Discrepancy between perfusion- and diffusion weighted images in ischemic stroke: A case report

Rationale: With the development of multi-slice computed tomography (CT) technology, perfusion CT angiography (p-CTA) is now widely used for the diagnosis of acute cerebral infarction. Although p-CTA has the advantage of distinguishing between an ischemic penumbra and an infarct core, more research is needed with respect to its clinical use. Patientconcerns: Ahealthy 36-year-oldman experienced sudden dizziness whileswimming. His dizziness persisted irrespective of the change in position, and then improved during transport.Hehad no neurological abnormality when he arrived at theemergency room. Diagnoses: CT perfusion findings suggested left cerebellar infarction. P-CTA revealed a markedly delayed mean transit time, delayed time to peak, and increased cerebral blood volume in the left posterior inferior cerebellar artery territory at admission. However, the diffusion-weighted image (DWI) taken a few hours later revealed a large right cerebellar infarction. Interventions: Because of the time window, thrombolysis could not be performed and anti-platelet therapy was started. Outcomes: Dysarthria and right-sided limb ataxia were newly developed before DWI (after p-CTA). Persistent foramen ovale was detected through transesophageal echography and identified as the cause of the stroke. Lessons: This case report suggests that dynamic image changes can occur within a short period of time depending on the vascular status and hemodynamic changes of the patients.