Early regression of DWI–FLAIR-positive cortical lesions in acute ischemic stroke

Introduction: Ischemic lesions that appear hyperintense on diffusion-weighted imaging (DWI) and FLAIR sequences are generally regarded as established infarcts. This report aims to present a patient in whom early radiological regression was observed in DWI–FLAIR-positive cortical lesions even though no reperfusion therapy was given.Case: A 42-year-old man presented with speech disturbance and right-sided weakness that had persisted for four days. His history included uncontrolled type 2 diabetes mellitus, a below-knee amputation for peripheral arterial disease, and clopidogrel and insulin treatments that he had discontinued one month earlier. His HbA1c was 13.4%. Neurological examination revealed global aphasia and right hemiplegia. Non-contrast brain computed tomography showed a hypodense area in the left posterior parietal cortex. Brain MRI showed a large cortical ischemic lesion in the left posterior parietal cortex and multiple small cortical ischemic lesions in the left frontal lobe. All lesions were hyperintense on DWI and FLAIR sequences. CT angiography showed a long-segment thrombus extending from the left common carotid artery into the internal and external carotid arteries. Because of late presentation and FLAIR positivity, neither intravenous thrombolysis nor interventional treatment was performed. Enoxaparin 8,000 IU twice daily was started because of the ongoing risk of embolization. On the third day of treatment, the hemiplegia had resolved completely and the aphasia had partially improved; follow-up imaging showed that the frontal cortical lesions had disappeared completely on both DWI and FLAIR sequences. Repeat CT angiography on day 10 showed that the thrombus had almost completely regressed (Figure 1–3). At one month, only minimal aphasia remained.Discussion/Conclusion: DWI–FLAIR positivity may not indicate irreversible ischemic damage in every patient. In young patients, early spontaneous reperfusion following dynamic distal microembolization may explain the clinical and radiological regression of cortical lesions.Keywords: