Thesis (M.Sc.) - Cairo University - Faculty of science - Department of Biophysics

Background: Myocardial perfusion imaging (MPI) using 99mTc-labeled sesta MIBI is used in various clinical settings to provide invaluable information about coronary artery disease. Image reconstruction algorithm such as filtered-back-projection (FBP) and iterative reconstructions (2D and 3D) with resolution recovery are playing a pivotal role in image quality evaluation of (MPI). Aims: The aim of the present study was to provide a comparative analysis among the three reconstruction algorithms FBP, 2D ordered subset expectation maximization (2D-OSEM) and 3D-OSEM (Flash-3D) with resolution recovery provided by system manufacturer in evaluating image quality of gated MPI Materials and Methods: The patient population was divided into three groups such that the first group (gp1) received the full standard dose and scanned using the adopted acquisition protocol routinely used in our clinic (32 views, 20 sec/view, 64x64 matrix size, using 925 MBq administered activity), group 2 (gp2) in which the acquisition protocol was reduced to 16 views using 20 sec/view, matrix size of 64x64 with injected activity of 925 MBq and the last group (gp3) was examined using the same imaging protocol like group 1 but with half dose (i.e. 444 MBq). All patients acquired data were processed using FBP (Butterworth filter: cut-off=0.5, order=5), OSEM-2D (8 subsets, 12 iterations, FWHM=11 mm) and Flash-3D iterative algorithms (8 subsets, 12 iterations, FWHM=11 mm). Quality of the reconstructed data were evaluated in terms of image contrast, relative noise level as well as contrast to noise ratio. Results: in terms of image noise, Flash-3D reconstruction algorithm increased the image noise (P>0.05) as compared with FBP and OSEM-2D. Also, OSEM-2D iterative algorithm increased the image noise (P>0.05) as compared with FBP. Flash-3D reconstruction algorithm significantly increased the image contrast (P<0.05) as compared with FBP and OSEM-2D. Also, OSEM-2D iterative algorithm significantly increased the image contrast (P<0.05) as compared with FBP. Flash 3D reconstruction algorithm reduced the image CNR by 13.3% (P=NS) than FBP and 4.82% (P=NS) than OSEM2-D respectively. Also, the OSEM-2D reconstruction algorithm decreased the image CNR by 8.1% (P = NS) than FBP

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