Brain involvement in systemic immune mediated diseases: magnetic resonanceand magnetisation transfer imaging study

Objective-Magnetisation transfer imaging (MTI) provides information about b rain damage with increased pathological specificity over conventional MRI a nd detects subtle abnormalities in the normal appearing brain tissue, which go undetected with conventional scanning. Brain MRI and MTI findings were compared in patients with multiple sclerosis (MS) and systemic immune media ted diseases (SIDs) affecting the CNS to investigate their roles in underst anding the nature of brain damage in these diseases. Methods-Brain dual echo, T1 weighted and MTI scans were obtained in patient s affected by systemic lupus erithematosus (SLE) with (NSLE, n=9) and witho ut clinical CNS involvement (n=15), Behcet's disease (BD) (n=5), Wegener's granulomatosis (WG) (n=9), and antiphospholipid antibody syndrome (APLAS) ( n=6). Ten patients with clinically definite MS and 15 healthy controls also underwent the same scanning protocol. Brain MRI and MT ratio (MTR) images of the same subject were coregistered and postprocessed to obtain MTR histo grams of the whole brain and of the NABT. Results-Brain hyperintense lesions were found in all patients with MS and w ith NSLE and in 5/15 patients with SLE, 5/9 with WG, 1/5 with BD, and 3/6 w ith APLAS. The lesion burden in the brain was significantly higher in patie nts with MS compared with all the other disease groups. All MTR histogram p arameters were significantly different among patient subgroups. Patients wi th MS had significantly lower average MTR than all except patients with NSL E and significantly lower peak height and location than patients with SLE. patients with NSLE had significantly lower average MTR than patients with S LE. Conclusions-Microscopic brain tissue damage is relevant in patients with MS , but, apart from patients with NSLE, it seems to be absent in systemic imm une mediated diseases, even in the presence of macroscopic MRI lesions or c linical evidence of CNS involvement.