New horizons in radionuclide brain scanning

After the introduction of X-ray computerized tomography (CT) in the early 1970s, radionuclide brain imaging received a setback, although it was still an important investigation in the developing countries, where CT service is not readily available. There has been a resurgence of interest in brain imaging in recent years because of three developments: (1) single photon emmission tomography (SPECT), (2) use of lipophilic compounds which cross the blood-brain barrier and are retained in the brain in relation to blood flow, receptor binding or metabolic activity, and (3) development of positron emission tomography (PET). Recent experience of SPECT brain imaging with 99Tcm HMPAO, one of the lipophilic compounds, is reviewed in the paper and a description is given of some results obtained in Kuwait. The procedure was found to be diagnostically useful, and often more helpful than CT, in a variety of neurological disorders such as dementia, degenerative disorders of the brain, epilepsy, cerebrovascular accidents, subarachnoid haemorrhage and head injuries. Cerebral perfusion study with radionuclide imaging is the most definitive criterion of acute brain death. It is felt that new horizons have opened up in nuclear medicine as a result of the new developments. (author)