Delayed cerebral ischemia (DCI) due to cerebral vasospasm following aneurysmal subarachnoid hemorrhage (aSAH) has long been recognized as a major source of morbidity and mortality. Early detection of cerebral vasospasm and identification of patients who are likely to become symptomatic is crucial to guide aggressive medical and/or endovascular interventions. Magnetic resonance imaging using arterial spin-label (ASL) is a noninvasive mean for assessing cerebral blood flow and is based on direct magnetic labeling of arterial blood water protons. The diagnostic role of ASL in acute ischemic stroke, epilepsy, and neurodegenerative disorders has been explained in multiple studies but its ability to predict vasospasm in aSAH has not been published before. The purpose of this study is to highlight the diagnostic implications of different perfusion patterns of ASL in patients with aSAH which can be utilized to prevent DCI in such patients when other commonly used modalities are not available, contraindicated, or fail to detect vasospasm.