Positron emission tomography: new analytic tool for vascular disease

Positron emission tomography (PET) is a noninvasive technique that allows the quantification of regional physiologic and biochemical function in vivo. Biochemically active compounds, labeled with positron-emitting isotopes, are administered and the subsequent distribution of radioactivity measured. Although images are produced, they are of secondary importance to the ability to measure cellular metabolic function. The capability of PET to measure regional blood flow, oxygen, and substrate metabolism make it particularly useful in conditions of vascular compromise. Brain and heart have been studied extensively during normal function and while ischemic. PET is able to distinguish ischemic tissue from normal and reversibly from irreversibly injured tissue. PET has been used to document the need for and the metabolic response to vascular surgery. Although PET is complex and expensive, it may offer a means for establishing a more scientific basis for the therapy of vascular disease.