Magnetic Resonance Evidence of Cerebellar Cortical Pathology in Multiple Sclerosis.

BACKGROUND: Although neuropathological observations suggest that cerebellar cortex is a major site of demyelination in multiple sclerosis (MS), only a few MRI studies on cerebellar cortical pathology in MS are available. OBJECTIVE: To analyse cerebellar cortical volume (CCV) and leucocortical lesions (CL) in MS, and their impact on clinical disability. METHODS: The authors studied 125 patients divided into 38 Clinical Isolated Syndrome (CIS), 35 relapsing remitting multiple sclerosis (RRMS), 27 secondary progressive multiple sclerosis (SPMS) and 25 primary progressive multiple sclerosis, and 32 normal controls (NC). CCV and cerebellar CL number and volume were evaluated by means of Freesurfer software and Double Inversion Recovery, respectively. RESULTS: Compared with NC (mean 113.2 + or - 2.6 cm(3)), the CCV was significantly reduced in CIS (105.4 + or - 2.2 cm(3), p=0.018), RRMS (104.0 + or - 2.0 cm(3), p=0.012), SPMS (98.8 + or - 2.0 cm(3), p<0.001) and PPMS (100.6 + or - 2.2 cm(3), p<0.001), even after age, gender and mean cortical volume correction. CL were observed in all patient groups and were an independent predictor of CCV and cerebellar dysfunction. DISCUSSION: The authors confirm that the cerebellar cortex is severely and early affected by MS pathology. The monitoring of cerebellar cortical atrophy and CL may help to understand the mechanism underlying disability progression in MS.