High-Speed Nuclear Imaging Helps Doctors Predict Heart Attack Risk
Doctors at Nebraska Medicine have added a new high-speed cardiac nuclear imaging camera that can improve doctors’ ability to evaluate a patient’s risk of having a heart attack to their arsenal of cardiac diagnostic tools.
Compared to older nuclear imaging cameras, the new technology offers a solid state technology that results in images of higher quality and can reduce imaging time from approximately 15 to 20 minutes per scan to as low as two to four minutes per scan. As a result, it has the potential to significantly reduce radiation exposure for patients. Additionally, the camera allows patients to be scanned in a much more comfortable, sitting position, than the standard supine position with the arms raised above the head.
"This provides us with another important non-invasive diagnostic tool to risk stratify our patients," says Kiran Gangahar, MD, cardiologist at Nebraska Medicine. "Currently, it is the only high-speed, solid-state, cardiac nuclear imaging camera available in Omaha."
Nuclear cardiac imaging offers an alternative to patients who are unable to undergo other forms of stress imaging, such as stress echo, because of the inability to image the heart by ultrasound, intolerance to some of the pharmaceutical agents used, physical limitations or body habitus. The test can be used for assessment of ischemia, ejection fraction and myocardial viability.
It is also an effective alternative when echo images are of poor quality. "The time period allowed for echo imaging is much shorter," says Dr. Gangahar. "With nuclear imaging we have 15 to 30 minutes to take pictures compared to just a few minutes allowed with echo. This allows us to perform multiple pictures to ensure we get the right one."
In addition, the pharmacological agent used has a shorter half life so it is eliminated from the body much faster so patient tolerance is much better. The testing area can also accommodate obese patients up to 550 pounds as long as the patient is mobile.
Typical candidates for the procedure are those at intermediate risk for coronary artery disease. "These are patients who have risk factors for coronary artery disease, but may have atypical symptoms," says Dr. Gangahar.
To perform the procedure, the patient is injected with a nuclear tracer fluid based on their body mass index (BMI). The patient’s chest is then imaged in a comfortable sitting position. The patient will then have either an exercise or pharmaceutical stress test, as determined by their physician. This is followed by an imaging post stress in sitting and reclining positions.
"Nuclear stress tests are strong predictors of future cardiac events," says Dr. Gangahar. "The goal is to identify patients who are at high risk for cardiac events so that further, invasive diagnostic testing such as cardiac catheterization, appropriate medications and aggressive risk factor modification can be implemented."