MRI-serum-based score accurately identifies patients undergoing liver transplant without rejection avoiding the need for liver biopsy: A multisite European study.

Serum liver tests (serum tests) and histological assessment for T-cell-mediated rejection are essential for post-liver transplant monitoring. Liver biopsy carries a risk of complications that are preferably avoided in low-risk patients. Multiparametric magnetic resonance imaging (mpMRI) is a reliable noninvasive diagnostic method that quantifies liver disease activity and has prognostic utility. Our aim was to determine whether using mpMRI in combination with serum tests could noninvasively identify low-risk patients who underwent liver transplants who are eligible to avoid invasive liver biopsies. In a multicenter prospective study (RADIcAL2), including 131 adult and pediatric (children and adolescent) patients with previous liver transplants from the Netherlands, Portugal, and the United Kingdom, concomitant mpMRI and liver biopsies were performed. Biopsies were centrally read by 2 expert pathologists. T-cell-mediated rejection was assessed using the BANFF global assessment. Diagnostic accuracy to discriminate no rejection versus indeterminate or T-cell-mediated liver transplant rejection was performed using the area under the receiver operating characteristic curve. In this study, 52% of patients received a routine (protocol) biopsy, while 48% had a biopsy for suspicion of pathology. Thirty-eight percent of patients had no rejection, while 62% had either indeterminate (21%) or T-cell-mediated rejection (41%). However, there was a high interobserver variability (0 < Cohen's Kappa < 0.85) across all histology scores. The combined score of mpMRI and serum tests had area under the receiver operating characteristic curve 0.7 (negative predictive value 0.8) to identify those without either indeterminate or T-cell-mediated rejection. Combining both imaging and serum biomarkers into a composite biomarker (imaging and serum biomarkers) has the potential to monitor the liver graft to effectively risk stratify patients and identify those most likely to benefit from a noninvasive diagnostic approach, reducing the need for liver biopsy.

Multiparametric Magnetic Resonance Imaging and Magnetic Resonance Elastography to Evaluate the Early Effects of Bariatric Surgery on Nonalcoholic Fatty Liver Disease.

Background: Bariatric surgery is the most effective treatment for morbid obesity and reduces the severity of nonalcoholic fatty liver disease (NAFLD) in the long term. Less is known about the effects of bariatric surgery on liver fat, inflammation, and fibrosis during the early stages following bariatric surgery. Aims: This exploratory study utilises advanced imaging methods to investigate NAFLD and fibrosis changes during the early metabolic transitional period following bariatric surgery. Methods: Nine participants with morbid obesity underwent sleeve gastrectomy. Multiparametric MRI (mpMRI) and magnetic resonance elastography (MRE) were performed at baseline, during the immediate (1 month), and late (6 months) postsurgery period. Liver fat was measured using proton density fat fraction (PDFF), disease activity using iron-correct T1 (cT1), and liver stiffness using MRE. Repeated measured ANOVA was used to assess longitudinal changes and Dunnett's method for multiple comparisons. Results: All participants (Age 45.1 ± 9.0 years, BMI 39.7 ± 5.3 kg/m2) had elevated hepatic steatosis at baseline (PDFF >5%). In the immediate postsurgery period, PDFF decreased significantly from 14.1 ± 7.4% to 8.9 ± 4.4% (p = 0.016) and cT1 from 826.9 ± 80.6 ms to 768.4 ± 50.9 ms (p = 0.047). These improvements continued to the later postsurgery period. Bariatric surgery did not reduce liver stiffness measurements. Conclusion: Our findings support using MRI as a noninvasive tool to monitor NAFLD in patient with morbid obesity during the early stages following bariatric surgery.

Comparison between magnetic resonance and ultrasound-derived indicators of hepatic steatosis in a pooled NAFLD cohort.

BACKGROUND & AIMS: MRI-based proton density fat fraction (PDFF) and the ultrasound-derived controlled attenuation parameter (CAP) are non-invasive techniques for quantifying liver fat, which can be used to assess steatosis in patients with non-alcoholic fatty liver disease (NAFLD). This study compared both of these techniques to histopathological graded steatosis for the assessment of fat levels in a large pooled NAFLD cohort. METHODS: This retrospective study pooled N = 581 participants from two suspected NAFLD cohorts (mean age (SD) 56 (12.7), 60% females). Steatosis was graded according to NASH-CRN criteria. Liver fat was measured non-invasively using PDFF (with Liver MultiScan's Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation method, LMS-IDEAL, Perspectum, Oxford) and CAP (FibroScan, Echosens, France), and their diagnostic performances were compared. RESULTS: LMS-IDEAL and CAP detected steatosis grade ≥ 1 with AUROCs of 1.00 (95% CI, 0.99-1.0) and 0.95 (95% CI, 0.91-0.99), respectively. LMS-IDEAL was superior to CAP for detecting steatosis grade ≥ 2 with AUROCs of 0.77 (95% CI, 0.73-0.82] and 0.60 (95% CI, 0.55-0.65), respectively. Similarly, LMS-IDEAL outperformed CAP for detecting steatosis grade ≥ 3 with AUROCs of 0.81 (95% CI, 0.76-0.87) and 0.63 (95% CI, 0.56-0.70), respectively. CONCLUSION: LMS-IDEAL was able to diagnose individuals accurately across the spectrum of histological steatosis grades. CAP performed well in identifying individuals with lower levels of fat (steatosis grade ≥1); however, its diagnostic performance was inferior to LMS-IDEAL for higher levels of fat (steatosis grades ≥2 and ≥3). TRIAL REGISTRATION: ClinicalTrials.gov (NCT03551522); https://clinicaltrials.gov/ct2/show/NCT03551522. UMIN Clinical Trials Registry (UMIN000026145); https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000026145.