Comprehensive quantitative magnetic resonance imaging assessment of skeletal muscle pathophysiology in golden retriever muscular dystrophy: Insights from multicomponent water T2 and extracellular volume fraction.

Quantitative MRI and MRS have become important tools for the assessment and management of patients with neuromuscular disorders (NMDs). Despite significant progress, there is a need for new objective measures with improved specificity to the underlying pathophysiological alteration. This would enhance our ability to characterize disease evolution and improve therapeutic development.

Effect of sirolimus on muscle in inclusion body myositis observed with magnetic resonance imaging and spectroscopy.

Background: Finding sensitive clinical outcome measures has become crucial in natural history studies and therapeutic trials of neuromuscular disorders. Here, we focus on 1-year longitudinal data from quantitative magnetic resonance imaging (MRI) and phosphorus magnetic resonance spectroscopy (P MRS) in a placebo-controlled study of sirolimus for inclusion body myositis (IBM), also examining their links to functional, strength, and clinical parameters in lower limb muscles.

Methods: Quantitative MRI and P MRS data were collected at 3 T from a single site, involving 44 patients (22 on placebo, 22 on sirolimus) at baseline and year-1, and 21 healthy controls.

Multiparametric Aging Study Across Adulthood in the Leg Through Quantitative MR Imaging, H Spectroscopy, and P Spectroscopy at 3T.

Background: Improved characterization of healthy muscle aging is needed to establish early biomarkers in age-related diseases.

Purpose: To quantify age-related changes on multiple MRI and clinical variables evaluated in the same cohort and identify correlations among them.

Study Type: Prospective.

GDF5 as a rejuvenating treatment for age-related neuromuscular failure.

Sarcopenia involves a progressive loss of skeletal muscle force, quality and mass during ageing, which results in increased inability and death; however, no cure has been established thus far. Growth differentiation factor 5 (GDF5) has been described to modulate muscle mass maintenance in various contexts. For our proof of concept, we overexpressed GDF5 by AAV vector injection in tibialis anterior muscle of adult aged (20 months) mice and performed molecular and functional analysis of skeletal muscle.

Reduced subjective sleep quality in people rating themselves as electro-hypersensitive: An observational study.

Background: Disturbed sleep is among the most frequent health complaints of people exposed to radio frequency electromagnetic fields (RF-EMF) used in mobile telecommunication, particularly in individuals who consider themselves as EMF hypersensitive (EHS). We aimed at investigating whether the EHS status per se is associated with sleep complaints. Because allelic variants of the gene encoding the L-type, voltage-gated calcium channel Ca1.

Compositional and Functional MRI of Skeletal Muscle: A Review.

Due to its exceptional sensitivity to soft tissues, MRI has been extensively utilized to assess anatomical muscle parameters such as muscle volume and cross-sectional area. Quantitative Magnetic Resonance Imaging (qMRI) adds to the capabilities of MRI, by providing information on muscle composition such as fat content, water content, microstructure, hypertrophy, atrophy, as well as muscle architecture. In addition to compositional changes, qMRI can also be used to assess function for example by measuring muscle quality or through characterization of muscle deformation during passive lengthening/shortening and active contractions.

Bi-component dictionary matching for MR fingerprinting for efficient quantification of fat fraction and water T in skeletal muscle.

Purpose: To propose an efficient bi-component MR fingerprinting (MRF) fitting method using a Variable Projection (VARPRO) strategy, applied to the quantification of fat fraction (FF) and water T1 ( ) in skeletal muscle tissues.

Methods: The MRF signals were analyzed in a two-step process by comparing them to the elements of separate water and fat dictionaries (bi-component dictionary matching). First, each pair of water and fat dictionary elements was fitted to the acquired signal to determine an optimal FF that was used to merge the fingerprints in a combined water/fat dictionary.

Assessment of Extracellular Volume Fraction in Becker Muscular Dystrophy by Using MR Fingerprinting.

Background Quantitative MRI is increasingly proposed in clinical trials related to dystrophinopathies, including Becker muscular dystrophy (BMD). Purpose To establish the sensitivity of extracellular volume fraction (ECV) quantification using an MR fingerprinting sequence with water and fat separation as a quantitative imaging biomarker of skeletal muscle tissue alterations in BMD compared with fat fraction (FF) and water relaxation time quantification. Materials and Methods In this prospective study, study participants with BMD and healthy volunteers were included from April 2018 until October 2022 ( identifier NCT02020954).

New Insights into the Spread of MRS-Based Water T2 Values Observed in Highly Fatty Replaced Muscles.

Background: The reference standard for assessing water T (T ) at high fat fraction (FF) is H MRS. T (T ) dependence on FF (FF ) has recently been demonstrated in muscle at high FF (i.e.

Sodium and quantitative hydrogen parameter changes in muscle tissue after eccentric exercise and in delayed-onset muscle soreness assessed with magnetic resonance imaging.

The objective of the current study was to assess sodium ( Na) and quantitative proton ( H) parameter changes in muscle tissue with magnetic resonance imaging (MRI) after eccentric exercise and in delayed-onset muscle soreness (DOMS). Fourteen participants (mean age: 25 ± 4 years) underwent Na/ H MRI of the calf muscle on a 3-T MRI system before exercise (t0), directly after eccentric exercise (t1), and 48 h postintervention (t2). In addition to tissue sodium concentration (TSC), intracellular-weighted sodium (ICwS) signal was acquired using a three-dimensional density-adapted radial projection readout with an additional inversion recovery preparation module.

Methodologies and MR Parameters in Quantitative Magnetic Resonance Neurography: A Scoping Review Protocol.

Magnetic resonance neurography (MRN), the MR imaging of peripheral nerves, is clinically used for assessing and monitoring peripheral neuropathies based on qualitative, weighted MR imaging. Recently, quantitative MRN has been increasingly reported with various MR parameters as potential biomarkers. An evidence synthesis mapping the available methodologies and normative values of quantitative MRN of human peripheral nerves, independent of the anatomical location and type of neuropathy, is currently unavailable and would likely benefit this young field of research.

Interleaved and simultaneous multi-nuclear magnetic resonance in vivo. Review of principles, applications and potential.

Magnetic resonance signals from different nuclei can be excited or received at the same time,rendering simultaneous or rapidly interleaved multi-nuclear acquisitions feasible. The advan-tages are a reduction of total scan time compared to sequential multi-nuclear acquisitions or that additional information from heteronuclear data is obtained at thesame time and anatomical position. Information content can be qualitatively increased by delivering a more comprehensive MR-based picture of a transient state (such as an exercise bout).

Epicardial and Pericardial Adiposity Without Myocardial Steatosis in Cushing Syndrome.

Context: Cardiovascular disease is the leading cause of death in patients with Cushing syndrome. Cortisol excess and adverse metabolic profile could increase cardiac fat, which can subsequently impair cardiac structure and function.

Objective: We aimed to evaluate cardiac fat mass and distribution in patients with Cushing syndrome.

Water-Fat Separation in MR Fingerprinting for Quantitative Monitoring of the Skeletal Muscle in Neuromuscular Disorders.

Background Quantitative MRI is increasingly proposed in clinical trials related to neuromuscular disorders (NMDs). Purpose To investigate the potential of an MR fingerprinting sequence for water and fat fraction (FF) quantification (MRF T1-FF) for providing markers of fatty replacement and disease activity in patients with NMDs and to establish the sensitivity of water T1 as a marker of disease activity compared with water T2 mapping. Materials and Methods Data acquired between March 2018 and March 2020 from the legs of patients with NMDs were retrospectively analyzed.

Repeatability of multinuclear interleaved acquisitions with nuclear Overhauser enhancement effect in dynamic experiments in the calf muscle at 3T.

Purpose: To evaluate the repeatability of multinuclear interleaved H/ P NMR dynamic acquisitions in skeletal muscle and the impact of nuclear Overhauser enhancement (nOe) on the P results at 3T in exercise-recovery and ischemia-hyperemia paradigms.

Methods: A H/ P interleaved pulse sequence was used to measure every 2.5 s a perfusion-weighted image, a map, a P spectrum and 32 H spectra sensitive to deoxymyoglobin.

Sirolimus for treatment of patients with inclusion body myositis: a randomised, double-blind, placebo-controlled, proof-of-concept, phase 2b trial.

Background: Inclusion body myositis is the most frequent myositis in patients older than 50 years. Classical immunosuppressants are ineffective in treating inclusion body myositis, and to date there are no recommendations for pharmacological approaches to treatment. When used after organ transplantation, sirolimus can block the proliferation of effector T cells, while preserving T regulatory cells, and induce autophagy, all of which are processes that are impaired in inclusion body myositis.

Lean regional muscle volume estimates using explanatory bioelectrical models in healthy subjects and patients with muscle wasting.

Background: The availability of non-invasive, accessible, and reliable methods for estimating regional skeletal muscle volume is paramount in conditions involving primary and/or secondary muscle wasting. This work aimed at (i) optimizing serial bioelectrical impedance analysis (S ) by computing a conductivity constant based on quantitative magnetic resonance imaging (MRI) data and (ii) investigating the potential of S for estimating lean regional thigh muscle volume in patients with severe muscle disorders.

Methods: Twenty healthy participants with variable body mass index and 20 patients with idiopathic inflammatory myopathies underwent quantitative MRI.

Global versus individual muscle segmentation to assess quantitative MRI-based fat fraction changes in neuromuscular diseases.

Objectives: Magnetic resonance imaging (MRI) constitutes a powerful outcome measure in neuromuscular disorders, yet there is a broad diversity of approaches in data acquisition and analysis. Since each neuromuscular disease presents a specific pattern of muscle involvement, the recommended analysis is assumed to be the muscle-by-muscle approach. We, therefore, performed a comparative analysis of different segmentation approaches, including global muscle segmentation, to determine the best strategy for evaluating disease progression.

Quantitative H and Na muscle MRI in Facioscapulohumeral muscular dystrophy patients.

Objective: Our aim was to assess the role of quantitative H and Na MRI methods in providing imaging biomarkers of disease activity and severity in patients with Facioscapulohumeral muscular dystrophy (FSHD).

Methods: We imaged the lower leg muscles of 19 FSHD patients and 12 controls with a multimodal MRI protocol to obtain STIR-Tw images, fat fraction (FF), water T (wT), water T (wT), tissue sodium concentration (TSC), and intracellular-weighted sodium signal (inversion recovery (IR) and triple quantum filter (TQF) sequence). In addition, the FSHD patients underwent muscle strength testing.

Quantitative Skeletal Muscle Imaging Using 3D MR Fingerprinting With Water and Fat Separation.

Background: Quantitative muscle MRI is a robust tool to monitor intramuscular fatty replacement and disease activity in patients with neuromuscular disorders (NMDs).

Purpose: To implement a 3D sequence for quantifying simultaneously fat fraction (FF) and water T (T ) in the skeletal muscle, evaluate regular undersampling in the partition-encoding direction, and compare it to a recently proposed 2D MR fingerprinting sequence with water and fat separation (MRF T -FF).

Study Type: Prospective.

Multiexponential Analysis of the Water T2-Relaxation in the Skeletal Muscle Provides Distinct Markers of Disease Activity Between Inflammatory and Dystrophic Myopathies.

Background: The monoexponential water T (T ) is a proven biomarker of disease activity in neuromuscular disorders (NMDs). However, it lacks specificity, being elevated in the presence of several pathological processes and pathomorphological alterations in the muscle tissue.

Purpose: To investigate the multiexponential behavior of the water T -relaxation in the skeletal muscle of NMD patients, aiming to identify more sensitive and specific biomarkers of disease activity.

Relationship between markers of disease activity and progression in skeletal muscle of GNE myopathy patients using quantitative nuclear magnetic resonance imaging and P nuclear magnetic resonance spectroscopy.

Background: Quantitative nuclear magnetic resonance imaging (NMRI) is an objective and precise outcome measure for evaluating disease progression in neuromuscular disorders. We aimed to investigate predictive 'disease activity' NMR indices, including water T and P NMR spectroscopy (NMRS), and its relation to NMR markers of 'disease progression', such as the changes in fat fraction (ΔFat%) and contractile cross-sectional area (ΔcCSA), in GNE myopathy (GNEM) patients.

Methods: NMR was performed on a 3T clinical scanner, at baseline and at a 1-year interval, in 10 GNEM patients and 29 age-matched controls.