High-speed SPECT technology provides quantitative measures of myocardial perfusion and function comparable to those with conventional SPECT in one-seventh of the acquisition time, according to results from a multicenter trial published May 4 in the Journal of the American College of Cardiology.
A new, compact gamma camera system using a novel design of photon acquisition and image reconstruction was recently developed by Spectrum Dynamics (Ceasaria, Israel).
A total of 238 patients underwent myocardial perfusion imaging with conventional and high-speed SPECT at four U.S. centers—Cedars-Sinai Medical Center, Los Angeles; Brigham and Women’s Hospital, Boston; Baptist Hospital of Miami; and Vanderbilt University Medical Center, Nashville, Tenn.
An additional 63 patients with a low pre-test likelihood of coronary artery disease underwent myocardial perfusion imaging with both technologies to develop method- and sex-specific normal limits in the study.
Rest/stress acquisition times were, respectively, 20/15 min and 4/2 min for conventional and high-speed SPECT. Stress and rest quantitative total perfusion deficit, post-stress left ventricular end-diastolic volume and ejection fraction were derived for the 238 patients by the two methods, according to Daniel S. Berman, MD, director of cardiac imaging and of nuclear cardiology at Cedars-Sinai, and colleagues.
Berman et al found that high-speed stress and rest total perfusion deficit correlated linearly with conventional SPECT total perfusion deficit, with good concordance in the three vascular territories.
The percentage of ischemic myocardium by both imaging modalities was significantly larger in patients with high coronary artery disease likelihood than in those with a low and intermediate likelihood. The average amount of ischemia was slightly but significantly larger by high-speed SPECT compared with conventional SPECT in high-likelihood patients (4.6 vs. 3.9 percent, respectively). Post-stress ejection fraction and end-diastolic volume by the two methods were linearly correlated.
Quantitative measures of myocardial perfusion and function, obtained using normal limits specific for the high-speed SPECT technology correlated extremely well with respective conventional SPECT measures, acquired over as much as eight-times a longer duration, with no influence of patient characteristics, type of stress, or radiopharmaceutical used, wrote Berman and colleagues.
"These findings support the use of this technology in nuclear laboratories using various radiopharmaceutical and stress protocols, evaluating patient populations with different demographic and clinical characteristics", they concluded.