Abstract
2531
Objectives Accurate detection and localization of significant coronary artery disease requires correct and consistent orientation of myocardial perfusion image (MPI) slices. Physicians during image interpretation not uncommonly disagree with original oblique angle selection resulting in either suboptimal interpretation or off-line reorientation and delayed interpretation. To develop a software tool to allow real-time oblique angle slice re-orientation during MPI interpretation within the Emory Cardiac Toolbox™ (ECTb).
Methods Stress or rest data is identified for adjustment, angles are interactively set on reference mid vertical or horizontal long axis, and a new SA dataset is produced without the need for reconstruction. To validate whether this approach yielded similar diagnostic results compared to re-reconstructing and re-selecting the correct oblique angles, 20 99mTc stress tetrofosmin studies (15 males) were used. Studies were reconstructed and re-oriented by a single operator in several iterations: correct angles (CORR1), transaxial (TX) +10 degrees, TX -10 degrees, vertical long (VLA) +15 degrees, VLA -15 degrees. Reconstruction was repeated correctly in a separate session (CORR2). Perfusion defect extent (DE) was calculated from CORR1 slices using ECTb. For each non-CORR image set with significantly different DE from CORR1 results, oblique angles were adjusted in real-time using the new tool and re-analyzed.
Results CORR1 DE matched CORR2 DE in 90% of LAD (18/20), 90% of LCX (18/20) and 95% of RCA (19/20) territories. With incorrect orientation, there were 18 instances of clinically significant changes vs CORR1 in at least one coronary territory, involving 10 of the 20 patients. After angle adjustment, correct DE was obtained for 100% of LAD (18/18), 83% of LCX (15/18) and 94% of RCA (17/18) instances.
Conclusions Using a new software tool, image slice orientation can be corrected in real-time during MPI review. Corrected slices yield similar quantitative results to original correct slices.