SPECT adenosine myocardial perfusion images are shown.
View main image(mi) in a separate image viewer
View second image(an). Image from coronary angiography of the left anterior descending artery.
View third image(an). Image from angiography of the right coronary artery.
Full history/Diagnosis is available below
Coronary angiography demonstrates high-grade (>90%) stenosis in both the left anterior descending and right coronary arteries.
Balanced 3-vessel coronary artery disease creates a diagnostic dilemma for the nuclear medicine physician. If all three main coronary arteries have an equivalent degree of disease, the radiotracer will demonstrate equal uptake in all portions of the myocardium. Because of the reliance on differentiation of relative perfusion to make the diagnosis of ischemia, balanced 3-vessel disease can produce a false-negative myocardial perfusion scintigram. With an exercise study, hopefully the EKG findings will be positive for ischemia. In an adenosine study, this may be problematic as adenosine is a strict vasodilator and rarely causes ischemia. The ischemic changes seen in this patient's EKG may be due to a coronary artery "steal" during an episode of maximal coronary artery vasodilatation. The dilated cardiomyopathy and hypokinesis on gated images also alerted the nuclear medicine physician that the SPECT study may be underestimating the amount of coronary artery disease.
2. Balanced three-vessel coronary artery disease may produce false-negative myocardial perfusion studies.
3. Adenosine rarely causes ischemia except in the case of a coronary artery "steal".
References and General Discussion of Myocardial Imaging (Anatomic field:Heart and Great Vessels, Category:Organ specific)
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