In patients with renal insufficiency or x-ray contrast allergy, TOF MRA can be used to delineate arterial anatomy without putting the patient at risk and inform subsequent therapeutic decisions [52]. Cerebrovascular Diseases-Stroke MRI Head Perfusion With IV Contrast MRI head perfusion is sensitive and specific in the detection of reversible ischemia. MRI head perfusion may delay EVT in the setting of stroke due to LVO, which detracts from the usefulness of this study in the acute phase due to the potential harm of delayed treatment [39]. Although major RCTs showing a benefit of EVT 6 to 24 hours after onset permitted eligibility based on MRI perfusion or CTP [46,57], the rapidity of diagnosis afforded by CTP is a strongly relevant clinical consideration in this situation in most settings. MRI Head Without and With IV Contrast Rarely, brain tumors or other conditions can mimic ischemic stroke. MRI without and with IV contrast may be helpful in the secondary workup of patients presenting with stroke-like symptoms [62]. MRI Head Without IV Contrast Although sensitive and specific in the detection of the extent of irreversible ischemia, MRI head may delay EVT in the setting of stroke due to anterior circulation LVO, which detracts from the usefulness of this study due to the potential harm of delayed treatment [39,46,56]. Although a major RCT showing benefit of EVT 6 to 24 hours after onset permitted eligibility based on DWI-MRI or CTP [46], the rapidity of diagnosis afforded by CTP is a strongly relevant clinical consideration in this situation in most settings Similarly, the 2 positive RCTs for EVT in basilar occlusion used pc-ASPECTS from either DWI-MRI or noncontrast CT for eligibility. The rapidity of CT makes it preferable in this situation as well [48,49].
Cerebrovascular Diseases Stroke and Stroke Related Conditions PCAs. In patients with renal insufficiency or x-ray contrast allergy, TOF MRA can be used to delineate arterial anatomy without putting the patient at risk and inform subsequent therapeutic decisions [52]. Cerebrovascular Diseases-Stroke MRI Head Perfusion With IV Contrast MRI head perfusion is sensitive and specific in the detection of reversible ischemia. MRI head perfusion may delay EVT in the setting of stroke due to LVO, which detracts from the usefulness of this study in the acute phase due to the potential harm of delayed treatment [39]. Although major RCTs showing a benefit of EVT 6 to 24 hours after onset permitted eligibility based on MRI perfusion or CTP [46,57], the rapidity of diagnosis afforded by CTP is a strongly relevant clinical consideration in this situation in most settings. MRI Head Without and With IV Contrast Rarely, brain tumors or other conditions can mimic ischemic stroke. MRI without and with IV contrast may be helpful in the secondary workup of patients presenting with stroke-like symptoms [62]. MRI Head Without IV Contrast Although sensitive and specific in the detection of the extent of irreversible ischemia, MRI head may delay EVT in the setting of stroke due to anterior circulation LVO, which detracts from the usefulness of this study due to the potential harm of delayed treatment [39,46,56]. Although a major RCT showing benefit of EVT 6 to 24 hours after onset permitted eligibility based on DWI-MRI or CTP [46], the rapidity of diagnosis afforded by CTP is a strongly relevant clinical consideration in this situation in most settings Similarly, the 2 positive RCTs for EVT in basilar occlusion used pc-ASPECTS from either DWI-MRI or noncontrast CT for eligibility. The rapidity of CT makes it preferable in this situation as well [48,49].