Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology Computer Derived Transient Ischemic Dilation Ratio for Identifying Extensive Coronary Artery Disease Using a CZT Camera and Imaging in the Upright Position Zenith Jameria, MD§; Mouhamad Abdallah, MD*; Alok Dwivedi, PhD¶; Erica Washburn, CNMT*; Naseer Khan, MD*; Mahyar Khaleghi, MD*; Nischelle Kalakota, BS*; Myron C. Gerson, MD*   *University of Cincinnati Medical Center, Cincinnati, Ohio ; §University of Illinois at Chicago, Chicago, Illinois; ¶Texas Tech University Health Science Center, El Paso, Texas Copyright American Society of Nuclear Cardiology

Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology BACKGROUND Transient ischemic dilation (TID) of the left ventricle has proven to be a useful diagnostic and prognostic marker of severe and extensive CAD Even in the presence of uniform myocardial perfusion, it is associated with a relatively unfavorable prognosis in patients with diabetes and/or LV hypertrophy A cutoff for an abnormal TID ratio is not yet available for a newly introduced upright CZT SPECT camera We investigated the threshold for an abnormal TID ratio and its utility on a CZT SPECT camera Copyright American Society of Nuclear Cardiology

METHODS Study type: Retrospective cross-sectional Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology METHODS Study type: Retrospective cross-sectional Subjects: All patients who underwent stress myocardial perfusion imaging using a CZT SPECT camera in the upright position from 11/2013-6/2014, followed by coronary angiography were included. Study goals: Determine abnormal thresholds of TID ratios for exercise and pharmacologic stress tests Assess performance of abnormal TID as a marker of extensive CAD Assess the combined diagnostic performance of the TID ratio with LVEF and average Summed Stress Score in differentiating patients with extensive CAD from non-extensive CAD Copyright American Society of Nuclear Cardiology

Performance of Abnormal TID Ratio in Identifying Extensive CAD Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology RESULTS Abnormal TID Cutoff Exercise SPECT ≥1.16 Pharmacologic SPECT ≥1.29 (TID cutoff = Mean + 2SD of normal exercise or pharmacologic stress subjects) Performance of Abnormal TID Ratio in Identifying Extensive CAD Exercise SPECT Pharmacologic SPECT Sensitivity 25.0% 5.0% Specificity 94.6% 93.8% Positive predictive value 50.0% 20% Negative predictive value 85.4% 75.90% Copyright American Society of Nuclear Cardiology

Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology RESULTS Copyright American Society of Nuclear Cardiology

Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology RESULTS Copyright American Society of Nuclear Cardiology

Journal of Nuclear Cardiology | Official Journal of the American Society of Nuclear Cardiology CONCLUSIONS Abnormal TID cutoffs using exercise and pharmacologic stress tests were ≥1.16 and ≥1.29, respectively, and are associated with extensive CAD. These thresholds provide high specificity, so that subjects without extensive CAD seldom had an elevated TID ratio. Extensive CAD was associated with known CAD and previous coronary revascularization, and with an upright exercise LVEF < 50%. Upright TID measurements can serve in an adjunctive role to summed stress score, and may be most effective in patients with a normal upright exercise LVEF. Copyright American Society of Nuclear Cardiology