The Additive Value of Radiomics Features Extracted from Baseline MR Images to the Barcelona Clinic Liver Cancer (BCLC) Staging System in Predicting Transplant-Free Survival in Patients with Hepatocellular Carcinoma: A Single-Center Retrospective Analysis.

BACKGROUND: To study the additive value of radiomics features to the BCLC staging system in clustering HCC patients. METHODS: A total of 266 patients with HCC were included in this retrospective study. All patients had undergone baseline MR imaging, and 95 radiomics features were extracted from 3D segmentations representative of lesions on the venous phase and apparent diffusion coefficient maps. A random forest algorithm was utilized to extract the most relevant features to transplant-free survival. The selected features were used alongside BCLC staging to construct Kaplan-Meier curves. RESULTS: Out of 95 extracted features, the three most relevant features were incorporated into random forest classifiers. The Integrated Brier score of the prediction error curve was 0.135, 0.072, and 0.048 for the BCLC, radiomics, and combined models, respectively. The mean area under the receiver operating curve (ROC curve) over time for the three models was 81.1%, 77.3%, and 56.2% for the combined radiomics and BCLC models, respectively. CONCLUSIONS: Radiomics features outperformed the BCLC staging system in determining prognosis in HCC patients. The addition of a radiomics classifier increased the classification capability of the BCLC model. Texture analysis features could be considered as possible biomarkers in predicting transplant-free survival in HCC patients.

Multicenter Reproducibility of Liver Iron Quantification with 1.5-T and 3.0-T MRI.

Background MRI is a standard of care tool to measure liver iron concentration (LIC). Compared with regulatory-approved R2 MRI, R2* MRI has superior speed and is available in most MRI scanners; however, the cross-vendor reproducibility of R2*-based LIC estimation remains unknown. Purpose To evaluate the reproducibility of LIC via single-breath-hold R2* MRI at both 1.5 T and 3.0 T with use of a multicenter, multivendor study. Materials and Methods Four academic medical centers using MRI scanners from three different vendors (three 1.5-T scanners, one 2.89-T scanner, and two 3.0-T scanners) participated in this prospective cross-sectional study. Participants with known or suspected liver iron overload were recruited to undergo multiecho gradient-echo MRI for R2* mapping at 1.5 T and 3.0 T (2.89 T or 3.0 T) on the same day. R2* maps were reconstructed from the multiecho images and analyzed at a single center. Reference LIC measurements were obtained with a commercial R2 MRI method performed using standardized 1.5-T spin-echo imaging. R2*-versus-LIC calibrations were generated across centers and field strengths using linear regression and compared using F tests. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic performance of R2* MRI in the detection of clinically relevant LIC thresholds. Results A total of 207 participants (mean age, 38 years ± 20 [SD]; 117 male participants) were evaluated between March 2015 and September 2019. A linear relationship was confirmed between R2* and LIC. All calibrations within the same field strength were highly reproducible, showing no evidence of statistically significant center-specific differences (P > .43 across all comparisons). Calibrations for 1.5 T and 3.0 T were generated, as follows: for 1.5 T, LIC (in milligrams per gram [dry weight]) = -0.16 + 2.603 × 10-2 R2* (in seconds-1); for 2.89 T, LIC (in milligrams per gram) = -0.03 + 1.400 × 10-2 R2* (in seconds-1); for 3.0 T, LIC (in milligrams per gram) = -0.03 + 1.349 × 10-2 R2* (in seconds-1). Liver R2* had high diagnostic performance in the detection of clinically relevant LIC thresholds (area under the ROC curve, >0.98). Conclusion R2* MRI enabled accurate and reproducible quantification of liver iron overload over clinically relevant ranges of liver iron concentration (LIC). The data generated in this study provide the necessary calibrations for broad clinical dissemination of R2*-based LIC quantification. ClinicalTrials.gov registration no.: NCT02025543 © RSNA, 2022 Online supplemental material is available for this article.

Role of MRI-Derived Radiomics Features in Determining Degree of Tumor Differentiation of Hepatocellular Carcinoma.

Background: To investigate radiomics ability in predicting hepatocellular carcinoma histological degree of differentiation by using volumetric MR imaging parameters. Methods: Volumetric venous enhancement and apparent diffusion coefficient were calculated on baseline MRI of 171 lesions. Ninety-five radiomics features were extracted, then random forest classification identified the performance of the texture features in classifying tumor degree of differentiation based on their histopathological features. The Gini index was used for split criterion, and the random forest was optimized to have a minimum of nine participants per leaf node. Predictor importance was estimated based on the minimal depth of the maximal subtree. Results: Out of 95 radiomics features, four top performers were apparent diffusion coefficient (ADC) features. The mean ADC and venous enhancement map alone had an overall error rate of 39.8%. The error decreased to 32.8% with the addition of the radiomics features in the multi-class model. The area under the receiver-operator curve (AUC) improved from 75.2% to 83.2% with the addition of the radiomics features for distinguishing well- from moderately/poorly differentiated HCCs in the multi-class model. Conclusions: The addition of radiomics-based texture analysis improved classification over that of ADC or venous enhancement values alone. Radiomics help us move closer to non-invasive histologic tumor grading of HCC.

Integrating baseline MR imaging biomarkers into BCLC and CLIP improves overall survival prediction of patients with hepatocellular carcinoma (HCC).

OBJECTIVES: We aimed to evaluate the independent predictive role of baseline imaging biomarkers for overall survival (OS) and transplant-free survival (TFS) in patients with HCC and assess the incremental value of these biomarkers to current staging systems. METHODS: In this retrospective IRB approved study, the clinical, laboratory, and imaging parameters of 304 HCC patients were collected. Cox regression model was utilized to identify the potential predictors of survival. Recursive partitioning test was utilized to identify the optimal ADC cutoff for stratifying patients' OS. Patients were stratified based on Barcelona Clinic Liver Cancer (BCLC) and Cancer of the Liver Italian Program (CLIP). Binary ADC value (above vs. below the cutoff) and tumor margin (well- vs. ill-defined) were integrated into BCLC and CLIP. OS and TFS was compared for patients based on standard criteria with and without imaging biomarkers. RESULTS: At baseline, patients with low tumor ADC and well-defined tumor margin (favorable imaging biomarkers) had longer survival, as compared to those with high ADC and ill-defined tumor margin (unfavorable imaging biomarkers) (median OS of 43 months vs. 7 months, respectively) (p < 0.001). Tumor ADC and tumor margin remained strong independent predictors of survival after adjustment for demographics, BCLC and CLIP staging, and tumor burden. Incorporating ADC and tumor margin improved performance of OS prediction by 9% in BCLC group and 6% in CLIP group. CONCLUSION: Incorporating ADC and tumor margin to current staging systems for HCC significantly improve prediction of OS and TFS of these criteria. KEY POINTS: • ADC and tumor margin are predictors of overall survival in HCC patients, independent of clinical, laboratory, and other imaging variables. • Adding ADC and tumor margin improved the prognostic value of BCLC and CLIP criteria by 9% and 6%, respectively. • High ADC and ill-defined tumor margin at baseline predicted poor survival, regardless of patient's liver function and general health status.

Post-TACE changes in ADC histogram predict overall and transplant-free survival in patients with well-defined HCC: a retrospective cohort with up to 10 years follow-up.

OBJECTIVES: To evaluate the role of change in apparent diffusion coefficient (ADC) histogram after the first transarterial chemoembolization (TACE) in predicting overall and transplant-free survival in well-circumscribed hepatocellular carcinoma (HCC). METHODS: Institution database was searched for HCC patients who got conventional TACE during 2005-2016. One hundred four patients with well-circumscribed HCC and complete pre- and post-TACE liver MRI were included. Volumetric MRI metrics including tumor volume, mean ADC, skewness, and kurtosis of ADC histograms were measured. Univariate and multivariable Cox models were used to test the independent role of change in imaging parameters to predict survival. P values < 0.05 were considered significant. RESULTS: In total, 367 person-years follow-up data were analyzed. After adjusting for baseline liver function, tumor volume, and treatment modality, incremental percent change in ADC (ΔADC) was an independent predictor of longer overall and transplant-free survival (p = 0.009). Overall, a decrease in ADC-kurtosis (ΔkADC) showed a strong role in predicting longer survival (p = 0.021). Patients in the responder group (ΔADC ≥ 35%) had the best survival profile, compared with non-responders (ΔADC < 35%) (p < 0.001). ΔkADC, as an indicator of change in tissue homogeneity, could distinguish between poor and fair survival in non-responders (p < 0.001). It was not a measure of difference among responders (p = 0.244). Non-responders with ΔkADC ≥ 1 (homogeneous post-TACE tumor) had the worst survival outcome (HR = 5.70, p < 0.001), and non-responders with ΔkADC < 1 had a fair survival outcome (HR = 2.51, p = 0.029), compared with responders. CONCLUSIONS: Changes in mean ADC and ADC kurtosis, as a measure of change in tissue heterogeneity, can be used to predict overall and transplant-free survival in well-circumscribed HCC, in order to monitor early response to TACE and identify patients with treatment failure and poor survival outcome. KEY POINTS: • Changes in the mean and kurtosis of ADC histograms, as the measures of change in tissue heterogeneity, can be used to predict overall and transplant-free survival in patients with well-defined HCC. • A ≥ 35% increase in volumetric ADC after TACE is an independent predictor of good survival, regardless of the change in ADC histogram kurtosis. • In patients with < 35% ADC change, a decrease in ADC histogram kurtosis indicates partial response and fair survival, while ∆kurtosis ≥ 1 correlates with the worst survival outcome.

Diagnosing arrhythmogenic right ventricular cardiomyopathy by 2010 Task Force Criteria: clinical performance and simplified practical implementation.

AIMS: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is diagnosed by a complex set of clinical tests as per 2010 Task Force Criteria (TFC). Avoiding misdiagnosis is crucial to prevent sudden cardiac death as well as unnecessary implantable cardioverter-defibrillator implantations. This study aims to validate the overall performance of the TFC in a real-world cohort of patients referred for ARVC evaluation. METHODS AND RESULTS: We included patients consecutively referred to our centres for ARVC evaluation. Patients were diagnosed by consensus of three independent clinical experts. Using this as a reference standard, diagnostic performance was measured for each individual criterion as well as the overall TFC classification. Of 407 evaluated patients (age 38 ± 17 years, 51% male), the expert panel diagnosed 66 (16%) with ARVC. The clinically observed TFC was false negative in 7/66 (11%) patients and false positive in 10/69 (14%) patients. Idiopathic outflow tract ventricular tachycardia was the most common alternative diagnosis. While the TFC performed well overall (sensitivity and specificity 92%), signal-averaged electrocardiogram (SAECG, P = 0.43), and several family history criteria (P ≥ 0.17) failed to discriminate. Eliminating these criteria reduced false positives without increasing false negatives (net reclassification improvement 4.3%, P = 0.019). Furthermore, all ARVC patients met at least one electrocardiogram (ECG) or arrhythmia criterion (sensitivity 100%). CONCLUSION: The TFC perform well but are complex and can lead to misdiagnosis. Simplification by eliminating SAECG and several family history criteria improves diagnostic accuracy. Arrhythmogenic right ventricular cardiomyopathy can be ruled out using ECG and arrhythmia criteria alone, hence these tests may serve as a first-line screening strategy among at-risk individuals.

Role of baseline volumetric functional MRI in predicting histopathologic grade and patients' survival in hepatocellular carcinoma.

OBJECTIVES: We aimed to evaluate the role of volumetric ADC (vADC) and volumetric venous enhancement (vVE) in predicting the grade of tumor differentiation in hepatocellular carcinoma (HCC). METHODS: The study population included 136 HCC patients (188 lesions) who had baseline MR imaging and histopathological report. Measurements of vVE and vADC were performed on baseline MRI. Tumors were histologically classified into low-grade and high-grade groups. The parameters between the two groups were compared using Mann-Whitney U and chi-square tests for continuous and categorical parameters, respectively. Area under receiver operating characteristic (AUROC) was calculated to investigate the accuracy of vADC and vVE. Logistic regression and multivariable Cox regression were used to unveil the potential parameters associated with high-grade HCC and patient's survival, respectively. RESULTS: Lesions with higher vADC values and a higher absolute vADC skewness were more likely to be high grade on histopathology assessment (p = 0.001 and p = 0.0291, respectively). Also, vVE showed a trend to be higher in low-grade lesions (p = 0.079). Adjusted multivariable model including vADC, vVE, and vADC skewness could strongly predict HCC degree of differentiation (AUROC = 83%). Additionally, a higher Child-Pugh score (HR = 2.39 [p = 0.02] for score 2 and HR = 3.47 [p = 0.001] for score 3), vADC skewness (HR = 1.52, p = 0.02; per increments in skewness), and tumor volume (HR = 1.1, p = 0.001; per 100 cm3 increments) showed the highest association with patients' survival. CONCLUSIONS: vADC and vVE have the potential to accurately predict HCC differentiation. Additionally, some imaging features in combination with patients' clinical characteristics can predict patient survival. KEY POINTS: • Volumetric functional MRI metrics can be considered as non-invasive measures for determining tumor histopathology in HCC. • Estimating patient survival based on clinical and imaging parameters can be used for modifying management approach and preventing unnecessary adverse events.

Correlation between incidental fat deposition in the liver and pancreas in asymptomatic individuals.

PURPOSE: To explore the utility of two different fat quantification methods in the liver and pancreas and to test the accuracy of multi-echo Dixon as a single sequence in detecting early stage of fat deposition. METHODS: 58 healthy potential liver donors underwent abdominal 3T MRI, prospectively. Single-voxel MR Spectroscopy (MRS), dual-echo Dixon, and multi-echo Dixon were performed. Two independent readers obtained proton density fat fraction (PDFF) of the liver and pancreas by placing ROIs on the 2 Dixon sequences. Correlation between the two PDFF measurements was assessed in the liver and pancreas. Values in the liver were also compared to those obtained by MRS. RESULTS: PDFF in the liver was 6.3 ± 4.2%, 5.5 ± 3.9%, and 5.1 ± 4.1% by MRS, dual-echo Dixon, and multi-echo Dixon, respectively. Dual-echo Dixon and multi-echo Dixon showed good correlation in PDFF quantification of the liver (r = 0.82, p < 0.0005). Multi-echo Dixon showed a good correlation (r = 0.72, p = 0.0005) between the fat measured in the liver and in the pancreas. To differentiate between normal (PDFF ≤ 6%) and mild fat deposition (PDFF: 6-33%) in the liver, analysis showed sensitivity, specificity, and accuracy of 74%, 81%, and 80% for dual-echo Dixon and 85%, 96%, and 89% for multi-echo Dixon, respectively. Mean PDFF in the pancreas was 7.2 ± 2.8% and 6.7 ± 3.3%, by dual-echo and multi-echo Dixon, respectively. Dual-echo Dixon and multi-echo Dixon showed good correlation in PDFF quantification of the pancreas (r = 0.58, p < 0.0005). CONCLUSION: Multi-echo Dixon in liver has high accuracy in distinguishing between subjects with normal liver fat and those with mildly elevated liver fat. Multi-echo Dixon can be used to screen for early fat deposition in the liver and pancreas.

Comparison between ROI-based and volumetric measurements in quantifying heterogeneity of liver stiffness using MR elastography.

OBJECTIVES: This study was conducted to quantify the heterogeneity of liver stiffness (LS) on MR elastography (MRE) by comparing ROI-based and volumetric measurements. METHODS: LS was measured by ROI-based and volumetric segmentation of the liver parenchyma. Mean LS (MLS) was calculated and used to assign stages of fibrosis. Volumetric measurements of stiffness maps were used to determine the percentage of liver volume above/below MLS and presence of LS heterogeneity. Heterogeneous stiffness was defined when the first and second most predominant stages were more than one category apart. MLS values by each method were compared using the Wilcoxon signed-rank test. RESULTS: We included 128 patients with suspected liver fibrosis (mean age 54.4 ± 14.8 years). MLS was 2.7 ± 1.0 kPa for ROI measurements and 2.6 ± 0.9 kPa for the volumetric method (p = 0.001). Of 59 patients with normal stage (F0), 31 patients (52.5%) had > 20% of liver volume with abnormal LS (F1-F4). Heterogeneous LS was reported in 18 patients (14%). CONCLUSIONS: MLS measurement may not represent the entire spectrum of hepatic fibrosis. Volumetric segmentation may potentially improve the detection of heterogeneous fibrosis and the accuracy of LS measurement. KEY POINTS: • Heterogeneity of hepatic fibrosis may occur in patients with chronic liver disease. • MR elastography is used to assess hepatic fibrosis by measuring liver stiffness. • Measuring liver stiffness by the ROI method and reporting a mean value may fail to detect heterogeneity of hepatic fibrosis. Volumetric assessment of liver stiffness by MR elastography may detect heterogeneity of parenchymal involvement.

Correction to: Correlation between incidental fat deposition in the liver and pancreas in asymptomatic individuals.

Unfortunately the article was published with a spell error in the co-author names "Ankur Pandy and Pallavi Pandy". The correct co-author names should be Ankur Pandey and Pallavi Pandey".

Follow-up of Incidentally Detected Pancreatic Cystic Neoplasms: Do Baseline MRI and CT Features Predict Cyst Growth?

Background Incidental detection of pancreatic cystic neoplasm (PCN) has increased. Since a small percentage of PCNs possess malignant potential, management is challenging. The recently revised American College of Radiology (ACR) recommendations define PCN measurement and growth for different categories based on baseline cyst size. However, no data are available regarding PCN growth rate under the ACR-defined size categories. Purpose To assess growth of incidentally detected PCNs on long-term imaging follow-up using revised ACR recommendations and to evaluate the association between baseline imaging features and growth. Materials and Methods This retrospective study included PCNs with baseline imaging performed between January 2002 and May 2017, with two or more cross-sectional imaging studies performed at least 12 months apart. PCN assessment was based on ACR 2017 recommendations. Cyst features, including location, septations, and mural nodules and multiplicity, were noted. Time to cyst progression (growth by ACR criteria) was examined by using baseline PCN size, among other factors. Results A total of 646 cysts in 390 patients were followed up for a median of 50 months (range, 12-186 months). A total of 184 (28.5%) cysts increased in size, 52 (8.1%) decreased in size, and 410 (63.4%) remained stable. For groups in which baseline PCN size was smaller than 5 mm, 5-14 mm, 15-25 mm, and larger than 25 mm, growth was noted in seven (13.2%), 106 (28.9%), 49 (32.2%), and 22 (29.7%) cysts, respectively. ACR baseline size categories (subhazard ratio: 2.8 [5-14-mm PCN group], 3.4 [15-25-mm PCN group], and 2.7 [>25 mm group], as compared with the <5 mm PCN group; P < .05 for each) demonstrated association with growth. Presence of mural nodules, septations, or lesion multiplicity failed to demonstrate association with growth. Among PCNs smaller than 5 mm at baseline, 100% of PCNs at 3-year follow-up and 94.2% of PCNs at 5-year follow-up were likely to remain stable. Conclusion American College of Radiology baseline size category of 15-25-mm pancreatic cystic neoplasms (PCNs) demonstrated the highest (3.1 times) likelihood of growth, as compared with the category of PCNs smaller than 5 mm. PCNs smaller than 5 mm at baseline did not demonstrate growth at 3-year imaging follow-up. © RSNA, 2019 Online supplemental material is available for this article.

Epicardial Fat Distribution Assessed with Cardiac CT in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

Purpose To compare epicardial fat in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) with that in healthy subjects. Materials and Methods In this retrospective study, cardiac CT scans in 44 patients with ARVD/C (mean age, 39 years ± 12; 23 men) were compared with those in 45 control group participants between January 2008 and July 2015. Volumes of intrathoracic adipose tissue, mediastinal adipose tissue (MAT), and total epicardial adipose tissue (EAT) were quantified. EAT was subdivided into three regions-right ventricular (RV) EAT, left ventricular (LV) EAT, and peri-atrial EAT (atrial EAT)-and normalized to MAT for all regions. Logistic regression and receiver operating characteristic analysis were performed to evaluate the association between epicardial fat with the diagnosis of ARVD/C. Results Total EAT volume was higher in patients with ARVD/C than in healthy control group participants (median, 98 mL vs 76 mL, respectively; P = .04). Regionally, LV and RV EAT volumes were higher in patients with ARVD/C than in control group participants, most notably when indexed to MAT (median LV EAT index: 0.49 vs 0.15, respectively; median RV EAT index: 0.91 vs 0.52; P ˂ .0005 for both). The optimal cutoff for diagnosis of ARVD/C was an LV EAT index of 0.24, with a sensitivity and specificity of 91% and 71%, respectively. Atrial EAT volume and total intrathoracic adipose tissue volume were not different between groups. RV diameter showed a positive correlation with total EAT index and LV EAT index (r = 0.21, P = .05 and r = 0.33, P = .002, respectively). Conclusion Higher amounts of right ventricular and left ventricular epicardial fat are found in hearts with arrhythmogenic right ventricular dysplasia/cardiomyopathy, particularly adjacent to the left ventricle, which correlates with disease severity and helps differentiate patients from healthy subjects. © RSNA, 2018 Online supplemental material is available for this article.

Unresectable Intrahepatic Cholangiocarcinoma: Multiparametric MR Imaging to Predict Patient Survival.

Purpose To determine the performance of magnetic resonance (MR) imaging-based tumor metrics for evaluation of response to transarterial chemoembolization (TACE) in patients with unresectable intrahepatic cholangiocarcinoma (ICCA). Materials and Methods Ninety-four patients with unresectable ICCA underwent baseline and follow-up MR imaging after TACE and were followed up until death or end of study duration. Lesions were analyzed for anatomic (Response Evaluation Criteria in Solid Tumors [RECIST] and tumor volume) and functional (viable tumor volume, viable tumor burden, and apparent diffusion coefficient [ADC]) volumetric MR parameters by using semiautomatic software. Response was assessed by using changes in viable tumor volume by using modified RECIST (mRECIST)-derived thresholds (three-dimensional mRECIST), viable tumor burden, and ADC. Overall survival was the primary endpoint. Cox-regression and Kaplan-Meier survival analysis were used. Results Tumor volume did not change after TACE (P = .07) whereas RECIST diameter showed a small change (-2.6%; P = .02). There was an increase in ADC (20.7%) and a decrease in viable tumor volume (-29.3%) and viable tumor burden (-29.1%; P < .001 for all). Higher overall survival was noted among responders by using thresholds of 25% increase in ADC, 66% decrease in viable tumor volume, and 50% decrease in viable tumor burden (log-rank test, P < .05). Hazard ratio for nonresponders by using ADC, three-dimensional mRECIST, and viable tumor burden at multivariable analysis was 2.9 (P = .004), 4.1 (P = .009), and 4.0 (P = .002), respectively. Survival differences were noted for patients who showed response by using all three parameters (ADC, three-dimensional mRECIST, and viable tumor burden) versus those who showed response by using either one or two of these parameters versus those who showed no response (P < .001). Conclusion Changes in volumetric ADC, viable tumor volume, and viable tumor burden at MR imaging provide prognostic information among patients with unresectable ICCA who undergo TACE. © RSNA, 2018 Online supplemental material is available for this article.

Prediction of post-TACE necrosis of hepatocellular carcinoma usingvolumetric enhancement on MRI and volumetric oil deposition on CT, with pathological correlation.

OBJECTIVE: To investigate whether volumetric enhancement on baseline MRI and volumetric oil deposition on unenhanced CT would predict HCC necrosis and response post-TACE. METHOD: Of 115 retrospective HCC patients (173 lesions) who underwent cTACE, a subset of 53 HCC patients underwent liver transplant (LT). Semiautomatic volumetric segmentation of target lesions was performed on dual imaging to assess the accuracy of predicting tumour necrosis after TACE in the whole cohort and at pathology in the LT group. Predicted percentage tumour necrosis is defined as 100 % - (%baseline MRI enhancement - %CT oil deposition). RESULTS: Mean predicted tumour necrosis by dual imaging modalities was 61.5 % ± 31.6%; mean percentage tumour necrosis on follow-up MRI was 63.8 % ± 31.5 %. In the LT group, mean predicted tumour necrosis by dual imaging modalities was 77.6 % ± 27.2 %; mean percentage necrosis at pathology was 78.7 % ± 31.5 %. There was a strong significant correlation between predicted tumour necrosis and volumetric necrosis on MRI follow-up (r = 0.889, p<0.001) and between predicted tumour necrosis and pathological necrosis (r = 0.871, p<0.001). CONCLUSION: Volumetric pre-TACE enhancement on MRI and post-TACE oil deposition in CT may accurately predict necrosis in treated HCC lesions. KEY POINTS: • Imaging-based tumour response can assist in therapeutic decisions. • Lipiodol retention as carrier agent in cTACE is a tumour necrosis biomarker. • Predicting tumour necrosis with dual imaging potentially obviates immediate post-treatment MRI. • Predicting tumour necrosis would facilitate further therapeutic decisions in HCC post-cTACE. • Pre-TACE MRI and post-TACE CT predict necrosis in treated HCC.

Multisite, multivendor validation of the accuracy and reproducibility of proton-density fat-fraction quantification at 1.5T and 3T using a fat-water phantom.

PURPOSE: To evaluate the accuracy and reproducibility of quantitative chemical shift-encoded (CSE) MRI to quantify proton-density fat-fraction (PDFF) in a fat-water phantom across sites, vendors, field strengths, and protocols. METHODS: Six sites (Philips, Siemens, and GE Healthcare) participated in this study. A phantom containing multiple vials with various oil/water suspensions (PDFF:0%-100%) was built, shipped to each site, and scanned at 1.5T and 3T using two CSE protocols per field strength. Confounder-corrected PDFF maps were reconstructed using a common algorithm. To assess accuracy, PDFF bias and linear regression with the known PDFF were calculated. To assess reproducibility, measurements were compared across sites, vendors, field strengths, and protocols using analysis of covariance (ANCOVA), Bland-Altman analysis, and the intraclass correlation coefficient (ICC). RESULTS: PDFF measurements revealed an overall absolute bias (across sites, field strengths, and protocols) of 0.22% (95% confidence interval, 0.07%-0.38%) and R2 > 0.995 relative to the known PDFF at each site, field strength, and protocol, with a slope between 0.96 and 1.02 and an intercept between -0.56% and 1.13%. ANCOVA did not reveal effects of field strength (P = 0.36) or protocol (P = 0.19). There was a significant effect of vendor (F = 25.13, P = 1.07 × 10-10 ) with a bias of -0.37% (Philips) and -1.22% (Siemens) relative to GE Healthcare. The overall ICC was 0.999. CONCLUSION: CSE-based fat quantification is accurate and reproducible across sites, vendors, field strengths, and protocols. Magn Reson Med 77:1516-1524, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Diagnostic Accuracy of Coronary Calcium Score Less than 100 in Excluding Coronary Artery Disease.

BACKGROUND: Coronary artery calcium score (CACS) is a quantitative assessment of calcifications and an established predictor of cardiovascular events. OBJECTIVES: In this study, we evaluated the diagnostic accuracy, negative predictive value (NPV), positive predictive value (PPV), specificity and sensitivity of CACS less than 100 in predicting significant coronary artery stenosis in patients with risk of coronary artery disease (CAD) in a vessel-based analysis. PATIENTS AND METHODS: A cross sectional study was carried out on a study population of 2527 consecutive stable patients with symptoms suggestive of CAD who were referred for coronary computed tomographic angiography (CCTA). We performed 1343 studies with 256 slice machine in Shahid Rajaee hospital and the other studies were carried out with 64 slice machine in Imam Khomeini hospital and the calcium score was quantified according to the Agatston method. RESULTS: At the cutoff point of 100 for coronary calcium scoring, there was high specificity (87%), high sensitivity (79%), high efficiency (84%), high PPV (79%), and high NPV (87%) in the diagnosis of significant stenosis in the whole heart. The frequency of zero calcium scoring was 59% in normal or nonsignificant stenosis and 7.6% in significant stenosis in the whole heart. Calcium scoring increased with greater severity of the arterial stenosis (P values < 0.001). CONCLUSION: We conclude that coronary calcium scoring provided useful information in the management of patients. In CACS less than 100, it has a NPV of 87% in excluding significant stenosis in patients with the risk of CAD but it does not have enough diagnostic accuracy for surely excluding coronary stenosis, so we should perform a combination of CACS and coronary CT angiography for patients.

Prostate Biopsy Using Transrectal Ultrasonography; The Optimal Number of Cores Regarding Cancer Detection Rate and Complications.

BACKGROUND: Transrectal ultrasound guided biopsy of the prostate is the most common modality used to diagnose prostate cancer. OBJECTIVES: The aim of this study was to evaluate the optimal number of cores at prostate biopsy, which have the most diagnostic value with least adverse effects. PATIENTS AND MATERIALS: Transrectal ultrasonography (TRUS) guided biopsy was performed in 180 patients suspicious for prostate cancer due to either abnormal rectal examination or elevated PSA. The patients were divided randomly into three groups of six-core, twelve-core and eighteen-core biopsies. The detection rate of prostate cancer in each group with the rate of post biopsy urinary infection and prostatitis were compared. RESULTS: Prostate cancer was diagnosed in 8 (13.3%), 21 (35%) and 24 (40%) patients in six, twelve and eighteen core biopsy groups, respectively. Urinary tract infection and prostatitis occurred in 17 (28.3%), 23 (38.3%) and 35 (58.3%) patients in six, twelve and eighteen core biopsy groups, respectively. Considering the detection rate of prostate cancer, there was a significant difference between 6 and 12 core biopsy groups (P = 0.006) and 12-core biopsies detected more cases of prostate cancer, but there was no significant difference between 12 and 18 core biopsy groups (P = 0.572). Considering the infection rate, there was no significant difference between 6 and 12 core biopsy groups (P = 0.254), but there was a significant difference between 12 and 18 core biopsy groups (P = 0.028) and infectious complications occurred more frequently in 18-core biopsy group. CONCLUSIONS: The best balance between detection rate of prostate cancer and infectious complications of biopsies achieved in twelve-core biopsy protocol. Twelve-core biopsy enhances the rate of prostate cancer detection with minimum adverse effects.

Diagnostic efficacy of vessel specific coronary calcium score in detection of coronary artery stenosis.

BACKGROUND: Coronary artery calcification which is determined quantitatively by coronary calcium scoring has been known as a sign of coronary stenosis and thus future cardiac events; hence it has been noticed on spotlight of researchers in recent years. Developing different method for early and optimal detection of coronary artery disease (CAD) is really essential as CAD are the first cause of death in population. OBJECTIVES: To evaluate predictive value of vessel specific coronary artery calcium (CAC) score in predicting obstructive coronary artery disease. PATIENTS AND METHODS: In this diagnostic test study we evaluated patients with coronary computed tomography angiography (CCTA) and CAC score which had been referred to two referral radiology center in Tehran, Iran and finally we selected 2525 patients in a single and sequential pattern to create a diagnostic study. The whole-heart CAC scores and vessel specific CAC scores were calculated individually for the 4 major epicardial coronary arteries in 2 distinct group; group A ( patients with previous history of CABG) and group B (patients without history of CABG). For evaluation of obstruction tree cut off points were described: 0 > ; at least 1 segment with any kind of stenosis, ≥ 50; at least 1 segment with stenosis ≥ 50, ≥ 70; at least 1 segment with stenosis ≥ 70. RESULTS: Mean of coronary calcium scores in terms of each coronary artery vessel increase by increasing coronary stenosis grade in group B; LAD, RCA, LCX respectively have mean CAC score 6.06, 6.21 and 5.04 in normal patients and 221.6, 226.7 and 106.6 in patients with complete stenosis. As expected these findings don't work for group A. Also By increasing calcium score cutoff in all four vessels sensitivity decreased and specificity increased but steal LAD had higher sensitivity than other vessels and LM had higher specificity. Thus using calcium score method is useful for ruling out stenosis in LAD while calcium score of LM can predict existence of stenosis in LM. However none of the vessel specific CAC can reach to 100% sensitivity and specificity of CCTA method. CONCLUSIONS: CCTA is highly superior than vessel specific CAC score thus to minimize patients radiation does maybe we can eliminate CAC scan as a routinely perform procedure at the beginning of the CCTA.

MRI in prostate cancer.

Imaging studies play an important role in detection and management of prostate cancer and MRI especially with the use of endorectal coil because of high contrast resolution is recognized as the best imaging modality in evaluation of prostate cancer. Multiparametric MR study including T1 and T2 weighted images, diffusion weighted images, dynamic contrast study and MR spectroscopy is useful for detection and local staging of prostate cancer as well as posts treatment evaluation of patients either after surgery or radiation therapy for detection of local recurrence.