Semiqualitative visual and quantitative morphometric evaluations of reduced scan time and wide-beam reconstruction in...

SPECT myocardial perfusion imaging (MPI) now accounts for well over 90% of all MPI studies performed in the United States. A means of reducing the acquisition time while maintaining diagnostic-quality images would be beneficial for both patients and nuclear cardiology clinics. Wide-beam reconstruction (WBR) is a processing algorithm that attempts to address the challenge of obtaining diagnostic-quality images with shorter counting times. This study was designed to incorporate semiqualitative assessments (physician rankings of image parameters) into quantitative assessments (morphologic measurements), as other researchers have done, in an effort to compare filtered backprojection (FBP)-the gold standard-with WBR.

Forty-seven MPI studies (from 34 men and 13 women) were masked to 3 physicians who qualitatively rated the images for image quality, myocardial normality, lesion reversibility, and treatment recommendation on a scale of 1-5, with 1 representing "good" and 5 representing "poor." Quantitative values for summed stress scores, summed rest scores, summed difference scores (SDS), end-diastolic volume, end-systolic volume, and the ejection fraction were calculated and reported.

The semiqualitative analyses of image interpretation indicated that WBR yielded significant improvements over FBP in image quality and showed very good to moderate agreement with FBP among physicians for myocardial normality, lesion reversibility, and treatment recommendation. The quantitative analyses of the morphometric values representing myocardial perfusion, through SDS comparisons, were equivalent for the 2 reconstruction methods. Regression analysis indicated that WBR seemed to underestimate the gated stress-derived FBP ejection fraction by 9%-10%.

Overall, the WBR method was equivalent or superior to the FBP reconstruction method for MPI with a rest-gated stress same-day protocol in terms of image quality, interpretation, and SDS. Additionally, the advantage of patient comfort derived from shorter imaging times should help reduce motion artifacts and repeat acquisitions as well as enhance patient care and throughput.