Multi-center study confirms efficacy of high-speed SPECT camera

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The D-SPECT high-speed SPECT camera was proven, in a single-center study, to be equal to conventional SPECT regarding its quantification of myocardial perfusion, albeit at seven-times the speed. Now, researchers from four centers testing the new technology confirm the earlier findings in a study presented at the American Society of Nuclear Cardiology (ASNC) conference.

“Part of the introduction of new technology into medical practice is to demonstrate it works in multiple centers. We had four centers, each with a different patient population, a different likelihood of coronary artery disease and differing body masses and we had comparable findings between the centers. It provides validation for the method,” co-author Daniel Berman, MD, director of cardiovascular imaging at Cedars-Sinai Medical Center, Los Angeles, told Cardiovascular Business News.

Led by Tali Sharir, MD, from Procardia Maccabi Healthcare Services in Tel Aviv, Israel, researchers compared the quantitative results of myocardial perfusion and function by the high-speed SPECT camera (D-SPECT, Spectrum Dynamics) to conventional SPECT (Anger or A-SPECT, Siemens Healthcare).

Screen shot from QPS software, which researchers used to automatically segment, quantify and analyze myocardial perfusion SPECT images. Source: Cedars-Sinai Medical Center

They examined 224 patients (127 males), who underwent one-day Tc-99cm sestamibi rest/stress SPECT with D-SPECT and A-SPECT at four centers: Cedars-Sinai (57 patients); Vanderbilt University Medical Center in Nashville, Tenn. (54 patients); Brigham and Women’s Hospital in Boston (58 patients); and Miami Baptist Hospital (55 patients).

The investigators performed myocardial perfusion imaging using D-SPECT within 30 minutes of using A-SPECT. The rest/stress acquisition times were 20 and 15 minutes, respectively, for A-SPECT, and four and two minutes, respectively, for D-SPECT.

They then analyzed perfusion using quantitative perfusion SPECT (QPS) software, deriving the total perfusion defect of stress and rest, expressing overall extent and severity of perfusion defects. QPS is an interactive standalone application for the automatic segmentation, quantification, analysis and display of static (ungated) short-axis myocardial perfusion SPECT images.

D-SPECT stress and rest total perfusion defect in the entire cohort correlated linearly to A-SPECT total perfusion defect over a wide range of perfusion abnormality. A high linear correlation between D-SPECT and A-SPECT stress total perfusion defect was seen at each of the participating centers, according to Berman, who presented the study.

Investigators found that normalcy rate in 61 patients with low prescan likelihood of coronary artery disease were 95.1 percent and 90.2 percent for D-SPECT and A-SPECT, respectively. They also found that the post-stress ejection fraction (EF), end-diastolic volume and end-systolic volume by D-SPECT correlated linearly to A-SPECT over a wide range of EF and volumes.

Berman commented that the fast acquisition means the exam is more convenient to the patient, as well as having the potential to deliver less radiation dose.

While this study found the new technology comparable to the conventional camera, the improved spatial resolution of the D-SPECT camera offers the promise of improved myocardial perfusion abnormality detection and “paves the way to have dynamic studies capture the initial arrival of the radiotracer in the heart, which would allow quantification of coronary flow reserve,” Berman said.