99mTc-HM-PAO and 123I-amphetamine cerebral scintigraphy: a new, non invasive method in determination of brain death in children.

Determination of brain death in infants and children is difficult and criteria used in adult brain death are regarded insufficient in pediatric cases. In comatose children, clinical signs of brain death and EEG monitoring may be of limited value, while intercerebral blood flow estimations can provide more direct information. Beside radionuclide bolus angiography of polar radiopharmaceuticals with sequential technique, two radioisotopes are introduced for static brain images. Injection of 123I-amphetamine or the 99mTc labelled lipophilic complex HM-PAO into the peripheral venous circulation enables more precise static imaging of parenchymatous brain perfusion and cellular function in contrast to conventional dynamic imaging because of retention in the intact brain parenchyma. Critical deficits or complete loss of cerebral perfusion can be readily documented. These studies are particularly helpful when clinical signs and EEG alone cannot establish the definite diagnosis of brain death. Their easy application and wide availability renders them especially useful in children.