PET makes pictures or images non-invasively of the blood flow and/or metabolic activity of the heart using a safe, short-lived radionuclide (figure 2). The resulting image is a three-dimensional picture of the heart's blood flow capacity (figure 3).
Figure 2
The PET Scanner takes pictures of the heart muscle blood flow and metabolism after intravenous injection of a positron radiotracer.
Figure 3
The diagnosis of coronary atherosclerosis by PET is astonishingly accurate. It is better than the arteriogram because it identifies effects of diffuse coronary atherosclerosis that are not detectable by coronary arteriography, now shown to miss 79% of this common form of coronary atherosclerosis. The initial PET imaging provides early diagnosis that allows treatment to begin long before symptoms develop. Follow-up imaging definitively indicates whether there is progression (figure 4) or regression (figure 5) of coronary heart disease, and whether more vigorous treatment is needed.
Figure 4
The vigorous dietary and drug treatment regimen relieves pain, partly reverses and prevents additional vascular disease, heart attacks, sudden death and the need for balloon dilation or bypass surgery. It is considerably less costly than these procedures with better outcomes.
One of the great advantages of PET is its superior ability to diagnose or assess the severity of coronary heart disease early in its development when a patient has the best opportunity for optimal survival and/or quality of life. PET offers diagnosis and follow-up assessment with an accuracy greater than tests using ECG monitoring, traditional nuclear studies, or coronary angiograms. Standard exercise testing with ECG monitoring or standard imaging technology gives erroneous results in 50 percent or more of patients, particularly women. Even standard coronary angiograms are often erroneous: visual estimates of specific arterial narrowing by board certified cardiologists over-estimate the severity of narrowing by as much as 60 percent. Moreover, in 79% of subjects with elevated cholesterol, coronary angiograms fail to identify more general, diffuse build-up of cholesterol throughout the walls of the arteries, a condition which causes most heart attacks and strokes. In contrast, PET imaging has an accuracy of 96 to 98 percent in identifying the severity of narrowing of coronary arteries. PET also identifies the abnormalities of blood flow in heart muscle caused by diffuse build-up of cholesterol throughout the walls of the artery that are often not apparent on an angiogram (figure 6).
Figure 6
