Quantitative Neuromuscular MRI in CIDP Patients: Interest of a Multiparametric Approach

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is characterized by heterogeneous clinical presentations and the absence of validated imaging biomarkers. Although several quantitative MRI (qMRI) parameters have been investigated individually, their respective diagnostic and clinical relevance remains unclear.

Twenty-eight CIDP patients (21 typical, 7 multifocal) were prospectively enrolled and compared with 13 age- and sex-matched healthy controls and 17 patients with symptomatic hereditary transthyretin amyloid neuropathy (vATTR). All participants underwent 1.5 T qMRI of the sciatic and tibial nerves and of the thigh and leg muscles. Nerve and muscle volume, magnetization transfer ratio (MTR), fat fraction (FF), and T2 relaxation time were extracted. Clinical assessment included ONLS, RODS, and MRC sum score, while electrophysiological evaluation included fibular compound motor action potentials and tibialis anterior MUNIX. Imaging parameters were compared between groups and correlated with clinical and neurophysiological measures.

CIDP patients showed significant differences compared with controls in both nerve and muscle metrics. Nerve volume was increased and MTR decreased at both sciatic and tibial levels (p < 0.005). At the muscle level, leg muscles showed increased fat fraction and decreased MTR, while T2 values and muscle volume did not differ significantly. MTR showed the strongest correlations with disability scores and MUNIX. Compared with vATTR patients, CIDP patients had lower sciatic nerve MTR, whereas vATTR patients exhibited larger nerve volumes and more pronounced muscle abnormalities.

Nerve volume appears to be a sensitive diagnostic marker, while MTR may reflect disease burden. A multiparametric qMRI approach may improve diagnosis and monitoring in CIDP.