Validation of the CBF, CBV, and MTT values by perfusion MRI in chronic occlusive cerebrovascular disease: A comparison with 15O-PET 1

Abstract

Rationale and objectives To evaluate the reliability of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) values obtained by deconvolution algorithm perfusion-weighted MR imaging (D-PWI), we compared these values with those obtained by first-moment algorithm perfusion-weighted MR imaging (F-PWI) and 15O-PET. Subjects and methods Six healthy volunteers and eleven patients with chronic occlusive cerebrovascular disease were studied with both perfusion-weighted MR imaging and 15O-PET, and region-of-interest analyses were performed. Normalization factors for CBF and CBV values obtained by D-PWI were determined as the mean values of 15O-PET divided by those of D-PWI in healthy volunteers. Then these values were used in analyzing the data of the patients. Results The MTT value obtained by D-PWI was 6.1 ± 0.5 seconds on the non-occluded side, 6.4 ± 0.7 seconds on the minimally to moderately stenosed side, and 6.7 ± 1.2 seconds on the severely stenosed to occluded side. These values were significantly correlated with those obtained by F-PWI ( r = 0.83; P < .001), and with those obtained by 15O-PET ( r = 0.78; P < .05). However, the CBF and CBV values obtained by D-PWI did not correlate with those obtained by 15O-PET. Conclusion MTT values obtained by D-PWI were reliable parameters of cerebral hemodynamics, but the CBF and CBV values obtained by D-PWI were not always reliable.