Comparison of Gadobenate-Enhanced MRI and Gadoxetate-Enhanced MRI for Hepatocellular Carcinoma Detection Using LI-RADS Version 2018: A Prospective Intraindividual Randomized Study.

BACKGROUND. Gadobenate and gadoxetate show different degrees of intracellular accumulation within hepatocytes, potentially impacting these agents' relative performance for hepatocellular carcinoma (HCC) diagnosis. OBJECTIVE. The purpose of this article was to perform an intraindividual comparison of gadobenate-enhanced MRI and gadoxetate-enhanced MRI for detection of HCC and to assess the impact of inclusion of hepatobiliary phase images on HCC detection for both agents. METHODS. This prospective study enrolled 126 patients (112 men, 14 women; mean age, 52.3 years) at high risk for HCC who consented to undergo two 3-T liver MRI examinations (one using gadobenate [0.05 mmol/kg], one using gadoxetate [0.025 mmol/kg]) separated by 7-14 days. The order of the two contrast agents was randomized. All examinations included postcontrast dynamic and hepatobiliary phase images (120 minutes for gadobenate, 20 minutes for gadoxetate). Three radiologists independently reviewed the gadobenate and gadoxetate examinations in separate sessions and recorded the location of detected observations. Observations were classified using LI-RADS version 2018 and using a LI-RADS modification whereby hepatobiliary phase hypointensity may upgrade observations from category LR-4 to LR-5. Observations classified as LR-5 were considered positive interpretations for HCC. Diagnostic performance for histologically confirmed HCC (n = 96) was assessed. RESULTS. Across readers, sensitivity for HCC for gadobenate versus gadoxetate was 74.0-80.2% versus 54.2-67.7% using dynamic images alone and 82.1-87.4% versus 66.3-81.1% using dynamic and hepatobiliary phase images. For HCCs measuring 1.0-2.0 cm, sensitivity for gadobenate versus gadoxetate was 61.9% (all readers) versus 38.1-57.1% using dynamic images alone and 76.2-85.7% versus 52.4-61.9% using dynamic and hepatobiliary phase images. PPV for HCC ranged from 88.6% to 97.4% across readers, agents, and image sets. CONCLUSION. Sensitivity for HCC was higher for gadobenate than for gadoxetate, whether using dynamic images alone or dynamic and hepatobiliary phase images; the improved sensitivity using gadobenate was more pronounced for small HCCs. Whereas hepatobiliary phase images improved sensitivity for both agents, sensitivity of gadobenate using dynamic images alone compared favorably with that of gadoxetate using dynamic and hepatobiliary phase images. CLINICAL IMPACT. The findings support gadobenate as a preferred agent over gadoxetate when performing liver MRI in patients at high risk for HCC.

Accuracies of Chemical Shift In/Opposed Phase and Chemical Shift Encoded Magnetic Resonance Imaging to Detect Intratumoral Fat in Hepatocellular Carcinoma.

BACKGROUND: Magnetic Resonance Imaging (MRI) being a noninvasive modality may help in preoperative evaluation of intratumoral fat in hepatocellular carcinoma (HCC) using chemical shift encoded (CSE) MRI and in-/opposed-phase (IOP) imaging sequences. PURPOSE: To compare the diagnostic accuracy of chemical shift encoded fat fraction at three different flip angles (FAs) using quantitative chemical shift encoded MRI (CSE-MRI) with in-/opposed phase (IOP) imaging to evaluate intratumoral fat in HCC. STUDY TYPE: Retrospective. POPULATION: Eighty-six patients with 87 pathology proven HCCs. FIELD STRENGTH/SEQUENCE: IOP (LAVA-Flex) and CSE-MRI (IDEAL IQ) a three-dimensional spoiled gradient-echo pulse sequences acquired at 3 T. ASSESSMENT: Regions of interest (ROIs) were manually drawn by two observers in the tumors to measure mean fat fractions. Surgical specimens were reassessed for intratumoral fat content. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were assessed for CSE-MRI sequence at FA 3°, 8°, and 9°. STATISTICAL TESTS: Intraclass correlation coefficient (ICC) was expressed in terms of inter- and intra-observer agreements. Receiver operating characteristic curve analysis was performed for the diagnostic performance followed by combined metric of both. SNR/CNR were analyzed by Kruskal-Wallis test. RESULTS: Excellent inter- and intra-observer agreements (ICC >0.95, P < 0.001) were observed for both IOP and CSE-MRI. IOP (86.4%) showed higher sensitivity than CSE-MRI at FA 3° (72.5%), FA 8° (76.4%) and FA 9° (76.3%). In contrast, the specificity for CSE-MRI at FA 3° (86%), FA 8° (87%), and FA 9° (87%) were greater than IOP (72%). A combined metric of IOP and CSE-MRI derived fat fractions at FA 8° gave highest AUC of 87% and accuracy of 86%. SNR and CNR for CSE-MRI were significantly higher at FA 8° and FA 9° than FA 3° (P < 0.05). DATA CONCLUSION: IOP and quantitative CSE-MRI are both feasible methods to detect intratumoral fat in HCC with higher accuracy and SNR for CSE-MRI at FA 8° and 9°. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 2.

The role of lesion hypointensity on gadobenate dimeglumine-enhanced hepatobiliary phase MRI as an additional major imaging feature for HCC classification using LI-RADS v2018 criteria.

OBJECTIVES: To determine the value of lesion hypointensity in the hepatobiliary phase (HBP) on gadobenate dimeglumine-enhanced MRI as an additional major imaging feature for diagnosis of hepatocellular carcinoma (HCC) using LI-RADS v2018 criteria. METHODS: Between March 2016 and August 2018, 235 patients with 250 hepatic nodules at high risk of HCC underwent gadobenate dimeglumine-enhanced MRI. Two radiologists independently evaluated the imaging features and classified the nodules based on LI-RADS v2018 criteria, and their consensus data were used to calculate the diagnostic performance of LI-RADS categories. Two modified LI-RADS definitions were as follows: (1) LI-RADS-m1: HBP hypointensity as an additional major feature; (2) LI-RADS-m2: HBP hypointensity as an alternative to "enhancing capsule" as an additional major feature. The diagnostic performance of LR-5 categories was compared using McNemar's test. RESULTS: The sensitivity and specificity for LR-5 classification using original LI-RADS v2018 criteria were 78.1% and 96.3%, respectively. Significantly improved sensitivity (82.7%; p = 0.004) with unchanged specificity (96.3%; p = 1.00) was seen for LR-5 classification using LI-RADS-m1. Similar sensitivity and specificity (82.7% and 96.3%, respectively) were also seen using LI-RADS-m2. Significantly improved sensitivity (79.5% vs. 64.0%; p = 0.031) with unchanged specificity (96.2% vs. 96.2%, p = 1.00) was seen using both LI-RADS-m1 and LI-RADS-m2 compared to the original LI-RADS v2018 for 39 HCC nodules measuring 10-19 mm. CONCLUSIONS: Lesion hypointensity on gadobenate dimeglumine-enhanced HBP MRI may improve sensitivity for LR-5 classification beyond that achievable using conventional LI-RADS v2018 criteria. Lesion hypointensity may prove a suitable alternative imaging feature to enhancing capsule for accurate LR-5 classification. KEY POINTS: • Including lesion hypointensity in the HBP as an additional major feature improved sensitivity for LR-5 classification on gadobenate dimeglumine-enhanced MRI. • Lesion hypointensity in the HBP can replace "enhancing capsule" as an additional major feature for LR-5 classification without impairing specificity.

Preoperative prediction of pathologic grade of HCC on gadobenate dimeglumine-enhanced dynamic MRI.

PURPOSE: To evaluate the value of gadobenate dimeglumine-enhanced MRI in predicting the pathologic grade of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Patients with pathologically proven HCC who underwent preoperative gadobenate dimeglumine-enhanced dynamic MRI were included. Two radiologists blinded to pathology results evaluated images in consensus. Lesions were evaluated quantitatively in terms of ratio of enhancement (RE), and qualitatively based on image features related to tumor aggressiveness. Logistic regression and ROC analyses were used to determine the value of these parameters to predict pathologic grade. RESULTS: In total, 221 patients (194 males, 27 females, aged 52.9 ± 11.7 years) with 49 poorly differentiated HCCs and 172 well/moderately differentiated HCCs were evaluated. Features significantly related to poorer pathologic grade at univariate analysis included lower RE in the early arterial phase (EAP) (p = 0.001), nonsmooth margins (p = 0.001), absence of capsule (p < 0.001), arterial peritumoral hyperenhancement (p < 0.001), higher AFP (p = 0.004), multiple tumors (p = 0.026), and larger tumor size (p = 0.028). At multivariate analysis, lower RE (EAP) (OR = 0.144, p = 0.002), absence of capsule (OR = 0.281, p = 0.004), and arterial peritumoral hyperenhancement (OR = 4.117, p < 0.001) were independent predictive factors for poorer pathologic grade. ROC analysis showed lower RE (EAP) was predictive of poorer pathologic grade (AUC = 0.667). AUC increased to 0.797 when combined with absence of capsule and presence of peritumoral hyperenhancement. CONCLUSIONS: Lower RE (EAP), absence of capsule, and arterial peritumoral hyperenhancement were predictive biomarkers for poorer pathologic grade of HCC on gadobenate dimeglumine-enhanced dynamic MRI. KEY POINTS: • Gadobenate dimeglumine-enhanced dynamic MRI was a useful quantitative biomarker for preoperative prediction of pathologic grade in patients with HCC. • Lower RE in the early arterial phase, absence of capsule, and arterial peritumoral hyperenhancement were potential imaging indicators for preoperative prediction of poorer pathologic grade of HCC on gadobenate dimeglumine-enhanced MRI. • A lower RE in the early arterial phase was effective at predicting poorer pathologic grade of HCCs but prediction is improved when combined with absence of capsule and presence of peritumoral hyperenhancement.

Comparison of the diagnostic performance of 2D and 3D MR elastography in staging liver fibrosis.

OBJECTIVES: To compare the diagnostic performance and image quality of state-of-the-art 2D MR elastography (MRE) and 3D MRE in the basic application of liver fibrosis staging. METHODS: This retrospective study assessed data from 293 patients who underwent 2D and 3D MRE examinations. MRE image quality was assessed with a qualitative 2-point grading system by evaluating artifacts. Two experienced analysts independently measured mean liver stiffness values. The interobserver agreement of liver stiffness measurement was assessed by the intraclass correlation coefficient (ICC). The area under the receiver operating characteristic curve (AUC) was used to assess the diagnostic performance of 2D and 3D MRE and blood-based markers for fibrosis staging using the pathology-proven liver fibrosis stage as the gold standard. RESULTS: The image quality provided by 3D MRE was graded as significantly higher than that obtained with the 2D MRE method (p < 0.01). Interobserver agreement in liver stiffness measurements was higher for 3D MRE (ICC: 3D 0.979 vs 2D 0.955). The AUC values for discriminating ≥ F1, ≥ F2, ≥ F3, and F4 fibrosis for 3D MRE (0.89, 0.92, 0.95, and 0.93) were similar to those for 2D MRE (0.89, 0.91, 0.94, and 0.92). Both the 2D and 3D MRE methods provided superior accuracy to the blood-based biomarkers, including APRI, FIB-4, and Forns index, especially for ≥ F2, ≥ F3, and F4 fibrosis stages (all p < 0.01). CONCLUSIONS: While 3D MRE offers certain advantages and opportunities for new applications of MRE, current widely deployed 2D MRE technology has comparable performance in the basic application of detecting and staging liver fibrosis. KEY POINTS: • 2D MRE and 3D MRE have comparable diagnostic performance in detecting and staging liver fibrosis. • 3D MRE has superior image quality and interobserver agreement compared to 2D MRE.

3D MR Elastography of Hepatocellular Carcinomas as a Potential Biomarker for Predicting Tumor Recurrence.

BACKGROUND: Preoperative prediction of tumor recurrence is important in the management of patients with hepatocellular carcinoma (HCC). PURPOSE: To investigate whether tumor stiffness derived by magnetic resonance elastography (MRE) could predict early recurrence of HCC after hepatic resection. STUDY TYPE: Retrospective. POPULATION: In all, 99 patients with pathologically confirmed HCCs after surgical resection. FIELD STRENGTH/SEQUENCE: 3.0T; preoperative MRE with 60-Hz mechanical vibrations using an active acoustic driver. ASSESSMENT: Regions of interest (ROIs) were manually drawn in the tumors to measure mean tumor stiffness. Surgical specimens were reviewed for histological grade, capsule, vascular invasion, and surgical margins. The early recurrence of HCC was defined as that occurring within 2 years after resection. STATISTICAL TESTS: Cox proportional hazard models were used to evaluate risk factors associated with the time to early recurrence. RESULTS: HCCs with recurrence had higher tumor stiffness, higher rate of advanced T stage, vascular invasion, lower rate of capsule formation, larger tumor size, higher aspartate aminotransferase (AST), and hepatitis B virus (HBV)-DNA level and aspartate aminotransferase / alanine aminotransferase ratio (P = 0.031, 0.007, 0.01, <0.001, 0.015, 0.034, 0.01, and 0.014, respectively) than HCCs without recurrence. Vascular invasion (hazard ratio [HR] = 2.922; 95% confidence interval [CI]: [1.079, 7.914], P = 0.035) and mean tumor stiffness (HR = 1.163; 95% CI: [1.055, 1.282], P = 0.002) were risk factors associated with early recurrence. Each 1-kPa increase in tumor stiffness was associated with a 16.3% increase in the risk for tumor recurrence. DATA CONCLUSION: The mean stiffness of HCCs may be a useful, noninvasive, quantitative biomarker for the prediction of early HCC recurrence after hepatic resection. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;49:719-730.

Can IVIM help predict HCC recurrence after hepatectomy?

PURPOSE: To determine the diagnostic performance of intravoxel incoherent motion (IVIM) parameters to predict tumor recurrence after hepatectomy in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). MATERIALS AND METHODS: One hundred and fifty-seven patients (mean age 52.54 ± 11.32 years, 87% male) with surgically and pathologically confirmed HCC were included. Regions of interests were drawn including the tumors by two independent radiologists. ADC and IVIM-derived parameters (true diffusion coefficient [D]; pseudodiffusion coefficient [D*]; pseudodiffusion fraction [f]) were obtained preoperatively. The Cox proportional hazards model was used to analyze the predictors associated with tumor recurrence after hepatectomy. RESULTS: Forty-seven of 157 (29.9%) patients experienced tumor recurrence. The multivariate Cox proportional hazards model revealed that a D value < 0.985 × 10-3 mm2/s (hazard ratio (HR), 0.190; p = 0.023) was a risk factor for tumor recurrence. Additional risk factors included younger age (HR, 0.328; p = 0.034) and higher serum alpha-fetoprotein (AFP) level (HR, 2.079; p = 0.013). Further, receiver operating characteristic (ROC) analysis showed that the area under the curve (AUC) of the obtained Cox regression model improved from 0.68 for the combination of AFP and age alone to 0.724 for the combination of D value, AFP, and age. CONCLUSION: The D value derived from the IVIM model is a potential biomarker for the preoperative prediction of recurrence after hepatectomy in patients with HCC. When combined with age and AFP levels, D can improve the predictive performance for tumor recurrence. KEY POINTS: • The recurrence rate of HCC after hepatectomy was higher in patients with ADC, D, and f values that were lower than the optimal cutoff values. • The optimal cutoff values of ADC, D, D*, and f for predicting recurrence in HBV associated HCC were 0.858 × 10-3 mm2/s, 0.985 × 10-3 mm2/s, 12.5 × 10-3 mm2/s, and 23.4%, respectively. • The D value derived from IVIM diffusion-weighted imaging may be a useful biomarker for preoperative prediction of recurrence after hepatectomy in patients with HCC. When combined with age and AFP levels, D can improve the predictive performance for tumor recurrence.

Liver Imaging Reporting and Data System Category 5: MRI Predictors of Microvascular Invasion and Recurrence After Hepatectomy for Hepatocellular Carcinoma.

OBJECTIVE. We investigated in Liver Imaging Reporting and Data System category 5 (LR-5) observations whether imaging features, including LI-RADS imaging features, could predict microvascular invasion (MVI) and posthepatectomy recurrence in high-risk adult patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS. We retrospectively identified 149 high-risk patients who underwent 3-T MRI within 1 month before hepatectomy for HCC; 81 of 149 patients with no HCC recurrence were followed for more than 1 year. Tumors with clear surgical margins were confirmed in each hepatectomy specimen. MVI was evaluated histologically by a histopathologist. Tumor recurrence was determined by clinical and imaging follow-up. Two independent radiologists reviewed the prehepatectomy MR images and assessed LI-RADS v2018 imaging features as well as some non-LI-RADS features in all LR-5 observations in consensus. Alpha-fetoprotein level, tumor number, and imaging features were analyzed as potential predictors for MVI and posthepatectomy recurrence using multivariate logistic regression and Cox proportional hazards models. RESULTS. One hundred forty-nine patients with pathologically confirmed HCC were included; 64 of 149 (43.0%) patients had MVI, whereas 48 of 129 (37.2%) patients had tumor recurrence within 3 years after hepatectomy. Mosaic architecture (odds ratio, 3.420; p < 0.001) and nonsmooth tumor margin (odds ratio, 2.554; p = 0.011) were independent predictors of MVI. Multifocal tumors (hazard ratio, 2.101; p = 0.034), absence of fat in mass (hazard ratio, 2.109; p = 0.015), and nonsmooth tumor margin (hazard ratio, 2.415; p = 0.005) were independent predictors of posthepatectomy recurrence. CONCLUSION. In high-risk patients with LR-5 HCC, mosaic architecture and non-smooth tumor margin independently predicted MVI. Multifocal tumors, absence of fat in mass, and nonsmooth tumor margin independently predicted recurrence.

Magnetic resonance elastography of the prostate in patients with lower urinary tract symptoms: feasibility of the modified driver at high multi-frequencies.

PURPOSE: To demonstrate the feasibility and diagnostic value of high-frequency magnetic resonance elastography (MRE) for evaluation of prostatic disease in patients with lower urinary tract symptoms (LUTS). METHODS: 41 patients who underwent preoperative prostate MRI and MRE with a modified driver were enrolled retrospectively from May 2016 to September 2021. All were included in the assessment of MRE image quality, using a qualitative visual inspection and a quantitative confidence map. 35 patients (prostate cancer (PCa), n = 13; non-PCa, n = 22) undergoing prostatectomy or biopsy were evaluated for the diagnostic performance of stiffness values. The confidence values and the stiffness values were analyzed by one-way analysis of variance (ANOVA) and independent samples T test, respectively. Area under the receiver operating characteristic (AUROC) analysis was performed. RESULTS: Through the qualitative analysis, all MRE acquisitions were successful at 60, 90, 120 and 150 Hz. The quantitative confidence values were significantly lower at 60 Hz (0.683 ± 0.055) and 90 Hz (0.762 ± 0.048) than that at 120 Hz (0.814 ± 0.049) and 150 Hz (0.840 ± 0.049), all P < 0.001. The stiffness of PCa was higher than non-PCa at 90 Hz (P = 0.008), 120 Hz (P < 0.001) and 150 Hz (P < 0.001). The AUCs were 0.773, 0.881 and 0.944, respectively. CONCLUSION: Prostate MRE using the modified driver is feasible at 60-150 Hz and image quality is better at higher frequencies. Prostate MRE may be useful and helpful to evaluate prostate diseases in patients with LUTS at higher frequencies; however, further study may be warranted with larger population in future.

Liver Imaging and Data System (LI-RADS) Version 2018 and Other Imaging Features in Intrahepatic Cholangiocarcinoma in Chinese Adults with vs. without Chronic Hepatitis B Viral Infection.

Purpose: To describe liver imaging reporting and data system (LI-RADS) version 2018 and other MRI imaging features in intrahepatic mass-forming cholangiocarcinoma (iCCA) in Chinese adults with vs. without chronic hepatitis B viral (HBV) infection. Methods: We retrospectively enrolled 89 patients with pathologically proven iCCA after multiphase imaging performed between 2004 and 2017 at a tertiary medical center in southern China. Based on whether patients had chronic HBV, iCCA was divided into two subgroups: HBV-positive (n = 50 patients, including 9 with cirrhosis) vs. HBV-negative (n = 39 patients, including 14 with hepatolithiasis and 25 with no identifiable risk factor for iCCA; none had cirrhosis). Two independent abdominal radiologists in consensus reviewed the largest mass in each patient to assign LI-RADS v2018 features; they also scored each observation's shape and location. Imaging features were compared using chi-square or Fisher's exact tests. Results: Most iCCAs in HBV-positive (88% (44/50)) and HBV-negative (97% (38/39)) patients had at least one LR-M feature. Compared to iCCAs in HBV-negative patients, iCCAs in HBV-positive patients were more likely to have at least one major feature of HCC (46% (23/50) vs. 8% (3/39), P < 0.001) and more likely to be smooth (42% (21/50) vs. 10% (4/39), P = 0.001). Six of 50 (12%) iCCAs in HBV-positive patients and 1/39 (3%) iCCAs in HBV-negative patients had at least one major feature of HCC without any LR-M feature. Conclusions: In this retrospective single-center study in Chinese adults, iCCAs in HBV-positive patients were more likely to resemble HCCs than iCCAs in HBV-negative patients.

Increasing the sensitivity of LI-RADS v2018 for diagnosis of small (10-19 mm) HCC on extracellular contrast-enhanced MRI.

PURPOSE: To evaluate whether the LI-RADS v2018 LR-5 criteria can be modified to increase sensitivity without reducing specificity for diagnosing small (10-19 mm) HCC. METHODS: 167 consecutive high-risk patients with 174 small observations reported clinically on extracellular contrast-enhanced MRI from 2014 to 2018 were retrospectively studied. The best available reference standard was applied for each observation. Blinded to the reference standard, two radiologists scored LI-RADS imaging features retrospectively and assigned each observation a LI-RADS category using LI-RADS v2018 and each of four modified LI-RADS versions (mLI-RADS I to IV) with successively more expansive LR-5 criteria. Per-observation sensitivity and specificity of LR-5 for small HCC using each version were assessed. Each modified version was compared to v2018 (McNemar test). RESULTS: The 174 observations included 135 HCC, 8 non-HCC malignancies, and 31 benign entities. Using LI-RADS v2018, LR-5 provided 70% (both readers) sensitivity and 95% (both readers) specificity for small HCC. Expanding the LR-5 criteria to include nonrim APHE plus at least one additional major feature (mLI-RADS I) or no APHE plus at least two additional major features (mLI-RADS II) significantly increased sensitivity (reader 1/reader 2: 75%/75% vs. 70%, p = 0.016/0.031; 78%/79% vs. 70%, p = 0.001/0.001) without significantly reducing specificity (reader 1/reader 2: 90%/92% vs. 95%, p = 0.500/1.000 for both). mLI-RADS III and IV further increased sensitivity (reader 1/reader 2: 80%/81% vs. 70%, p < 0.001/< 0.001; 94%/92% vs. 70, p < 0.001/< 0.001) but with trend-level (reader 1/reader 2: 85%/80% vs. 95%, p = 0.125/0.063) or significant (reader 1/reader 2: 64%/62% vs. 95%, p < 0.001/< 0.001) specificity reductions. CONCLUSIONS: Expanding the v2018 LR-5 criteria to include nonrim APHE plus at least one additional major feature or no APHE plus at least two additional major features significantly increases sensitivity without significantly reducing specificity for small HCC. Confirmation is warranted in multi-center prospective studies.

Tumor stiffness measured by 3D magnetic resonance elastography can help predict the aggressiveness of endometrial carcinoma: preliminary findings.

BACKGROUND: Preoperative evaluation of aggressiveness, including tumor histological subtype, grade of differentiation, Federation International of Gynecology and Obstetrics (FIGO) stage, and depth of myometrial invasion, is significant for treatment planning and prognosis in endometrial carcinoma (EC). The purpose of this study was to evaluate whether three-dimensional (3D) magnetic resonance elastography (MRE) can help predict the aggressiveness of EC. METHODS: From August 2015 to January 2019, 82 consecutive patients with suspected uterine tumors underwent pelvic MRI and MRE scans, and 15 patients with confirmed EC after surgical resection were enrolled. According to pathological results (tumor grade, histological subtype, FIGO stage, and myometrial invasiveness), the patients were divided into two subgroups. The independent-samples t-test or Mann-Whitney U test was used to compare the stiffness between different groups. The diagnostic performance was determined with receiver operating characteristic (ROC) curve analysis. RESULTS: The stiffness of EC with ≥ 50 % (n = 6) myometrial invasion was significantly higher than that with < 50 % (n = 9) myometrial invasion (3.68 ± 0.59 kPa vs. 2.61 ± 0.72 kPa, p = 0.009). Using a stiffness of 3.04 kPa as a cutoff value resulted in 100 % sensitivity and 77.8 % specificity for differentiating ≥ 50 % myometrial invasion from < 50 % myometrial invasion of EC. The stiffness of poorly differentiated EC (n = 8) was significantly higher than that of well/moderately differentiated EC (n = 7) (3.47 ± 0.64 kPa vs. 2.55 ± 0.82 kPa, p = 0.028). Using a stiffness of 3.04 kPa as a cutoff value resulted in 75 % sensitivity and 71.4 % specificity for differentiating poorly differentiated from well/moderately differentiated EC. The stiffness of FIGO stage II/III EC was significantly higher than that of FIGO stage I EC (3.69 ± 0.65 kPa vs. 2.72 ± 0.76 kPa, p = 0.030). Using a stiffness of 3.04 kPa as a cutoff value resulted in 100 % sensitivity and 70 % specificity for differentiating FIGO stage I EC from FIGO stage II/III EC. The tumor stiffness value in type II (n = 3) EC was higher than that in type I (n = 12) EC (3.67 ± 0.59 kPa vs. 2.88 ± 0.85 kPa), but the difference was not significant (p = 0.136). CONCLUSIONS: Tumor stiffness measured by 3D MRE may be potentially useful for predicting tumor grade, FIGO stage and myometrial invasion of EC and can aid in the preoperative risk stratification of EC.

Evaluation of MR elastography for prediction of lymph node metastasis in prostate cancer.

PURPOSE: To assess the relationship between MRE stiffness of prostate cancer (PCa) and the extent of lymph node metastasis (LNM) in patients with PCa undergoing radical prostatectomy (RP) and extended pelvic lymph node dissection (ePLND). MATERIALS: The local institutional review board approved this retrospective study. We retrospectively analyzed 49 patients, who had undergone MRE, mpMRI and pelvic MRI on a 3.0 T MRI scanner, with histopathological confirmed PCa after RP (from June 2015 to December 2019). For each patient, preoperative clinical data and characteristics of MRE, mpMRI and pelvic MRI were recorded. Independent-samples t test, univariate and multivariate logistic regression analyses were performed. And receiver operating characteristic (ROC) analysis were performed to compare the diagnostic performances of multivariate models with the Briganti 2019 nomogram. RESULTS: PCa MRE stiffness and maximum diameter were independent predictors of LNM. When PCa MRE stiffness at 60 Hz (odds ratio [OR] = 20.223, P = 0.013) and maximum diameter (OR = 4.575, P = 0.046) were combined, the sensitivity and specificity were 100% and 91.9% to predict LNM. When PCa MRE stiffness at 90 Hz (OR = 7.920, P = 0.013) and maximum diameter (OR = 2.810, P = 0.045) were combined, the sensitivity and specificity were 100% and 86.5% to predict LNM. The areas under curves (AUCs) of the combinations were higher than the AUC of the Briganti 2019 nomogram (0.982 vs. 0.904, P = 0.040 [60 Hz]; 0.975 vs. 0.904, P = 0.060 [90 Hz], respectively). CONCLUSIONS: MRE-based assessment of PCa stiffness may be useful for predicting LNM of PCa preoperatively and noninvasively.

[Low dose contrast-enhanced 4D DSA with the 320-detector row computed tomography scanner for post-operative evaluation of the hepatic artery complications after liver transplantation].

OBJECTIVE: To evaluate the value of low-dose contrast-enhanced 4D DSA acquired from 320-detector row CT on the diagnosis of the hepatic artery complications after liver transplantation. METHODS: 320-detector row CT were performed in fifth patients with liver dynamic enhanced using volume CT body-perfusion protocol, hepatic artery phase images obtained after intravenous injection of 50 ml of contrast at a rate of 6 ml/s were acquired based on 4D DSA. The time-density curve (TDC) of the hepatic artery was delineated. The time to peak, peak contrast enhancement were recorded. The data of artery phase were sent to workstation to reconstruct the hepatic artery with VR, MIP and MPR. RESULTS: The delay mean time and the peak CT value of hepatic artery was 20 (10.0 - 24.2) s and 373 (310 - 440) HU; 4D DSA revealed hepatic artery pseudo-aneurysm (n = 2), and hepatic artery mild stenosis (n = 3), moderate stenosis (n = 4), severe stenosis (n = 1) and occlusion (n = 1). Compensatory circulation was seen in 2 cases. 4 patients were appeared segmental stenosis and hepatoportal arteriovenous fistulas (HPAVF). Hepatic arterial branch are decreased and opened in 9 cases and 4 cases. 4D DSA also displayed other signs including hepatic hemangioma and the splenic artery aneurysms (SAA) and ectasi (n = 1), donor-recipient hepatic artery mismatch (n = 3). CONCLUSION: 4D DSA provided a safe, noninvasive and accurate method for guiding the diagnosis of hepatic artery complication and play an effective role after liver transplantation.

[The clinical application of 320-slice Computed Tomography (CT) hepatic artery images in patients with liver transplantation].

OBJECTIVE: To evaluate the clinical significance of 320-slice CT hepatic artery images in patients with liver transplantation. METHODS: A total of 58 patients underwent CT scanning by 320-slice scanner after liver transplantation. They were divided into 2 groups according to the concentration of contrast media as follows: Group A (27 cases, 350 mgI/ml iopromide), Group B (31 cases, 370 mgI/ml iopromide). Contrast medium was infused at 6 ml/s, with a total dose of 50 ml. Images were generated by dynamic volume scanning and were processed by 4D digital subtraction angiography (DSA) imaging software. The time-density curve (TDC) of the hepatic artery was delineated. The time to peak, peak contrast enhancement were recorded. The physiological parameters such as body weight and height were analyzed. RESULTS: (1) There were no differences in clinical parameters such as age, sex, height, weight, or BMI between groups. The time to peak of hepatic artery of group A and B was (19.71+/-3.11) s and (20.06+/-3.67) s, and had no significant difference. The maximum peak enhancement of hepatic artery in groups B was higher than that group A (P < 0.05). (2) 4D DSA revealed hepatic artery pseudo-aneurysm (n = 2), and hepatic artery mild stenosis (n = 13), moderate stenosis (n = 5), severe stenosis (n = 9) and occlusion (n = 1), segmental moderate and severe stenosis (n = 4), and compensatory circulation with hepatic artery severe stenosis and occlusion (n = 6). hepatoportal arteriovenous fistulas (HPAVF, n = 12), donor-recipient hepatic artery mismatch (n = 3). Hepatic arterial branch are decreased and opened in 15 cases and 8 cases. CONCLUSION: 320-slice CT hepatic artery images is safe, noninvasive, and accurate technique to evaluate hepatic arterial complications after liver transplantation.

A comparative study of monoexponential versus biexponential models of diffusion-weighted imaging in differentiating histologic grades of hepatitis B virus-related hepatocellular carcinoma.

PURPOSE: To compare the diagnostic value of apparent diffusion coefficient (ADC) and intravoxel incoherent motion metrics in discriminating histologic grades of hepatocellular carcinoma (HCC) in patients with hepatitis B virus (HBV) infection. METHODS: 117 chronic HBV patients with 120 pathologically confirmed HCCs after surgical resection or liver transplantation were enrolled in this retrospective study. Diffusion-weighted imaging was performed using eleven b values (0-1500 s/mm2) and two b values (0, 800 s/mm2) successively on a 3.0 T system. ADC0, 800, ADCtotal, diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) were calculated. The parameters of three histologically differentiated subtypes were investigated using Kruskal-Wallis test, Spearman rank correlation, and receiver-operating characteristic analysis. Interobserver agreement was assessed using the intraclass correlation coefficient. RESULTS: There was excellent agreement for ADCtotal/D/f, good agreement for ADC0,800, and moderate agreement for D*. ADCtotal, ADC0, 800,D, and f were significantly different for well, moderately, and poorly differentiated HCCs (P < 0.001), and they were all inversely correlated with histologic grades: r = - 0.633, - 0.394, - 0.435, and - 0.358, respectively (P < 0.001). ADCtotal demonstrated higher performance than ADC0,800 in diagnosing both well and poorly differentiated HCCs (P < 0.001 and P = 0.04, respectively). ADCtotal showed higher performance than D and f in diagnosing well differentiated HCCs (P < 0.001) and similar performance in diagnosing poorly differentiated HCCs (P = 0.06 and 0.13, respectively). CONCLUSIONS: ADCtotal showed better diagnostic performance than ADC0,800, D, and f to discriminate histologic grades of HCC.

Diagnostic performance of LI-RADS version 2018 in differentiating hepatocellular carcinoma from other hepatic malignancies in patients with hepatitis B virus infection.

The diagnostic performance of the Liver Imaging Reporting and Data System (LI-RADS) in differentiating hepatocellular carcinoma (HCC) from other hepatic malignancies has not been investigated in Chinese patients with chronic liver disease from hepatitis B virus (HBV) infection. The aim of this study was to evaluate the accuracy of the LI-RADS version 2018 in differentiating HCC, intrahepatic cholangiocarcinoma (ICCA), and combined HCC-cholangiocarcinoma (cHCC-CCA) in Chinese patients with HBV infection. Seventy consecutive HBV-infected patients with ICCA (n = 48) or cHCC-CCA (n = 22) who underwent contrast-enhanced magnetic resonance imaging (CE-MRI) between 2006 and 2017 were enrolled along with a comparison cohort of 70 patients with HCC and CE-MRI-matched for tumor size (10-19 mm, 20-30 mm, 31-50 mm, and >50 mm). Imaging feature frequencies for each tumor type were compared using Fisher's exact test. The classification accuracy of LR-5 and LR-M was estimated for HCC versus non-HCC (ICCA and cHCC-CCA). The interobserver agreement was good for LI-RADS categories of HCC and moderate for non-HCC. After consensus read, 66 of 70 (94%) HCCs were categorized LR-5 (including tumor in vein [TIV] with LR-5), while 42 of 48 (88%) ICCAs and 13 of 22 (59%) cHCC-CCAs were categorized LR-M (including TIV with LR-M) (p < 0.001). Thus, assignment of LR-5 provided 94% sensitivity and 81% specificity for HCC. LR-M provided 79% sensitivity and 97% specificity for non-HCC (ICCA and cHCC-CCA); and the sensitivity and accuracy were lower in differentiating HCC from non-HCC (tumor size <20 mm). LI-RADS v2018 category 5 and M reliably differentiated HBV-related HCC from ICCA. However, a substantial proportion of cHCC-CCAs were categorized LR-5 rather than LR-M. While management is controversial for these combined tumors, accurate prospective differentiation is desired for optimal treatment.

Deep learning assisted differentiation of hepatocellular carcinoma from focal liver lesions: choice of four-phase and three-phase CT imaging protocol.

PURPOSE: To evaluate whether a three-phase dynamic contrast-enhanced CT protocol, when combined with a deep learning model, has similar accuracy in differentiating hepatocellular carcinoma (HCC) from other focal liver lesions (FLLs) compared with a four-phase protocol. METHODS: Three hundred and forty-two patients (mean age 49.1 ± 10.5 years, range 19-86 years, 65.8% male) scanned with a four-phase CT protocol (precontrast, arterial, portal-venous and delayed phases) were retrospectively enrolled. A total of 449 FLLs were categorized into HCC and non-HCC groups based on the best available reference standard. Three convolutional dense networks (CDNs) with the input of four-phase CT images (model A), three-phase images without portal-venous phase (model B) and three-phase images without precontrast phase (model C) were trained on 80% of lesions and evaluated in the other 20% by receiver operating characteristics (ROC) and confusion matrix analysis. The DeLong test was performed to compare the areas under the ROC curves (AUCs) of A with B, B with C, and A with C. RESULTS: The diagnostic accuracy in differentiating HCC from other FLLs on test sets was 83.3% for model A, 81.1% for model B and 85.6% for model C, and the AUCs were 0.925, 0.862 and 0.920, respectively. The AUCs of models A and C did not differ significantly (p = 0.765), but the AUCs of models A and B (p = 0.038) and of models B and C (p = 0.028) did. CONCLUSIONS: When combined with a CDN, a three-phase CT protocol without precontrast showed similar diagnostic accuracy as a four-phase protocol in differentiating HCC from other FLLs, suggesting that the multiphase CT protocol for HCC diagnosis might be optimized by removing the precontrast phase to reduce radiation dose.

Multiphase convolutional dense network for the classification of focal liver lesions on dynamic contrast-enhanced computed tomography.

BACKGROUND: The accurate classification of focal liver lesions (FLLs) is essential to properly guide treatment options and predict prognosis. Dynamic contrast-enhanced computed tomography (DCE-CT) is still the cornerstone in the exact classification of FLLs due to its noninvasive nature, high scanning speed, and high-density resolution. Since their recent development, convolutional neural network-based deep learning techniques has been recognized to have high potential for image recognition tasks. AIM: To develop and evaluate an automated multiphase convolutional dense network (MP-CDN) to classify FLLs on multiphase CT. METHODS: A total of 517 FLLs scanned on a 320-detector CT scanner using a four-phase DCE-CT imaging protocol (including precontrast phase, arterial phase, portal venous phase, and delayed phase) from 2012 to 2017 were retrospectively enrolled. FLLs were classified into four categories: Category A, hepatocellular carcinoma (HCC); category B, liver metastases; category C, benign non-inflammatory FLLs including hemangiomas, focal nodular hyperplasias and adenomas; and category D, hepatic abscesses. Each category was split into a training set and test set in an approximate 8:2 ratio. An MP-CDN classifier with a sequential input of the four-phase CT images was developed to automatically classify FLLs. The classification performance of the model was evaluated on the test set; the accuracy and specificity were calculated from the confusion matrix, and the area under the receiver operating characteristic curve (AUC) was calculated from the SoftMax probability outputted from the last layer of the MP-CDN. RESULTS: A total of 410 FLLs were used for training and 107 FLLs were used for testing. The mean classification accuracy of the test set was 81.3% (87/107). The accuracy/specificity of distinguishing each category from the others were 0.916/0.964, 0.925/0.905, 0.860/0.918, and 0.925/0.963 for HCC, metastases, benign non-inflammatory FLLs, and abscesses on the test set, respectively. The AUC (95% confidence interval) for differentiating each category from the others was 0.92 (0.837-0.992), 0.99 (0.967-1.00), 0.88 (0.795-0.955) and 0.96 (0.914-0.996) for HCC, metastases, benign non-inflammatory FLLs, and abscesses on the test set, respectively. CONCLUSION: MP-CDN accurately classified FLLs detected on four-phase CT as HCC, metastases, benign non-inflammatory FLLs and hepatic abscesses and may assist radiologists in identifying the different types of FLLs.

[Diagnostic value of multislice spiral CT and MRI in detection of tumor recurrence after liver transplantation for hepatocellular carcinoma].

OBJECTIVE: To investigate the manifestation and diagnostic value of multislice spiral CT (MSCT) and MRI imaging in detection of tumor recurrence after liver transplantation for hepatocellular carcinoma (HCC). METHODS: The clinical data of 161 consecutive HCC patients who underwent orthotopic liver transplantation were retrospectively reviewed. Twenty-nine HCC patients were classified by pTNM according to the "Pittsburgh criteria". MSCT and MRI findings of tumor recurrence after liver transplantation were evaluated retrospectively in 29 stage II-IVb HCC patients. The recurrence site and relapse interval between liver transplantation and recurrence were analyzed. RESULTS: Lung tumor recurrence were found in 21 cases, presented as cotton-like lesions in a diameter of 2 - 3 cm, with a clear margin and homogeneous density. Pleural tumor recurrence was detected in 4 cases. Liver tumor recurrence were found in 9 cases, which can be divided into four subtypes: multinodular in 4 cases, diffuse lesion in 2 cases, huge mass in 2 cases, and uninodular in 1 case. Two cases showed tumor thrombus in the inferior vena cava and portal vein. Lymph node tumor recurrence was found in 9 cases, presented as multiple nodules at hepatic hilum, lesser peritoneal sac, posterior mediastinum, retroperitoneum, or around pancreatic head, and accompanied with merging and necrosis in one case. Bone tumor recurrence were found as osteolytic destruction in 4 cases, and accompanied with adjacent soft-tissue mass in 2 cases. The recurrence sites of the 29 cases were as following: lung (21 cases, 72.4%), liver (9 cases, 31.0%), lymph nodes (9 cases, 31.0%), bone (4 cases, 13.8%) and other sites (3 cases, 10.3%). Lung tumor recurrence was found in all the 10 stage IVb patients with tumor recurrence after liver transplantation, significantly more frequent than that in stage IVa patients (P = 0.023). After liver transplantation, all 25 patients with stage III approximately IVb HCC developed recurrence within one year, but in the 4 cases with stage II HCC at one year later (P = 0.009). CONCLUSION: The results of our study show that in hepatocellular carcinoma patients after liver transplantation, the lung and pleura are the most frequent site of recurrence, followed by liver, lymph node and bone as the second and third sites. The Stage IVb hepatocellular carcinoma should be regarded as a contradiction for liver transplantation due to rapid recurrence. Tumor recurrence occurs later in stage II HCC than in stage III approximately IVb patients. MSCT and MRI are of significant importance in diagnosis and formulating operation plan in HCC patients with recurrence after liver transplantation.