Body composition and muscle composition phenotypes in patients on waitlist and shortly after liver transplant - results from a pilot study.

BACKGROUND: Sarcopenia is common in end-stage liver disease and negatively impacts patients awaiting or undergoing liver transplantation (LT). Magnetic resonance imaging (MRI) may be used to measure body composition and sarcopenia. We aimed to evaluate the feasibility of MRI-based LT body composition profiling, describe waitlist body composition, and assess the natural rate of change in body composition while on the waitlist and post-LT. METHODS: This prospective pilot study recruited adults listed for LT at an urban, tertiary care facility. Eighteen participants were scanned at time of waitlisting and 15 had follow-up MRIs (waitlist and/or post-LT). An 8-min MRI was used to measure body composition (AMRA® Researcher) including thigh fat-free muscle volume (FFMV) and fat infiltration (MFI), visceral (VAT) and abdominal subcutaneous (ASAT) adipose tissue volumes, and liver fat. A sex- and BMI invariant FFMV z-score (z-FFMV) was calculated, and muscle composition (MC) phenotypes were defined using the muscle assessment score (consisting of the FFMV z-score and sex-adjusted MFI). Rate of body composition change was calculated using mixed-effect modelling and is presented as rate per 30 days. RESULTS: At time of waitlisting, 73% of the 18 participants had high MFI and 39% had the adverse MC (low FFMV z-score and high MFI) phenotype. Seven participants received an LT. Post-LT serial MRIs, at a median of 147 days apart within the first 200 days post-LT, demonstrated increased z-FFMV 0.22 SDs/(30 days) (p = 0.002), VAT 0.23 (p < 0.001), and ASAT 0.52 (p = 0.001) L/(30 days), but no change in MFI (p = 0.200) nor liver fat (p = 0.232). CONCLUSION: MRI-based body composition profiling is feasible in LT patients and shortly after LT. This can be amended to routine clinical scans and may help in early identification of patients who may benefit from interventions to improve body composition. In addition, body composition changes significantly over time after LT.

Assessing Tissue Hydration Dynamics Based on Water/Fat Separated MRI.

BACKGROUND: Optimal fluid status is an important issue in hemodialysis. Clinical evaluation of volume status and different diagnostic tools are used to determine hydration status in these patients. However, there is still no accurate method for this assessment. PURPOSE: To propose and evaluate relative lean water signal (LWSrel ) as a water-fat MRI-based tissue hydration measurement. STUDY TYPE: Prospective. POPULATION: A total of 16 healthy subjects (56 ± 6 years, 0 male) and 11 dialysis patients (60.3 ± 12.3 years, 9 male; dialysis time per week 15 ± 3.5 hours, dialysis duration 31.4 ± 27.9 months). FIELD STRENGTH/SEQUENCE: A 3 T; 3D spoiled gradient echo. ASSESSMENT: LWSrel , a measurement of the water concentration of tissue, was estimated from fat-referenced MR images. Segmentations of total adipose tissue as well as thigh and calf muscles were used to measure LWSrel and tissue volumes. LWSrel was compared between healthy subjects and dialysis patients, the latter before and after dialysis. Bioimpedance-based body composition monitor over hydration (BCM OH) was also measured. STATISTICAL TESTS: T-tests were used to compare differences between the healthy subjects and dialysis patients, as well as changes between before and after dialysis. Pearson correlation was calculated between MRI and non-MRI biomarkers. A P value <0.05 was considered statistically significant. RESULTS: The LWSrel in adipose tissue was significantly higher in the dialysis cohort compared with the healthy cohort (246.8% ± 60.0% vs. 100.0% ± 10.8%) and decreased significantly after dialysis (246.8 ± 60.0% vs. 233.8 ± 63.4%). Thigh and calf muscle volumes also significantly decreased by 3.78% ± 1.73% and 2.02% ± 2.50% after dialysis. There was a significant correlation between changes in adipose tissue LWSrel and ultrafiltration volume (r = 87), as well as with BCM OH (r = 0.66). DATA CONCLUSION: MRI-based LWSrel and tissue volume measurements are sensitive to tissue hydration changes occurring during dialysis. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 3.

A rapid, non-invasive, clinical surveillance for CachExia, sarcopenia, portal hypertension, and hepatocellular carcinoma in end-stage liver disease: the ACCESS-ESLD study protocol.

BACKGROUND: Liver cirrhosis, the advanced stage of many chronic liver diseases, is associated with escalated risks of liver-related complications like decompensation and hepatocellular carcinoma (HCC). Morbidity and mortality in cirrhosis patients are linked to portal hypertension, sarcopenia, and hepatocellular carcinoma. Although conventional cirrhosis management centered on treating complications, contemporary approaches prioritize preemptive measures. This study aims to formulate novel blood- and imaging-centric methodologies for monitoring liver cirrhosis patients. METHODS: In this prospective study, 150 liver cirrhosis patients will be enrolled from three Swedish liver clinics. Their conditions will be assessed through extensive blood-based markers and magnetic resonance imaging (MRI). The MRI protocol encompasses body composition profile with Muscle Assement Score, portal flow assessment, magnet resonance elastography, and a abbreviated MRI for HCC screening. Evaluation of lifestyle, muscular strength, physical performance, body composition, and quality of life will be conducted. Additionally, DNA, serum, and plasma biobanking will facilitate future investigations. DISCUSSION: The anticipated outcomes involve the identification and validation of non-invasive blood- and imaging-oriented biomarkers, enhancing the care paradigm for liver cirrhosis patients. Notably, the temporal evolution of these biomarkers will be crucial for understanding dynamic changes. TRIAL REGISTRATION: Clinicaltrials.gov, registration identifier NCT05502198. Registered on 16 August 2022. Link: https://classic. CLINICALTRIALS: gov/ct2/show/NCT05502198 .

Morphology and composition of the ventral neck muscles in individuals with chronic whiplash related disorders compared to matched healthy controls: a cross-sectional case-control study.

BACKGROUND: OBJECTIVE: Studies of cross-sectional area (CSA) (morphology) and muscle fat infiltration (MFI) (composition) in ventral neck muscles is scarce in patients with chronic whiplash associated disorders (WAD), especially for men and those with severe WAD compared with matched healthy controls. The aim was to compare CSA and MFI of sternocleidomastoid (SCM), longus capitis (LCA) and longus colli (LCO) in patients with chronic right-sided dominant moderate (Neck Disability Index: NDI < 40) or severe WAD (NDI ≥ 40), compared to age- and sex-matched healthy controls. METHODS: Cross-sectional case-control study with blinded investigators. Thirty-one patients with chronic WAD (17 women and 14 men, mean age 40 years) (SD 12.6, range 20-62)) and 31 age- and sex-matched healthy controls underwent magnetic resonance imaging of ventral neck muscles segmental level C4. RESULTS: Unique to the severe group was a larger magnitude of MFI in right SCM (p = 0.02) compared with healthy controls. There was no significant difference between the groups with regards to the other muscles and measures. CONCLUSIONS: Individuals with severe right-sided dominant WAD have a higher MFI in the right SCM compared to healthy controls. No other differences were found between the groups. The present study indicates that there are changes in the composition of muscles on the side of greatest pain.

Cardiovascular risk factors and body composition in adults with achondroplasia.

PURPOSE: An increased cardiovascular mortality has been reported in achondroplasia. This population-based, case-control study investigated cardiovascular risk factors and body composition in Norwegian adults with achondroplasia. METHODS: We conducted anthropometric, clinical, and laboratory assessments in 49 participants with achondroplasia, of whom 40 completed magnetic resonance imaging (MRI) for body composition analysis. Controls consisted of 98 UK Biobank participants, matched for body mass index (BMI), sex, and age. RESULTS: Participants were well matched for BMI (33.3 versus 32.5 kg/m2) and sex, but achondroplasia participants were younger than controls (mean age 41.1 versus 54.3 years). Individuals with achondroplasia had lower age-adjusted mean blood pressure, total and low-density lipoprotein (LDL) cholesterol, and triglycerides compared with controls, but similar fasting glucose and HbA1c values. Age-adjusted mean visceral fat store was 1.9 versus 5.3 L (difference -2.7, 95% confidence interval [CI] -3.6 to -1.9; P < 0.001), abdominal subcutaneous fat was 6.0 versus 11.2 L (-4.7, 95% CI -5.9 to -3.4; P < 0.001), and liver fat was 2.2 versus 6.9% (-2.8, 95% CI -5.2 to -0.4; P = 0.02). CONCLUSION: Despite a high BMI, the cardiovascular risks appeared similar or lower in achondroplasia compared with controls, indicating that other factors might contribute to the increased mortality observed in this condition.

MRI in Neuromuscular Diseases: An Emerging Diagnostic Tool and Biomarker for Prognosis and Efficacy.

There is an unmet need to identify biomarkers sensitive to change in rare, slowly progressive neuromuscular diseases. Quantitative magnetic resonance imaging (MRI) of muscle may offer this opportunity, as it is noninvasive and can be carried out almost independent of patient cooperation and disease severity. Muscle fat content correlates with muscle function in neuromuscular diseases, and changes in fat content precede changes in function, which suggests that muscle MRI is a strong biomarker candidate to predict prognosis and treatment efficacy. In this paper, we review the evidence suggesting that muscle MRI may be an important biomarker for diagnosis and to monitor change in disease severity. ANN NEUROL 2020;88:669-681.

MRI Assessment of Treatment Response in HIV-associated NAFLD: A Randomized Trial of a Stearoyl-Coenzyme-A-Desaturase-1 Inhibitor (ARRIVE Trial).

Aramchol, an oral stearoyl-coenzyme-A-desaturase-1 inhibitor, has been shown to reduce hepatic fat content in patients with primary nonalcoholic fatty liver disease (NAFLD); however, its effect in patients with human immunodeficiency virus (HIV)-associated NAFLD is unknown. The aramchol for HIV-associated NAFLD and lipodystrophy (ARRIVE) trial was a double-blind, randomized, investigator-initiated, placebo-controlled trial to test the efficacy of 12 weeks of treatment with aramchol versus placebo in HIV-associated NAFLD. Fifty patients with HIV-associated NAFLD, defined by magnetic resonance imaging (MRI)-proton density fat fraction (PDFF) ≥5%, were randomized to receive either aramchol 600 mg daily (n = 25) or placebo (n = 25) for 12 weeks. The primary endpoint was a change in hepatic fat as measured by MRI-PDFF in colocalized regions of interest. Secondary endpoints included changes in liver stiffness using magnetic resonance elastography (MRE) and vibration-controlled transient elastography (VCTE), and exploratory endpoints included changes in total-body fat and muscle depots on dual-energy X-ray absorptiometry (DXA), whole-body MRI, and cardiac MRI. The mean (± standard deviation) of age and body mass index were 48.2 ± 10.3 years and 30.7 ± 4.6 kg/m2 , respectively. There was no difference in the reduction in mean MRI-PDFF between the aramchol group at -1.3% (baseline MRI-PDFF 15.6% versus end-of-treatment MRI-PDFF 14.4%, P = 0.24) and the placebo group at -1.4% (baseline MRI-PDFF 13.3% versus end-of-treatment MRI-PDFF 11.9%, P = 0.26). There was no difference in the relative decline in mean MRI-PDFF between the aramchol and placebo groups (6.8% versus 1.1%, P = 0.68). There were no differences in MRE-derived and VCTE-derived liver stiffness and whole-body (fat and muscle) composition analysis by MRI or DXA. Compared to baseline, end-of-treatment aminotransferases were lower in the aramchol group but not in the placebo arm. There were no significant adverse events. Conclusion: Aramchol, over a 12-week period, did not reduce hepatic fat or change body fat and muscle composition by using MRI-based assessment in patients with HIV-associated NAFLD (clinicaltrials.gov ID:NCT02684591).

Biomarkers of liver fibrosis: prospective comparison of multimodal magnetic resonance, serum algorithms and transient elastography.

BACKGROUND AND AIMS: Accurate biomarkers for quantifying liver fibrosis are important for clinical practice and trial end-points. We compared the diagnostic performance of magnetic resonance imaging (MRI), including gadoxetate-enhanced MRI and 31P-MR spectroscopy, with fibrosis stage and serum fibrosis algorithms in a clinical setting. Also, in a subset of patients, MR- and transient elastography (MRE and TE) was evaluated when available. METHODS: Patients were recruited prospectively if they were scheduled to undergo liver biopsy on a clinical indication due to elevated liver enzyme levels without decompensated cirrhosis. Within a month of the clinical work-up, an MR-examination and liver needle biopsy were performed on the same day. Based on late-phase gadoxetate-enhanced MRI, a mathematical model calculated hepatobiliary function (relating to OATP1 and MRP2). The hepatocyte gadoxetate uptake rate (KHep) and the normalised liver-to-spleen contrast ratio (LSC_N10) were also calculated. Nine serum fibrosis algorithms were investigated (GUCI, King's Score, APRI, FIB-4, Lok-Index, NIKEI, NASH-CRN regression score, Forns' score, and NAFLD-fibrosis score). RESULTS: The diagnostic performance (AUROC) for identification of significant fibrosis (F2-4) was 0.78, 0.80, 0.69, and 0.78 for MRE, TE, LSC_N10, and GUCI, respectively. For the identification of advanced fibrosis (F3-4), the AUROCs were 0.93, 0.84, 0.81, and 0.82 respectively. CONCLUSION: MRE and TE were superior for non-invasive identification of significant fibrosis. Serum fibrosis algorithms developed for specific liver diseases are applicable in this cohort of diverse liver diseases aetiologies. Gadoxetate-MRI was sufficiently sensitive to detect the low function losses associated with fibrosis. None was able to efficiently distinguish between stages within the low fibrosis stages.Lay summaryExcessive accumulation of scar tissue, fibrosis, in the liver is an important aspect in chronic liver disease. To replace the invasive needle biopsy, we have explored non-invasive methods to assess liver fibrosis. In our study we found that elastographic methods, which assess the mechanical properties of the liver, are superior in assessing fibrosis in a clinical setting. Of interest from a clinical trial point-of-view, none of the tested methods was sufficiently accurate to distinguish between adjacent moderate fibrosis stages.

Pilot study on longitudinal change in pancreatic proton density fat fraction during a weight-loss surgery program in adults with obesity.

BACKGROUND: Quantitative-chemical-shift-encoded (CSE)-MRI methods have been applied to the liver. The feasibility and potential utility CSE-MRI in monitoring changes in pancreatic proton density fat fraction (PDFF) have not yet been demonstrated. PURPOSE: To use quantitative CSE-MRI to estimate pancreatic fat changes during a weight-loss program in adults with severe obesity and nonalcoholic fatty liver disease (NAFLD). To explore the relationship of reduction in pancreatic PDFF with reductions in anthropometric indices. STUDY TYPE: Prospective/longitudinal. POPULATION: Nine adults with severe obesity and NAFLD enrolled in a weight-loss program. FIELD STRENGTH/SEQUENCE: CSE-MRI fat quantification techniques and multistation-volumetric fat/water separation techniques were performed at 3 T. ASSESSMENT: PDFF values were recorded from parametric maps colocalized across timepoints. STATISTICAL TESTS: Rates of change of log-transformed variables across time were determined (linear-regression), and their significance assessed compared with no change (Wilcoxon test). Rates of change were correlated pairwise (Spearman's correlation). RESULTS: Mean pancreatic PDFF decreased by 5.7% (range 0.7-17.7%) from 14.3 to 8.6%, hepatic PDFF by 11.4% (2.6-22.0%) from 14.8 to 3.4%, weight by 30.9 kg (17.3-64.2 kg) from 119.0 to 88.1 kg, body mass index by 11.0 kg/m2 (6.3-19.1 kg/m2 ) from 44.1 to 32.9 kg/m2 , waist circumference (WC) by 25.2 cm (4.0-41.0 cm) from 133.1 to 107.9 cm, HC by 23.5 cm (4.5-47.0 cm) from 135.8 to 112.3 cm, visceral adipose tissue (VAT) by 2.9 L (1.7-5.7 L) from 7.1 to 4.2 L, subcutaneous adipose tissue (SCAT) by 4.0 L (2.9-7.4 L) from 15.0 to 11.0 L. Log-transformed rate of change for pancreatic PDFF was moderately correlated with log-transformed rates for hepatic PDFF, VAT, SCAT, and WC (ρ = 0.5, 0.47, 0.45, and 0.48, respectively), although not statistically significant. DATA CONCLUSION: Changes in pancreatic PDFF can be estimated by quantitative CSE-MRI in adults undergoing a weight-loss surgery program. Pancreatic and hepatic PDFF and anthropometric indices decreased significantly. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;50:1092-1102.

Using a 3% Proton Density Fat Fraction as a Cut-Off Value Increases Sensitivity of Detection of Hepatic Steatosis, Based on Results From Histopathology Analysis.

It is possible to estimate hepatic triglyceride content by calculating the proton density fat fraction (PDFF), using proton magnetic resonance spectroscopy (1H-MRS), instead of collecting and analyzing liver biopsy specimens to detect steatosis. However, the current PDFF cut-off value (5%) used to define steatosis by magnetic resonance was derived from studies that did not use histopathology as the reference standard. We performed a prospective study to determine the accuracy of 1H-MRS PDFF in the measurement of steatosis using histopathology analysis as the standard. We collected clinical, serologic, 1H-MRS PDFF, and liver biopsy data from 94 adult patients with increased levels of liver enzymes (≥6 mo) referred to the Department of Gastroenterology and Hepatology at Linköping University Hospital in Sweden from 2007 through 2014. Steatosis was graded using the conventional histopathology method and fat content was quantified in biopsy samples using stereologic point counts (SPCs). We correlated the 1H-MRS PDFF findings with SPCs (r = 0.92; P < .001). 1H-MRS PDFF results correlated with histopathology results (ρ = 0.87; P < .001), and SPCs correlated with histopathology results (ρ = 0.88; P < .001). All 25 subjects with PDFF values of 5.0% or more had steatosis based on histopathology findings (100% specificity for PDFF). However, of 69 subjects with PDFF values less than 5.0% (negative result), 22 were determined to have steatosis based on histopathology findings (53% sensitivity for PDFF). Reducing the PDFF cut-off value to 3.0% identified patients with steatosis with 100% specificity and 79% sensitivity; a PDFF cut-off value of 2.0% identified patients with steatosis with 94% specificity and 87% sensitivity. These findings might be used to improve noninvasive detection of steatosis.

Whole-body adipose tissue and lean muscle volumes and their distribution across gender and age: MR-derived normative values in a normal-weight Swiss population.

PURPOSE: To determine age- and gender-dependent whole-body adipose tissue and muscle volumes in healthy Swiss volunteers in Dixon MRI in comparison with anthropometric and bioelectrical impedance (BIA) measurements. METHODS: Fat-water-separated whole-body 3 Tesla MRI of 80 healthy volunteers (ages 20 to 62 years) with a body mass index (BMI) of 17.5 to 26.2 kg/m2 (10 men, 10 women per decade). Age and gender-dependent volumes of total adipose tissue (TAT), visceral adipose tissue (VAT), total abdominal subcutaneous adipose tissue (ASAT) and total abdominal adipose tissue (TAAT), and the total lean muscle tissue (TLMT) normalized for body height were determined by semi-automatic segmentation, and correlated with anthropometric and BIA measurements as well as lifestyle parameters. RESULTS: The TAT, ASAT, VAT, and TLMT indexes (TATi, ASATi, VATi, and TLMTi, respectively) (L/m2 ± standard deviation) for women/men were 6.4 ± 1.8/5.3 ± 1.7, 1.6 ± 0.7/1.2 ± 0.5, 0.4 ± 0.2/0.8 ± 0.5, and 5.6 ± 0.6/7.1 ± 0.7, respectively. The TATi correlated strongly with ASATi (r > 0.93), VATi, BMI and BIA (r > 0.70), and TAATi (r > 0.96), and weak with TLMTi for both genders (r > -0.34). The VAT was the only parameter showing an age dependency (r > 0.32). The BMI and BIA showed strong correlation with all MR-derived adipose tissue volumes. The TAT mass was estimated significantly lower from BIA than from MRI (both genders P < .001; mean bias -5 kg). CONCLUSIONS: The reported gender-specific MRI-based adipose tissue and muscle volumes might serve as normative values. The estimation of adipose tissue volumes was significantly lower from anthropometric and BIA measurements than from MRI. Magn Reson Med 79:449-458, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Robust water fat separated dual-echo MRI by phase-sensitive reconstruction.

PURPOSE: The purpose of this work was to develop and evaluate a robust water-fat separation method for T1-weighted symmetric two-point Dixon data. THEORY AND METHODS: A method for water-fat separation by phase unwrapping of the opposite-phase images by phase-sensitive reconstruction (PSR) is introduced. PSR consists of three steps; (1), identification of clusters of tissue voxels; (2), unwrapping of the phase in each cluster by solving Poisson's equation; and (3), finding the correct sign of each unwrapped opposite-phase cluster, so that the water-fat images are assigned the correct identities. Robustness was evaluated by counting the number of water-fat swap artifacts in a total of 733 image volumes. The method was also compared to commercial software. RESULTS: In the water-fat separated image volumes, the PSR method failed to unwrap the phase of one cluster and misclassified 10. One swap was observed in areas affected by motion and was constricted to the affected area. Twenty swaps were observed surrounding susceptibility artifacts, none of which spread outside the artifact affected regions. The PSR method had fewer swaps when compared to commercial software. CONCLUSION: The PSR method can robustly produce water-fat separated whole-body images based on symmetric two-echo spoiled gradient echo images, under both ideal conditions and in the presence of common artifacts. Magn Reson Med 78:1208-1216, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Test-retest reliability of rapid whole body and compartmental fat volume quantification on a widebore 3T MR system in normal-weight, overweight, and obese subjects.

PURPOSE: To measure the test-retest reliability of rapid (<15 min) whole body and visceral fat volume quantification in normal and obese subjects on a widebore 3T MR system and compare it with conventional manual segmentation. MATERIALS AND METHODS: Thirty participants (body mass index [BMI] 20.1-48.6 kg/m2 ) underwent two whole-body magnetic resonance imaging (MRI) examinations on a widebore 3T machine using a 2-point Dixon technique. Phase sensitive reconstruction and intensity inhomogeneity correction produced quantitative datasets of total adipose tissue (TAT), abdominal subcutaneous adipose tissue (ASAT), and visceral adipose tissue (VAT). The quantification was performed automatically using nonrigid atlas-based segmentation and compared with manual segmentation (SliceOmatic). RESULTS: The mean TAT was 31.74 L with a coefficient of variation (CV) of 0.79% and a coefficient of repeatability (CR) of 0.49 L. The ASAT was 7.92 L with a CV of 2.98% and a CR of 0.46 L. There was no significant difference in the semiautomated and manually segmented VAT (P = 0.73) but there were differences in the reliability of the two techniques. The mean semiautomated VAT was 2.56 L, CV 1.8%, and CR 0.09 L compared to the mean manually segmented VAT of 3.12 L, where the CV was 6.3% and the CR was 0.39 L. CONCLUSION: Rapid semiautomated whole body and compartmental fat volume quantification can be derived from a widebore 3T system, for a range of body sizes including obese patients, with "almost perfect" test-retest reliability. J. Magn. Reson. Imaging 2016;44:1464-1473.

Consistent intensity inhomogeneity correction in water-fat MRI.

PURPOSE: To quantitatively and qualitatively evaluate the water-signal performance of the consistent intensity inhomogeneity correction (CIIC) method to correct for intensity inhomogeneities METHODS: Water-fat volumes were acquired using 1.5 Tesla (T) and 3.0T symmetrically sampled 2-point Dixon three-dimensional MRI. Two datasets: (i) 10 muscle tissue regions of interest (ROIs) from 10 subjects acquired with both 1.5T and 3.0T whole-body MRI. (ii) Seven liver tissue ROIs from 36 patients imaged using 1.5T MRI at six time points after Gd-EOB-DTPA injection. The performance of CIIC was evaluated quantitatively by analyzing its impact on the dispersion and bias of the water image ROI intensities, and qualitatively using side-by-side image comparisons. RESULTS: CIIC significantly ( P1.5T≤2.3×10-4,P3.0T≤1.0×10-6) decreased the nonphysiological intensity variance while preserving the average intensity levels. The side-by-side comparisons showed improved intensity consistency ( Pint⁡≤10-6) while not introducing artifacts ( Part=0.024) nor changed appearances ( Papp≤10-6). CONCLUSION: CIIC improves the spatiotemporal intensity consistency in regions of a homogenous tissue type.

Characterization of brown adipose tissue by water-fat separated magnetic resonance imaging.

BACKGROUND: To evaluate the possibility of quantifying brown adipose tissue (BAT) volume and fat concentration with a high resolution, long echo time, dual-echo Dixon imaging protocol. METHODS: A 0.42 mm isotropic resolution water-fat separated MRI protocol was implemented by using the second opposite-phase echo and third in-phase echo. Fat images were calibrated with regard to the intensity of nearby white adipose tissue (WAT) to form relative fat content (RFC) images. To evaluate the ability to measure BAT volume and RFC contrast dynamics, rats were divided into two groups that were kept at 4° or 22°C for 5 days. The rats were then scanned in a 70 cm bore 3.0 Tesla MRI scanner and a human dual energy CT. Interscapular, paraaortal, and perirenal BAT (i/pa/pr-BAT) depots as well as WAT and muscle were segmented in the MRI and CT images. Biopsies were collected from the identified BAT depots. RESULTS: The biopsies confirmed that the three depots identified with the RFC images consisted of BAT. There was a significant linear correlation (P < 0.001) between the measured RFC and the Hounsfield units from DECT. Significantly lower iBAT RFC (P = 0.0064) and significantly larger iBAT and prBAT volumes (P = 0.0017) were observed in the cold stimulated rats. CONCLUSION: The calibrated Dixon images with RFC scaling can depict BAT and be used to measure differences in volume, and fat concentration, induced by cold stimulation. The high correlation between RFC and HU suggests that the fat concentration is the main RFC image contrast mechanism.

Test-retest reliability of automated whole body and compartmental muscle volume measurements on a wide bore 3T MR system.

PURPOSE: To measure the test-retest reproducibility of an automated system for quantifying whole body and compartmental muscle volumes using wide bore 3 T MRI. MATERIALS AND METHODS: Thirty volunteers stratified by body mass index underwent whole body 3 T MRI, two-point Dixon sequences, on two separate occasions. Water-fat separation was performed, with automated segmentation of whole body, torso, upper and lower leg volumes, and manually segmented lower leg muscle volumes. RESULTS: Mean automated total body muscle volume was 19·32 L (SD9·1) and 19·28 L (SD9·12) for first and second acquisitions (Intraclass correlation coefficient (ICC) = 1·0, 95% level of agreement -0·32-0·2 L). ICC for all automated test-retest muscle volumes were almost perfect (0·99-1·0) with 95% levels of agreement 1.8-6.6% of mean volume. Automated muscle volume measurements correlate closely with manual quantification (right lower leg: manual 1·68 L (2SD0·6) compared to automated 1·64 L (2SD 0·6), left lower leg: manual 1·69 L (2SD 0·64) compared to automated 1·63 L (SD0·61), correlation coefficients for automated and manual segmentation were 0·94-0·96). CONCLUSION: Fully automated whole body and compartmental muscle volume quantification can be achieved rapidly on a 3 T wide bore system with very low margins of error, excellent test-retest reliability and excellent correlation to manual segmentation in the lower leg. KEY POINTS: Sarcopaenia is an important reversible complication of a number of diseases. Manual quantification of muscle volume is time-consuming and expensive. Muscles can be imaged using in and out of phase MRI. Automated atlas-based segmentation can identify muscle groups. Automated muscle volume segmentation is reproducible and can replace manual measurements.

Liver transplant recipients have worse metabolic body phenotype compared with matched non-transplant controls.

Background and Aim: Quantification of body compartments, particularly the interaction between adipose tissue and skeletal muscle, is emerging as novel a biomarker of metabolic health. The present study evaluated the impact of liver transplant (LT) on body compartments. Methods: Totally 66 adult LT recipients were enrolled in whom body compartments including visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (ASAT), muscle fat infiltration (MFI), fat-free muscle volume (FFMV), and liver fat (LF) were quantified via whole body magnetic resonance imaging (MRI). To provide non-LT comparison, each LT recipient was matched to at least 150 non-LT controls for same sex, age, and body mass index (BMI) from the UK Biobank registry. Results: LT recipients (vs matched non-LT controls) had significantly higher subcutaneous (13.82 ± 5.47 vs 12.10 ± 5.10 L, P < 0.001) and visceral fat (7.59 ± 3.75 vs 6.72 ± 3.06 L, P = 0.003) and lower LF (5.88 ± 7.14 vs 8.75 ± 6.50%, P < 0.001) and muscle volume (11.69 ± 2.95 vs 12.12 ± 2.90 L, P = 0.027). In subgroup analysis, patients transplanted for metabolic dysfunction-associated steatohepatitis (MASH) cirrhosis (vs non-MASH cirrhosis) had higher ASAT, VAT, and MFI. A trend toward higher LF content was noted; however, this did not reach statistical significance (6.90 ± 7.35 vs 4.04 ± 6.23%, P = 0.189). Finally, compared with matched non-LT controls, patients transplanted for MASH cirrhosis had higher ASAT and VAT; however, FFMV and MFI were similar. Conclusion: Using non-LT controls, the current study established the higher-than-expected adiposity burden among LT recipients, which is even higher among patients transplanted for MASH cirrhosis. These findings provide data needed to design future studies developing radiomics-based risk-stratification strategies in LT recipients.

Safety and efficacy of losmapimod in facioscapulohumeral muscular dystrophy (ReDUX4): a randomised, double-blind, placebo-controlled phase 2b trial.

BACKGROUND: Facioscapulohumeral muscular dystrophy is a hereditary progressive myopathy caused by aberrant expression of the transcription factor DUX4 in skeletal muscle. No approved disease-modifying treatments are available for this disorder. We aimed to assess the safety and efficacy of losmapimod (a small molecule that inhibits p38α MAPK, a regulator of DUX4 expression, and p38ß MAPK) for the treatment of facioscapulohumeral muscular dystrophy. METHODS: We did a randomised, double-blind, placebo-controlled phase 2b trial at 17 neurology centres in Canada, France, Spain, and the USA. We included adults aged 18-65 years with type 1 facioscapulohumeral muscular dystrophy (ie, with loss of repression of DUX4 expression, as ascertained by genotyping), a Ricci clinical severity score of 2-4, and at least one skeletal muscle judged using MRI to be suitable for biopsy. Participants were randomly allocated (1:1) to either oral losmapimod (15 mg twice a day) or matching placebo for 48 weeks, via an interactive response technology system. The investigator, study staff, participants, sponsor, primary outcome assessors, and study monitor were masked to the treatment allocation until study closure. The primary endpoint was change from baseline to either week 16 or 36 in DUX4-driven gene expression in skeletal muscle biopsy samples, as measured by quantitative RT-PCR. The primary efficacy analysis was done in all participants who were randomly assigned and who had available data for assessment, according to the modified intention-to-treat principle. Safety and tolerability were assessed as secondary endpoints. This study is registered at ClinicalTrials.gov, number NCT04003974. The phase 2b trial is complete; an open-label extension is ongoing. FINDINGS: Between Aug 27, 2019, and Feb 27, 2020, 80 people were enrolled. 40 were randomly allocated to losmapimod and 40 to placebo. 54 (68%) participants were male and 26 (33%) were female, 70 (88%) were White, and mean age was 45·7 (SD 12·5) years. Least squares mean changes from baseline in DUX4-driven gene expression did not differ significantly between the losmapimod (0·83 [SE 0·61]) and placebo (0·40 [0·65]) groups (difference 0·43 [SE 0·56; 95% CI -1·04 to 1·89]; p=0·56). Losmapimod was well tolerated. 29 treatment-emergent adverse events (nine drug-related) were reported in the losmapimod group compared with 23 (two drug-related) in the placebo group. Two participants in the losmapimod group had serious adverse events that were deemed unrelated to losmapimod by the investigators (alcohol poisoning and suicide attempt; postoperative wound infection) compared with none in the placebo group. No treatment discontinuations due to adverse events occurred and no participants died during the study. INTERPRETATION: Although losmapimod did not significantly change DUX4-driven gene expression, it was associated with potential improvements in prespecified structural outcomes (muscle fat infiltration), functional outcomes (reachable workspace, a measure of shoulder girdle function), and patient-reported global impression of change compared with placebo. These findings have informed the design and choice of efficacy endpoints for a phase 3 study of losmapimod in adults with facioscapulohumeral muscular dystrophy. FUNDING: Fulcrum Therapeutics.

Preoperative and postoperative 1H-MR spectroscopy changes in frontal deep white matter and the thalamus in idiopathic normal pressure hydrocephalus.

BACKGROUND: In a previous study we found significantly decreased N-acetyl aspartate (NAA) and total N-acetyl (tNA) groups in the thalamus of patients with idiopathic normal pressure hydrocephalus (iNPH) compared with healthy individuals (HI). No significant difference between the groups could be found in the frontal deep white matter (FDWM). OBJECTIVE: The primary aim of this study was to investigate if these metabolites in the thalamus were normalised after shunt surgery. The secondary aim was to investigate postoperative metabolic changes in FDWM. SUBJECTS AND METHODS: Fourteen patients with iNPH, mean age 74 years, and 15 HI, also mean age 74 years, were examined. Assessment of a motor score (MOSs) was performed before and after shunt surgery. Absolute quantitative (1)H-MR spectroscopy (1.5 T, volumes of interest 2.5-3 ml) was performed on the patients in the FDWM and in the thalamus, before and 3 months after shunt surgery, and also once on the HI. The following metabolites were analysed: tNA, NAA, total creatine, total choline (tCho), myo-inositol (mIns), glutamate and lactate concentrations. MRI volumetric calculations of the lateral ventricles were also performed. RESULTS: At 3 months postoperatively, we found no significant changes of tNA or NAA in the thalamus. In contrast, in the FDWM, there was a significant increase of tCho (p=0.01) and a borderline significant decrease of mIns (p=0.06). 12/14 patients were shunt responders (motor function). Median reduction of the lateral ventricle was 16%. A weak correlation between MOS and ventricular reduction was seen. CONCLUSIONS: Normalisation of thalamic tNA and NAA could not be detected postoperatively. The increased tCho and decreased mIns in the FDWM postoperatively might relate to clinical improvement.