Document Type : Original Article
                            
                        
                                                    Authors
                            
                                                            
                                                                            1
                                                                        Nuclear Medicine and Molecular Imaging Research Center, Namazi Teaching Hospital, Shiraz University of Medical Sciences, Shiraz, Iran                                
                                                            
                                                                            2
                                                                        Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran                                
                                                            
                                                                            3
                                                                        Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran                                
                                                            
                                                                            4
                                                                        Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran                                
                                                            
                                                                            5
                                                                        PET/CT and Cyclotron Center, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran                                
                                                            
                                                                            6
                                                                        Cardiovascular Interventional Research Center, Department of Nuclear Medicine, Rajaei Cardiovascular, Medical, and Research Center, Iran University of Medical Sciences,Tehran, Iran                                
                                                            
                                                                            7
                                                                        Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA                                
                                                            
                                                                            8
                                                                        Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA                                
                            
                                                
                        
                            Abstract
                            Introduction: Metallic artifacts due to pacemaker/ implantable cardioverter defibrillator (ICD) leads in CT images can produce artifactual uptake in cardiac SPECT/CT images. The aim of this study was to determine the influence of the metallic artifacts due to pacemaker and ICD leads on myocardial SPECT/CT imaging.
 Methods: The study included 9 patients who underwent myocardial perfusion imaging (MPI). A cardiac phantom with an inserted solid defect was used. The SPECT images were corrected for attenuation using both artifactual CT and CT corrected using metal artifact reduction (MAR). VOI-based analysis was performed in artifactual regions.
 Results:In phantom studies, mean-of-relative-difference in white-region, between artifact-free attenuation-map without/with MAR were changed from 9.2 and 2.1 to 3.7 and 1.2 for ICD and pacemaker lead, respectively. However, these values for typical patient were 9.7±7.0 and 3.8±2.4 for ICD and pacemaker leads respectively, in white-region. MAR effectively reduces the artifacts in white-regions while this reduction is not significant in black-regions.
 
 Conclusion: Following application of MAR, visual and quantification analyses revealed that while quality of CT images were significantly improved, the improvements in the SPECT/CT images were not as pronounced or significant. Therefore cardiac SPECT images corrected for attenuation using CT in the presence of metallic-leads can be interpreted without correction for metal artefacts.
                        
                        
                        
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