IMAGE RECONSTRUCTION IN CARDIAC SPECT IMAGE PROCESSING

Aim: The purpose of this study was to assess the effects of two reconstruction techniques of myocardial perfusion images (MPI) in cardiac patients considered at low risk for myocardial perfusion abnormalities. Materials and methods: We evaluated 36 patients (10 males, 26 females; median age 61 years) with rest MPI studies by comparing their myocardial SPECT images reconstructed using two different algorithms. All patients underwent myocardial SPECT imaging with 99m Tc Tetrofosmin at rest, using a Symbia Evo Excel SPECT or a Siemens e. cam dual head system. SPECT images were reconstructed using filtered back projection method, and an iterative reconstruction method using the 3D Flash algorithm. For the quantitative evaluation of the reconstructed images by two methods, the contrast, contrast to noise ratio and signal to noise ratio were calculated. Using a standard template of coronary artery distribution and the polar map displays, the summed rest scores (SRS) were calculated according to the standard coronary artery distribution. Results: 3D Flash reconstruction algorithm significantly increases image contrast by 31% (p < 0.005). There were significant differences between FBP and 3D FLASH reconstruction in reducing the perfusion artifacts in right coronary artery (RCA) territories. Summed Rest Score (SRS) showed a significant decrease by 64 % (p<0.01) between the long-established FBP reconstruction and 3D Flash algorithm. Conclusions: 3D Flash-based reconstruction showed a significant improvement in image contrast and a decrease in many artifacts at the level of the inferior wall.