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Background & Aims: Despite the clinical and genetic significance of macrotrabecular-massive hepatocellular carcinoma (MTM-HCC), its characteristics on imaging have not been described. This study aimed to characterise MTM-HCC on gadoxetic acid-enhanced MRI and to evaluate the diagnostic accuracy and prognostic value of these imaging characteristics., Methods: We enrolled 3 independent cohorts from 2 tertiary care centres. The 3 cohorts consisted of a total of 476 patients who underwent gadoxetic acid-enhanced MRI and surgical resection for treatment-naïve single HCCs. Independent review of histopathology and MRI by 2 reviewers was performed for each cohort, and inter-reader agreement was evaluated. Based on the result of MRI review in the training cohort (cohort 1), we developed 2 diagnostic criteria for MTM-HCC and evaluated their prognostic significance. The diagnostic performance and prognostic significance were validated in 2 validation cohorts (cohorts 2 and 3)., Results: We developed 2 diagnostic MRI criteria (MRIC) for MTM-HCC: MRIC-1, ≥20% arterial phase hypovascular component; MRIC-2, ≥50% hypovascular component and 2 or more ancillary findings (intratumoural artery, arterial phase peritumoural enhancement, and non-smooth tumour margin). MRIC-1 showed high sensitivity and negative predictive value (88% and 95% in the training cohort, and 88% and 97% in the pooled validation cohorts, respectively), whereas MRIC-2 demonstrated moderate sensitivity and high specificity (47% and 94% in the training cohort, and 46% and 96% in the pooled validation cohorts, respectively). MRIC-2 was an independent poor prognostic factor for overall survival in both training and pooled validation cohorts., Conclusions: Using gadoxetic acid-enhanced MRI findings, including an arterial phase hypovascular component, we could stratify the probability of MTM-HCC and non-invasively obtain prognostic information., Lay Summary: Macrotrabecular-massive hepatocellular carcinoma (MTM-HCC) is a histopathologic subtype of HCC characterised by aggressive biological behaviour and poor prognosis. We developed imaging criteria based on liver MRI that could be used for the non-invasive diagnosis of MTM-HCC. HCCs showing imaging findings of MTM-HCC were associated with poor outcomes after hepatic resection., Competing Interests: Conflict of interests The authors declare no conflicts of interest that pertain to this work. Please refer to the accompanying ICMJE disclosure forms for further details., (Copyright © 2020 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Objective: To compare the stretched exponential model of diffusion-weighted imaging (DWI) with monoexponential and biexponential models in terms of the ability to characterize focal liver lesions (FLLs)., Methods: This retrospective study included 180 patients with FLLs who underwent magnetic resonance imaging including DWI with nine b values at 3.0 T. The distributed diffusion coefficient (DDC) and intravoxel diffusion heterogeneity index (α) from a stretched exponential model; true diffusion coefficient (D t ), pseudo-diffusion coefficient (D p ), and perfusion fraction (f) from a biexponential model; and apparent diffusion coefficient (ADC) were calculated for each lesion. Diagnostic performances of the parameters were assessed through receiver operating characteristic (ROC) analysis. For 20 patients with treated hepatic metastases, the correlation between the DWI parameters and the percentage of tumor necrosis on pathology was evaluated using the Spearman correlation coefficient., Results: DDC had the highest area under the ROC curve (AUC, 0.905) for differentiating malignant from benign lesions, followed by D t (0.903) and ADC (0.866), without significant differences among them (DDC vs. D t , p = 0.946; DDC vs. ADC, p = 0.157). For distinguishing hypovascular from hypervascular lesions, and hepatocellular carcinoma from metastasis, f  had a significantly higher AUC than the other DWI parameters (p < 0.05). The α had the strongest correlation with the degree of tumor necrosis (ρ = 0.655, p = 0.002)., Conclusion: The DDC from stretched exponential model of DWI demonstrated excellent diagnostic performance for differentiating malignant from benign FLLs. The α is promising for evaluating the degree of necrosis in treated metastases., Key Points: • The stretched exponential DWI model is valuable for characterizing focal liver lesions. • The DDC from stretched exponential model shows excellent performance for differentiating malignant from benign focal liver lesions. • The α from stretched exponential model is promising for evaluating the degree of necrosis in hepatic metastases after chemotherapy.

Objective: The purpose of this study is to evaluate the clinical effect of liver stiffness measured using MR elastography (MRE) in patients with cholestasis due to biliary obstruction., Materials and Methods: In this retrospective study, 69 consecutive patients with no history of diffuse liver disease who underwent pancreaticobiliary imaging with MRE were included. Quantitative MRI parameters (i.e., liver stiffness, apparent diffusion coefficient, R2*, and proton density fat fraction) and laboratory results (i.e., aspartate aminotransferase, alanine aminotransferase, and total bilirubin levels) were measured. Patients were classified as having either normal bilirubin (group A; n = 49) or hyperbilirubinemia (group B; n = 20). Continuous variables were compared using the independent t test or Mann-Whitney U test. Correlation between parameters was analyzed using the Pearson correlation coefficient. The ROC curve analysis was used to evaluate the diagnostic performance and clinical effect of MRE., Results: Liver stiffness was significantly higher in group B (mean ± SD, 3.8 ± 0.7 kPa) than in group A (2.8 ± 0.5 kPa) (p < 0.001); there were no differences in other MRI parameters. There were positive correlations between liver stiffness and total bilirubin (r = 0.609; p < 0.001), aspartate aminotransferase (r = 0.376; p = 0.001), and alanine aminotransferase (r = 0.285; p = 0.017) levels. There was a negative correlation between the degree of biliary decompression 1 week after bile drainage and liver stiffness (r = -0.71; p = 0.003). The sensitivity and specificity for predicting biliary decompression were 83.3% and 100%, respectively, at a liver stiffness cutoff of 4.0 kPa., Conclusion: Liver stiffness measured by MRE increases as cholestasis increases and can be a predictive factor for the sufficiency of biliary decompression after biliary drainage.

Objective: The objective of our study was to investigate the prognostic value of total glycolysis of the remnant liver, which reflects both metabolic and anatomic liver function, for predicting postoperative hepatic insufficiency., Materials and Methods: Patients who underwent 18 F-FDG PET/CT and abdominal CT within 1 month of major hepatectomy were retrospectively analyzed. Total liver volume, remnant liver volume, the ratio of the remnant hepatic volume to the preoperative hepatic volume (RFRHV), and mean standardized uptake value (SUV mean ) were measured, and total glycolysis of the remnant liver was calculated. Clinical hepatic function reserve values, including the indocyanine green retention rate at 15 minutes, the model for end-stage liver disease (MELD) score, and aspartate aminotransferase to platelet ratio index (APRI), were calculated. Univariate and multivariate analyses were performed, and an optimal model for predicting hepatic insufficiency was developed. ROC curves were used to compare diagnostic performance., Results: Of 149 patients, seven patients had hepatic insufficiency. The SUV mean showed the highest sensitivity (100%; specificity, 31.7%) for predicting hepatic insufficiency, and total glycolysis of the remnant liver showed the highest specificity (96.5%; sensitivity, 57.1%) for predicting hepatic insufficiency. On multivariate analysis, the odds ratio of APRI (> 5.4) and total glycolysis of the remnant liver (≤ 625.6) was 46.3 and 82.9, respectively, for predicting hepatic insufficiency. On ROC curve analysis, a new model composed of APRI and total glycolysis of the remnant liver showed a higher area under the ROC curve (A z ) value (A z = 0.899) than SUV mean (0.659), MELD score (0.618), APRI (0.693), RFRHV (0.797), and remnant liver volume (0.762)., Conclusion: The total glycolysis of the remnant liver has moderate sensitivity and high specificity for predicting hepatic insufficiency. Combining the total glycolysis of the remnant liver and APRI yielded the best diagnostic performance for predicting hepatic insufficiency.

As a result of recent developments in imaging modalities and wide spread routine medical checkups and screening, more incidental liver lesions are found frequently on US these days. When incidental liver lesions are found on US, physicians have to make a decision whether to just follow up or to undergo additional imaging studies for lesion characterization. In order to choose the next appropriate imaging modality, the diagnostic accuracy of each imaging study needs to be considered. Therefore, we tried to compare the accuracy of contrast-enhanced multidetector CT (MDCT) and Gd-EOB-DTPA-enhanced MRI for characterization of incidental liver masses. We included 127 incidentally found focal liver lesions (94 benign and 33 malignant) from 80 patients (M∶F = 45∶35) without primary extrahepatic malignancy or chronic liver disease. Two radiologists independently reviewed Gd-EOB-DTPA-enhanced MRI and MDCT. The proportion of confident interpretations for differentiation of benign and malignant lesions and for the specific diagnosis of diseases were compared. The proportion of confident interpretations for the differentiation of benign and malignant lesions was significantly higher with EOB-MRI(94.5%-97.6%) than with MDCT (74.0%-92.9%). In terms of specific diagnosis, sensitivity and accuracy were significantly higher with EOB-MRI than with MDCT for the diagnosis of focal nodular hyperplasia (FNH) and focal eosinophilic infiltration. The diagnoses of the remaining diseases were comparable between EOB-MRI and MDCT. Hence, our results suggested that Gd-EOB-MRI may provide a higher proportion of confident interpretations than MDCT, especially for the diagnosis of incidentally found FNH and focal eosinophilic infiltration.

Objective: The purpose of our study was to evaluate interobserver variability between the radiologist and emergency physician in detecting blunt liver trauma by conventional and contrast-enhanced ultrasound (US) (CEUS)., Methods: We created 20 sites of blunt liver trauma in rabbits and performed conventional US and CEUS on the animals. A radiologist and an emergency physician independently evaluated the degree of liver trauma. Using contrast-enhanced computed tomography as a reference standard, the diagnostic performance of US and CEUS was calculated. Interobserver variability between radiologist and emergency physician was compared before and after contrast enhancement of US., Results: Overall sensitivity and specificity for detecting liver trauma on conventional US, regardless of the degree of trauma, were 61.1% and 100% for the radiologist and 50% and 100% for the emergency physician. On CEUS, the sensitivity and specificity were 94.4% and 100% for both the radiologist and emergency physician. The interobserver agreement between emergency physician and radiologist increased from 0.867 to 0.955 after contrast enhancement on US., Conclusions: Contrast-enhanced US may permit a more accurate diagnosis for liver trauma than conventional US by both the radiologist and emergency physician. Contrast-enhanced US may also reduce interobserver variability for this diagnosis., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The objective of this study was to determine the optimal scan delay time after hepatic parenchymal enhancement using a 16-channel multidetector row helical CT (MDCT) scanner. Two hundred fifty-five consecutive patients underwent biphasic CT scans using a 16-channel MDCT. In group A (n = 125), two hepatic venous phase scans (HVP1 and HVP2) were obtained at 40 and 60 seconds, after 100-HU threshold time (T100HU) in the abdominal aorta. In group B (n = 130), HVP1 and HVP2 scans were obtained 50 and 70 seconds after T100HU. Both groups were divided into subgroups that were given different contrast media. Groups A1 and B1 received a contrast medium of 300 mgI/mL; groups A2 and B2 received a contrast medium of 370 mgI/mL. Each patient was injected with contrast medium at a dose of 2 mL/kg at a rate adjusted to the patient's body weight with a constant injection duration of 47 seconds. The attenuation values (HU) for the liver, portal vein, hepatic vein, and aorta were measured. The average HU was compared between the groups. Hepatic enhancement in the images obtained at 50 and 60 seconds after T100HU was greater (P < 0.05) than in images obtained at 40 and 70 seconds. These results were obtained with both contrast media. A few patients showed greater enhancement at a 40 seconds or 70 seconds. Hepatic enhancement was significantly greater in all scans using a contrast medium dose of 370 mgI/mL compared with the 300-mgI/mL dose (P < 0.05). Independent of the concentration of contrast medium, scan delays of 50 to 60 seconds after T100HU may provide optimal hepatic enhancement.

Purpose To compare the breathhold, navigator-triggered, and free-breathing techniques in diffusion-weighted magnetic resonance imaging (MRI) for the evaluation of focal liver lesions on a 3.0T system. Materials and Methods Fifty-two patients (36 men, 16 women; mean age, 56.4 years) with focal liver lesions underwent breathhold, navigator-triggered, and free-breathing diffusion-weighted imaging (DWI) of the liver on a 3.0 Tesla (T) system. All sequences were performed with b values of 50 and 800 s/mm2 and identical parameters except for signal averages (two for navigator-triggered, one for breathhold, and four for free-breathing) and repetition time (3389 ms for navigator-triggered, 1500 ms for breathhold, and 4400 ms for free-breathing). A total of 74 lesions (50 malignant, 24 benign) were evaluated. The signal-to-noise ratios (SNR) of the liver and lesions, contrast-to-noise ratios (CNR) of each lesion, and ADC values of the liver and lesions were compared for each DWI sequence. The detection sensitivity and characterization accuracy were also compared. Results The SNRs of the liver and lesions were significantly lower for breathhold DWI than for non-breathhold DWI (navigator-triggered and free-breathing DWI) for all b values. The CNRs of the lesions were also significantly lower for breathhold DWI than for non-breathhold DWI. The ADC values of the liver and focal lesions measured using the three DWI techniques were not significantly different and showed good correlation. For lesion detection and characterization, there were no significant differences between breathhold and non-breathhold DWI. Conclusion Both breathhold and non-breathhold DWI are comparable for the detection or characterization of focal liver lesions at 3.0T; however, non-breathhold DWI provides higher SNR and CNR than breathhold DWI. In addition, although free-breathing and navigator-triggered DWI sequences show similar performance for 3.0T liver imaging, free-breathing DWI is more time efficient than navigator-triggered DWI. J. Magn. Reson. Imaging 2013;38:109-118. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]