Current Noninvasive MR-Based Imaging Methods in Assessing NAFLD Patients

The chapter will focus on the different aspects of nonalcoholic fatty liver disease (NAFLD). An update in noninvasive MR-based imaging will be offered in detail, pointing mainly to fat, iron, and fibrosis deposition and the accuracy of quantitative methods in disease grading and severity assessment. NAFLD is the most common cause of chronic liver disease (CLD) in Western countries. MRI is used to evaluate the disease, to assess the severity, and to quantify the amount of fat deposition, being also the method of choice to evaluate and quantify iron overload. Diagnosis and staging of liver fibrosis is one of the most challenging aspects of noninvasive imaging. “Virtual biopsy” refers to the possibility of imaging techniques to depict, map, and measure fibrosis minimizing the need for invasive liver biopsies in CLD. MRI allows an accurate determination of steatosis, iron overload, and fibrosis, even if they coexist

Liver Multiacinar Regenerative Nodules: Imaging Findings and Clinical Implications

Introduction: Multiacinar regenerative nodules are benign hepatocellular nodules related to vascular disturbances of the liver. They strongly resemble conventional focal nodular hyperplasia but are connected to different clinical settings, typically chronic liver disease. The purpose of the present study was to describe the key imaging features of these lesions and compare them with a control arm of focal nodular hyperplasia. Material and Methods: A blinded consensus review of liver magnetic resonance consisting of 26 cases of multiacinar regenerative nodules and 25 cases of focal nodular hyperplasia was performed. Lesion size, shape, margins, structure, T1 and T2 signal intensity, diffusion and contrast-enhanced features (including hepatobiliary phase), presence of a central scar and of a peripheral hypointense rim were compared between the two groups. Results: Significant differences between multiacinar regenerative nodules and focal nodular hyperplasia included size (median 2.35 cm, IQR: 2.13, vs 6.00 cm, IQR: 5.20, respectively, p < 0.001), presence of a peripheral hypointense rim after contrast (n = 9 vs n = 2 cases, p = 0.038) and of a central scar (n = 9 vs n = 20, p = 0.002). There were no other significant differences. Discussion: Overall multiacinar regenerative nodules and focal nodular hyperplasia have very similar imaging features but lack of a central scar and presence of a hypointense rim should suggest a diagnosis of multiacinar regenerative nodules. Conclusions: Recognition of the imaging findings of multiacinar regenerative nodules can explain some atypical cases of focal nodular hyperplasia, avoiding unnecessary biopsies. They may also be the trigger to investigate an unsuspected underlying liver vascular abnormality

Noninvasive Monitoring of Liver Disease Regression after Hepatitis C Eradication Using Gadoxetic Acid-Enhanced MRI

We evaluated changes in relative liver enhancement (RLE) obtained by gadoxetic acid-enhanced MRI (GA-MRI) in the hepatobiliary phase and changes in splenic volume (SV) after hepatitis C virus (HCV) eradication as well as their predictive value for the development of (further) hepatic decompensation during follow-up. This retrospective study comprised 31 consecutive patients with HCV-induced advanced chronic liver disease who underwent GA-MRI before and after successful interferon-free treatment, as well as a cohort of 14 untreated chronic HCV-patients with paired GA-MRI. RLE increased by 66% (20%–94%; P<0.001) from pre- to posttreatment, while SV decreased by −16% (−28% to −8%; P<0.001). However, SV increased in 16% (5/31) of patients, the identical subjects who showed a decrease in RLE (GA-MRI-nonresponse). We observed an inverse correlation between the changes in RLE and SV (ρ=−0.608;  P<0.001). In the untreated patients, there was a decrease in RLE by −11% (−25% to −3%; P=0.019) and an increase in SV by 23% (7%–43%; P=0.004) (both P<0.001 versus treated patients). Interestingly, GA-MRI-nonresponse was associated with a substantially increased risk of (further) hepatic decompensation 2 years after the end of treatment: 80% versus 8%; P<0.001. GA-MRI might distinguish between individuals at low and high risk of (further) hepatic decompensation (GA-MRI-nonresponse) after HCV eradication. This could allow for individualized surveillance strategies

Hepatocellular adenomas: Understanding the pathomolecular lexicon, MRI features, terminology, and pitfalls to inform a standardized approach.

Hepatocellular adenomas (HCAs) are benign hepatic tumors that can be complicated by bleeding and/or malignant transformation. The epidemiology of HCAs has changed over recent decades, primarily influenced by an increased incidence of obesity in both men and women. Currently, at least eight distinct pathomolecular subtypes of HCAs have been identified, several of which have distinguishing and pertinent imaging features on MRI. Emerging evidence suggests that hepatobiliary phase appearance may provide diagnostic and prognostic information. The purpose of this article is to review the current pathomolecular lexicon and imaging features with emphasis on hepatobiliary phase appearance. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:1630-1640

European Radiology / The Efficacy of MRI in the diagnostic workup of cystic fibrosis-associated liver disease : A clinical observational cohort study

Purpose To identify independent imaging features and establish a diagnostic algorithm for diagnosis of cystic fibrosis (CF)-associated liver disease (CFLD) in CF patients compared to controls using gadoxetic acid-enhanced MRI. Methods A total of 90 adult patients were enrolled: 50 with CF, 40 controls. The CF group was composed of two subgroups: a retrospective test subgroup (n = 33) and a prospective validation subgroup (n = 17). Controls (patients with normal liver enzymes and only benign focal liver lesions) were divided accordingly (27:13). MRI variables, including quantitative and qualitative parameters, were used to distinguish CFLD from controls using clinical symptoms, laboratory tests and Debray criteria. Disease severity was classified according to Child-Pugh and Albumin-Bilirubin (ALBI) scores. Fifteen qualitative single-lesion CF descriptors were defined. Two readers independently evaluated the images. Univariate statistical analysis was performed to obtain significant imaging features that differentiate CF patients from controls. Through multivariate analysis using chi-squared automatic interaction detector (CHAID) methodology the most important descriptors were identified. Diagnostic performance was assessed by receiver-operating characteristic (ROC) analysis. Results Three independent imaging descriptors distinguished CFLD from controls: (1) presence of altered gallbladder morphology; (2) periportal tracking; and (3) periportal fat deposition. Prospective validation of the classification algorithm demonstrated a sensitivity of 94.1% and specificity of 84.6% for discriminating CFLD from controls. Disease severity was well associated with the imaging features. Conclusions A short unenhanced MRI protocol can identify the three cardinal imaging features of CFLD. The hepatobiliary phase of gadoxetic acid-enhanced MRI can define CFLD progression.(VLID)362009

European Radiology / Inter- and intra-reader agreement for gadoxetic acidenhanced MRI parameter readings in patients with chronic liver diseases

Objectives To examine inter- and intra-observer agreement for four simple hepatobiliary phase (HBP)based scores on gadoxetic acid (GA)enhanced MRI and their correlation with liver function in patients with mixed chronic liver disease (CLD). Methods This single-center, retrospective study included 287 patients (62% male, 38% female, mean age 53.5 13.7 years) with mixed CLD (20.9% hepatitis C, 19.2% alcoholic liver disease, 8% hepatitis B) who underwent GA-enhanced MRI of the liver for clinical care between 2010 and 2015. Relative liver enhancement (RLE), contrast uptake index (CUI), hepatic uptake index (HUI), and liver-to-spleen contrast index (LSI) were calculated by two radiologists independently using unenhanced and GA-enhanced HPB (obtained 20 min after GA administration) images; 50 patients selected at random were reviewed twice by one reader to assess intra-observer reliability. Agreement was assessed by intraclass correlation coefficient (ICC). The albumin-bilirubin (ALBI) score, the model of end-stage liver disease (MELD), and the Child-Turcotte-Pugh (CTP) score were calculated as standards of reference for hepatic function. Results Intra-observer ICCs ranged from 0.814 (0.6680.896) for CUI to 0.969 (0.9450.983) for RLE. Inter-observer ICCs ranged from 0.777 (0.6050.874) for HUI to 0.979 (0.9630.988) for RLE. All HBP-based scores correlated significantly (all p < 0.001) with the ALBI, MELD, and CTP scores and were able to discriminate patients with a MELD score 15 versus 14, with area under the curve values ranging from 0.760 for RLE to 0.782 for HUI. Conclusion GA-enhanced, MRI-derived, HBP-based parameters showed excellent inter- and intra-observer agreement. All HBP-based parameters correlated with clinical and laboratory scores of hepatic dysfunction, with no significant differences between each other. Key Points Radiological parameters that quantify the hepatic uptake of gadoxetic acid are highly reproducible. These parameters can be used interchangeably because they correlate with each other and with scores of hepatic dysfunction. Assessment of these parameters may be helpful in monitoring disease progression.(VLID)504051