Contrast enhancement and contrast extravasation on computed tomography after intra-arterial thrombolysis in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE The goal of this study was to determine the CT findings and clinical consequences of contrast enhancement and contrast extravasation on CT scans obtained after intra-arterial thrombolytic therapy for treatment of acute ischemic stroke. METHODS Sixty-two patients were treated with intra-arterial thrombolysis. All patients underwent nonenhanced CT scans immediately and 24 hours after thrombolytic therapy. Contrast enhancement was defined as a hyperdense lesion that disappeared on a 24-hour follow-up CT scan. Contrast extravasation was defined as a hyperdense lesion with maximum Hounsfield unit >90 that persisted on a follow-up CT scan. We evaluated the differences in the clinical and radiological data between 3 groups: contrast enhancement, contrast extravasation, and control groups. RESULTS Contrast enhancement was found in 14 of 62 patients (22.6%); contrast extravasation was seen in 7 (11.3%). Compared with the control group, the contrast enhancement group had a lower recanalization grade (64.3% versus 34.1%, P=0.048) and a lower incidence of hemorrhagic transformation (14.3% versus 43.9%, P=0.047). The contrast extravasation group had a higher incidence of both hemorrhage (100% versus 43.9%, P=0.006) and symptomatic hemorrhage (100% versus 14.6%, P<0.001) than the control group. Poor outcomes were more frequent in the contrast extravasation group (100% versus 38.9%, P=0.003) than the control group. CONCLUSIONS Contrast enhancement on CT scans obtained after intra-arterial thrombolysis is usually not associated with hemorrhagic complications. However, contrast extravasation is highly associated with parenchymatous hematoma and should be considered a negative prognostic sign.