Regional left ventricular function from short SPECT gated blood pool studies

SPECT gated blood pool scans can provide accurate 3D assessments of resting regional left-ventricular (LV) function. However, due to limited scan times for stress studies, SPECT GBP images are too noisy for standard visual analysis. In this study, a counts-based scheme for measuring regional ejection fraction (REF) and relative regional phase (RRP) was investigated. Constructing a rest normal database from the 30-min. SPECT GBPs of 10 volunteers, the mean and standard deviation (σ_{(rest NLDB)}) of these parameters was calculated for each of 12 3D regions. Adding statistical noise, the expected normal database variability at stress (σ_{stress NLDB}) from 3-min. scans was estimated for each parameter. The variability due only to increased noise (σ_noise) was an average of 15% of the total σ_{stress NLDB} for REF and 30% for RRP. Analyzing rest scans from two patients with regional defects, regions were classified twice; first based on a criterion of ±2σ _{rest NLDB} about the average normal database value for that region, then, again, using ±2σ_{stress NLDB}. Of the 19 abnormal regions identified at rest, 18 were still detected with the ±2σ_{stress NLDB} criterion. This suggests that quantitative regional analysts may be relatively insensitive to the increased noise from a 3-min. scan, making stress SPECT GBP studies potentially feasible