Abstract Number ‐ 249: Differential Ischemic Vulnerability depicted by White Matter‐Sparing Infarction following Alteplase Recanalization

IntroductionGray and white matter possess different ischemic thresholds and therefore will undergo infarction at different rates of cerebral blood flow. We present a patient that presented with a large vessel occlusion and recanalized following alteplase administration within hours of symptom onset. Follow‐up imaging revealed a white matter‐sparing infarction, visually depicting the differential ischemic vulnerability between gray and white matter.MethodsCase Report.ResultsAn 83‐year‐old woman with a medical history of dementia, hypertension, and atrial fibrillation, not on anticoagulation due to recent gastrointestinal hemorrhage, presented with speech difficulty and right sided weakness. Her blood pressure was elevated at 170/86 and neurological exam demonstrated mixed aphasia, right homonymous hemianopia, left gaze deviation, and dense right hemiparesis with a National Institutes of Health Stroke Scale of 23. Non‐contrast CT of the head showed a hyperdense left terminal internal cerebral artery (ICA) and was otherwise unremarkable (Figure 1, A). CT angiography of the head and neck revealed an ICA “T” occlusion with no flow seen at the ICA terminus, the left anterior cerebral (A1) and middle cerebral (M1) segments (Figure 1, B). She was treated with intravenous alteplase 132 minutes from when she was last known normal. She was transferred to our comprehensive stroke center for mechanical thrombectomy, however, catheter angiography showed spontaneous recanalization of left ICA (Figure 1, C). Brain MRI the following day showed a white matter‐sparing infarction involving the left ICA territory (Figure 1, D‐F). She was discharged to rehab with moderate improvement in her aphasia and right hemiparesis.ConclusionsThis case visually depicts the differential ischemic vulnerability between gray and white matter since recanalization likely occurred at a cerebral blood flow level below the gray matter ischemic threshold while remaining above the white matter threshold. While pretreatment ischemic core volumes are inversely correlated with functional outcomes after recanalization of large vessel occlusions,1 selective white matter‐sparing infarction on post‐treatment MRI is associated with more favorable outcomes.2 Predicting ischemic core volume with perfusion imaging using the same CBF threshold for both gray and white matter may over‐estimate the ischemic core if CBF is between the gray and white matter thresholds.