SPECT Functional Brain Imaging: Technical Considerations

The technical aspects of functional brain single-photon emission computed tomography (SPECT) imaging, referring primarily to the most common SPECT brain function measure-regional cerebral blood flow-are reviewed. SPECT images of regional cerebral blood flow are mfluenced by a number of factors unrelated to pathology, including tomographic quality, radiopharmaceuticals, environmental conditions at the t1me of rad1otracer administration, charactenst1cs of the subject (e.g., age, sex), image presentation, and image processing techniques. Modern SPECT scans yield excellent image quality, and instrumentation continues to improve. The armamentarium of regional cerebral blood flow and receptor radiopharmaceuticals 1s rapidly expanding. Standards regarding the environment for patient imaging and image presentation are emerg1ng. However, there 1s still much to learn about the circumstances for performance and evaluation of SPECT functional brain imaging. Challenge tests, primarily established in cerebrovascular disease (i.e , the acetazolamide test), offer great promise in defining the extent and nature of disease, as well as predicting therapeutic responses. Clearly, SPECT brain imaging is a powerful clinical and research tool. However, SPECT will only achieve its full potential in the management of patients with cerebral pathology through close cooperation among members of the nuclear medicine, neurology, psychiatry, neurosurgery, and internal medicine specialties.