During the COVID-19 pandemic in 2020, an 81-year-old afebrile woman was transported to our institute at 44 minutes after she was found to have global aphasia and weakness of the right extremities. The onset time was unclear. CT showed an occlusion of the left middle cerebral artery without early ischemic changes. MRI revealed a negative fluid-attenuated inversion recovery (FLAIR) pattern, in which several small acute infarcts were seen in diffusion-weighted images with no corresponding hyperintensity lesions on FLAIR. Accordingly, intravenous thrombolysis with alteplase (0.6 mg/kg, the dose approved in Japan) was administered at 1,660 minutes after the last known well and 116 minutes after the symptom recognition. An immediate internal carotid angiogram showed severe stenosis at the distal end of the horizontal portion of the left middle cerebral artery. In the follow-up angiogram at 164 minutes after the symptom recognition, the stenotic lesion almost resolved with the restoration of quick and nearly complete antegrade flow. Her symptoms also resolved promptly. Although the use of MRI is recommended to be minimized in the emergency stroke management during the COVID-19 pandemic, MRI is occasionally mandatory for patient selection, such as cases with unclear onset to perform intravenous thrombolysis. The individualized protected code stroke is essential and must be well considered by each institute for diagnosing patients by selecting appropriate modalities.
Keywords: COVID-19; MRI; intravenous thrombolysis; stroke; unclear onset.