[Migratory hyperdense posterior cerebral artery sign following intravenous thrombolysis]

Computed tomography (CT) scanning of the brain continues to be the basic imaging mode in the acute phase of stroke. The hyperdense posterior cerebral artery sign is an early and infrequent radiological finding with topographic and prognostic value that must be taken into account in the initial CT scans.

We report the case of a 79-year-old woman who suddenly presented with severe left homonymous hemianopsia, mild lower left facial paresis, 3/5 left hemiparesis and severe left hypaesthesia. In the initial brain CT scan, calcium hyper-density of the P1 segment is observed in the right posterior cerebral artery. Intravenous fibrinolytic therapy is administered. The patient shows clinical improvement, and in the follow-up brain CT scan at 24 hours after fibrinolysis, hyperdensity of the P3 segment is observed in the right posterior cerebral artery.

Evidence of posterior cerebral artery hyperdensity is a rare radiological finding associated with an increased volume of ischaemic stroke. A computed tomography scan of the head in the acute phase is essential to try to clarify its causation. Calcium emboli are an under-diagnosed cause of stroke and occur spontaneously in a large proportion of cases. If calcium embolism is suspected, a study must be conducted in search of a carotid, valvular or aortic arch pathology. Migration of the arterial hyperdensity towards distal is associated with a better prognosis. This case presented good progress in contrast to the poor prognosis described in the literature in cases of arterial hyperdensity as an early marker of stroke in the acute phase.