Does quantification of myocardial perfusion SPECT study differ while image reconstruction is carried out using iteration algorithm instead of filtered back-projection? - preliminary report

Abstract

BACKGROUND: The purpose of this study was to compare the performance of two reconstruction algorithms: conventional filtered back-projection (FBP) and an iterative algorithm -ITW- in quantitative analysis of myocardial perfusion SPECT studies. The defect size and defect severity were assessed on ^99m Tc - MIBI images reconstructed using both methods and estimation of sensitivity in the detection of perfusion deficits and myocardial viability were performed as well.
METHODS AND RESULTS: The study group comprised 43 patients (38 men and 5 women) in the age of 40-73 years (mean 59 years). Heart perfusion scintigraphy was performed following an injection of 22 to 25 mCi 99m Tc-MIBI for exercise and rest myocardial perfusion study. Images were reconstructed using
FBP and ITW algorithms. Defect size (DS) was quantified by a threshold program and CEqual programme. Defect severity (nadir) was calculated as the ratio of minimal/maximum counts from bull?s eye polar map. Coronary arteriography was performed in all patients.
RESULTS: Defect size calculated by threshold method on resting images did not differ between reconstruction methods (p=0.61 for cut-off 50% and p = 0.24 for cut-off 60%); defect severity was higher on images reconstructed with ITW (CI 0.95 = 2.4%¸5.2% of maximal counts).
CONCLUSIONS: Sensitivity for detection of heart perfusion defects and estimation of myocardial viability were similar on images reconstructed by both algorithms.