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.