Changes in integrity of normal-appearing white matter in patients with moyamoya disease: a diffusion tensor imaging study.

BACKGROUND AND PURPOSE DTI is widely used for the evaluation of white matter integrity in various neurologic diseases. The purpose of this study was to investigate changes in white matter integrity by using DTI in NAWM of patients with MMD and to evaluate the correlation between diffusion and perfusion characteristics through an interhemispheric comparison. MATERIALS AND METHODS We retrospectively reviewed 20 primary MMD patients with asymmetric disease stage and 20 age-matched healthy controls. FA(CS) and ADC(CS) values of bilateral centrum semiovale were measured by using region of interest analysis. Mean FA(CS) and ADC(CS) were compared between patient and control groups by unpaired t test. Interhemispheric differences in FA(CS) and ADC(CS) were assessed and compared between the H-TTP(delayed) and the H-TTP(shorter) by using paired t test. AIs also were assessed to verify interhemispheric differences. RESULTS The patient group showed a significantly lower mean FA(CS) and a higher mean ADC(CS) value than the control group. In the patient group, the H-TTP(delayed) had a significantly lower FA(CS) and higher ADC(CS) value than the H-TTP(shorter). Both AI(FA) and AI(ADC) were significantly higher in the patient compared with the control group. CONCLUSIONS DTI can describe subtle changes in white matter integrity in NAWM of patients with primary MMD that are not detected by conventional MR imaging. In addition, diffusion characteristics are well correlated with perfusion characteristics. We believe that DTI is a useful ancillary tool to evaluate patients with MMD.