ST. LOUIS – Electron-beam computed tomography (EBCT) is moreaccurate than conventional catheter angiography for detecting adangerous congenital heart abnormality that could cause sudden death,according to research by a Saint Louis University radiologist publishedlast month in Catheterization and Cardiovascular Interventions: Journalof the Society for Cardiovascular Angiography and Interventions.
EsatMemisoglu, M.D., assistant professor of radiology at Saint LouisUniversity School of Medicine, and his team – which included anotherradiologist and several cardiologists – studied 28 adults at a hearthospital and imaging center in Istanbul, Turkey, who had undergoneconventional X-ray angiography for chest pain or shortness of breathand then later underwent an EBCT.
In half of the patients,angiography showed a congenital abnormality – for example, a leftcoronary artery originating from the right side of the aorta, or viceversa. EBCT also detected the abnormalities, but in more than a thirdof the cases, it was able to provide information the angiography couldnot. Specifically, it could confidently determine whether the arterytraveled perilously between the aorta and pulmonary artery, puttingthat patient at risk for a heart attack or sudden death, Memisoglu says.
“Themost crucial clinical question is whether the artery is coursingbetween the aorta and pulmonary artery. Angiography did not always giveus the correct answer, but it was very easy to tell using EBCT,”Memisoglu says.
Traditional catheter angiography, an invasivetwo-dimensional projectional X-ray technique that involves passing acatheter through a patient’s groin artery to the heart vessels, iscommonly used when physical examinations and other non-invasive testsare found to be negative in younger patients who experience chest painor fainting during strenuous physical activity. However, catheterangiography “can lead to ambiguities because of its in defining complexvascular anatomy,” Dr. Memisoglu says.
In contrast, EBCT, whichuses a specialized stationary X-ray tube and a high-resolution detectorsystem, enables doctors to capture “practically blur-free”cross-sectional images of the beating heart, says Memisoglu.
Becauseof its speed in capturing images – the study is completed in fewer than30 seconds – patients don’t need medication to slow their heart rate.
EBCT,along with multi-slice computed tomography (MSCT) – which features amoving X-ray tube but is comparable to EBCT in diagnosis – producesstunning three-dimensional images of the heart that help radiologistsdetect congenital defects that otherwise might not have been picked up.EBCT and MSCT can also rule out the presence of significant coronaryartery blockages with a high degree of accuracy.
“Up to 40percent of all patients in the U.S. who go through invasive catheterangiography do not end up needing revascularization treatment, such asstenting or bypass surgery. That means a major role for MSCT and EBCTwould be gatekeeping – telling us which patients would benefit mostfrom an invasive procedure,” Memisoglu says.
Memisoglu also sees an economic advantage to using EBCT or MSCT scans in place of catheter angiography.
“Liberaluse of coronary catheterizations are costing taxpayers millions ofdollars, driving the cost of medical insurance and creating a burden onthe economy,” he says.
He predicts non-invasive scans – such asEBCT, MSCT and magnetic resonance imaging (MRI) – will one day replacecatheter angiography entirely to detect heart vessel blockages andcongenital abnormalities; conventional catheter angiography will thenbe used for treatment only, he suspects.
“We don’t want to blockaccess to catheter angiography for patients who really need it,”Memisoglu says. “But EBCT and MSCT can help avert the unnecessaryphysical and psychological consequences of an invasive procedure.”
Establishedin 1836, Saint Louis University School of Medicine has the distinctionof awarding the first M.D. degree west of the Mississippi River. SaintLouis University School of Medicine is a pioneer in geriatric medicine,organ transplantation, chronic disease prevention, cardiovasculardisease, neurosciences and vaccine research, among others. The Schoolof Medicine trains physicians and biomedical scientists, conductsmedical research, and provides health services on a local, national andinternational level.
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