Reliability and Sensitivity to Longitudinal CBF Changes in Steno‐Occlusive Diseases: ASL Versus 123I‐IMP‐SPECT

Background Noninvasive cerebral blood flow (CBF) monitoring using arterial spin labeling (ASL) magnetic resonance imaging is useful for managing large cerebral artery steno‐occlusive diseases. However, knowledge about its measurement characteristics in comparison with reference standard perfusion imaging is limited. Purpose To evaluate perfusion in a longitudinal manner in patients with steno‐occlusive disease using ASL and compare with single‐photon emission computed tomography (SPECT). Study Type Prospective. Population Moyamoya (n = 10, eight females) and atherosclerotic diseases (n = 2, two males). Field Strength/Sequence 3.0 T; gradient‐echo three‐dimensional T1‐weighted and spin‐echo ASL. Assessment Multi‐delay ASL and [123I]‐iodoamphetamine SPECT CBF measurements were performed both before and within 9 days of anterior‐circulation revascularization. Reliability and sensitivity to whole‐brain voxel‐wise CBF changes (ΔCBF) and their postlabeling delay (PLD) dependency with varied PLDs (in milliseconds) of 1000, 2333, and 3666 were examined. Statistical Tests Reliability and sensitivity to ΔCBF were examined using within‐subject standard deviation (Sw) and intraclass correlation coefficients (ICCs). For statistical comparisons, standard deviation of longitudinal ΔCBF within the hemisphere contralateral to surgery, and the ratio between it and average ΔCBF within the ipsilateral regions of interest were subjected to paired t tests, respectively. P