Hyperdense Posterior Cerebral Artery Sign in a Setting of Spontaneous Vertebral Artery Dissection: A Blessing in Disguise?

OBJECTIVE To report a case of a hyperdense posterior cerebral artery (PCA) sign in the setting of spontaneous vertebral artery dissection. CLINICAL PRESENTATION AND INTERVENTION A 28-year-old, previously healthy female presented with rapidly progressive coma. A noncontrast computerized tomographic (CT) scan showed a hyperdense PCA sign, which prompted an urgent arteriogram. She was found to have spontaneous vertebral artery dissection with an occluding thrombus. She underwent intra-arterial thrombolysis with tissue plasminogen activator. Follow-up magnetic resonance imaging showed an area of acute infarction in the medial temporal and occipital regions corresponding to the area supplied by the left PCA. The patient was started on systemic anticoagulation therapy with intravenous heparin. She showed slow and continued recovery but was left with significant neurological deficits that required posthospital discharge to a long-term rehabilitation facility. CONCLUSION This case showed that the hyperdense PCA sign on a noncontrast CT scan necessitated an emergent CT angiogram that showed vertebral artery dissection and a devastating vascular occlusion. Hence, we suggest an early intervention that may allow for potential revascularization therapy.