Dr. Kent G. Meredith

PET/CT cardiac imaging offers new level of diagnostic outcome: study

March 17, 2015
by John W. Mitchell, Senior Correspondent
A new generation of PET/CT cardiac imaging scanners offers patients significantly improved diagnostic outcomes with lower radiation doses than the more common SPECT technology, especially in female, obese and patients with comorbid liver and gastro conditions, according to researchers at Intermountain Medical Center Heart Institute in Salt Lake City.

“The PET/CT was correct 88 percent of the time as opposed just 30 percent of the time in the standard SPECT imaging in identifying a blocked artery. This is nearly as good as the current gold standard of coronary angiogram, which is an invasive procedure done in a cardiac cath lab where the patient must undergo anesthesia,” Dr. Kent Meredith, the lead author of the study, told DOTmed News.

He presented his results at the 64th Annual Scientific Session of the American College of Cardiology.

Some 5 million patients with stable chest pain present in hospital emergency rooms a year, as well as many others in doctor’s offices. There are several diagnostic protocols available, including treadmill stress tests, echocardiograms, nuclear medicine stress tests and advanced technology scanning such as the SPECT (Single-Proton Emission Computerized Tomography) and now PET/CT (Computed Tomography - Positron Emission Tomography - Computed Tomography).

The study was conducted by comparing the results of a 2,483 SPECT and 2,178 PET/CT scans conducted at Intermountain Heart Institute and screening for patients who had both a scan and a heart catheter procedure.

According to Dr. Meredith patients receiving PET/CT have a reduced exposure to radiation by a factor of 10. He said this is an important benefit as patients exposed to higher levels of diagnostic radiation over a lifetime are at a higher risk of cancer. SPECT patients also receive a false negative about six percent of the time, while there were no false negatives noted using the PET/CT during the study period.

“The reduction in false positives prevents patients from undergoing unnecessary invasive procedures in the cath lab. This is safer for the patient and reduces health care costs. We also saw a reduction in false negatives for patients, so both of these situations are highly desirable for patients,” says Dr. Meredith. “Not only was the accuracy greatly improved using the PET/CT imaging, but we also get a lot of additional information that helps with decisions about patient care.”