Intravoxel incoherent motion perfusion in patients with Moyamoya disease: comparison with (15)O-gas positron emission tomography

BACKGROUND: Intravoxel incoherent motion magnetic resonance imaging (IVIM) enables non-invasive measurement of brain perfusion. PURPOSE: To investigate whether IVIM could be used to evaluate the hemodynamic disturbance of Moyamoya disease (MMD) by comparison with the gold-standard (15)O-gas positron emission tomography (PET) method. MATERIAL AND METHODS: Ten consecutive patients with MMD (six women; mean age = 42.8 years) and 10 age-matched healthy controls were evaluated by diffusion-weighted images with 12 different b values in the range of 0–900 s/mm(2) and (15)O-gas PET. Tomographic maps of IVIM parameters, perfusion fraction (f ), pseudo-diffusion coefficient (D*), and f・D*, as well as cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) maps obtained with PET, were normalized and hemispheric gray and white matter values were calculated. IVIM parametric values were compared with PET parameters and with clinically assessed disease severity. RESULTS: There was significant correlation between D* and MTT (r = –0.74, P < 0.001) and between f・D* and CBF (r = 0.52, P = 0.02) in the cortical areas. The f values in the white matter were significantly higher in symptomatic MMD patients than in healthy controls (P = 0.01). CONCLUSION: IVIM may be used to non-invasively investigate cerebral hemodynamic impairment in patients with MMD. Further evaluation is needed to establish IVIM usage in clinical settings.