Prolonged Mean Transit Time Detected by Dynamic Susceptibility Contrast Magnetic Resonance Imaging Predicts Cerebrovascular Reserve Impairment in Patients with Moyamoya Disease

Background: Evaluating cerebrovascular reserve (CVR) is important for patients with moyamoya disease (MMD). I-123-iodoamphetamine single-photon emission CT (SPECT) with acetazolamide (ACZ) challenge is widely carried out, but using ACZ becomes problematic owing to its off-label use and its adverse effects. Here, we report the efficacy of dynamic susceptibility contrast MRI (DSC-MRI) for the evaluation of CVR in MMD patients. Methods: All 33 MMD patients underwent both SPECT and DSC-MRI at an interval of < 10 days from each other (mean age 38.3 years). The region of interest (ROI) was the anterior cerebral artery (ACA) territory, middle cerebral artery (MCA) territory, basal ganglia and cerebellum hemisphere for cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) images. The ratios of the ROIs to the ipsilateral cerebellum were calculated for each parameter and evaluated. The CVR was calculated using images acquired by SPECT before and after ACZ administration. The ratios of DSC-MRI parameters and CVR were compared and evaluated for each ROI. Results: The MTT of the ACA and MCA territories significantly correlated with CVR (p < 0.0001). However, CBF and CBV had no correlation with CVR. The MTT ratio had a threshold of 1.966, with a sensitivity of 68.4% and a specificity of 91.5% for predicting decreased CVR (<10%). Conclusion: MTT had a negative correlation with CVR. DSC-MRI is easy, safe and useful for detecting decreased CVR and can be used as a standard examination in MMD patient's care. (C) 2016 S. Karger AG, Basel