PET/CT tops angiography in coronary artery disease diagnosis

One of the first studies of its kind has found integrated PET/CT to be a highly accurate method for diagnosing coronary artery disease. The combined imaging approach can help physicians decide whether to treat these patients with revascularization or proceed conservatively, according to a study in the June issue of the Journal of Nuclear Medicine.

Standard imaging with coronary angiography is costly compared with alternatives such as CT angiography or intravascular coronary ultrasound. It is also invasive and carries a small risk. An average 30% of coronary angiograms yield clinically insignificant disease, and angiography cannot predict the physiologic implications of stenoses such as ischemic recurrence or vessel reocclusion after lytic therapy.

An imaging test that combines functional and anatomic capabilities could render coronary angiography unnecessary. PET/CT could be that test, according to Dr. Mehdi Namdar and colleagues at the University Hospital of Zurich in Switzerland.

Researchers enrolled 25 consecutive patients who underwent CT angiography and PET scanning on a four-slice PET/CT system. All patients had been referred for a PET myocardial perfusion scan due to a clinical history of coronary disease. They had previously undergone coronary angiography for recurrent chest pain. The investigators compared PET/CT with PET plus coronary angiography.

They found that PET/CT's high negative predictive value could help pick the right candidates for revascularization. Hybrid imaging selected 11 stenotic lesions producing perfusion defects amenable to revascularization therapy, the same number that PET plus angiography picked up. PET plus angiography and PET/CT outcomes confirmed 89 and 82 lesions for conservative treatment, respectively.

Seven arterial segments could not be evaluated by CT because of rapid vessel motion. These vessels, however, were correctly categorized by PET alone. The integration of more powerful 16- or 64-slice CT scanners into PET/CT hybrids should make up for such shortcomings and could speed clinical implementation of the technique, the researchers said.

PET/CT adds functional information on the pathophysiologic impact of a lesion, allowing accurate clinical decision making on the best therapeutic strategy. However, larger trials are necessary to obtain further confirmation, researchers said.

For more information from the Diagnostic Imaging archives:

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