Memory dysfunction in multiple sclerosis corresponds to juxtacortical lesion load on fast fluid-attenuated inversion-recovery MR images

BACKGROUND AND PURPOSE: MR imaging is a sensitive diagnostic tool and parac linical marker of disease activity and prognosis in multiple sclerosis (MS) , yet the role of MR imaging of MS is controversial, The aim of this study was to describe the relationship between cognitive function and MS lesion s ize and position, as shown on comparative images from conventional spin-ech o (CSE) and fast fluid-attenuated inversion-recovery (fast FLAIR) MR studie s. METHODS: CSE and fast FLAIR sequences consisted of 40 noncontiguous, 3-mm-t hick axial sections matched for geometric position in 18 patients with rela psing-remitting MS. Lesions were scored for size, anatomic position, and th eir comparative appearance on CSE and fast FLAIR images. The neuropsycholog ical assessment tested general psychological performance, memory, and front al lobe executive function. RESULTS: Fast FLAIR images showed significantly more small (146 versus six) and medium-sized (18 versus four) juxtacortical lesions than did CSE seque nces, Small juxtacortical lesions displayed only on fast FLAIR images had a distinctive appearance, suggestive of small areas of perivascular inflamma tion, The number of these lesions corresponded to reduced performance on th e fifth and delayed trials of the Rey Auditory Verbal Learning memory funct ion test. CONCLUSION: Fast FLAIR images show small lesions at the juxtacortical bound ary that are not seen on CSE studies. The presence of such lesions correlat es with impaired retention of information in memory tasks, which is charact eristic of cognitive problems in patients with MS.