Feasibility of SPECT for studies of brain perfusion during cardiopulmonary bypass.

Single-photon emission computed tomography (SPECT) and transcranial Doppler (TCD) ultrasonography were used to assess brain perfusion during cardiopulmonary bypass. Intravenous injections of technetium 99 m-hexamethylpropyleneamineoxime (99mTc-HMPAO) were administered before surgery and intraoperatively after the first 2 minutes in the first patient and at the end (42 minutes) of cardiopulmonary bypass in the second patient. The total middle cerebral artery territory counts were calculated using the region-of-interest method and compared to cerebellar regional counts.