DIRECT COMPARISON OF TC-99M DTPA AND TC-99M HMPAO FOR EVALUATING BRAIN-DEATH

Portable cerebral perfusion studies provide a quick and accurate alter native to traditional confirmatory examinations (such as four-vessel a ngiography and electroencephalography) to determine brain death. The a uthors retrospectively analyzed 26 cerebral perfusion studies using bo th Tc-99m DTPA and Tc-99m HMPAO. The flow agents gave identical result s. Additionally, the delayed-phase Tc-99m HMPAO images gave the same r esults for brain death (14 positive and 12 negative) as the flow image s from either agent. Because the Tc-99m HMPAO delayed images can be us ed for diagnosis, many technical problems become less crucial. Unlike Tc-99m DTPA, Tc-99m HMPAO normally visualizes the gray mater of the ce rebellum, midbrain, and medulla. These areas must be evaluated to ensu re that they meet the strict criteria for brain death. These differenc es and the present study suggest that Tc-99m HMPAO is a superior agent for cerebral perfusion studies to determine brain death.