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Background & aimsNon-alcoholic steatohepatitis (NASH) is prevalent in adults with obesity and can progress to cirrhosis. In a secondary analysis of prospectively acquired data from the multicenter, randomized, placebo-controlled FLINT trial, we investigated the relationship between reduction in adipose tissue compartment volumes and hepatic histologic improvement.MethodsAdult participants in the FLINT trial with paired liver biopsies and abdominal MRI exams at baseline and end-of-treatment (72 weeks) were included (n = 76). Adipose tissue compartment volumes were obtained using MRI.ResultsTreatment and placebo groups did not differ in baseline adipose tissue volumes, or in change in adipose tissue volumes longitudinally (p = 0.107 to 0.745). Deep subcutaneous adipose tissue (dSAT) and visceral adipose tissue volume reductions were associated with histologic improvement in NASH (i.e., NAS [non-alcoholic fatty liver disease activity score] reductions of ≥2 points, at least 1 point from lobular inflammation and hepatocellular ballooning, and no worsening of fibrosis) (p = 0.031, and 0.030, respectively). In a stepwise logistic regression procedure, which included demographics, treatment group, baseline histology, baseline and changes in adipose tissue volumes, MRI hepatic proton density fat fraction (PDFF), and serum aminotransferases as potential predictors, reductions in dSAT and PDFF were associated with histologic improvement in NASH (regression coefficient = -2.001 and -0.083, p = 0.044 and 0.033, respectively).ConclusionsIn adults with NASH in the FLINT trial, those with greater longitudinal reductions in dSAT and potentially visceral adipose tissue volumes showed greater hepatic histologic improvements, independent of reductions in hepatic PDFF.Clinical trial numberNCT01265498.Impact and implicationsAlthough central obesity has been identified as a risk factor for obesity-related disorders including insulin resistance and cardiovascular disease, the role of central obesity in non-alcoholic steatohepatitis (NASH) warrants further clarification. Our results highlight that a reduction in central obesity, specifically deep subcutaneous adipose tissue and visceral adipose tissue, may be related to histologic improvement in NASH. The findings from this analysis should increase awareness of the importance of lifestyle intervention in NASH for clinical researchers and clinicians. Future studies and clinical practice may design interventions that assess the reduction of deep subcutaneous adipose tissue and visceral adipose tissue as outcome measures, rather than simply weight reduction.

BackgroundRetrospective studies report that visualisation of the liver may be severely limited using ultrasound (US), potentially contributing to diminished sensitivity for detection of hepatocellular carcinoma (HCC) among patients with nonalcoholic fatty liver disease (NAFLD) and cirrhosis, but there are limited prospective data.AimsTo compare liver visualisation scores prospectively for US and abbreviated hepatobiliary phase (HBP) magnetic resonance imaging (AMRI) in a cohort of participants with NAFLD cirrhosis and a clinical indication for HCC surveillance.MethodsThis prospective multicenter study included 54 consecutive participants (67% women) with NAFLD cirrhosis who underwent contemporaneous US as well as HBP-AMRI with gadoxetic acid. Primary outcome was the proportion of imaging examinations with severe limitations in liver visualisation (visualisation score C) compared head-to-head between US and AMRI.ResultsThe mean (± standard deviation) age was 63.3 years (±8.4) and body mass index was 32.0 kg/m2 (±6.0). Nineteen participants (35%) had severe visualisation limitations on US, compared with 10 (19%) with AMRI, p

To detect potentially curable hepatocellular carcinoma (HCC), clinical practice guidelines recommend semiannual surveillance US of the liver in adult patients at risk for developing this malignancy, such as those with cirrhosis and some patients with chronic hepatitis B infection. However, cirrhosis and a large body habitus, both of which are increasingly prevalent in the United States and the rest of the world, may impair US visualization of liver lesions and reduce the sensitivity of surveillance with this modality. The low sensitivity of US for detection of early-stage HCC contributes to delayed diagnosis and increased mortality. Abbreviated MRI, a shortened MRI protocol tailored for early-stage detection of HCC, has been proposed as an alternative surveillance option that provides high sensitivity and specificity. Abbreviated MRI protocols include fewer sequences than a complete multiphase MRI examination and are specifically designed to identify small potentially curable HCCs that may be missed at US. Three abbreviated MRI strategies have been studied: (a) nonenhanced, (b) dynamic contrast material-enhanced, and (c) hepatobiliary phase contrast-enhanced abbreviated MRI. Retrospective studies have shown that simulated abbreviated MRI provides high sensitivity and specificity for early-stage HCC, mostly in nonsurveillance cohorts. If it is supported by scientific evidence in surveillance populations, adoption of abbreviated MRI could advance clinical practice by increasing early detection of HCC, allowing effective treatment and potentially prolonging life in the growing number of individuals with this cancer. Online supplemental material is available for this article. ©RSNA, 2020.

The aim of this study was to estimate parameters determining liver triglyceride composition (TC) using 1 H MRS and to assess how TC estimability is affected by proton density fat fraction (PDFF) in adults with nonalcoholic fatty liver disease (NAFLD). In this prospective single-site study, 199 adults with known or suspected NAFLD in whom other causes of liver disease were excluded underwent two 1 H MRS STimulated Echo Acquisition Method (STEAM) sequences at 3 T. A respiratory-gated water-suppressed free breathing sequence (TE 10 ms, 16 signal averages) was used to assess TC in terms of the number of double bonds (ndb) and methylene-interrupted double bonds (nmidb), and a single breath-hold-long TR, multi-TE sequence (TR 3500 ms), which acquired five single average spectra over TE 10-30 ms, was used to estimate liver PDFF. Ndb and nmidb estimability was qualitatively assessed for each case and summarized descriptively. The consistency of ndb and nmidb estimation was examined using ROC analysis. The relationship between ndb and nmidb values and PDFF was presented graphically. Quality-of-fit of ndb and nmidb versus PDFF was evaluated by Pearson-r correlation. A significance level of 0.05 was used. In 263 1 H MRS examinations performed on 199 adult participants, ndb and nmidb were successfully estimated in 7/53 (13.2%) examinations with PDFF < 4%, 13/30 (43.3%) examinations with PDFF between 4% and 7%, 33/41 (80.5%) examinations with PDFF between 7% and 10%, and 124/139 (89.2%) examinations with PDFF > 10% (maximum PDFF 38.1%). Liver TC could be estimated consistently for PDFF > 6.7%. Both ndb and nmidb decreased with increasing PDFF (ndb = 2.83-0.0160·PDFF, r = -0.449, P < 0.0001); nmidb = 0.75-0.0088·PDFF, r = -0.350, P < 0.0001). In a cohort of adults with known or suspected NAFLD, liver TC becomes more saturated as PDFF increases.

Purpose To determine in a large multicenter multireader setting the interreader reliability of Liver Imaging Reporting and Data System (LI-RADS) version 2014 categories, the major imaging features seen with computed tomography (CT) and magnetic resonance (MR) imaging, and the potential effect of reader demographics on agreement with a preselected nonconsecutive image set. Materials and Methods Institutional review board approval was obtained, and patient consent was waived for this retrospective study. Ten image sets, comprising 38-40 unique studies (equal number of CT and MR imaging studies, uniformly distributed LI-RADS categories), were randomly allocated to readers. Images were acquired in unenhanced and standard contrast material-enhanced phases, with observation diameter and growth data provided. Readers completed a demographic survey, assigned LI-RADS version 2014 categories, and assessed major features. Intraclass correlation coefficient (ICC) assessed with mixed-model regression analyses was the metric for interreader reliability of assigning categories and major features. Results A total of 113 readers evaluated 380 image sets. ICC of final LI-RADS category assignment was 0.67 (95% confidence interval [CI]: 0.61, 0.71) for CT and 0.73 (95% CI: 0.68, 0.77) for MR imaging. ICC was 0.87 (95% CI: 0.84, 0.90) for arterial phase hyperenhancement, 0.85 (95% CI: 0.81, 0.88) for washout appearance, and 0.84 (95% CI: 0.80, 0.87) for capsule appearance. ICC was not significantly affected by liver expertise, LI-RADS familiarity, or years of postresidency practice (ICC range, 0.69-0.70; ICC difference, 0.003-0.01 [95% CI: -0.003 to -0.01, 0.004-0.02]. ICC was borderline higher for private practice readers than for academic readers (ICC difference, 0.009; 95% CI: 0.000, 0.021). Conclusion ICC is good for final LI-RADS categorization and high for major feature characterization, with minimal reader demographic effect. Of note, our results using selected image sets from nonconsecutive examinations are not necessarily comparable with those of prior studies that used consecutive examination series. © RSNA, 2017.

We propose a novel method, the adaptive local window, for improving level set segmentation technique. The window is estimated separately for each contour point, over iterations of the segmentation process, and for each individual object. Our method considers the object scale, the spatial texture, and the changes of the energy functional over iterations. Global and local statistics are considered by calculating several gray level co-occurrence matrices. We demonstrate the capabilities of the method in the domain of medical imaging for segmenting 233 images with liver lesions. To illustrate the strength of our method, those lesions were screened by either Computed Tomography or Magnetic Resonance Imaging. Moreover, we analyzed images using three different energy models. We compared our method to a global level set segmentation, to a local framework that uses predefined fixed-size square windows and to a local region-scalable fitting model. The results indicate that our proposed method outperforms the other methods in terms of agreement with the manual marking and dependence on contour initialization or the energy model used. In case of complex lesions, such as low contrast lesions, heterogeneous lesions, or lesions with a noisy background, our method shows significantly better segmentation with an improvement of 0.25 ± 0.13 in Dice similarity coefficient, compared with state of the art fixed-size local windows (Wilcoxon, p

PurposeTo determine per-lesion sensitivity and positive predictive value (PPV) of gadoxetic acid-enhanced 3-T magnetic resonance (MR) imaging for the diagnosis of malignant lesions by using matched (spatially correlated) hepatectomy pathologic findings as the reference standard. Materials andMethodsIn this prospective, institutional review board-approved, HIPAA-compliant study, 20 patients (nine men, 11 women; mean age, 59 years) with malignant liver lesions who gave written informed consent underwent preoperative gadoxetic acid-enhanced 3-T MR imaging for surgical planning. Two image sets were independently analyzed by three readers to detect liver lesions (set 1 without and set 2 with hepatobiliary phase [HBP] images). Hepatectomy specimen ex vivo MR imaging assisted in matching gadoxetic acid-enhanced 3-T MR imaging findings with pathologic findings. Interreader agreement was assessed by using the Cohen κ coefficient. Per-lesion sensitivity and PPV were calculated.ResultsCohen κ values were 0.64-0.76 and 0.57-0.84, and overall per-lesion sensitivity was 45% (42 of 94 lesions) to 56% (53 of 94 lesions) and 58% (55 of 94 lesions) to 64% (60 of 94 lesions) for sets 1 and 2, respectively. The addition of HBP imaging did not affect interreader agreement but significantly improved overall sensitivity for one reader (P < .05) and almost for another (P = .05). Sensitivity for 0.2-0.5-cm lesions was 0% (0 of 26 lesions) to 8% (two of 26 lesions) for set 1 and 4% (one of 26 lesions) to 12% (three of 26 lesions) for set 2. Sensitivity for 0.6-1.0-cm lesions was 28% (nine of 32 lesions) to 59% (19 of 32 lesions) for set 1 and 66% (21 of 32 lesions) to 69% (22 of 32 lesions) for set 2. Sensitivity for lesions at least 1.0 cm in diameter was at least 81% (13 of 16 lesions) for set 1 and was not improved for set 2. PPV was 98% (56 of 57 lesions) to 100% (60 of 60 lesions) for all readers without differences between image sets or lesion size.ConclusionGadoxetic acid-enhanced 3-T MR imaging provides high per-lesion sensitivity and PPV for preoperative malignant liver lesion detection overall, although sensitivity for 0.2-0.5-cm malignant lesions is poor.

The aim of this study was to estimate parameters determining liver triglyceride composition (TC) using 1H MRS and to assess how TC estimability is affected by proton density fat fraction (PDFF) in adults with nonalcoholic fatty liver disease (NAFLD). In this prospective single‐site study, 199 adults with known or suspected NAFLD in whom other causes of liver disease were excluded underwent two 1H MRS STimulated Echo Acquisition Method (STEAM) sequences at 3 T. A respiratory‐gated water‐suppressed free breathing sequence (TE 10 ms, 16 signal averages) was used to assess TC in terms of the number of double bonds (ndb) and methylene‐interrupted double bonds (nmidb), and a single breath‐hold‐long TR, multi‐TE sequence (TR 3500 ms), which acquired five single average spectra over TE 10‐30 ms, was used to estimate liver PDFF. Ndb and nmidb estimability was qualitatively assessed for each case and summarized descriptively. The consistency of ndb and nmidb estimation was examined using ROC analysis. The relationship between ndb and nmidb values and PDFF was presented graphically. Quality‐of‐fit of ndb and nmidb versus PDFF was evaluated by Pearson‐r correlation. A significance level of 0.05 was used. In 263 1H MRS examinations performed on 199 adult participants, ndb and nmidb were successfully estimated in 7/53 (13.2%) examinations with PDFF < 4%, 13/30 (43.3%) examinations with PDFF between 4% and 7%, 33/41 (80.5%) examinations with PDFF between 7% and 10%, and 124/139 (89.2%) examinations with PDFF > 10% (maximum PDFF 38.1%). Liver TC could be estimated consistently for PDFF > 6.7%. Both ndb and nmidb decreased with increasing PDFF (ndb = 2.83‐0.0160·PDFF, r = ‐0.449, P < 0.0001); nmidb = 0.75‐0.0088·PDFF, r = ‐0.350, P < 0.0001). In a cohort of adults with known or suspected NAFLD, liver TC becomes more saturated as PDFF increases. [ABSTRACT FROM AUTHOR]

BACKGROUND. Histologic fibrosis stage is the most important prognostic factor in chronic liver disease. MR elastography (MRE) is the most accurate noninvasive method for detecting and staging liver fibrosis. Although accurate, manual ROI-based MRE analysis is complex, time-consuming, requires specialized readers, and is prone to methodologic variability and suboptimal interreader agreement. OBJECTIVE. The purpose of this study was to develop an automated convolutional neural network (CNN)-based method for liver MRE analysis, evaluate its agreement with manual ROI-based analysis, and assess its performance for classifying dichotomized fibrosis stages using histology as the reference standard. METHODS. In this retrospective cross-sectional study, 675 participants who underwent MRE using different MRI systems and field strengths at 28 imaging sites from five multicenter international clinical trials of nonalcoholic steatohepatitis were included for algorithm development and internal testing of agreement between automated CNN-based and manual ROI-based analyses. Eighty-one patients (52 women, 29 men; mean age, 54 years) who underwent MRE using a single 3-T system and liver biopsy for clinical purposes at a single institution were included for external testing of agreement between the two analysis methods and assessment of fibrosis stage discriminative performance. Agreement was evaluated using intraclass correlation coefficients (ICCs). Bootstrapping was used to compute 95% CIs. Discriminative performance of each method for dichotomized histologic fibrosis stage was evaluated by AUC and compared using bootstrapping. RESULTS. Mean CNN- and manual ROI-based stiffness measurements ranged from 3.21 to 3.34 kPa in trial participants and from 3.21 to 3.30 kPa in clinical patients. ICC for CNN- and manual ROI-based measurements was 0.98 (95% CI, 0.97-0.98) in trial participants and 0.99 (95% CI, 0.98-0.99) in clinical patients. AUCs for classification of dichotomized fibrosis stage ranged from 0.89 to 0.93 for CNN-based analysis and 0.87 to 0.93 for manual ROI-based analysis ( p = .23-.75). CONCLUSION. Stiffness measurements using the automated CNN-based method agreed strongly with manual ROI-based analysis across MRI systems and field strengths, with excellent discriminative performance for histology-determined dichotomized fibrosis stages in external testing. CLINICAL IMPACT. Given the high incidence of chronic liver disease worldwide, it is important that noninvasive tools to assess fibrosis are applied reliably across different settings. CNN-based analysis is feasible and may reduce reliance on expert image analysts.

To detect potentially curable hepatocellular carcinoma (HCC), clinical practice guidelines recommend semiannual surveillance US of the liver in adult patients at risk for developing this malignancy, such as those with cirrhosis and some patients with chronic hepatitis B infection. However, cirrhosis and a large body habitus, both of which are increasingly prevalent in the United States and the rest of the world, may impair US visualization of liver lesions and reduce the sensitivity of surveillance with this modality. The low sensitivity of US for detection of early-stage HCC contributes to delayed diagnosis and increased mortality. Abbreviated MRI, a shortened MRI protocol tailored for early-stage detection of HCC, has been proposed as an alternative surveillance option that provides high sensitivity and specificity. Abbreviated MRI protocols include fewer sequences than a complete multiphase MRI examination and are specifically designed to identify small potentially curable HCCs that may be missed at US. Three abbreviated MRI strategies have been studied: (a) nonenhanced, (b) dynamic contrast material-enhanced, and (c) hepatobiliary phase contrast-enhanced abbreviated MRI. Retrospective studies have shown that simulated abbreviated MRI provides high sensitivity and specificity for early-stage HCC, mostly in nonsurveillance cohorts. If it is supported by scientific evidence in surveillance populations, adoption of abbreviated MRI could advance clinical practice by increasing early detection of HCC, allowing effective treatment and potentially prolonging life in the growing number of individuals with this cancer. Online supplemental material is available for this article. © RSNA, 2020.

The aim of this study was to estimate parameters determining liver triglyceride composition (TC) using 1 H MRS and to assess how TC estimability is affected by proton density fat fraction (PDFF) in adults with nonalcoholic fatty liver disease (NAFLD). In this prospective single-site study, 199 adults with known or suspected NAFLD in whom other causes of liver disease were excluded underwent two 1 H MRS STimulated Echo Acquisition Method (STEAM) sequences at 3 T. A respiratory-gated water-suppressed free breathing sequence (TE 10 ms, 16 signal averages) was used to assess TC in terms of the number of double bonds (ndb) and methylene-interrupted double bonds (nmidb), and a single breath-hold-long TR, multi-TE sequence (TR 3500 ms), which acquired five single average spectra over TE 10-30 ms, was used to estimate liver PDFF. Ndb and nmidb estimability was qualitatively assessed for each case and summarized descriptively. The consistency of ndb and nmidb estimation was examined using ROC analysis. The relationship between ndb and nmidb values and PDFF was presented graphically. Quality-of-fit of ndb and nmidb versus PDFF was evaluated by Pearson-r correlation. A significance level of 0.05 was used. In 263 1 H MRS examinations performed on 199 adult participants, ndb and nmidb were successfully estimated in 7/53 (13.2%) examinations with PDFF < 4%, 13/30 (43.3%) examinations with PDFF between 4% and 7%, 33/41 (80.5%) examinations with PDFF between 7% and 10%, and 124/139 (89.2%) examinations with PDFF > 10% (maximum PDFF 38.1%). Liver TC could be estimated consistently for PDFF > 6.7%. Both ndb and nmidb decreased with increasing PDFF (ndb = 2.83-0.0160·PDFF, r = -0.449, P < 0.0001); nmidb = 0.75-0.0088·PDFF, r = -0.350, P < 0.0001). In a cohort of adults with known or suspected NAFLD, liver TC becomes more saturated as PDFF increases., (© 2020 John Wiley & Sons, Ltd.)

Objective: The purposes of this study were to determine the prevalence of altered MRI appearances of "posterior medial meniscus root ligament (PMMRL)" lesions, introduce a classification of lesion types, and report associated findings., Materials and Methods: We retrospectively reviewed 419 knee MRI studies to identify the presence of PMMRL lesions. Classification was established on the basis of lesions encountered. The medial compartment was assessed for medial meniscal tears in the meniscus proper, medial meniscal extrusion, insertional PMMRL osseous changes, regional synovitis, osteoarthritis, insufficiency fracture, and cruciate ligament abnormality., Results: PMMRL abnormalities occurred in 28.6% (120/419) of the studies: degeneration, 14.3% (60/419) and tear, 14.3% (60/419). Our classification system included degeneration and tearing. Tearing was categorized as partial or complete with delineation of the point of failure as entheseal, midsubstance, or junction to meniscus. Of all tears, 93.3% (56/60) occurred at the meniscal junction. Univariate analysis revealed significant differences between the knees with and without PMMRL lesions in age, medial meniscal tear, medial meniscal extrusion, insertional PMMRL osseous change, regional synovitis, osteoarthritis, insufficiency fracture (p=0.017), and cruciate ligament degeneration (p<0.001)., Conclusion: PMMRL lesions are commonly detected in symptomatic patients. We have introduced an MRI classification system. PMMRL lesions are significantly associated with age, medial meniscal tears, medial meniscal extrusion, insertional PMMRL osseous change, regional synovitis, osteoarthritis, insufficiency fracture, and cruciate ligament degeneration.