| Semin Nucl Med 1992 Oct;22(4):224-232 |
Positron emission tomography in cerebrovascular disorders.
Broich K, Alavi A, Kushner M.
The introduction of positron emission tomography (PET) as a powerful imaging modality has
played a major role in the understanding of the pathophysiological bases for
cerebrovascular disorders. PET is the only technique that allows measurement of regional
cerebral blood flow, blood volume, oxygen extraction fraction, and oxygen and glucose
metabolism with detail and accuracy. Using PET, these physiological parameters can be
measured to determine the extent of the disease from the early stages of cerebrovascular
disorders to acute cerebral infarction. Significant hemodynamic and metabolic
abnormalities are noted in chronic ischemia, but no structural changes are noted on
anatomic images. PET studies have shown that in many patients in the early phases (10 to
12 hours) of clinically diagnosed acute stroke, a substantial area of ischemia exists,
which, if untreated, will become irreversibly damaged. Similar to the results achieved in
patients with acute myocardial infarction, appropriate intervention in patients with
cerebrovascular disorders may significantly reduce the extent of injury to the brain. PET
also has been useful in predicting functional recovery and monitoring the effects of
various therapeutic approaches. Although functional imaging of the brain with single
photon emission computed tomography can successfully be used in the investigation of
several disorders of the brain, its role in cerebrovascular disorders is quite limited.
PET is a unique modality that studies ischemic diseases of the brain, and it potentially
could play a significant role in the management of patients with cerebrovascular disease.
This will be further realized when aggressive approaches are used routinely in the future.
