Parenchymal hyperdensity on computed tomography after intra-arterial reperfusion therapy for acute middle cerebral artery occlusion - Incidence and clinical significance

Background and Purpose-The purpose of the present study was to assess the i ncidence and clinical significance of the I intraparenchymal hyperdense are as on the posttherapeutic CT scan just after intra-arterial reperfusion the rapy. Methods-Seventy-seven patients with acute middle cerebral artery occlusion were studied prospectively with posttherapeutic CT. Hyperdense areas were c lassified into three groups: those in the lentiform nucleus, insular cortex and cerebral cortex. We investigated the incidence of hyperdense areas and hemorrhagic transformations and assessed whether location of hyperdense ar eas may play a role in the incidence of hemorrhagic transformations. We als o evaluated correlation between early CT signs and hyperdense areas. Results-Forty-five hyperdense areas were seen in 37 of the 77 patients (48. 1%): 19 of the 45 (42.2%) were confirmed to be hematomas themselves, 6 (13. 4%) showed later conversion to petechial hemorrhages, and 20 (44.4%) showed rapid disappearance without hemorrhagic transformations. Eleven of the 37 patients (29.7%) had neurological worsening due to massive hematoma (sympto matic hemorrhage), whereas none of the 40 patients without hyperdense areas had symptomatic hemorrhage. The incidence of hemorrhage among hyperdense a reas was significantly lower in the insular cortex than in the other 2 regi ons (P < 0.01). On the other hand, hyperdense areas in the lentiform nucleu s had a significantly higher incidence of neurological worsening (P < 0.05) . There was a significant correlation between early CT signs and hyperdense areas (P < 0.0001). Conclusions-The presence of hyperdense areas was a significant risk factor for severe hemorrhagic transformations, although only 29.7% of patients wit h hyperdense areas had symptomatic hemorrhage. On the contrary, the absence of hyperdense areas was a reliable negative predictor for symptomatic hemo rrhage.