Investigation of the impact of compensation for the distance dependent resolution on the uniformity of maximum heart wall counts and wall thickness in cardiac perfusion imaging in SPECT

The authors investigated the impact on the uniformity of the polar map of the maximum wail count, and cardiac wall thickness of several methods used to compensate for distance dependent resolution (DDR) in cardiac perfusion imaging. Comparison was made of: (1) filtered backprojection (FBP) reconstruction with no correction for attenuation and DDR; (2) FBP with Bellini attenuation compensation (AC); (3) FBP with Bellini AC and frequency distance relationship (FDR) restoration filtering prior to reconstruction; (4) ordered-subset maximum likelihood estimation-maximization (OSEM) reconstruction with just AC; and (5) including DDR compensation and AC in OSEM reconstruction with 3D post-reconstruction Gaussian filtering. This investigation shows that compensation for DDR results in a trade-off between uniformity of maximal wall counts and noise control versus average normalized wall thickness. Thus observer detection studies are needed to determine if compensation for DDR does result in improved lesion detection