Investigation of Emission–Transmission Misalignment Artifacts on Rubidium-82 Cardiac PET with Adenosine Pharmacologic Stress

Abstract

This study was undertaken to determine if artifacts from misalignment of cardiac emission to transmission data is present in adenosine stress studies and if the artifact could be reproduced by intentional misalignment in normal exams. Seventy consecutive 82Rb myocardial perfusion studies were reviewed. Utilizing a quality control program, misalignment was assessed. The study was reprocessed after manual realignment to determine if the defect extent changed. Emission and transmission acquisitions in six normal studies also were intentionally misaligned. Twenty of 69 rest studies (29.0%) and 17 of 69 (24.6%) stress studies demonstrated misalignment. In four patients with stress misalignment, there was a significant change in clinical interpretation. Upon intentionally misaligning six normal studies, a lateral wall defect was reproduced. Emission-transmission misalignment occurs in 29.0% and 24.6% of 82Rb rest and adenosine stress studies, respectively. While there is a positive correlation of artifactual defects with misalignment, the presence and size of artifacts is variable and unpredictable at seemingly lesser degrees of misalignment.