Scintigraphic confirmation of brain death

Abstract

The concept of brain death has gained importance in the past few decades to prevent futile attempts to sustain ventilation and blood circulation when the brain has lost all function and to procure beneficial tissues or life-saving organs for transplantation. However, differences remain among professional societies and various study group recommendations, as well as among individual legal statutes, in how brain death is defined and the methodology for which the diagnosis is attained. Furthermore, reports have appeared both in the medical literature and the lay press concerning quality assurance measures in brain death documentation. Scintigraphy is a commonly used technique in the evaluation of brain death and can be performed with the use of either nonspecific tracers, such as Tc99m diethylene triamine pentaacetic acid, or brain-specific tracers, such as Tc99m hexamethylpropyleneamineoxime (HMPAO). Planar imaging, with or without radionuclide angiography, continues to be the mainstay for the scintigraphic confirmation of brain death. Flow with multiprojection static planar imaging with the use of Tc99m HMPAO can be used to evaluate the cerebral hemispheres, basal ganglia, thalamus, and cerebellum. Single-photon emission computed tomography (SPECT) can provide cross-sectional information but can be difficult to perform in the context of brain death. The current use of SPECT primarily is supplemental to help differentiate overlying scalp from intracerebral activity. The reliability of SPECT to exclude flow and metabolism in the brainstem remains to be scientifically validated.