ORIGINAL ARTICLE Feasibility and operator variability of myocardial blood flow and reserve measurements with 99m Tc-sestamibi quantitative dynamic SPECT/CT imaging Ran Klein, PhD, a Guang-Uei Hung, MD, b Tao-Cheng Wu, MD, c Wen-Sheng Huang, MD, d Dianfu Li, MD, PhD, e Robert A. deKemp, PhD, a and Bailing Hsu, PhD f a University of Ottawa Heart Institute, Cardiac PET Centre, Ottawa, ON, Canada b Department of Nuclear Medicine, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan c Section of Cardiology, Department of Internal Medicine, Taipei Veterans General Hospital, Taipei, Taiwan d Departments of Medical Research & Nuclear Medicine, Changhua Christian Hospital, Chang- hua, Taiwan e Section of Nuclear Cardiology, Department of Cardiology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China f Nuclear Science and Engineering Institute, University of Missouri-Columbia, Columbia, MO Received Mar 22, 2014; accepted Jul 14, 2014 doi:10.1007/s12350-014-9971-8 Purpose. Myocardial blood flow (MBF) quantification with dynamic SPECT could lead to widespread utilization of MBF imaging in clinical practice with little cost increase over current standard SPECT myocardial perfusion imaging. This work evaluates the feasibility and operator-dependent variability of MBF and flow reserve measurements with 99m Tc-sestamibi (MIBI) dynamic SPECT imaging using a standard dual-head SPECT camera. Methods. Twenty-eight patients underwent dipyridamole-stress and rest imaging with dynamic SPECT/CT acquisition. Quantitative images were iteratively reconstructed with all physical corrections and then myocardial and arterial blood regions of interest (ROI) were defined semi-automatically. A compartmental model was fitted to these ROI-sampled time- activity-curves, and flow-dependent MIBI extraction correction was applied to derive regional MBF values. Myocardial flow reserve (MFR) was estimated as stress/rest MBF ratio. MBF and MFR in low and high risk populations were evaluated for ability to detect disease. Images were each processed twice (‡7 days apart) by one expert and one novice operator to evaluate intra- and inter-operator variability of MBF and MFR measurement in the three coronary artery vascular territories. Results. Mean rest flow, stress flow, and MFR values were 0.83, 1.82 mLÁminute 21 Ág 21 , and 2.45, respectively. For stress/rest MFR, the inter-operator reproducibility was r 2 5 0.86 with RPC 5 1.1. Stress MBF and MFR were significantly reduced (P < .05) in high risk (n 5 9) vs low risk populations (n 5 19), indicating ability to detect disease. For expert and novice Ran Klein, Guang-Uei Hung, and Bailing Hsu have contributed equally to this study. Reprint requests: Ran Klein, PhD, University of Ottawa Heart Institute, Cardiac PET Centre, 40 Ruskin St., Ottawa, ON K1Y 4W7, Canada; rklein@ottawaheart.ca 1071-3581/$34.00 Copyright Ó 2014 American Society of Nuclear Cardiology. 1075