Magnetization transfer ratio in neuro-Behçet disease.

The aim of this study was to determine the contribution of magnetization transfer ratios (MTRs) in detecting disease in normal-appearing brain regions of patients with neuro-Behçet (NB) disease. Thirty-two patients with NB disease were assessed. Fifteen healthy volunteers were examined as the control group. Magnetic resonance (MR) imaging of the head was performed without and with magnetization transfer (MT) contrast. Signal intensity measurements were obtained from ten anatomical regions (centrum semiovale, corona radiata, internal capsule, forceps major, forceps minor, thalamus, substantia nigra pars compacta, substantia nigra pars grisea, inferior pons and middle cerebellar peduncle) in both groups. Also measured in the NB group were parenchymal lesions in the brain stem, basal ganglia and cerebral deep white matter. MTR was calculated for each measurement. Statistical analysis was performed with Mann-Whitney U and independent t-tests with computer-based SPSS 11.0 for Windows software. A P value below 0.05 was considered statistically significant. The mean MTR of the parenchymal lesions in the NB group was lower than the mean MTR of the normal-appearing parenchyma in both the NB patients and the normal group. For the normal-appearing parenchyma the mean MTR in the NB group was higher than that for the controls for all regions except the corona radiata; however, the difference was statistically significant only for the thalamus. The MRI-visible parenchymal involvement of Behçet's disease causes a decrease in MTR. For the normal-appearing brain, although lacking statistical significance for the most regions studied, the tendency for higher MTR in NB patients compared with controls may offer an insight into the pathophysiology of Behçet's disease.