Emergency departments everywhere are faced with important diagnostic decisions whenever someone arrives with acute chest pain. Effectively triaging these patients requires a cost-effective, fast, noninvasive test that can tell doctors when coronary artery disease can be excluded and patients can be safely discharged. It’s not simple, and billions of dollars are spent each year in the United States conducting diagnostic radiology tests to inform emergency decisions.
Many hospitals take a defensive approach so as to minimize the risk of overlooking heart disease, yet of patients hospitalized for further evaluation, only 17% are ultimately diagnosed with heart disease. What’s more, an estimated 2% to 6% of patients discharged from emergency departments really do have heart disease. A new study comparing two medical imaging techniques, SPECT myocardial perfusion and coronary CT angiography, may shed light on the optimal way to triage patients who arrive at the emergency department with acute chest pain.
Medical Imaging Using SPECT Myocardial Perfusion
Myocardial perfusion imaging shows how well blood flows through the heart muscle and can depict areas that aren’t getting sufficient blood flow. Also known as a “nuclear stress test,” it uses single photon emission computed tomography (SPECT) to show how well the heart is pumping.
The technique involves IV injection of a radioactive tracer that is readily taken up by heart muscle cells, so that the tracer distribution indicates where healthy myocardial tissue is located. Though SPECT myocardial perfusion doesn’t show heart arteries, it can indicate location of potentially blocked arteries and show if a patient has had a previous heart attack. If a myocardial perfusion imaging study is normal, doctors can be reasonably confident that a patient’s chest pain is not heart-related.
Why Radiologists Use Coronary CT Angiography
Radiologists like Richard Spira, MD may elect to use coronary CT angiography to examine the arteries that supply the heart with blood. Unlike the traditional coronary angiogram, coronary CT angiography does not use a catheter threaded through blood vessels to the heart. The procedure is noninvasive and there’s no recovery time.
This type of diagnostic radiology may be preferable in people not suspected of having heart disease, because it’s a noninvasive type of medical imaging that can rule out further problems, whereas traditional angiography is invasive. On the other hand, traditional angiography is a diagnostic radiology technique that allows doctors to treat coronary artery disease during the procedure.
Diagnostic Radiology Outcomes: No Significant Differences
Researchers from Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York conducted a randomized, controlled trial to measure comparative effectiveness of coronary CT angiography and SPECT myocardial perfusion imaging on 400 chest pain patients with a mean age of 57 years. They followed up after one year to determine whether further interventions were necessary and whether there were other outcomes like non-fatal heart attack, death, or renal dysfunction.
Fifteen percent of those who had coronary CT angiography and 16% of those who had SPECT myocardial perfusion imaging ended up having cardiac catheterization within a year. Of these, 7.5% of the CT angiography patients and 10% of the SPECT myocardial perfusion imaging patients did not need surgical or other revascularization. These differences were not statistically significant. Hospital stay lengths, non-fatal cardiac events, and re-hospitalizations were also not statistically different between the two groups.
Coronary CT Angiography Offers Lower Radiation Medical Imaging
Radiologists like David H. Ring, Jr. MD have to take into account numerous factors when determining which type of medical imaging to use on patients with chest pain. One consideration is radiation dosage, and between cardiac CT angiography and SPECT myocardial perfusion imaging, CT angiography results in significantly lower radiation exposure.
Other factors may influence a decision in an emergency situation, including availability and expertise of the physicians on duty. But the study in New York shows that cardiac CT angiography and SPECT myocardial perfusion do not lead to significantly different patient outcomes, and this knowledge is valuable to radiologists and cardiac specialists.
South Florida Radiologists at the Forefront of Research
The owner-operator Board-certified radiologists of SteleRAD have decades of combined experience in diagnostic radiology and medical imaging of every type. Not only do they keep up with the latest in medical imaging research, many of them are involved with this research as well. If you are interested in learning more about how SteleRAD can help your imaging center, physician practice, or hospital, we encourage you to call SteleRAD at 954-358-5250 or contact us online at any time.