A multiparametric MRI study of frontal lobe dementia in multiple sclerosis

Previous studies achieved conflicting results when correlating magnetic res onance imaging (MRT) abnormalities and cognitive impairment in multiple scl erosis (MS) patients. Recently, the estimation of MS lesion load on T1-weig hted images and the analysis of magnetization transfer ratio (MTR) histogra ms, increased the degree of the correlation between physical disability and MRI findings in MS. We assessed the relationship of conventional and non-c onventional MRI-derived measures with frontal lobe dementia in MS. Dual ech o, T1-weighted and MT MRI scans of the brain were obtained in 11 MS patient s with and in 11 without frontal lobe dementia, matched for age, sex, educa tion and disability. Total (TLL) and frontal (FLL) lesion loads were assess ed from T2- and T1-weighted scans. MTR histogram analysis was performed for the whole brain, the frontal lobe and the cerebellum. Median TLL and FLL w ere significantly higher in cognitively impaired patients on both T2- and T 1-weighted scans. The MRI measure that better discriminated the two groups of patients was T1-weighted TLL (median values were 19.1 ml for demented an d 1.9 ml for non-demented patients, P=0.006). Average MTR, peak height and location of overall brain and frontal lobe histograms were significantly lo wer for cognitively impaired than for cognitively intact patients (P values ranged from 0.0001 to 0.001). Cerebellar MTR histogram metrics did not sig nificantly differ in patients with and without cognitive decline. The prese nce of cognitive decline in MS is associated with the extent and pathologic al severity of brain MRI abnormalities. (C) 1999 Elsevier Science B.V. All rights reserved.