six readers. However, the response of board-certified radiologists and residents differed in artificial sensation (all p ≤.003). D-ULDCT showed significantly lower image noise, higher SNR, and higher CNR (all p <.001). Conclusion: An IDLDA can provide better ULDCT image quality and enhance diagnostic performance for less-experienced radiologists. [ABSTRACT FROM AUTHOR]

Purpose: Gold–silica nanoshell therapy [AuroShells with subsequent focal laser therapy (AuroLase)] is an emerging targeted treatment modality for prostate cancer. We reviewed pre- and post-treatment unenhanced CT imaging to assess for retained gold–silica nanoshells in the abdomen and pelvis. Methods: This single-institution retrospective study identified patients in the AuroLase pilot who underwent pre- and post-treatment unenhanced abdominopelvic CT. The attenuation, before and after gold–silica nanoshell administration, of the liver, spleen, pancreas, kidneys, prostate, blood pool, paraspinal musculature, and abnormal lymph nodes were manually measured by two readers. After inter-reader agreement was calculated using intraclass correlation (ICC), a permutation test was used to assess pre- and post-therapy attenuation differences. Results: Four patients met the inclusion criteria. Mean age was 72.3 ± 5.9 years. Median time interval between pre-treatment CT and treatment, and between treatment and post-treatment CT, was 232 days and 236.5 days, respectively. The two readers' attenuation measurements had very high agreement (ICC = 0.99, p < 0.001). The highest differences in organ attenuation between pre- and post-therapy scans were seen in all four patients in the liver and spleen (liver increased by an average of 28.9 HU, p = 0.010; spleen increased by an average of 63.7 HU, p = 0.012). A single measured lymph node increased by an average of 58.9 HU. In the remainder of the measured sites, the change in attenuation from pre- to post-therapy scans ranged from -0.1 to 3.8 HU (p > 0.05). Conclusion: Increased attenuation of liver and spleen at CT can be an expected finding in patients who have received gold–silica nanoshell therapy. [ABSTRACT FROM AUTHOR]

Background: The application of radiomics in thoracic lymph node metastasis (LNM) of lung adenocarcinoma is increasing, but diagnostic performance of radiomics from primary tumor to predict LNM has not been systematically reviewed. Therefore, this study sought to provide a general overview regarding the methodological quality and diagnostic performance of using radiomic approaches to predict the likelihood of LNM in lung adenocarcinoma. Methods: Studies were gathered from literature databases such as PubMed, Embase, the Web of Science Core Collection, and the Cochrane library. The Radiomic Quality Score (RQS) and the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) were both used to assess the quality of each study. The pooled sensitivity, specificity, and area under the curve (AUC) of the best radiomics models in the training and validation cohorts were calculated. Subgroup and meta-regression analyses were also conducted. Results: Seventeen studies with 159 to 1202 patients each were enrolled between the years of 2018 to 2022, of which ten studies had sufficient data for the quantitative evaluation. The percentage of RQS was between 11.1% and 44.4% and most of the studies were considered to have a low risk of bias and few applicability concerns in QUADAS-2. Pyradiomics and logistic regression analysis were the most commonly used software and methods for radiomics feature extraction and selection, respectively. In addition, the best prediction models in seventeen studies were mainly based on radiomics features combined with non-radiomics features (semantic features and/or clinical features). The pooled sensitivity, specificity, and AUC of the training cohorts were 0.84 (95% confidence interval (CI) [0.73–0.91]), 0.88 (95% CI [0.81–0.93]), and 0.93(95% CI [0.90–0.95]), respectively. For the validation cohorts, the pooled sensitivity, specificity, and AUC were 0.89 (95% CI [0.82–0.94]), 0.86 (95% CI [0.74–0.93]) and 0.94 (95% CI [0.91–0.96]), respectively. Conclusions: Radiomic features based on the primary tumor have the potential to predict preoperative LNM of lung adenocarcinoma. However, radiomics workflow needs to be standardized to better promote the applicability of radiomics. Trial registration: CRD42022375712. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate the distribution of coronal plane alignment of the knee (CPAK) classification and functional knee phenotypes in a Chinese osteoarthritis (OA) population and to compare different lower limb alignment targets according to the distribution characteristics to find suitable total knee arthroplasty (TKA) bone cut strategies for the Chinese OA patients. Methods: The computed tomography (CT) images were retrospectively collected and the three‐dimensional (3D) models were reconstructed from 434 Chinese OA patients, including 93 males and 341 females, with a mean age of 66.4 ± 9.3 years. Femoral mechanical angle (FMA), tibial mechanical angle (TMA) and mechanical hip–knee–ankle angle (mHKA) were measured on the 3D models. Arithmetic hip–knee–ankle angle (aHKA) was calculated using FMA plus TMA, and joint line obliquity was calculated as 180 + TMA–FMA. The CPAK according to MacDessi and the functional knee phenotypes according to Hirschmann were performed. In addition, the suitable TKA bone cut strategies were explored according to the phenotypes and based on the characteristics of different alignment targets, such as mechanical alignment, anatomic alignment (AA), kinematic alignment, restricted KA (rKA) and adjusted MA (aMA). Statistical differences were determined using the independent‐samples t‐test or the two independent‐samples Wilcoxon test, with p < 0.05 considered statistically significant. Results: The Chinese OA population showed a varus alignment tendency (mHKA = 172.1° ± 7.2°), to which the TMA was a major contributor (TMA = 84.7° ± 4.4° vs. FMA = 91.3° ± 3.2°). The mHKA was on average 3.9° more varus than the aHKA. A total of 140 functional knee phenotypes were found and 45.6% were concentrated in VARFMA3°–NEUFMA0° to VARTMA3°–NEUTMA0°. More than 70% of patients had different FMA and TMA phenotypes. There were 92.9% of CPAK distributed in types I to IV, with type I accounting for 53.9%. The FMA phenotypes were less changed if the aMA and rKA were chosen, and the TMA phenotypes were less changed if the AA and rKA were chosen. Conclusion: Compared with the CPAK, the functional knee phenotypes were more suitable for the Chinese OA population with a wide distribution and a varus tendency, and it seemed more appropriate to choose aMA and rKA as TKA alignment targets for resection. Level of Evidence: Level Ⅲ. [ABSTRACT FROM AUTHOR]

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Objective To explore the value of quantitative dual-energy CT(DECT)parameters for predicting lateral cervical lymph node metastasis(LLNM)in patients with papillary thyroid carcinoma(PTC). Methods DECT of 216 patients with pathologically confirmed PTC including 174 with LLNM and 42 without LLNM was retrospectively analyzed. Quantitative DECT parameters including iodine concentration(IC), effective atomic number(Zeff), slope of spectral Hounsfield unit curve(λHU), normalized IC(NIC)and normalized Zeff(NZeff)in the non-contrast, arterial and venous phases were compared. Binary logistic regression was applied to analyze the independent predictors. Receiver operating characteristic(ROC)curve analysis was used to evaluate the performance of independent predictors and their combinations for predicting the LLNM. Results Compared with the non-LLNM group, LLNM group showed significantly lower NIC(Z=-2. 279, P=0. 023)in the non-contrast phase, higher IC, NIC, NZeff and λHU in the arterial phase(all P＜0. 05), and higher IC, NIC, Zeff and λHU in the venous phase(all P＜0. 05). Binary logistic regression analysis showed that NICs in the non-contrast and venous phases were independent predictors of LLNM. The predictive performance of the combined non-contrast and venous phase model is optimal with an area under ROC curves(AUC)of 0. 672(95％CI:0. 605-0. 734), sensitivity of 63. 79％, specificity of 66. 67％, followed by NIC in the venous phase(AUC=0. 634)and NIC in the non-contrast phase(AUC=0. 613). Conclusion DECT derived quantitative parameters can assist in predicting LLNM in patients with PTC. [ABSTRACT FROM AUTHOR]

Objective To investigate the efficacy of geometric characteristics and hemodynamics for evaluating the risk of abdominal aortic aneurysm(AAA)rupture. Methods Twenty-five patients with intact AAAs(iAAA group)and 25 patients with ruptured AAAs(rAAA group)from June 2019 to August 2023 were matched 1∶1 with covariates of gender and age. Geometric characteristics,risk factors for rupture,and hemodynamics of the AAAs were analyzed. Results The maximal AAA diameter[(Dmax:(5. 92±1. 50)cm,t=6. 947,P＜0. 05],diameter of AAA neck[Dneck:(2. 38±0. 50)cm,t=2. 563,P＜0. 05],the ratio of Dmax to diameter of normal aorta(Dmax/DAO:2. 54±0. 67,t=6. 567,P＜0. 05),Dmax/Dneck(2. 53±0. 62,t=6. 567,P＜0. 05),and normalized length of AAA(Lnor:22. 73±11. 08,t=4. 982,P＜0. 05)in rAAA group were significantly greater than that of iAAA group[(3. 67±0. 68)cm,(2. 06±0. 03)cm,1. 56±0. 34,1. 81±0. 38,10. 78±4. 59]. Multivariate logistic analysis showed that Dmax(OR=1. 824,95％CI:1. 459-6. 251)and Dmax/DAO(OR=4. 039,95％CI:3. 261-9. 155)were significant risk predictors for AAA rupture. The multivariate model using integrated geometric features had higher accuracy(94％)than conventional Dmax(88％)for predicting the risk of AAA rupture. rAAA had type Ⅲand iAAA had type Ⅱ blood flow patterns. rAAA had greater area of low wall shear stress(73. 9 cm²)than iAAA(67. 8 cm²). Conclusion Evaluation of AAA rupture risk is improved by geometric characteristics of Dmax and Dmax/DAO combined with blood flow pattern and area of low wall shear stress. [ABSTRACT FROM AUTHOR]

Objective To explore the diagnostic accuracy of risk nomogram model based on clinical and CT features for acute complicated appendicitis(ACA). Methods 478 patients with pathologically confirmed acute appendicitis(AA)from December 2020 to December 2022 were retrospectively classified as ACA(acute gangrenous appendicitis,acute perforated appendicitis,appendiceal abscess requiring surgery)and acute uncomplicated appendicitis(AUA:acute simple appendicitis,acute suppurative appendicitis). The clinical features,laboratory findings,and preoperative CT appearance between ACA and AUA groups were compared using single factor analysis. The high-risk factors were screened by multivariate logistic regression analysis and the corresponding nomogram model was constructed. Data from a separate group of 146 patients with AA from January 2023 to August 2023 were used to construct the validation model. Receiver operating characteristic(ROC)curve and decision curve analysis were used for internal validation of model results and compared with traditional Alvarado and the appendicitis inflammatory response(AIR)scoring methods. Results Of the 624 patients,13. 5％(84/624)had ACA. Regression analysis showed that age,duration of appendicitis symptoms,body temperature,percentage of neutrophil,and preoperative CT features were high risk factors for ACA. The nomogram model based on these factors had better diagnostic performance with area under the ROC curve(AUC)of 0. 831(95％CI:0. 783-0. 876),82. 0％sensitivity,72. 2％specificity,and 77. 1％accuracy compared to the Alvarado scoring method(AUC:0. 640,95％CI:0. 585-0. 696;sensitivity:73. 4％;specificity:46. 2％;accuracy:59. 8％)and AIR scoring method(AUC:0. 738,95％CI:0. 585-0. 890;sensitivity:66. 8％;specificity:72. 7％;accuracy:69. 8％). Conclusion Risk nomogram model based on clinical and CT features has high accuracy and reliability in diagnosing ACA. [ABSTRACT FROM AUTHOR]

The goal of this experimental study was to quantify the influence of helical pitch and gantry rotation time on image quality and file size in ultrahigh-resolution photon-counting CT (UHR-PCCT). Cervical and lumbar spine, pelvis, and upper legs of two fresh-frozen cadaveric specimens were subjected to nine dose-matched UHR-PCCT scan protocols employing a collimation of 120 × 0.2 mm with varying pitch (0.3/1.0/1.2) and rotation time (0.25/0.5/1.0 s). Image quality was analyzed independently by five radiologists and further substantiated by placing normed regions of interest to record mean signal attenuation and noise. Effective mAs, CT dose index (CTDIvol), size-specific dose estimate (SSDE), scan duration, and raw data file size were compared. Regardless of anatomical region, no significant difference was ascertained for CTDIvol (p ≥ 0.204) and SSDE (p ≥ 0.240) among protocols. While exam duration differed substantially (all p ≤ 0.016), the lowest scan time was recorded for high-pitch protocols (4.3 ± 1.0 s) and the highest for low-pitch protocols (43.6 ± 15.4 s). The combination of high helical pitch and short gantry rotation times produced the lowest perceived image quality (intraclass correlation coefficient 0.866; 95% confidence interval 0.807–0.910; p < 0.001) and highest noise. Raw data size increased with acquisition time (15.4 ± 5.0 to 235.0 ± 83.5 GByte; p ≤ 0.013). Rotation time and pitch factor have considerable influence on image quality in UHR-PCCT and must therefore be chosen deliberately for different musculoskeletal imaging tasks. In examinations with long acquisition times, raw data size increases considerably, consequently limiting clinical applicability for larger scan volumes. [ABSTRACT FROM AUTHOR]

Objective: To determine the value of CT-guided bone core biopsy and investigate factors that affect diagnostic yield and biopsy outcome. Materials and methods: The single-centre retrospective analysis included 447 patients who had CT-guided core biopsy with a 13-G needle (Bonopty®) from January 2016 to December 2021. Histological results or ≥ 6 months of clinical and radiological follow-up served as outcome references. A successful biopsy was classified as "diagnostic" when a definitive diagnosis was made and "adequate" when only the malignant or benign nature of the tumour could be determined. Biopsies were "nondiagnostic" when the nature of the lesion could not be determined. The occult lesions were defined as not seen on CT but visible on other modalities. Results: In 275 (62%) females and 172 (38%) males, the overall success rate was 85% (383 biopsies), with 314 (70%) diagnostic biopsies and 69 (15%) adequate biopsies. There was no relationship between biopsy success and the localisation of the lesion, length of biopsy material, or number of biopsy attempts. The lesions' nature had a statistically significant effect on biopsy success with lytic and mixed lesions having the highest success rate. Occult lesions had the lowest success rate. Conclusion: CT-guided bone core biopsy is an effective method in the workup of musculoskeletal diseases with the highest success rate in lytic and mixed lesions. No apparent relationship was found between biopsy success and biopsy length, number of attempts, or localisation of the lesion. [ABSTRACT FROM AUTHOR]

Objective: To compare the image quality of low-dose CT (LD-CT) with tin filtration of the lumbar spine after metal implants to standard clinical CT, and to evaluate the potential for metal artifact and dose reduction. Materials and methods: CT protocols were optimized in a cadaver torso. Seventy-four prospectively included patients with metallic lumbar implants were scanned with both standard CT (120 kV) and tin-filtered LD-CT (Sn140kV). CT dose parameters and qualitative measures (1 = worst,4 = best) were compared. Quantitative measures included noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and the width and attenuation of the most prominent hypodense metal artifact. Standard CT and LD-CT were assessed for imaging findings. Results: Tin-filtered LD-CT was performed with 60% dose saving compared to standard CT (median effective dose 3.22 mSv (quartile 1–3: 2.73–3.49 mSv) versus 8.02 mSv (6.42–9.27 mSv; p <.001). Image quality of CT and tin-filtered low-dose CT was good with excellent depiction of anatomy, while image noise was lower for CT and artifacts were weaker for tin-filtered LD-CT. Quantitative measures also revealed increased noise for tin-filtered low-dose CT (41.5HU), lower SNR (2) and CNR (0.6) compared to CT (32HU,3.55,1.03, respectively) (all p <.001). However, tin-filtered LD-CT performed superior regarding the width and attenuation of hypodense metal artifacts (2.9 mm and -767.5HU for LD-CT vs. 4.1 mm and -937HU for CT; all p <.001). No difference between methods was observed in detection of imaging findings. Conclusion: Tin-filtered LD-CT with 60% dose saving performs comparable to standard CT in detection of pathology and surgery related complications after lumbar spinal instrumentation, and shows superior metal artifact reduction. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate and analyze radiomics models based on non-contrast-enhanced computed tomography (CT) and different phases of contrast-enhanced CT in predicting Ki-67 proliferation index (PI) among patients with pathologically confirmed gastrointestinal stromal tumors (GISTs). Methods: A total of 383 patients with pathologically proven GIST were divided into a training set (n = 218, vendor 1) and 2 validation sets (n = 96, vendor 2; n = 69, vendors 3–5). Radiomics features extracted from the most recent non-contrast-enhanced and three contrast-enhanced CT scan prior to pathological examination. Random forest models were trained for each phase to predict tumors with high Ki-67 proliferation index (Ki-67>10%) and were evaluated using the area under the receiver operating characteristic curve (AUC) and other metrics on the validation sets. Results: Out of 107 radiomics features extracted from each phase of CT images, four were selected for analysis. The model trained using the non-contrast-enhanced phase achieved an AUC of 0.792 in the training set and 0.822 and 0.711 in the two validation sets, similar to models trained on different contrast-enhanced phases (p > 0.05). Several relevant features, including NGTDM Busyness and tumor size, remained predictive in non-contrast-enhanced and different contrast-enhanced images. Conclusion: The results of this study indicate that a radiomics model based on non-contrast-enhanced CT matches that of models based on different phases of contrast-enhanced CT in predicting the Ki-67 PI of GIST. GIST may exhibit similar radiological patterns irrespective of the use of contrast agent, and such radiomics features may help quantify these patterns to predict Ki-67 PI of GISTs. Clinical relevance statement: GIST may exhibit similar radiomics patterns irrespective of contrast agent; thus, radiomics models based on non-contrast-enhanced CT could be an alternative for risk stratification in GIST patients with contraindication to contrast agent. Key Points: • Performance of radiomics models in predicting Ki-67 proliferation based on different CT phases is evaluated. • Non-contrast-enhanced CT–based radiomics models performed similarly to contrast-enhanced CT in risk stratification in GIST patients. • NGTDM Busyness remains stable to contrast agents in GISTs in radiomics models. [ABSTRACT FROM AUTHOR]

Objectives: There is a need for CT pulmonary angiography (CTPA) lung segmentation models. Clinical translation requires radiological evaluation of model outputs, understanding of limitations, and identification of failure points. This multicentre study aims to develop an accurate CTPA lung segmentation model, with evaluation of outputs in two diverse patient cohorts with pulmonary hypertension (PH) and interstitial lung disease (ILD). Methods: This retrospective study develops an nnU-Net-based segmentation model using data from two specialist centres (UK and USA). Model was trained (n = 37), tested (n = 12), and clinically evaluated (n = 176) on a diverse 'real-world' cohort of 225 PH patients with volumetric CTPAs. Dice score coefficient (DSC) and normalised surface distance (NSD) were used for testing. Clinical evaluation of outputs was performed by two radiologists who assessed clinical significance of errors. External validation was performed on heterogenous contrast and non-contrast scans from 28 ILD patients. Results: A total of 225 PH and 28 ILD patients with diverse demographic and clinical characteristics were evaluated. Mean accuracy, DSC, and NSD scores were 0.998 (95% CI 0.9976, 0.9989), 0.990 (0.9840, 0.9962), and 0.983 (0.9686, 0.9972) respectively. There were no segmentation failures. On radiological review, 82% and 71% of internal and external cases respectively had no errors. Eighteen percent and 25% respectively had clinically insignificant errors. Peripheral atelectasis and consolidation were common causes for suboptimal segmentation. One external case (0.5%) with patulous oesophagus had a clinically significant error. Conclusion: State-of-the-art CTPA lung segmentation model provides accurate outputs with minimal clinical errors on evaluation across two diverse cohorts with PH and ILD. Clinical relevance: Clinical translation of artificial intelligence models requires radiological review and understanding of model limitations. This study develops an externally validated state-of-the-art model with robust radiological review. Intended clinical use is in techniques such as lung volume or parenchymal disease quantification. Key Points: • Accurate, externally validated CT pulmonary angiography (CTPA) lung segmentation model tested in two large heterogeneous clinical cohorts (pulmonary hypertension and interstitial lung disease). • No segmentation failures and robust review of model outputs by radiologists found 1 (0.5%) clinically significant segmentation error. • Intended clinical use of this model is a necessary step in techniques such as lung volume, parenchymal disease quantification, or pulmonary vessel analysis. [ABSTRACT FROM AUTHOR]