CEREBRAL BLOOD-FLOW MEASUREMENT IN PATIENTS WITH IMPAIRED CONSCIOUSNESS - USEFULNESS OF TC-99M-HMPAO SINGLE-PHOTON EMISSION TOMOGRAPHY IN CLINICAL-PRACTICE

The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexa methylpropylene amine oxime single-photon emission tomography (Tc-99m- HMPAO SPET) in patients with the following diseases: cerebral infarcti on, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumo ur and cerebral contusion. The clinical symptoms were evaluated accord ing to the severity of impaired consciousness, aphasia and dementia. F our hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBE Pat ients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional t o reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBE Patients with dementia showe d a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using 99mTc-HMPAO SPET i s reliable in clinical evaluations.