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Background: We evaluated the role of dual-energy computed tomography (DECT)-based collagen maps in assessing thoracic disc degeneration., Methods: We performed a retrospective analysis of patients who underwent DECT and magnetic resonance imaging (MRI) of the thoracic spine within a 2-week period from July 2019 to October 2022. Thoracic disc degeneration was classified by three blinded radiologists into three Pfirrmann categories: no/mild (grade 1-2), moderate (grade 3-4), and severe (grade 5). The DECT performance was determined using MRI as a reference standard. Interreader reliability was assessed using intraclass correlation coefficient (ICC). Five-point Likert scales were used to assess diagnostic confidence and image quality., Results: In total, 612 intervertebral discs across 51 patients aged 68 ± 16 years (mean ± standard deviation), 28 males and 23 females, were assessed. MRI revealed 135 no/mildly degenerated discs (22.1%), 470 moderately degenerated discs (76.8%), and 7 severely degenerated discs (1.1%). DECT collagen maps achieved an overall accuracy of 1,483/1,838 (80.8%) for thoracic disc degeneration. Overall recall (sensitivity) was 331/405 (81.7%) for detecting no/mild degeneration, 1,134/1,410 (80.4%) for moderate degeneration, and 18/21 (85.7%) for severe degeneration. Interrater agreement was good (ICC = 0.89). Assessment of DECT-based collagen maps demonstrated high diagnostic confidence (median 4; interquartile range 3-4) and good image quality (median 4; interquartile range 4-4)., Conclusion: DECT showed an overall 81% accuracy for disc degeneration by visualizing differences in the collagen content of thoracic discs., Relevance Statement: Utilizing DECT-based collagen maps to distinguish various stages of thoracic disc degeneration could be clinically relevant for early detection of disc-related conditions. This approach may be particularly beneficial when MRI is contraindicated., Key Points: A total of 612 intervertebral discs across 51 patients were retrospectively assessed with DECT, using MRI as a reference standard. DECT-based collagen maps allowed thoracic disc degeneration assessment achieving an overall 81% accuracy with good interrater agreement (ICC = 0.89). DECT-based collagen maps could be a good alternative in the case of contraindications to MRI., (© 2024. The Author(s).)

Background: Magnetic resonance elastography (MRE) can quantify tissue biomechanics noninvasively, including pathological hepatic states like metabolic dysfunction-associated steatohepatitis., Purpose: To compare the performance of 2D/3D-MRE using the gravitational (GT) transducer concept with the current commercial acoustic (AC) solution utilizing a 2D-MRE approach. Additionally, quality index markers (QIs) were proposed to identify image pixels with sufficient quality for reliably estimating tissue biomechanics., Study Type: Prospective., Population: One hundred seventy participants with suspected or confirmed liver disease (median age, 57 years [interquartile range (IQR), 46-65]; 66 females), and 11 healthy volunteers (median age, 31 years [IQR, 27-34]; 5 females)., Field Strength/sequence: Participants were scanned twice at 1.5 T and 60 Hz vibration frequency: first, using AC-MRE (2D-MRE, spin-echo EPI sequence, 11 seconds breath-hold), and second, using GT-MRE (2D- and 3D-MRE, gradient-echo sequence, 14 seconds breath-hold)., Assessment: Image analysis was performed by four independent radiologists and one biomedical engineer. Additionally, superimposed analytic plane shear waves of known wavelength and attenuation at fixed shear modulus were used to propose pertinent QIs., Statistical Tests: Spearman's correlation coefficient (r) was applied to assess the correlation between modalities. Interreader reproducibility was evaluated using Bland-Altman bias and reproducibility coefficients. P-values <0.05 were considered statistically significant., Results: Liver stiffness quantified via GT-2D/3D correlated well with AC-2D (r ≥ 0.89 [95% CI: 0.85-0.92]) and histopathological grading (r ≥ 0.84 [95% CI: 0.72-0.91]), demonstrating excellent agreement in Bland-Altman plots and between readers (κ ≥ 0.86 [95% CI: 0.81-0.91]). However, GT-2D showed a bias in overestimating stiffness compared to GT-3D. Proposed QIs enabled the identification of pixels deviating beyond 10% from true stiffness based on a combination of total wave amplitude, temporal sinusoidal nonlinearity, and wave signal-to-noise ratio for GT-3D., Conclusion: GT-MRE represents an alternative to AC-MRE for noninvasive liver tissue characterization. Both GT-2D and 3D approaches correlated strongly with the established commercial approach, offering advanced capabilities in abdominal imaging compared to AC-MRE., Evidence Level: 1 TECHNICAL EFFICACY: Stage 2., (© 2024 The Author(s). Journal of Magnetic Resonance Imaging published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Rationale and Objectives: To investigate the diagnostic value of radiomics features and dual-source dual-energy CT (DECT) based material decomposition in differentiating low-risk thymomas, high-risk thymomas, and thymic carcinomas., Materials and Methods: This retrospective study included 32 patients (16 males, mean age 66 ± 14 years) with pathologically confirmed thymic masses who underwent contrast-enhanced DECT between 10/2014 and 01/2023. Two experienced readers evaluated all patients regarding conventional radiomics features, as well as DECT-based features, including attenuation (HU), iodine density (mg/mL), and fat fraction (%). Data comparisons were performed using analysis of variance and chi-square statistic tests. Receiver operating characteristic curve analysis and Cox-regression tests were used to discriminate between low-risk/high-risk thymomas and thymic carcinomas., Results: Of the 32 thymic tumors, 12 (38%) were low-risk thymomas, 11 (34%) were high-risk thymomas, and 9 (28%) were thymic carcinomas. Values differed significantly between low-risk thymoma, high-risk thymoma, and thymic carcinoma regarding DECT-based features (p ≤ 0.023) and 30 radiomics features (p ≤ 0.037). The area under the curve to differentiate between low-risk/high-risk thymomas and thymic cancer was 0.998 (95% CI, 0.915-1.000; p < 0.001) for the combination of DECT imaging parameters and radiomics features, yielding a sensitivity of 100% and specificity of 96%. During a follow-up of 60 months (IQR, 35-60 months), the multiparametric approach including radiomics features, DECT parameters, and clinical parameters showed an excellent prognostic power to predict all-cause mortality (c-index = 0.978 [95% CI, 0.958-0.998], p = 0.003)., Conclusion: A multiparametric approach including conventional radiomics features and DECT-based features facilitates accurate, non-invasive discrimination between low-risk/high-risk thymomas and thymic carcinomas., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ibrahim Yel reports a relationship with Siemens that includes: speaking and lecture fees. Christian Booz reports a relationship with Siemens that includes: speaking and lecture fees., (Copyright © 2023 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Background: To investigate the potential of radiomic features and dual-source dual-energy CT (DECT) parameters in differentiating between benign and malignant mediastinal masses and predicting patient outcomes., Methods: In this retrospective study, we analysed data from 90 patients (38 females, mean age 51 ± 25 years) with confirmed mediastinal masses who underwent contrast-enhanced DECT. Attenuation, radiomic features and DECT-derived imaging parameters were evaluated by two experienced readers. We performed analysis of variance (ANOVA) and Chi-square statistic tests for data comparison. Receiver operating characteristic curve analysis and Cox regression tests were used to differentiate between mediastinal masses., Results: Of the 90 mediastinal masses, 49 (54%) were benign, including cases of thymic hyperplasia/thymic rebound (n = 10), mediastinitis (n = 16) and thymoma (n = 23). The remaining 41 (46%) lesions were classified as malignant, consisting of lymphoma (n = 28), mediastinal tumour (n = 4) and thymic carcinoma (n = 9). Significant differences were observed between benign and malignant mediastinal masses in all DECT-derived parameters (p ≤ .001) and 38 radiomic features (p ≤ .044) obtained from contrast-enhanced DECT. The combination of these methods achieved an area under the curve of .98 (95% CI, .893-1.000; p < .001) to differentiate between benign and malignant masses, with 100% sensitivity and 91% specificity. Throughout a follow-up of 1800 days, a multiparametric model incorporating radiomic features, DECT parameters and gender showed promising prognostic power in predicting all-cause mortality (c-index = .8 [95% CI, .702-.890], p < .001)., Conclusions: A multiparametric approach combining radiomic features and DECT-derived imaging biomarkers allows for accurate and noninvasive differentiation between benign and malignant masses in the anterior mediastinum., (© 2023 The Authors. European Journal of Clinical Investigation published by John Wiley & Sons Ltd on behalf of Stichting European Society for Clinical Investigation Journal Foundation.)

Background: Cancer is a well-known risk factor for venous thromboembolism (VTE). A combined strategy of D-dimer testing and clinical pre-test probability is usually used to exclude VTE. However, its effectiveness is diminished in cancer patients due to reduced specificity, ultimately leading to a decreased clinical utility. This review article seeks to provide a comprehensive summary of how to interpret D-dimer testing in cancer patients., Methods: In accordance with PRISMA standards, literature pertaining to the diagnostic and prognostic significance of D-dimer testing in cancer patients was carefully chosen from reputable sources such as PubMed and the Cochrane databases., Results: D-dimers have not only a diagnostic value in ruling out VTE but can also serve as an aid for rule-in if their values exceed 10-times the upper limit of normal. This threshold allows a diagnosis of VTE in cancer patients with a positive predictive value of more than 80%. Moreover, elevated D-dimers carry important prognostic information and are associated with VTE reoccurrence. A gradual increase in risk for all-cause death suggests that VTE is also an indicator of biologically more aggressive cancer types and advanced cancer stages. Considering the lack of standardization for D-dimer assays, it is essential for clinicians to carefully consider the variations in assay performance and the specific test characteristics of their institution., Conclusions: Standardizing D-dimer assays and developing modified pretest probability models specifically for cancer patients, along with adjusted cut-off values for D-dimer testing, could significantly enhance the accuracy and effectiveness of VTE diagnosis in this population., (© 2023 The Authors. European Journal of Clinical Investigation published by John Wiley & Sons Ltd on behalf of Stichting European Society for Clinical Investigation Journal Foundation.)

Background: The advent of next-generation computed tomography (CT)- and magnetic resonance imaging (MRI) opened many new perspectives in the evaluation of tumor characteristics. An increasing body of evidence suggests the incorporation of quantitative imaging biomarkers into clinical decision-making to provide mineable tissue information. The present study sought to evaluate the diagnostic and predictive value of a multiparametric approach involving radiomics texture analysis, dual-energy CT-derived iodine concentration (DECT-IC), and diffusion-weighted MRI (DWI) in participants with histologically proven pancreatic cancer., Methods: In this study, a total of 143 participants (63 years ± 13, 48 females) who underwent third-generation dual-source DECT and DWI between November 2014 and October 2022 were included. Among these, 83 received a final diagnosis of pancreatic cancer, 20 had pancreatitis, and 40 had no evidence of pancreatic pathologies. Data comparisons were performed using chi-square statistic tests, one-way ANOVA, or two-tailed Student's t-test. For the assessment of the association of texture features with overall survival, receiver operating characteristics analysis and Cox regression tests were used., Results: Malignant pancreatic tissue differed significantly from normal or inflamed tissue regarding radiomics features (overall P < .001, respectively) and iodine uptake (overall P < .001, respectively). The performance for the distinction of malignant from normal or inflamed pancreatic tissue ranged between an AUC of ≥ 0.995 (95% CI, 0.955-1.0; P < .001) for radiomics features, ≥ 0.852 (95% CI, 0.767-0.914; P < .001) for DECT-IC, and ≥ 0.690 (95% CI, 0.587-0.780; P = .01) for DWI, respectively. During a follow-up of 14 ± 12 months (range, 10-44 months), the multiparametric approach showed a moderate prognostic power to predict all-cause mortality (c-index = 0.778 [95% CI, 0.697-0.864], P = .01)., Conclusions: Our reported multiparametric approach allowed for accurate discrimination of pancreatic cancer and revealed great potential to provide independent prognostic information on all-cause mortality., (© 2023. The Author(s).)

Whole-body magnetic resonance imaging (MRI) has become increasingly popular in oncology. However, the long acquisition time might hamper its widespread application. We sought to assess and compare free-breathing sequences with conventional breath-hold examinations in whole-body MRI using an automated workflow process. This prospective study consisted of 20 volunteers and six patients with a variety of pathologies who had undergone whole-body 1.5-T MRI that included T1-weighted radial and Dixon volumetric interpolated breath-hold examination sequences. Free-breathing sequences were operated by using an automated user interface. Image quality, diagnostic confidence, and image noise were evaluated by two experienced radiologists. Additionally, signal-to-noise ratio was measured. Diagnostic performance for the overall detection of pathologies was assessed using the area under the receiver operating characteristics curve (AUC). Study participants were asked to rate their examination experiences in a satisfaction survey. MR free-breathing scans were rated as at least equivalent to conventional MR scans in more than 92% of cases, showing high overall diagnostic accuracy (95% [95% CI 92-100]) and performance (AUC 0.971, 95% CI 0.942-0.988; p < 0.0001) for the assessment of pathologies at simultaneously reduced examination times (25 ± 2 vs. 32 ± 3 min; p < 0.0001). Interrater agreement was excellent for both free-breathing (ϰ = 0.96 [95% CI 0.88-1.00]) and conventional scans (ϰ = 0.93 [95% CI 0.84-1.00]). Qualitative and quantitative assessment for image quality, image noise, and diagnostic confidence did not differ between the two types of MR image acquisition (all p > 0.05). Scores for patient satisfaction were significantly better for free-breathing compared with breath-hold examinations (p = 0.0145), including significant correlations for the grade of noise (r = 0.79, p < 0.0001), tightness (r = 0.71, p < 0.0001), and physical fatigue (r = 0.52, p = 0.0065). In summary, free-breathing whole-body MRI in tandem with an automated user interface yielded similar diagnostic performance at equivalent image quality and shorter acquisition times compared to conventional breath-hold sequences., (© 2022 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.)

Purpose: To assess and correlate pulmonary involvement and outcome of SARS-CoV-2 pneumonia with the degree of coronary plaque burden based on the CAC-DRS classification (Coronary Artery Calcium Data and Reporting System)., Methods: This retrospective study included 142 patients with confirmed SARS-CoV-2 pneumonia (58 ± 16 years; 57 women) who underwent non-contrast CT between January 2020 and August 2021 and were followed up for 129 ± 72 days. One experienced blinded radiologist analyzed CT series for the presence and extent of calcified plaque burden according to the visual and quantitative HU-based CAC-DRS Score. Pulmonary involvement was automatically evaluated with a dedicated software prototype by another two experienced radiologists and expressed as Opacity Score., Results: CAC-DRS Scores derived from visual and quantitative image evaluation correlated well with the Opacity Score (r=0.81, 95% CI 0.76-0.86, and r=0.83, 95% CI 0.77-0.89, respectively; p<0.0001) with higher correlation in severe than in mild stage SARS-CoV-2 pneumonia (p<0.0001). Combined, CAC-DRS and Opacity Scores revealed great potential to discriminate fatal outcomes from a mild course of disease (AUC 0.938, 95% CI 0.89-0.97), and the need for intensive care treatment (AUC 0.801, 95% CI 0.77-0.83). Visual and quantitative CAC-DRS Scores provided independent prognostic information on all-cause mortality (p=0.0016 and p<0.0001, respectively), both in univariate and multivariate analysis., Conclusions: Coronary plaque burden is strongly correlated to pulmonary involvement, adverse outcome, and death due to respiratory failure in patients with SARS-CoV-2 pneumonia, offering great potential to identify individuals at high risk., (Copyright © 2022 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the influence of intravenously injected contrast agent on bone mineral density (BMD) assessment in dual-source dual-energy CT., Methods: This retrospective study included 1,031 patients (mean age, 53 ± 7 years; 519 women) who had undergone third-generation dual-source dual-energy CT in context of tumor staging between January 2019 and December 2019. Dedicated postprocessing software based on material decomposition was used for phantomless volumetric BMD assessment of trabecular bone of the lumbar spine. Volumetric trabecular BMD values derived from unenhanced and contrast-enhanced portal venous phase were compared by calculating correlation and agreement analyses using Pearson product-moment correlation, linear regression, and Bland-Altman plots., Results: Mean BMD values were 115.53 ± 37.23 and 116.10 ± 37.78 mg/cm 3 in unenhanced and contrast-enhanced dual-energy CT series, respectively. Values from contrast-enhanced portal venous phase differed not significantly from those of the unenhanced phase (p = 0.44) and showed high correlation (r = 0.971 [95% CI, 0.969-0.973]) with excellent agreement in Bland-Altman plots. Mean difference of the two phases was 0.61 mg/cm 3 (95% limits of agreement, -17.14 and 18.36 mg/cm 3 )., Conclusion: Portal venous phase dual-source dual-energy CT allows for accurate opportunistic BMD assessment of trabecular bone of the lumbar spine compared to unenhanced imaging. Therefore, dual-source CT may provide greater flexibility regarding BMD assessment in clinical routine and reduce radiation exposure by avoiding additional osteodensitometry examinations, as contrast-enhanced CT scans in context of tumor staging are increasingly performed in dual-energy mode., (Copyright © 2021 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Objectives: To investigate the diagnostic accuracy of color-coded contrast-enhanced dual-energy CT virtual noncalcium (VNCa) reconstructions for the assessment of lumbar disk herniation compared to unenhanced VNCa imaging., Methods: A total of 91 patients were retrospectively evaluated (65 years ± 16; 43 women) who had undergone third-generation dual-source dual-energy CT and 3.0-T MRI within an examination interval up to 3 weeks between November 2019 and December 2020. Eight weeks after assessing unenhanced color-coded VNCa reconstructions for the presence and degree of lumbar disk herniation, corresponding contrast-enhanced portal venous phase color-coded VNCa reconstructions were independently analyzed by the same five radiologists. MRI series were additionally analyzed by one highly experienced musculoskeletal radiologist and served as reference standard., Results: MRI depicted 210 herniated lumbar disks in 91 patients. VNCa reconstructions derived from contrast-enhanced CT scans showed similar high overall sensitivity (93% vs 95%), specificity (94% vs 95%), and accuracy (94% vs 95%) for the assessment of lumbar disk herniation compared to unenhanced VNCa images (all p > .05). Interrater agreement in VNCa imaging was excellent for both, unenhanced and contrast-enhanced CT (κ = 0.84 vs κ = 0.86; p > .05). Moreover, ratings for diagnostic confidence, image quality, and noise differed not significantly between unenhanced and contrast-enhanced VNCa series (all p > .05)., Conclusions: Color-coded VNCa reconstructions derived from contrast-enhanced dual-energy CT yield similar diagnostic accuracy for the depiction of lumbar disk herniation compared to unenhanced VNCa imaging and therefore may improve opportunistic retrospective lumbar disk herniation assessment, particularly in case of staging CT examinations., Key Points: • Color-coded dual-source dual-energy CT virtual noncalcium (VNCa) reconstructions derived from portal venous phase yield similar high diagnostic accuracy for the assessment of lumbar disk herniation compared to unenhanced VNCa CT series (94% vs 95%) with MRI serving as a standard of reference. • Diagnostic confidence, image quality, and noise levels differ not significantly between unenhanced and contrast-enhanced portal venous phase VNCa dual-energy CT series. • Dual-source dual-energy CT might have the potential to improve opportunistic retrospective lumbar disk herniation assessment in CT examinations performed for other indications through reconstruction of VNCa images., (© 2021. The Author(s).)

Background: Dual-source dual-energy computed tomography (DECT) offers the potential for opportunistic osteoporosis screening by enabling phantomless bone mineral density (BMD) quantification. This study sought to assess the accuracy and precision of volumetric BMD measurement using dual-source DECT in comparison to quantitative CT (QCT)., Methods: A validated spine phantom consisting of three lumbar vertebra equivalents with 50 (L1), 100 (L2), and 200 mg/cm 3 (L3) calcium hydroxyapatite (HA) concentrations was scanned employing third-generation dual-source DECT and QCT. While BMD assessment based on QCT required an additional standardised bone density calibration phantom, the DECT technique operated by using a dedicated postprocessing software based on material decomposition without requiring calibration phantoms. Accuracy and precision of both modalities were compared by calculating measurement errors. In addition, correlation and agreement analyses were performed using Pearson correlation, linear regression, and Bland-Altman plots., Results: DECT-derived BMD values differed significantly from those obtained by QCT (p < 0.001) and were found to be closer to true HA concentrations. Relative measurement errors were significantly smaller for DECT in comparison to QCT (L1, 0.94% versus 9.68%; L2, 0.28% versus 5.74%; L3, 0.24% versus 3.67%, respectively). DECT demonstrated better BMD measurement repeatability compared to QCT (coefficient of variance < 4.29% for DECT, < 6.74% for QCT). Both methods correlated well to each other (r = 0.9993; 95% confidence interval 0.9984-0.9997; p < 0.001) and revealed substantial agreement in Bland-Altman plots., Conclusions: Phantomless dual-source DECT-based BMD assessment of lumbar vertebra equivalents using material decomposition showed higher diagnostic accuracy compared to QCT., (© 2021. The Author(s).)

Rationale and Objectives: To compare dual-energy CT virtual monoenergetic images (VMI) and standard reconstructions for reliability of quantitative size measurements and diagnostic accuracy for the detection of colorectal liver metastases (CRLM)., Materials and Methods: We retrospectively included 98 patients (mean age, 61.1±11.5 years) with colorectal cancer, of whom 49 subjects had CRLM. All patients underwent a portal-venous phase dual-energy CT examination. Standard linearly-blended reformats and 40-keV VMI were reconstructed. For both reconstruction techniques, two blinded readers performed measurements of CRLM twice in a preset sequence. Three additional radiologists independently assessed all liver lesions in terms of dignity (benign vs. malignant). Sensitivity, specificity and diagnostic accuracy were calculated on a per-patient basis using MRI as reference standard. Readers scored the suitability for metric measurements and their diagnostic confidence using 5-point Likert scales. Inter-rater agreement was evaluated using intraclass correlation coefficient (ICC)., Results: Inter-rater agreement for lesion size measurements was higher for 40-keV VMI (ICC, 0.88) compared to standard linearly-blended series (ICC, 0.80). Sensitivity and diagnostic accuracy for the detection of CRLM were significantly higher for VMI at 40-keV compared to standard reconstructions (90.6% vs. 80.6%, and 89.1% vs. 81.3%; p < 0.001). Reader scores indicated that 40-keV VMI were more suitable for metric lesion measurements and provided greater diagnostic confidence compared to standard reformats (median, 5 vs. 3, and 5 vs. 4; both p < 0.001)., Conclusion: Low-keV VMI reconstructions improve reliability of quantitative size measurements and diagnostic accuracy for the assessment of CRLM compared to standard linearly-blended images., (Copyright © 2019. Published by Elsevier Inc.)

Purpose: To examine predictive value of apparent diffusion coefficient (ADC) in diffusion-weighted imaging (DWI) for response of patients with primary and secondary lung neoplasms undergoing transpulmonary chemoembolization (TPCE) and transarterial chemoperfusion (TACP) treatment., Materials and Methods: Thirty-one patients (mean age ± SD 64 ± 12.4 y) with 42 lung target lesions (13 primary and 29 secondary) underwent DWI and subsequent ADC analysis on a 1.5T MR imaging scanner before and 30.3 days ± 6.4 after first session of TPCE or TACP. After 3.1 treatment sessions ± 1.4 performed in 2- to 4-week intervals, morphologic response was analyzed by comparing tumor diameter and volume before and after treatment on unenhanced T1-weighted MR images. On a per-lesion basis, response was classified according to Response Evaluation Criteria In Solid Tumors., Results: Threshold ADC increase of 20.7% indicated volume response with 88% sensitivity and 78% specificity (area under the curve [AUC] = 0.84). Differences between ADC changes in volume response groups were significant (P = .002). AUC for volume response predicted by ADC before treatment was 0.77. Median ADC before treatment and mean ADC change were 1.09 × 10 -3 mm 2 /second and 0.36 × 10 -3 mm 2 /second ± 0.23, 1.45 × 10 -3 mm 2 /second and 0.14 × 10 -3 mm 2 /second ± 0.16, and 1.30 × 10 -3 mm 2 /second and 0.06 × 10 -3 mm 2 /second ± 0.19 in partial response, stable disease, and progressive disease groups. In primary lung cancer lesions, strong negative correlation of ADC change with change in diameter (ρ = -.87, P < .001) and volume (ρ = -.66, P = .016) was found. In metastases, respective correlation coefficients were ρ = -.18 (P = .356) and ρ = -.35 (P = .061)., Conclusions: ADC quantification shows considerable diagnostic value for predicting response and monitoring TPCE and TACP treatment of patients with primary and secondary lung neoplasms., (Copyright © 2019 SIR. Published by Elsevier Inc. All rights reserved.)

Objectives: To evaluate the diagnostic value of Lipiodol distribution in angiography and CT to differentiate between hepatocellular carcinoma (HCC) and benign nodules of LI-RADS 3 and 4 lesions observed in MRI of liver cirrhosis., Methods: This retrospective study included all patients with liver cirrhosis who had diagnosis of LI-RADS 3 or 4 lesions by MRI who underwent a Lipiodol-based angiography and post-interventional unenhanced CT- and liver biopsy. Two independent radiologists evaluated appearance, contrast enhancement, Lipiodol uptake in angiography, and morphological parameters (size, form, and density) of the lesions in unenhanced post-angiography CT. α-Fetoprotein (AFP) levels and pre-existing liver conditions were additionally taken into consideration. Differences between HCC lesions and benign nodules were analyzed. Sensitivity and specificity were calculated. P < 0.05 was considered as statistically significant., Results: Of 60 patients (men, n = 42 [70.0%]; women, 18 [30.0%]; mean age, 61 ± 9.1 years) 36 (60.0%) had HCC and 24 (40.0%) benign nodules. Clear visibility in angiography (sensitivity [se], 100%; specificity [sp], 87.5%) with homogeneous or lacunar Lipiodol enhancement (se, 86.1%; sp, 100%) in consecutive CT can be diagnosed as HCC lesions in cirrhotic liver. Lesion form (p < 0.001), round or oval, and intense contrast (p < 0.001) are minor features which can facilitate the findings. Furthermore, patients with HCC showed a larger lesion size in CT (p = 0.026)., Conclusion: Clearly detectable lesions in Lipiodol-based angiography and a homogeneous or lacunar enhancement in post-angiographic non-contrast CT allow for differentiation of intrahepatic lesions classified as LI-RADS 3 or 4 into benign vs. malign liver lesions with high sensitivity and specificity in patients with liver cirrhosis. Definite diagnosis may not require an additional biopsy., Key Points: • Combination of clear visibility in Lipiodol-based angiography and homogeneous or lacunar enhancement in following native CT scan is HCC-defining. • In lesions classified with MRI as LI-RADS 3 or 4, evaluation based on Lipiodol angiography and following plain CT performed is highly sensitive and specific for the differentiation between HCC and benign nodules in a cirrhotic liver. • The results lead to an alternative pathway in the diagnosis of HCC in cirrhotic liver without the need of an additional liver biopsy.

Purpose:  The aim of the study was to evaluate high-pitch 70-kV CT examinations of the thorax in immunosuppressed patients regarding radiation dose and image quality in comparison with 120-kV acquisition., Materials and Methods:  The image data from 40 patients (14 women and 26 men; mean age: 40.9 ± 15.4 years) who received high-pitch 70-kV CT chest examinations were retrospectively included in this study. A control group (n = 40), matched by age, gender, BMI, and clinical inclusion criteria, had undergone standard 120-kV chest CT imaging. All CT scans were performed on a third-generation dual-source CT unit. For an evaluation of the radiation dose, the CT dose index (CTDIvol), dose-length product (DLP), effective dose (ED), and size-specific dose estimates (SSDE) were analyzed in each group. The objective image quality was evaluated using signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Three blinded and independent radiologists evaluated subjective image quality and diagnostic confidence using 5-point Likert scales., Results:  The mean dose parameters were significantly lower for high-pitch 70-kV CT examinations (CTDIvol, 2.9 ± 0.9 mGy; DLP, 99.9 ± 31.0 mGyxcm; ED, 1.5 ± 0.6 mSv; SSDE, 3.8 ± 1.2 mGy) compared to standard 120-kV CT imaging (CTDIvol, 8.8 ± 3.7mGy; DLP, 296.6 ± 119.3 mGyxcm; ED, 4.4 ± 2.1 mSv; SSDE, 11.6 ± 4.4 mGy) (P≤ 0.001). The objective image parameters (SNR: 7.8 ± 2.1 vs. 8.4 ± 1.8; CNR: 7.7 ± 2.4 vs. 8.3 ± 2.8) (P≥ 0.065) and the cumulative subjective image quality (4.5 ± 0.4 vs. 4.7 ± 0.3) (p = 0.052) showed no significant differences between the two protocols., Conclusion:  High-pitch 70-kV thoracic CT examinations in immunosuppressed patients resulted in a significantly reduced radiation exposure compared to standard 120-kV CT acquisition without a decrease in image quality., Key Points:   · Third-generation dual-source CT units enable high-pitch 70-kV CT examinations of the chest.. · High-pitch 70-kV CT examinations show a significantly reduced radiation dose compared to standard 120-kV CT examinations.. · High-pitch 70-kV CT examinations of the chest show comparable objective and subjective image quality.. · Subjectively deteriorated image noise and sharpness of 70-kV CT did not impact diagnostic confidence.., Citation Format: · Yel I, Martin SS, Wichmann JL et al. Evaluation of Radiation Dose and Image Quality using High-Pitch 70-kV Chest CT in Immunosuppressed Patients . Fortschr Röntgenstr 2019; 191: 122 - 129., Competing Interests: Moritz H. Albrecht hat Referentenhonorare von Siemens erhalten.Julian L. Wichmann hat Referentenhonorare von Siemens und General Electric erhalten., (© Georg Thieme Verlag KG Stuttgart · New York.)

Purpose:  This study was carried out to investigate the impact of abdominal dynamic four-dimensional CT angiography (4D-CTA) for guiding transarterial chemoembolization (TACE) on the amount of contrast material used, operator radiation exposure, catheter consumption, and diagnostic confidence., Materials and Methods:  Written consent was waived for this IRB-approved retrospective study. 29 patients (20 men; mean age: 65.7 ± 11.5 years) with malignant liver lesions underwent 4D-CTA, prior to initial TACE. Time-resolved volume-rendering technique (VRT), maximum-intensity projection (MIP), and multiplanar reconstruction (MPR) series were reconstructed, enabling a direct selective catheterization of the tumor-supplying artery without prior conventional digital subtraction angiography (DSA). 29 patients (16 men; mean age: 69.4 ± 13.9) who underwent traditional TACE served as the control group. The amount of administered contrast media, operator radiation exposure, and catheter consumption during TACE were compared. Two radiologists assessed diagnostic confidence in the exclusion of portal vein thrombosis., Results:  4D-CTA TACE resulted in a significant reduction in the amount of contrast media used, compared to traditional TACE (-61.0 ml/ -66.3 % intra-arterial, -12.8 ml/ -13.8 % overall; P < 0.001). The dose-area product indicating operator radiation exposure during intervention was reduced by 50.5 % (P < 0.001), and 0.7 fewer catheters on average were used (P = 0.063), while 4D-CTA data was available to guide TACE. Diagnostic confidence in the exclusion of portal vein thrombosis was significantly enhanced by 4D-CTA, compared to traditional DSA images (scores, 3.9 and 2.4, respectively; P < 0.001)., Conclusion:  Dynamic 4D-CTA enables TACE with a substantially reduced amount of contrast material, decreases operator radiation exposure, and increases diagnostic confidence in the exclusion of portal vein thrombosis., Key Points:   · 4D-CTA prior to TACE decreases the amount of utilized contrast material.. · The intra-arterial fraction of contrast media can be reduced by two-thirds.. · The risk of CIN may be decreased by means of 4D-CTA TACE.. · Operator radiation exposure is lower using 4D-CTA for guiding TACE.. · 4D-CTA portography allows for a higher diagnostic confidence than conventional DSA images.., Citation Format: · Albrecht MH, Vogl TJ, Wichmann JL et al. Dynamic 4D-CT Angiography for Guiding Transarterial Chemoembolization: Impact on the Reduction of Contrast Material, Operator Radiation Exposure, Catheter Consumption, and Diagnostic Confidence. Fortschr Röntgenstr 2018; 190: 513 - 520., Competing Interests: 'Moritz H. Albrecht received a speaker fee from Siemens. Julian L. Wichmann received speaker fees from Siemens and General Electric. Ralf W. Bauer received speaker fees from and was a consultant for Siemens.', (© Georg Thieme Verlag KG Stuttgart · New York.)

Purpose:  To assess the interrater agreement and reliability of experienced abdominal radiologists in the characterization and grading of arterial phase gadoxetate disodium-related respiratory motion artifact on liver MRI., Materials and Methods:  This prospective multicenter study was initiated by the working group for abdominal imaging within the German Roentgen Society (DRG), and approved by the local IRB of each participating center. 11 board-certified radiologists independently reviewed 40 gadoxetate disodium-enhanced liver MRI datasets. Motion artifacts in the arterial phase were assessed on a 5-point scale. Interrater agreement and reliability were calculated using the intraclass correlation coefficient (ICC) and Kendall coefficient of concordance (W), with p < 0.05 deemed significant., Results:  The ICC for interrater agreement and reliability were 0.983 (CI 0.973 - 0.990) and 0.985 (CI 0.978 - 0.991), respectively (both p < 0.0001), indicating excellent agreement and reliability. Kendall's W for interrater agreement was 0.865. A severe motion artifact, defined as a mean motion score ≥ 4 in the arterial phase was observed in 12 patients. In these specific cases, a motion score ≥ 4 was assigned by all readers in 75 % (n = 9/12 cases)., Conclusion:  Differentiation and grading of arterial phase respiratory motion artifact is possible with a high level of inter-/intrarater agreement and interrater reliability, which is crucial for assessing the incidence of this phenomenon in larger multicenter studies., Key Points:   · Inter- and intrarater agreement for motion artifact scoring is excellent among experienced readers.. · Interrater reliability for motion artifact scoring is excellent among experienced readers.. · Characterization of severe motion artifacts proved feasible in this multicenter study.., Citation Format: · Ringe KI, Luetkens JA, Fimmers R et al. Characterization of Severe Arterial Phase Respiratory Motion Artifact on Gadoxetate Disodium-Enhanced MRI - Assessment of Interrater Agreement and Reliability. Fortschr Röntgenstr 2017; 190: 341 - 347., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (© Georg Thieme Verlag KG Stuttgart · New York.)

Purpose  The locoregional interventional oncological treatment approach is an accepted modality for liver neoplasms, especially for hepatocellular carcinoma (HCC) and oligonodular liver metastases. Materials and Methods  The main aim of ablation therapies like microwave ablation (MWA) is to eradicate all malignant cells in a minimally invasive technique under imaging guidance while preserving the healthy tissue with a sufficient safety margin (at least 5 mm) surrounding the ablated lesion. Results  Ablation therapy can be performed via a percutaneous, laparoscopic or intraoperative approach under ultrasound, MRI or CT guidance for adequate localization and monitoring of the ablation process. Conclusion  Ablation is the method of choice for oligonodular HCCs ≤ 3 cm. The technical success rate varies from 88 % to 98 % and progression-free survival (PFS) at 3 years from 27 % to 91.7 %. The same criteria apply to the therapy of liver metastases. Key Points   · Careful selection of patients proves to be essential for optimum results of MWA. · Interventionists should be familiar with all aspects of complication and rapid assessment of imaging methods in order to evaluate induced damage by thermal ablation. · MWA seems to have some advantages over radiofrequency ablation, like shorter ablation time, less pain, less heat sink effect; however, scientific proof is needed. Citation Format · Vogl TJ, Nour-Eldin A, Hammerstingl RM et al. Microwave Ablation (MWA): Basics, Technique and Results in Primary and Metastatic Liver Neoplasms - Review Article. Fortschr Röntgenstr 2017; 189: 1055 - 1066., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (© Georg Thieme Verlag KG Stuttgart · New York.)

To present current data on diagnosis, indication and different therapy options in patients with cholangiocarcinoma (CC) based on an analysis of the current literature and clinical experience. The diagnostic routine includes laboratory investigations with parameters of cholestasis and also serum tumor markers CA19 - 9 and CEA. After ultrasound for clarifying a tumor and/or dilated bile ducts, contrast-enhanced magnetic resonance imaging (MRI) should be performed with magnetic resonance cholangiography (MRCP). The accuracy (positive predictive value) for diagnosing a CC is 37-84% (depending on the location) for ultrasound, 79-94% for computed tomography (CT), and 95% for MRI and MRCP. An endoscopic retrograde cholangiography (ERCP) can then be planned, especially if biliary drainage or cytological or histological specimen sampling is intended. A curative approach can be achieved by surgical resection, rarely by liver transplantation. However, many patients are not eligible for surgery. In addition to systemic chemotherapy, locoregional therapies such as transarterial chemoembolization (TACE), hepatic arterial infusion (HAI)--also known as chemoperfusion--, drug eluting beads-therapy (DEB) as well as thermoablative procedures, such as laser-induced thermotherapy (LITT), microwave ablation (MWA) and radiofrequency ablation (RFA) can be provided with a palliative intention., (© Georg Thieme Verlag KG Stuttgart · New York.)

Purpose: To asses if laser-induced thermotherapy (LITT) induces a specific cytotoxic T cell response in patients treated with LITT for colorectal cancer liver metastases., Methods: Eleven patients with liver metastases of colorectal cancer underwent LITT. Blood was sampled before and after LITT. Peripheral T cell activation was assessed by an interferon gamma (IFNg) secretion assay and flow cytometry. Test antigens were autologous liver and tumor lysate obtained from each patient by biopsy. T cells were stained for CD3/CD4/CD8 and IFNg to detect activated T cells. The ratio of IFNg positive to IFNg negative T cells was determined as the stimulation index (SI). To assess cytolytic activity, T cells were co-incubated with human colorectal cancer cells (CaCo) and cytosolic adenylate kinase release was measured by a luciferase assay., Results: IFNg secretion assay: before LITT SI was 12.73 (+/-4.83) for CD3+, 4.36 (+/-3.32) for CD4+ and 3.64 (+/-1.77) for CD8+ T cells against autologous tumor tissue. Four weeks after LITT SI had increased to 92.09 (+/-12.04) for CD3+ (P < 0.001), 42.92 (+/-16.68) for CD4+ (P < 0.001) and 47.54 (+/-15.68) for CD8+ T cells (P < 0.001) against autologous tumor tissue. No increased SI was observed with normal liver tissue at any time point. Cytotoxicity assay: before LITT activity against the respective cancer cells was low, with RLU = 1,493 (+/-1,954.68), whereas after LITT cytolytic activity had increased to RLU = 7,260 [+/-3,929.76 (P < 0.001)]., Conclusion: Patients with liver metastases of colorectal cancer show a tumor-specific cytotoxic T cell stimulation and a significantly increased cytolytic activity of CD3+, CD4+ and CD8+ T cells after LITT against an allogenic tumor (CaCo cell line).

Purpose: The purpose of this study was to evaluate the safety and clinical value of MR-guided biopsies in an open 0.2 T low-field system., Materials and Methods: A total of 322 patients with suspicious lesions of different body regions were biopsied in a low-field MRI system (0.2 T, Concerto, Siemens). The procedures were guided using T 1-weighted Flash sequences (TR/TE = 100/9; 70 degrees). The lesions were repeatedly biopsied using the coaxial technique with a 15-gauge (diameter 2 mm) puncture needle. Complications and biopsy findings were analyzed retrospectively., Results: In all cases the biopsy procedures were successfully performed with MR guidance. In 298 patients diagnosis was able to be confirmed on the basis of the probes. The clinical follow-up showed that in 24 patients the lesions were missed by MR-guided biopsy. From this a sensitivity of 86%, a specificity of 87% and an accuracy of 93% were calculated. In two patients major complications were observed (morbidity rate 0.6 %)., Conclusion: MR-guided biopsy can be performed safely and precisely in a low-field MR system and are a supplement to US or CT-guided biopsies.

Purpose: To evaluate the effect of preprocedural prediction of the best tube angle obliquity for visualization of the uterine artery origin by using three-dimensional (3D)-reconstructed contrast material-enhanced magnetic resonance (MR) angiography on the radiation dose, fluoroscopy time, and contrast medium volume during uterine artery embolization (UAE)., Materials and Methods: The study was approved by the institutional review board. Informed consent was obtained. The prospective study included 20 consecutive prospective patients (age range, 37-56 years) for whom preprocedural prediction of the best tube angle obliquity was determined by using 3D-reconstructed contrast-enhanced MR angiography; the best tube angle obliquity was provided to the interventionist. Three-dimensional reconstruction was performed by using an application of the angiographic unit. The radiation dose, fluoroscopy time, and contrast medium volume for those patients were compared with those data in 20 retrospectively assessed control patients (age range, 39-56 years) from the prior 20 procedures performed by the same interventionist., Results: Tube angle prediction resulted in a significant reduction in the radiation dose utilized (P < .001), fluoroscopy time (P = .002), and contrast medium volume (P < .001) for the sample patients compared with those for the control patients. Overall radiation dose was reduced from a mean of 11 044 microGy per square meter to a mean of 4172.5 microGy per square meter. Fluoroscopy time was reduced from a mean of 15 minutes 30 seconds to 8 minutes 49 seconds. Contrast medium volume was reduced from a mean of 135 mL to 75 mL., Conclusion: Preprocedural prediction of the best tube angle obliquity for visualization of the origin of the uterine artery by using 3D-reconstructed contrast-enhanced MR angiography results in significant reductions in radiation dose, fluoroscopy time, and contrast medium volume during UAE.

Purpose: The purpose of this study was to evaluate local transarterial chemoperfusion (TACP) in locally recurrent pancreatic carcinoma and advanced tumor stages which did not respond to prior systemic chemotherapy. The tumor response, survival, and pain response were retrospectively analyzed., Materials and Method: Forty outpatients (median age 62 years, range 36-79) were treated with a minimum of 3 (mean 6, range 3-12) applications per patient in four-week intervals. Twenty-eight patients were in advanced tumor stages, and 12 patients had locally recurrent tumors. Gemcitabine (1,000 mg/m(2)) and mitomycin C (8.5 mg/m(2)) were administered within 1 hour through a celiac trunk catheter. The tumor response (diameter, volume) was measured using MRI or CT and classified according to RECIST. The pain response was defined as a reduction of pain intensity of more than 50% on a visual analog scale, or a reduction of more than 50% in analgesics consumption, or a switch to a less potent analgesic agent., Results: The treatment was tolerated well by all patients. No clinically relevant problems or grade III or IV toxicity according to CTC (Common Toxicity Criteria) were observed. Tumor-related pain was relieved in 20/32 (62.5%) cases. Radiologically, "complete response" was found in 3/40 (7.5%), "partial response" in 9/40 (22.5%), "stable disease" in 16/40 (40%), and "progressive disease" in 12/40 (30%) of the patients. The median survival period since initial diagnosis and first TACP was 16.4 months and 8.1 months, respectively. Locally recurrent tumors showed better, but still not significant results regarding tumor response (41.7% vs. 25%) as well as survival (14.4 vs. 7 months) compared to advanced tumor stages. Responders (CR+PR) showed a significant survival advantage compared to patients with tumor progression (13.0 vs. 6.0 months; p=0.013)., Conclusion: TACP is a minimally invasive outpatient treatment for therapy-resistant locally recurrent pancreatic carcinoma and advanced tumor stages. It may be considered as an important aspect in palliative symptomatic pain-relieving treatment, or may even result in improved survival by achieving tumor response.

Purpose: To analyze the proton magnetic resonance spectroscopic data ( (1)H MRS) of normal liver parenchyma with regard to age, sex, body mass index and location in the liver., Materials and Methods: 45 healthy volunteers age 24 to 65 years were examined with an optimized single-voxel (1)H MRS using a 1.5-T scanner. A spin echo sequence with a TR of 1500 ms and a TE of 135 ms was used, allowing in-phase detection of the choline signal. Weak water suppression was achieved using a chemical shift selective suppression (CHESS) technique. Each examination included the measurement of three voxels with a voxel size of 18 x 18 x 18 mm (3) in different areas of the liver. The volunteers were divided into different age-based groups (young: < or = 44 years; older: > or = 44 years), BMI (normal weighted: < 25 kg/m (2); obese: > 25 kg/m (2)) and sex., Results: In the acquired spectra different lipid (e. g. [CH (2)] (n)), choline, glutamine, glutamate and glycogen-glucose-complex resonances were detected. The analysis of the spectra, however, only focused on the concentrations of choline and (CH (2)) (n) and the relative concentrations of the choline-to-(CH (2)) (n)-ratios. In the older volunteers the relative concentration of the choline-to-(CH (2)) (n)-ratio was significantly decreased by 0.213 +/- 0.193 in comparison to the younger subjects (p = 0,031). Further statistical analysis confirmed a significant decrease of the choline-to-(CH (2)) (n)-ratio by 0.223 +/- 0.180 in obese volunteers compared to volunteers of a standard weight (p = 0,016). The significant difference between the choline-to-(CH (2)) (n)-ratio in female versus male volunteers was calculated with an increase of 0.483 +/- 0.172 (p = 0,000). The location of the voxel in the liver parenchyma did not yield a significant difference in the choline-to-(CH (2)) (n)-ratio., Conclusion: The analysis of the proton liver MRS of healthy volunteers indicated a significant difference in the choline-to-(CH (2)) (n)-ratio depending on age, sex, and BMI with a confidence interval of 95 %. The different choline-to-(CH (2)) (n)-ratio could be the result of the body fat distribution depending on age and sex and also of the increased fat portion of the body in obese volunteers.

The aim of the study was to compare prospectively magnetic resonance cholangiography (MRC) and magnetic resonance imaging (MRI) with endoscopic retrograde cholangiography (ERC) in the diagnosis and staging of Klatskin tumours of the biliary tree (hilar cholangiocarcinomas). Forty-six patients with suspected Klatskin tumours of the biliary tract underwent MRI and heavily T2-weighted, non-breathhold, respiratory-triggered fast spin-echo MRC. Forty-two patients underwent ERC within 24 h; in four patients, ERC was not feasible, and percutaneous trans-hepatic cholangiography (PTC) was carried out instead. Two independent investigators evaluated imaging results for the presence of tumour, bile duct dilatation, and stenosis. Clinical and histopathological correlation revealed Klatskin tumours in 33 patients. MRI revealed a slightly hyperintense signal of infiltrated bile ducts in T2-weighted fast spin-echo sequences. The malignant lesion was regularly visualized as a hypointense area in T1-weighted gradient-echo sequences with substantial contrast enhancement along the involved bile duct walls. MRC revealed the location and extension of the tumour in 31 of 33 cases correctly (sensitivity 94%, specificity 100%, diagnostic accuracy 95%). In 27 of 31 cases, ERC enabled accurate staging and diagnosis of Klatskin tumours with a sensitivity of 87%. ERC and PTC combined yielded a sensitivity of 84% and a specificity of 97%. Tumours were grouped according to the Bismuth classification, with MRC allowing correct identification of type I tumour in seven patients, type II tumour in four patients, type III tumour in 12 patients, and type IV tumour in ten patients. MRC provided superior visualization of completely obstructed peripheral systems. MRC in combination with MRI is a reliable non-invasive diagnostic method for the pre-therapeutic staging of Klatskin tumours.

Multidetector computed tomography (MDCT), is the latest breakthrough in CT technology. Thin sections can now be acquired a routine basis in a single-breathhold with 3D-isotropic reconstructions. This results in improved lesion detection of benign as well as malignant abdominal tumours. The ability to scan through the entire abdomen in seconds allows multiphasic acquisitions. Therefore precise timing and optimized contrast is of great importance. Hypervascularized solid abdominal tumours are best depicted within the time generally regarded as the arterial dominant phase in MDCT, conversely hypovascular lesions are best depicted during venous phase imaging. The acquisition of an early arterial phase provides precise documentation of the arterial vascular system and should be obtained in preoperative abdominal imaging. Three clear separate circulatory phases enable best results in the pretherapeutic work-up of abdominal patients. Regarding follow-up oncologic work-up in colorectal metastatic disease a venous dominant phase might be the optimal protocol. Regarding contrast optimization, the traditional concept of imaging, where the injection duration equals the scanning duration cannot be used without modifications. To ensure adequate vessel opacification as well as soft tissue imaging with fast MDCT acquisitions, the iodine administration rate needs to be increased. This can be achieved either by an increase of injection flow rate or -more conveniently- by using a higher iodine concentration of the contrast medium. Especially for hypervascular tumours, e.g. HCC, a considerably to far higher contrasts can be achieved using higher concentrated contrast material. The overall improvement in precise timing and better visibility enable a comprehensive approach to abdominal imaging in MDCT.

The purpose of this study was to evaluate the diagnostic efficacy of iron-oxide-enhanced MRI vs CT during arterial portography (CTAP) and intraoperative ultrasound (IOUS) in detection of liver neoplasms. Seventeen patients with malignant focal liver lesions (liver metastases, n=7), hepatocellular carcinomas (HCC, n=9), and cholangiocellular carcinoma (CCC, n=1) underwent presurgical Resovist-enhanced MRI and CTAP. Two independent observers (A and B) assessed the blinded images of unenhanced and iron-oxide-enhanced MRI vs CTAP for the presence, number, and location of the liver lesions. These results were compared lesion by lesion and segment by segment with the results of intraoperative ultrasound ( n=17) serving as the reference standard. Eighty lesions were detected by intraoperative ultrasound in 17 patients. In comparison with IOUS (lesion-by-lesion analysis) the sensitivity was 86.8% for CTAP, 65% for combined unenhanced MR imaging, and 86.8% for combined Resovist-enhanced MRI as well as 86.8% for the combination of unenhanced and Resovist-enhanced MRI. Compared with the sensitivity of combined unenhanced MRI the sensitivity of CTAP as well as the sensitivity of combined Resovist-enhanced MRI was significantly higher (p<0.05). False-positive results were much higher in CTAP as compared with combined unenhanced and SPIO-enhanced MRI. Using the segment-by-segment analysis the specificity of combined unenhanced MRI with 100% (96.7-100%) as well as combined Resovist-enhanced MRI with 100% (96.7-100%) was significantly higher (p<0.05) in comparison with the specificity of CTAP with 91.1% (83.2-96.1%). The accuracy of combined unenhanced MRI was 100% (93.2-100%), combined Resovist-enhanced MRI 100% (93.6-100%) and of CTAP 85.2% (72.9-93.4%). In the detection of focal liver lesions iron-oxide-enhanced MR imaging is superior to unenhanced MRI and similar to CTAP.

For the diagnosis of liver cirrhosis ultrasound, computed tomography, magnetic resonance imaging, and angiography are recommended as imaging modalities. Ultrasound of the liver is used as a screening imaging tool in cases of patients suspicious for diffuse liver disease and is helpful in the term of follow-up examinations. Computed tomography is mainly performed to clarify the presence of liver disease detected by ultrasound. In this context, accurate examination of the vascular structures of the liver as well as extrahepatic situation, is of the essence. Diagnosis of diffuse liver disease and characterization of morphologic changes is improved using contrast-enhanced MR imaging with liver specific contrast media. Combined magnetic resonance imaging can provide comprehensive evaluation of cirrhosis. An improved detection rate and characterization of regenerating nodules can be achieved compared to imaging modalities such as ultrasound and computed tomography. MR imaging can be performed in a one-stop-technique using unenhanced and liver-specific-contrast-enhanced sequence protocols to evaluate the liver parenchyma itself, MR cholangiography to verify the bile duct system, and MR angiography to specify the vascular situation. This technique is the optimal protocol for diagnostic imaging in patients suffering from liver cirrhosis and the method of choice to reach the final diagnosis.

The development in oncologic liver surgery as well as modified interventional therapy strategies of the liver have resulted in improved diagnostic imaging. The evolution of contrast agents for MR imaging of the liver has proceeded along several different paths with the common goal of improving liver-lesion contrast. In MRI contrast agents act indirectly by their effects on relaxation times. Contrast agents used for hepatic MR imaging can be categorized in those that target the extracellular space, the hepatobiliary system, and the reticuloendothelial system. The first two result in a positive enhancement, the last one in a negative enhancement. Positive enhancers allow a better characterization of liver metastases using dynamic sequence protocols. Detection rate of liver metastases is increased using hepatobiliary contrast-enhanced MRI compared to unenhanced MRI. Negative enhancers, iron oxide particles, significantly increase tumor-to-liver contrast and allow detection of more lesions than other diagnostic methods. Iron-oxide enhanced MRI enables differential diagnosis of liver metastases comparing morphologic features using T2 and T1-weighted sequences.