"Cardiac hybrid imaging with CT and nuclear stress testing is an excellent longterm predictor of adverse cardiac events like heart attacks in patients being evaluated for coronary artery disease according to a study published in the journal Radiology.  Coronary artery disease is a leading cause of death and disability worldwide. Invasive coronary angiography ICA is considered the gold standard for determining the percent of stenosis or narrowing due to plaque in a coronary artery. However the degree of stenosis on ICA is not always an accurate predictor of heart attack risk because it gives no information on perfusion or the flow of blood into the heart muscle. Inadequate perfusion also known as ischemia is a potential danger to the patient.  In lesions with less than  percent narrowing one in five lesions still produce an ischemia said study coauthor Philipp A. Kaufmann M.D. professor and chair of nuclear medicine and director of cardiac imaging at University Hospital Zurich in Switzerland. Cardiac hybrid imaging combines coronary computed tomography angiography CCTA and myocardial perfusion imaging with single photon emission tomography SPECT to provide information on both stenosis and perfusion. The approach has shown promise in studies focusing on shortterm observations but information is lacking on longterm outcomes.  The research team looked at  patients who underwent hybrid imaging. During a median followup of . years a total of  major adverse cardiac events including  deaths were observed in the final study population. Patients with matched findingsstenosis of  percent or more on CCTA with evidence of ischemia on SPECT in the area of the heart to which the blocked vessel was supplying bloodhad more than five times the risk of adverse events than those with normal findings. Patients with unmatched findings or evidence of ischemia but not in the area of the heart being fed by the stenotic artery had three times the risk. Major adverse cardiac event rates were . percent for matched findings and . percent for unmatchedconsiderably higher than the . percent rate for normal findings.  The results show that cardiac hybrid imaging is an excellent longterm predictor of adverse cardiac events in patients evaluated for coronary artery disease. Dr. Kaufmann said that hybrid imaging findings could help guide treatment decisions such as whether or not a patient should have a revascularization procedure such as bypass or angioplasty.  In patients with multiple lesions or complex coronary anatomy it is in many cases very difficult to correctly identify the culprit lesion he said. In a previous multicenter trial with hybrid imaging we were able to see that about one in five patients should be revascularized in another coronary artery than originally planned. The present study now documents the prognostic importance of the comprehensive assessment provided by hybrid imaging. The study supports CCTA use for an initial noninvasive evaluation of patients with known or suspected stable coronary artery disease. No additional imaging would be necessary if the results were normal. If a lesion was evident then clinicians could employ a nuclear scan to assess ischemia and take advantage of both modalities by fusing the results together to make a hybrid image. The strategy of direct referral to invasive coronary angiography without noninvasive imaging is obsolete Dr. Kaufmann said. Even after documenting coronary artery disease with coronary CT angiography we need further noninvasive evaluation before deciding upon revascularization versus medication. The researchers hope to run a trial to show that hybrid imaging can have a positive impact on patient outcomes. They are also looking at what they call triple hybrid imaging which combines the CCTASPECT hybrid with information on coronary artery shear stress. The shear stress information could help identify lesions that do not yet have an impact on ischemia but will in the future.  Hybrid SPECT Perfusion Imaging and Coronary CT Angiography LongTerm Prognostic Value for Cardiovascular Outcomes. Collaborating with Dr. Kaufmann were Aju P. Pazhenkottil M.D. Dominik C. Benz M.D. Christoph Grni M.D. Michael A. Madsen M.D. Fran Mikulicic M.D. Elia von Felten M.D. Tobias A. Fuchs M.D. Beatrice Hirt Moch M.D. Julia Stehli M.D. Thomas F. Lscher M.D. Oliver Gaemperli M.D. and Ronny R. Buechel M.D. Radiology is edited by David A. Bluemke M.D. Ph.D. University of Wisconsin School of Medicine and Public Health Madison Wis. and owned and published by the Radiological Society of North America Inc. httpRSNA.orgradiology RSNA is an association of over  radiologists radiation oncologists medical physicists and related scientists promoting excellence in patient care and health care delivery through education research and technologic innovation. The Society is based in Oak Brook Ill. RSNA.org httpRSNA.org For patientfriendly information on cardiac imaging visit RadiologyInfo.org httpRadiologyInfo.org."