Noninvasive assessment of liver fibrosis by dual-layer spectral detector CT.

PURPOSE: To elucidate the diagnostic ability of liver fibrosis using (1) liver parenchymal iodine density on equilibrium computed tomographic imaging and (2) extracellular volume (ECV) measured by dual-layer spectral detector CT. METHODS: From April 2018 to June 2019, 68 patients [mean age, 62 years; 39 males, 29 females] underwent dynamic contrast-enhanced CT by a dual-layer spectral detector CT system before liver transplantation or liver resection. The iodine densities of liver parenchyma (I liver) and aorta (I aorta) were independently measured by two radiologists at the equilibrium phase. The iodine-density ratio (I-ratio) (I liver/ I aorta) and the CT-ECV were calculated. Spearman's rank correlation coefficient was used to analyze the relationship between the I-ratio or the CT-ECV and the fibrosis stage. A receiver operating characteristic (ROC) curve analysis was performed to determine the accuracy of the I-ratio and the CT-ECV for discriminating fibrosis stages. RESULTS: For both readers, the I-ratio and the CT-ECV increased significantly as the fibrosis stage advanced (I-ratio: rho = 0.380 and 0.443, p < 0.01; CT-ECV: rho = 0.423 and 0.469, p < 0.01). The CT-ECV showed better diagnostic accuracy for staging fibrosis, and the area under the ROC curve values for discriminating F4 stage were 0.884 and 0.925. The two readers' cutoff values of the CT-ECV for diagnosing fibrosis as F4 were 26.2 % and 29.3 %, with 95.0 % and 90.0 % sensitivity and 72.9 % and 85.4 % specificity, respectively. CONCLUSION: The liver parenchymal iodine density on the equilibrium phase and the CT-ECV can be useful for predicting a high stage of liver fibrosis.

Biliary Stricture: The Achilles Heel of Pediatric Living Donor Liver Transplantation.

Since a 1989 report demonstrating successful living donor liver transplantation (LDLT), living donors have been increasingly used to overcome the disparity between organ supply and demand, especially in the cases of pediatric patients. Although short-term graft outcomes after LDLT have improved significantly because of progress in surgical techniques and immunosuppression, biliary stricture (BS) remains the Achilles heel of pediatric LDLT and is the major cause of significant long-term morbidity. BS results in poor quality of life or even in graft loss after LDLT, with a reported incidence of BS after pediatric LDLT of 10% to 35%. The suggested risk factors for BS after LDLT are hepatic arterial thrombosis, bile duct ischemia, acute cellular rejection, older donor age, and ABO incompatibility. Duct-to-duct biliary reconstruction, which enables an endoscopic approach to be attempted after BS, is the preferred technique for LDLT. Endoscopic approaches are less invasive and more convenient for recipients than surgical and percutaneous interventions. However, the major cause of end-stage liver disease in pediatric recipients is biliary atresia, and hepaticojejunostomy is needed to reconstruct the bile duct because of the lack of recipient bile duct. Endoscopic approaches for BS are usually less favorable in patients with hepaticojejunostomy than in those with duct-to-duct biliary reconstruction. Treatment options for BS after hepaticojejunostomy at many centers thus involve interventional radiology or surgical reintervention. Although endoscopic approaches remain controversial in pediatric recipients, several reports have shown them to be safe and less invasive.

Functional remnant liver assessment predicts liver-related morbidity after hepatic resection in patients with hepatocellular carcinoma.

AIM: We aimed to evaluate whether functional assessment of the future remnant liver is a predictor of postoperative morbidity after hepatic resection in patients with hepatocellular carcinoma (HCC). METHODS: One hundred forty-six patients who underwent hepatic resection for HCC were enrolled in this study. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced MRI (EOB-MRI) analysis for functional liver assessment was carried out before hepatic resection. The signal intensity in the remnant liver was measured and divided by the signal intensity of the major psoas muscle (the liver to major psoas muscle ratio, LMR) for standardization. The remnant liver function was calculated using the formula (LMR on the hepatobiliary phase/LMR on the precontrast image). Computed tomography liver volumetry was also carried out. The remnant functional liver was calculated as the remnant liver volume or volumetric rate × remnant liver function by EOB-MRI. RESULTS: Morbidities developed in 19 (13.0%) patients. Morbidities associated with the liver occurred in 7 patients (4.7%). There was no mortality during surgery. Median remnant liver function scores using EOB-MRI and remnant functional liver using volumetric rate or volumetry were 1.82 (range, 1.25-2.96), 155.9 (range, 64.7-285.3), and 1027 (range, 369-2148), respectively. Logistic regression analysis identified the remnant functional liver volume as the only independent predictor for liver-related morbidity. CONCLUSION: Remnant functional liver volume using computed tomography liver volumetry and EOB-MRI was a significantly useful predictor for liver-related morbidity after hepatic resection in patients with HCC.

Fibrosis in nonalcoholic fatty liver disease: Noninvasive assessment using computed tomography volumetry.

AIM: To evaluate the diagnostic performance of computed tomography (CT) volumetry for discriminating the fibrosis stage in patients with nonalcoholic fatty liver disease (NAFLD). METHODS: A total of 38 NAFLD patients were enrolled. On the basis of CT imaging, the volumes of total, left lateral segment (LLS), left medial segment, caudate lobe, and right lobe (RL) of the liver were calculated with a dedicated liver application. The relationship between the volume percentage of each area and fibrosis stage was analyzed using Spearman's rank correlation coefficient. A receiver operating characteristic (ROC) curve analysis was performed to determine the accuracy of CT volumetry for discriminating fibrosis stage. RESULTS: The volume percentages of the caudate lobe and the LLS significantly increased with the fibrosis stage (r = 0.815, P < 0.001; and r = 0.465, P = 0.003, respectively). Contrarily, the volume percentage of the RL significantly decreased with fibrosis stage (r = -0.563, P < 0.001). The volume percentage of the caudate lobe had the best diagnostic accuracy for staging fibrosis, and the area under the ROC curve values for discriminating fibrosis stage were as follows: ≥ F1, 0.896; ≥ F2, 0.929; ≥ F3, 0.955; and ≥ F4, 0.923. The best cut-off for advanced fibrosis (F3-F4) was 4.789%, 85.7% sensitivity and 94.1% specificity. CONCLUSION: The volume percentage of the caudate lobe calculated by CT volumetry is a useful diagnostic parameter for staging fibrosis in NAFLD patients.

Assessment of graft fibrosis by transient elastography in patients with recurrent hepatitis C after living donor liver transplantation.

BACKGROUND: Transient elastography (FibroScan) is a simple and noninvasive method to assess liver fibrosis by measuring liver stiffness and therefore can be a promising tool to evaluate liver fibrosis and avoid liver biopsy. We prospectively assessed the performance of transient elastography in patients with recurrent hepatitis C virus after living donor liver transplantation, in comparison with the surrogate serum markers. METHODS: Fifty-six patients with recurrent hepatitis C virus after living donor liver transplantation, who underwent both liver biopsy and transient elastography were included in this study. The grade of liver fibrosis (the Scheuer classification) obtained by biopsy was compared to liver stiffness measured by the transient elastography. RESULTS: The fibrosis grades were as follows: F0, n=22; F1, n=13; F2, n=9; F3, n=7; and F4, n=5. Liver stiffness values ranged from 2.9 to 72.0 kPa. The optimal cutoff values were 8.8 kPa for F>or=1, 9.9 kPa for F>or=2, 15.4 kPa for F>or=3, and 26.5 kPa for F>or=4. The area under the receiver operator characteristic curve for the diagnosis of fibrosis (F>or=2) by transient elastography was 0.92, while that by hyaluronic acid, type 4 collagen, alanine aminotransferase, and the aspartate transaminase to platelets ratio index were 0.52, 0.62, 0.64, and 0.70, respectively. CONCLUSIONS: These data suggest that transient elastography is a simple, noninvasive and reliable tool to assess liver fibrosis in patients with recurrent hepatitis C virus after living donor liver transplantation.

Biliary strictures in living donor liver transplantation: incidence, management, and technical evolution.

Biliary complications, biliary strictures (BS) in particular, continue to be a significant cause of morbidity after LDLT despite technical refinement. In this study, we assessed the incidence of BS and their management in living donor liver transplantation (LDLT) with special reference to the type of biliary reconstruction. A total of 182 LDLTs performed at our institution for either adult (n = 157) or pediatric (n = 25) patients were included in the study. The duct-to-duct (DD) biliary reconstruction was performed for 106 cases, while the conventional Roux-en-Y hepaticojejunostomy (HJ) was utilized for the remaining 76 cases. Overall, BS developed in 46/182 (25.3%) of the cases (DD, 26.4%; HJ, 25.0%). The 1- and 3-year cumulative incidences of BS were 22.9% and 31.9%, respectively, in the DD group, and 15.2% and 29.1%, respectively, in the HJ group (P= not significant). The left-lobe LDLT was more prone to develop BS. Continuous anastomosis tended to be associated with the high incidence of BS in the DD group. The incidence of anastomotic leak was significantly lower in the DD group. Intervention via either pre-cutaneous or endoscopic approach was successful in the majority of cases, although recurrence could occur in some patients. In conclusion, BS was not associated with the type of reconstruction in LDLT. The primary radiological or endoscopic interventions were satisfactory treatments of choice. Technical refinement is an important factor to reduce the incidence of BS.