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

Uros Klickovic,Tarek A Yousry,Pietro Fratta,Katie Sidle,Michael G Hanna,Stephen J Wastling,Nikhil Sharma,Andrea Malaspina,Jasper M Morrow,Linda Greensmith,Robin S Howard,Christopher D.J Sinclair,Luca Zampedri,John S Thornton,Sachit Shah,Ahmed Emira,Karin Trimmel

doi:10.1212/wnl.0000000000008009

Abstract

ObjectiveTo investigate the use of muscle MRI for the differential diagnosis and as a disease progression biomarker for 2 major forms of motor neuron disorders: spinal bulbar muscular atrophy (SBMA) and amyotrophic lateral sclerosis (ALS).MethodsWe applied quantitative 3-point Dixon and semiquantitative T1-weighted and short tau inversion recovery (STIR) imaging to bulbar and lower limb muscles and performed clinical and functional assessments in ALS (n = 21) and SBMA (n = 21), alongside healthy controls (n = 16). Acquired images were analyzed for the presence of fat infiltration or edema as well as specific patterns of muscle involvement. Quantitative MRI measurements were correlated with clinical measures of disease severity in ALS and SBMA.ResultsQuantitative imaging revealed significant fat infiltration in bulbar (p < 0.001) and limb muscles in SBMA compared to controls (thigh: p < 0.001; calf: p = 0.001), identifying a characteristic pattern of muscle involvement. In ALS, semiquantitative STIR imaging detected marked hyperintensities in lower limb muscles, distinguishing ALS from SBMA and controls. Finally, MRI measurements correlated significantly with clinical scales of disease severity in both ALS and SBMA.ConclusionsOur findings show that muscle MRI differentiates between SBMA and ALS and correlates with disease severity, supporting its use as a diagnostic tool and biomarker for disease progression. This highlights the clinical utility of muscle MRI in motor neuron disorders and contributes to establish objective outcome measures, which is crucial for the development of new drugs.

Highlights

We applied quantitative 3-point Dixon and semiquantitative T1-weighted and short tau inversion recovery (STIR) imaging to bulbar and lower limb muscles and performed clinical and functional assessments in amyotrophic lateral sclerosis (ALS) (n = 21) and spinal bulbar muscular atrophy (SBMA) (n = 21), alongside healthy controls (n = 16)
Quantitative imaging revealed significant fat infiltration in bulbar (p < 0.001) and limb muscles in SBMA compared to controls, identifying a characteristic pattern of muscle involvement
Our findings show that muscle MRI differentiates between SBMA and ALS and correlates with disease severity, supporting its use as a diagnostic tool and biomarker for disease progression

Summary

Methods

We applied quantitative 3-point Dixon and semiquantitative T1-weighted and short tau inversion recovery (STIR) imaging to bulbar and lower limb muscles and performed clinical and functional assessments in ALS (n = 21) and SBMA (n = 21), alongside healthy controls (n = 16). Study design and patient recruitment We performed a prospective cross-sectional study assessing muscular MRI of the head-neck region and lower limbs in 21 consecutive men with SBMA and 21 consecutive male and female patients with ALS who were attending the national Kennedy disease clinic and MND clinic at the National Hospital for Neurology and Neurosurgery, Queen Square, London, UK, between 2015 and 2017. Patients eligible for the ALS group all presented with a history of at least clinically possible disease according to revised El Escorial criteria.[12]. General exclusion criteria for all participants were concomitant neuromuscular diseases and safety-related MRI contraindications

Results

Discussion

Conclusion