Extravasation of pertechnetate in cranial extracerebral tissues during first pass across the cerebral vasculature

By evaluating regional cerebral first pass curves following Pertechnetate administration in common, internal and external carotid artery, it has been shown that about 20% of the injected dose of Pertechnetate extravasates in cranial extracerebral tissues during the first pass. This extravasation may lead to an overestimation of about 1 sec in the determination of regional cerebral mean transit time by intravenous radionuclide Angiography.