[Pubmed] Can muscle ultrasound assessments aid in the diagnosis of Myasthenia gravis? Findings from a single-center case

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Clin Neurophysiol. 2026 May 24;189:2111939. doi: 10.1016/j.clinph.2026.2111939. Online ahead of print.

ABSTRACT

OBJECTIVE: Fatigability and fluctuating muscle weakness represent the hallmarks of Myasthenia gravis (MG). This study investigates whether muscle ultrasound (MUS) can detect muscle fatigability in patients with generalized MG (gMG).

METHODS: In this single-center case-control study, 35 gMG patients and 35 matched healthy controls underwent standardized MUS assessment of four limb muscles (deltoid, biceps brachii, rectus femoris, tibialis anterior). Muscle echogenicity, thickness, and area (A) were assessed during rest and maximum voluntary contraction, both before and after a standardized exercise protocol. Interphase changes were quantified to reflect baseline contractility, post-exercise contractility, and fatigability [(f); post- versus pre-exercise contractility)]. The potential of MUS parameters to distinguish gMG patients from healthy individuals was evaluated using receiver operating characteristic analyses. A data-driven approach based on individual indices was used to derive composite indices across muscles with potential superior discriminatory value.

RESULTS: Among all MUS parameters, fatigability-related changes in muscle area [A(f)] consistently differentiated gMG patients from controls across all examined muscles. Composite A(f) indices, which sum the number of fatigable muscles, demonstrated good to excellent accuracy, correctly classifying approximately 90% of participants. Discriminatory performance remained robust across subgroups defined by disease severity and cumulative corticosteroid exposure.

CONCLUSIONS: A(f) discerns gMG patients from healthy controls. Further validation in longitudinal and prediagnostic cohorts is warranted to examine the potential utility of MUS in pragmatic diagnostic settings.

SIGNIFICANCE: Given its ability to differentiate between patients and healthy individuals, MUS may serve as a complementary tool in diagnosis and monitoring of gMG.

PMID:42190394 | DOI:10.1016/j.clinph.2026.2111939


Source: https://pubmed.ncbi.nlm.nih.gov/4219039 ... 0&v=2.20.0