MR imaging quantitation of gray matter involvement in multiple sclerosis and its correlation with disability measures and neurocognitive testing

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) is the most common inflamma tory disease of the central nervous system and manifests both physical and neurocognitive disabilities, Although predominantly a disease of the white matter, MS is also characterized by lesions in the gray matter. Previous pa thologic studies have found that cortical and deep gray matter lesions comp rised 5% and 4%, respectively, of total lesions, Using software for lesion detection and quantitation, our study was designed to determine MS involvem ent in the cortical and deep gray matter and to correlate gray matter lesio n load with neurocognitive function and the Kurtzke Expanded Disability Sta tus Scale, METHODS: Using a semiautomated segmentation algorithm that detected and del ineated all possible brain MS lesions on MR images, we investigated gray ma tter lesion volume in 18 patients with untreated relapsing-remitting MS. Co rtical and deep gray matter lesions then were correlated with the neurocogn itive and physical disability measurements. RESULTS: We found that cortical gray matter lesions comprised approximately 5.7% of the total lesion volume, whereas deep gray matter lesions comprise d another 4.6% in this patient cohort. No strong correlations were found be tween gray matter lesions and disability status or neurocognitive function, CONCLUSION: These results are similar to those found in previous pathologic studies. The cortical lesion load in cases of relapsing-remitting MS, as m easured by MR imaging, represents less than 6% of the total lesion volume a nd does not correlate with disability measures or neurocognitive tests.