David Bendahan

Aix-Marseille University | AMU · Centre de Résonance Magnétique Biologique et Médicale (UMR 7339 CRMBM)

Segmentation of individual thigh muscles in MRI images is essential for monitoring neuromuscular diseases and quantifying relevant biomarkers such as fat fraction (FF). Deep learning approaches such as U-Net have demonstrated effectiveness in this field. However, the impact of reducing neural network complexity remains unexplored in the FF quantifi...

Introduction and Aims Mitochondrial myopathies are rare genetic disorders for which no effective treatment exists. We previously showed that the pharmacological cyclophilin inhibitor cyclosporine A (CsA) extends the lifespan of fast‐twitch skeletal muscle‐specific mitochondrial transcription factor A knockout ( Tfam KO) mice, lacking the ability to...

Background and Objectives Intramuscular fat fraction (FF), assessed using quantitative MRI (qMRI), has emerged as a promising biomarker for hereditary transthyretin amyloidosis (ATTRv) patients. Currently, the main drawbacks to its use in future therapeutic trials are its sensitivity to change over a short period of time and the time‐consuming manu...

Background and objectives: Intramuscular fat fraction (FF), assessed with quantitative MRI (qMRI), has emerged as one of the few responsive outcome measures in CMT1A patients. The main limitation for its use in future therapeutic trials is the time required for the manual segmentation of individual muscles. This study aimed to evaluate the accurac...

The detection of a secondary inorganic phosphate (Pi) resonance, a possible marker of mitochondrial content in vivo, using phosphorus magnetic resonance spectroscopy ( ³¹ P‐MRS), poses technical challenges at 3 Tesla (T). Overcoming these challenges is imperative for the integration of this biomarker into clinical research. To evaluate the repeatab...

Multi-echo turbo-spin echo (ME-TSE) is a pulse sequence commonly used for T2 mapping in MRI. As compared to other pulse sequences such as MESE, ME-TSE is largely faster. It has been previously shown that dictionary-based T2-mapping can be used to provide accurate T2 values from MESE datasets but the corresponding accuracy on ME-TSE datasets has nev...

Background and objectives: Intramuscular fat fraction (FF) assessed using quantitative MRI (qMRI) has emerged as one of the few responsive outcome measures in CMT1A suitable for future clinical trials. This study aimed to identify the relevance of multiple qMRI biomarkers for tracking longitudinal changes in CMT1A and to assess correlations betwee...

This dataset presents different abdominal metrics including visceral area, abdominal muscles lengths, thicknesses, radial displacements, radial and circumferentials strains. The considered abdominal muscle groups are rectus abdominis and lateral muscles. This dataset was derived from the segmentation masks of dynamic MRI of twenty healthy participa...

Purpose To investigate whether a T2 inter‐slice variation could occur when a multi‐slice multi‐echo spin echo (MESE) sequence is used for image acquisition and to propose an enhanced method for reconstructing T2 maps that can effectively address and correct these variations. Methods Bloch simulations were performed accounting for the direct satura...

Acoustic noise production during Magnetic Resonance Imaging is an important source of patient discomfort and leads to verbal communication problems, difficulties in sedation, and hearing impairment. To address these issues, in this paper we present a systematic characterization of the acoustic field distribution in a MRI cavity in a last generation...

Objective: To quantify using magnetic resonance imaging (MRI) fat infiltration (FF) and the magnetization transfer ratio (MTR) in individual muscles of symptomatic and asymptomatic transthyretin familial amyloid polyneuropathy (TTR-FAP) patients. Secondarily, we aimed to assess correlations with clinical and electrophysiologic variables. Methods:...

Purpose Although enthesitis is a hallmark of several rheumatologic conditions, current imaging methods are still unable to characterize entheses changes because of the corresponding short transverse relaxation times (T2). A growing number of MR studies have used Ultra-High Field (UHF) MRI in order to assess low-T2 tissues e.g., tendon but never in...

Purpose Automatic measurement of wrist cartilage volume in MR images. Methods We assessed the performance of four manually optimized variants of the U‐Net architecture, nnU‐Net and Mask R‐CNN frameworks for the segmentation of wrist cartilage. The results were compared to those from a patch‐based convolutional neural network (CNN) we previously de...

We propose an enhancement to label-to-image GANs. Based on a Pix2Pix architecture, ConText-GAN allows generating images in a controlled way. Given a feature map as input, ConText-GAN can generate images with a specified layout and label content. As an application, ConText-GAN is used to perform a more realistic than usual data augmentation from an...

Purpose: MRI's T2 relaxation time is a valuable biomarker for neuromuscular disorders and muscle dystrophies. One of the hallmarks of these pathologies is the infiltration of adipose tissue and a loss of muscle volume. This leads to a mixture of two signal components, from fat and from water, to appear in each imaged voxel, each having a specific...

Background: Deep learning methods have been shown to be useful for segmentation of lower limb muscle MRIs of healthy subjects but, have not been sufficiently evaluated on neuromuscular disease (NDM) patients. Purpose: Evaluate the influence of fat infiltration on convolutional neural network (CNN) segmentation of MRIs from NMD patients. Study t...

Hydroxyurea (HU) is commonly used as a treatment for Sickle Cell Disease (SCD) patients in order to produce fetal hemoglobin beneficial to compensate anemia (reduced oxygen transport), to reduce abnormal Hb content, which alleviate clinical symptoms such as vaso-occlusives crisis and acute chest syndrome. The effects of HU on skeletal muscle bioene...

The current definition of osteoporosis includes alteration of bone quality. The assessment of bone quality is improved by the development of new texture analysis softwares. Our objectives were to assess if proximal femoral trabecular bone texture measured in Ultra high field (UHF) 7 Tesla MRI and CT scan were related to biomechanical parameters, an...

Background Facioscapulohumeral dystrophy (FSHD) is a major muscular dystrophy characterized by asymmetric fatty replacement of muscles. We aimed to determine the initiation site and progression profile of the disease in lower extremity muscles of FSHD patients by assessing fat infiltration along their full proximo-distal axis using quantitative MRI...

Purpose To investigate the potential of texture parameters from opportunistic MRI and CT for the detection of patients with vertebral fragility fracture, to design a decision tree and to compute a Random Forest analysis for the prediction of fracture risk. Methods One hundred and eighty vertebrae of sixty patients with at least one (30) or without...

Although multiple structural, mechanical, and molecular factors are definitely involved in osteoporosis, the assessment of subregional bone mineral density remains the most commonly used diagnostic index. In this study, we characterized bone quality in the femoral neck of one osteoporotic patients as compared to an age-matched control subject, and...

Volume of myocardial fibrous tissue have been proposed as an objective prognostic criteria of a successful my- ocardial revascularization. Manual delineation of fibrosis tissue in magnetic resonance images is a very tedious task even when a contrast enhancement is used. Convolutional neural networks have been widely applied for hard semantic segmen...

A bstract Mitochondrial myopathies are rare genetic disorders characterized by muscle weakness and exercise intolerance. Currently, no effective treatment exists for these myopathies. Interestingly, the pharmacological cyclophilin inhibitor cyclosporine A (CsA) extended lifespan and prevented loss of force and mitochondrial Ca ²⁺ overload in muscle...

Citrulline malate (CM) has been shown to improve muscle performance in healthy participants during a single exercise session. Yet, within the framework of exercises repeated at close time interval, the consequences of CM ingestion on mechanical performance are controversial and the bioenergetics side remains undocumented. The aim of this double-bli...

No injection treatment has been proven to be effective in wrist osteoarthritis. When conservative measures fail, its management involves invasive surgery. Emergence of biotherapies based on adipose derived stem cells (ADSC) offers promising treatments for chondral degenerative diseases. Microfat (MF) and platelets-rich plasma (PRP) mixture, rich in...

Purpose: Infiltration of fat into lower limb muscles is one of the key markers for the severity of muscle pathologies. The level of fat infiltration varies in its severity across and within patients, and it is traditionally estimated using visual radiologic inspection. Precise quantification of the severity and spatial distribution of this patholog...

Background Knee osteoarthritis–related pain limits physical function and leads to functional disability. Physical activity is one of the central recommendations for the management of knee osteoarthritis. Although concentric muscle activities are often preferred to eccentric ones, the corresponding rationale remains controversial. Objective To expl...

Detection of cartilage loss is crucial for the diagnosis of osteo- and rheumatoid arthritis. A large number of automatic segmentation tools have been reported so far for cartilage assessment in magnetic resonance images of large joints. As compared to knee or hip, wrist cartilage has a more complex structure so that automatic tools developed for la...

Hydroxyurea (HU) is a ribonucleotide reductase inhibitor most commonly used as a therapeutic agent in sickle cell disease (SCD) with the aim of reducing the risk of vaso-occlusion and improving oxygen transport to tissues. Previous studies suggest that HU may be even beneficial in mild anemia. However, the corresponding effects on skeletal muscle e...

MRI could be applied for bone microarchitecture assessment; however, this technique is still suffering from low resolution compared to the trabecular dimension. A clear comparative analysis between MRI and X-ray microcomputed tomography (μCT) regarding microarchitecture met-rics is still lacking. In this study, we performed a comparative analysis b...

Background and Objective : Biomechanical assessment of the abdominal wall represents a major prerequisite for a better understanding of physiological and pathological situations such as hernia, post-delivery recovery, muscle dystrophy or sarcopenia. Such an assessment is challenging and requires muscular deformations quantification which have been...

Background Quantitative T2-relaxation-based contrast maps have shown to be highly beneficial for clinical diagnosis and follow-up. The generation of quantitative maps, however, is impaired by long acquisition times, and time-consuming post-processing schemes. The EMC platform is a dictionary-based technique, which involves simulating theoretical si...

The role of pyruvate dehydrogenase in mediating lipid-induced insulin resistance stands as a central question in the pathogenesis of type 2 diabetes mellitus. Many researchers have invoked the Randle hypothesis to explain the reduced glucose disposal in skeletal muscle by envisioning an elevated acetyl CoA pool arising from increased oxidation of f...

Imaging of subtle changes in hand structures is challenged by the limited image quality, especially at 1.5 T. Reduction of specific absorption rate in metamaterial-assisted 1.5 T MRI provides an opportunity to utilize efficient pulse sequences and to improve the quality of acquired images. This work is devoted to the assessment of potential improve...

Trabecular bone could be assessed non-invasively using MRI. However, MRI does not yet provide resolutions lower than trabecular thickness and a comparative analysis between different MRI sequences at different field strengths and X-ray microtomography (μCT) is still missing. In this study, we compared bone microstructure parameters and bone mineral...

Mitochondrial diseases are genetic disorders leading to an impaired mitochondrial function and resulting in exercise intolerance and muscle weakness. In patients, muscle fatigue due to defects in mitochondrial oxidative capacities commonly precedes muscle weakness. In mice, the fast-twitch skeletal muscle-specific Tfam deletion (Tfam KO) leads to d...

In clinical applications, using erroneous segmentations of medical images can have dramatic consequences. Current approaches dedicated to medical image segmentation automatic quality control do not predict segmentation quality at slice-level (2D), resulting in sub-optimal evaluations. Our 2D-based deep learning method simultaneously performs qualit...

Objective To comparatively assess the performance of highly selective pulses computed with the SLR algorithm in fast-spin echo (FSE) within the current radiofrequency safety limits using a metamaterial-based coil for wrist magnetic resonance imaging.Methods Apodized SINC pulses commonly used for clinical FSE sequences were considered as a reference...

Objective Psoriatic arthritis (PsA) is an inflammatory rheumatic disease, mediated in part by TNFα and associated with bone loss. Anti-TNFα treatment should inhibit this phenomenon and reduce the systemic bone loss. Ultra-high field MRI (UHF MRI) may be used to quantify bone microarchitecture (BM) in-vivo. In this study, we quantified BM using UHF...

Nemaline myopathy, a disease of the actin-based thin filament, is one of the most frequent congenital myopathies. To date, no specific therapy is available to treat muscle weakness in nemaline myopathy. We tested the ability of tirasemtiv, a fast skeletal troponin activator that targets the thin filament, to augment muscle force—both in vivo and in...

Neuromuscular disorders are rare diseases for which few therapeutic strategies currently exist. Assessment of therapeutic strategies efficiency is limited by the lack of biomarkers sensitive to the slow progression of neuromuscular diseases (NMD). Magnetic resonance imaging (MRI) has emerged as a tool of choice for the development of qualitative sc...

Bone microarchitecture has been shown to provide useful information regarding the evaluation of skeleton quality with an added value to areal bone mineral density, which can be used for the diagnosis of several bone diseases. Bone mineral density estimated from dual-energy X-ray absorptiometry (DXA) has shown to be a limited tool to identify patien...

Quantitative analysis of abdominal organs motion and deformation is crucial to better understand biomechanical alterations undermining respiratory, digestive or perineal pathophysiology. In particular, biomechanical characterization of the antero-lateral abdominal wall is central in the diagnosis of abdominal muscle deficiency. Here, we present a d...

Sickle cell anemia (SCA) is a genetic hemoglobinopathy associated with an impaired oxygen delivery to skeletal muscle that could alter ATP production processes and increase intramuscular acidosis. These alterations have been already reported in the Townes mouse model of SCA but the corresponding changes in humans have not been documented. In the pr...

Objective: Psoriatic arthritis (PA) is an inflammatory rheumatism, mediated in part by TNFα and associated with bone loss. Anti-TNFα treatment should inhibit this phenomenon and reduce the systemic bone loss. Ultra-high field MRI (UHF MRI) may be used to quantify bone microarchitecture (BM) in-vivo. In this study, we quantified BM using UHF MRI in...

Mutations in the RYR1 gene, encoding the skeletal muscle calcium channel RyR1, lead to congenital myopathies, through expression of a channel with abnormal permeability and/or in reduced amount, but the direct functional whole organism consequences of exclusive reduction in RyR1 amount have never been studied. We have developed and characterized a...

Diffusion tensor imaging (DTI) is becoming a relevant diagnostic tool to understand muscle disease and map muscle recovery processes following physical activity or after injury. Segmenting all the individual leg muscles, necessary for quantification, is still a time-consuming manual process. The purpose of this study was to evaluate the impact of a...

Some mutations in the RYR1 gene lead to congenital myopathies, through reduction in this calcium channel expression level, but the functional whole organism consequences of reduction in RyR1 amount have never been studied. We have developed and characterized a mouse model with inducible muscle specific RYR1 deletion. Recombination in the RYR1 gene...

The cover image is based on the Research Article Deep learning-based fully automatic segmentation of wrist cartilage in MR images by Ekaterina Brui et al., https://doi.org/10.1002/nbm.4320.

The study objective was to investigate the performance of a dedicated convolutional neural network (CNN) optimized for wrist cartilage segmentation from 2D MR images. CNN utilized a planar architecture and patch‐based (PB) training approach that ensured optimal performance in the presence of a limited amount of training data. The CNN was trained an...

Background Nerve tissue alterations have been rarely quantified in Charcot Marie Tooth type 1A (CMT1A) patients. The aim of the present study was to quantitatively assess the MRI anomalies of the sciatic and tibial nerves in CMT1A disease using quantitative neurography MRI (qMRI). We also intended to seek for correlations with clinical variables....

In this paper, we describe a dedicated radiofrequency coil for magnetic resonance imaging and spectroscopy (MRSI) at 4.7 T optimized for investigation of muscle energetics in a human forearm. The coil operating at the Larmor frequencies of protons 1H (200.1 MHz) and phosphorous 31P (81 MHz) is based on two cylindrical periodic structures made of th...

Purpose This study aimed at determining through MRI investigations, force and soreness assessments whether the modulation of muscle length is a relevant strategy for minimising neuromuscular electrical stimulation (NMES)-induced muscle damage in young healthy participants. Methods Comparison of 2 NMES sessions (40 isometric electrically-evoked con...

Objective: To quantitatively describe the MRI fat infiltration pattern of muscle degeneration in Charcot-Marie-Tooth (CMT) type 1A (CMT1A) disease and to look for correlations with clinical variables. Methods: MRI fat fraction was assessed in lower-limb musculature of patients with CMT1A and healthy controls. More particularly, 14 muscle compart...

Background and objectives: Sarcoma preoperative planning critically depends on MRI, sometimes uninformative when compartments barriers or critical structures are involved. objective: to prospectively assess the feasibility and the potential of 7T MRI in sarcoma. Methods: Two patients with femoral chondrosarcoma were CT and MRI (1.5 and 7T) scanned...

Introduction: The conditional nebulin knock-out mouse (Neb-cKO) is a new model mimicking nemaline myopathy, a rare disease characterized by muscle weakness and rods within muscle fibers. We investigated in vivo the impact of nebulin deficiency on muscle function. Methods: Neb-cKO mice and control littermates were studied at 10-12 months. Muscle...