The safety of fibrinolytic therapy is determined with the incidence of intraparenchymatous hemorrhage. When interpreting CT studies after local intra-arterial fibrinolysis (LIF) in the carotid territory, one must consider that a hyperdense lesion may also be caused by extravasation of contrast material during angiography. In this study we retrospectively analyzed CT scans of 24 patients performed within 24 h after LIF and correlated the results with clinical and angiographic findings before and after therapy. Three of 24 patients (12.5%) showed striatocapsular parenchymal hematomas, 2 patients died and 1 showed marked clinical deterioration. Fifteen of 24 patients (62.5%) showed hyperdense lesions without space-occupying effect within striatocapsular infarctions. In 6 of these patients (25%) these lesions were attributable to an extravasation of contrast medium during angiography. This extravasation required at least partial recanalization of the middle cerebral artery and always occurred within a striatocapsular infarction. The pathogenesis of extravasation of contrast medium during local intra-arterial fibrinolysis is unknown. The identification of these lesions, however, is essential for the assessment of safety of local intra-arterial fibrinolysis.