Muscle magnetic resonance imaging in congenital myasthenic syndromes

Abstract

IntroductionIn this study we investigated muscle magnetic resonance imaging in congenital myasthenic syndromes (CMS).MethodsTwenty‐six patients with 9 CMS subtypes and 10 controls were imaged. T1‐weighted (T1w) and short‐tau inversion recovery (STIR) 3‐Tesla MRI images obtained at thigh and calf levels were scored for severity.ResultsOverall mean the T1w score was increased in GFPT1 and DPAGT1 CMS. T1w scans of the AChR‐deficiency, COLQ, and CHAT subjects were indistinguishable from controls. STIR images from CMS patients did not differ significantly from those of controls. Mean T1w score correlated with age in the CMS cohort.ConclusionsMRI appearances ranged from normal to marked abnormality. T1w images seem to be especially abnormal in some CMS caused by mutations of proteins involved in the glycosylation pathway. A non‐selective pattern of fat infiltration or a normal‐appearing scan in the setting of significant clinical weakness should suggest CMS as a potential diagnosis. Muscle MRI could play a role in differentiating CMS subtypes. Muscle Nerve 54: 211–219, 2016

Skeletal muscle MRI differentiates SBMA and ALS and correlates with disease severity

“…Height and weight did not significantly differ between the two patient groups and controls, except for ALS patients having a significantly lower body mass index compared to their control group (p=0.009). In both patient groups, ALSFRS-R and its lower limb (LL) subscale scores were similar (ALSFRS-R -total score, SBMA: 42 (31-48), ALS: 41 (28-47); ALSFRS-R -LL subscore, SBMA: 5 (2-8), ALS: 5.5 (3)(4)(5)(6)(7)(8); ALSFRS-R -bulbar subscore, SBMA: 10.5 (9-12), ALS: 12 (5)(6)(7)(8)(9)(10)(11)(12) and significantly reduced compared to healthy controls (SBMA vs. CTR; p < 0.001, ALS vs. CTR; p < 0.001; Table 1).…”

“…Skeletal muscle MRI can sensitively detect muscle involvement in neuromuscular diseases 7,8 , and differentiate distinct pathological features, such as muscular fat infiltration or intra-muscular edema 9 associated with acute denervation 10 . Muscle MRI demonstrated promise as a biomarker of disease progression in both myopathies and neuropathies 11 .…”

Congenital myasthenic syndrome due to DPAGT1 mutations mimicking congenital myopathy in an Irish family

“…To date, muscle MRI has only been performed in one case with DPAGT1 CMS, demonstrating, in contrast to our patient, mild changes [5]. Among different CMS subtypes, a handful of patients with GFPT1 and DPAGT1 glycosylation pathway mutations exhibited the most severe fatty infiltration seen on muscle MRI [6]. DPAGT1 is required for efficient glycosylation of acetylcholine receptor (AChR) subunits and for adequate export of AChR to the cell surface.…”

Design and test of a double-nuclear RF coil for 1 H MRI and 13 C MRSI at 7 T

“…Given the specific geometry and size of the prototype coil, a potential application of this coil will be the human calf muscle imaging and spectroscopy in investigating muscle fiber orientation, intramyocellular lipids, congenital myasthenic syndromes, and energy metabolism [45-51]. It can be also used for human extremity 13 C/ 1 H spectroscopic imaging at the ultrahigh field of 7T.…”