Gray matter atrophy differs among MS phenotypes

Researchers who characterized components of gray matter atrophy in MS found patterns that varied by clinical phenotype, according to results published in Neurology.

“In the last decades, grey matter (GM) involvement has been increasingly recognized as a crucial component of pathophysiology in MS,” Maria A. Rocca, MD, head of the Neuroimaging of CNS White Matter Unit at IRCCS Ospedale San Raffaele in Milan, Italy, and colleagues wrote.

Rocca and colleagues conducted a multicenter study using source-based morphometry. They obtained clinical and MRI data from 170 healthy control participants and 398 patients with MS. Of those with MS, 34 had clinically isolated syndromes, 226 had relapsing-remitting MS, 95 had secondary progressive MS and 43 had primary progressive MS. One-year follow-up data were available for 57 controls and 144 patients with MS. Study outcomes of interest included gray matter loss, atrophy progression and correlations with disability and 1-year clinical worsening.

Gray matter atrophy progressed “in subcortical, cerebellar, sensorimotor, and fronto-temporo-parietal components” among patients with MS, the researchers wrote. They described varying patterns of gray matter atrophy between clinical phenotypes, including patients with CIS showing circumscribed subcortical, cerebellar, temporal and salience gray matter atrophy and patients with RRMS showing “widespread” gray matter atrophy. Patients with PPMS and SPMS had cerebellar, subcortical, sensorimotor, salience and fronto-parietal gray matter atrophy compared with healthy controls and patients with RRMS, respectively.

Baseline normalized gray matter volume (OR = 0.98; P = .008) and cerebellar gray matter atrophy (OR = 0.4; P = .01) were both independent predictors of clinical worsening.

Higher disability at baseline correlated with lower normalized brain volume at baseline (beta = –0.13; P = .001), greater sensorimotor gray matter atrophy (beta = 0.12; P = .002) and longer disease duration (beta = 0.09; P = .04).

The researchers said the findings are “in line with previous volumetric studies,” confirming “that there is a strong neurodegenerative component in MS leading to irreversible tissue loss.”