Single photon emission computed tomography (SPECT) myocardial perfusion imaging has attained widespread clinical acceptance as a standard of care for patients with known or suspected coronary artery disease. A significant contribution to this success has been the use of computer techniques to provide objective quantitative assessment in interpreting these studies. We have implemented the Emory Cardiac Toolbox (ECTb) as a pipeline to distribute the software tools that we and others have researched, developed, and validated to be clinically useful so that diagnosticians everywhere can benefit from our work. Our experience has demonstrated that integration of all software tools in a common platform is the optimal approach to promote both accuracy and efficiency. Important attributes of the ECTb approach are (1) our extensive number of normal perfusion databases for SPECT and positron emission tomography (PET) studies, each created with at least 150 patients; (2) our use of Fourier analysis of regional thickening to ensure proper temporal resolution and to allow accurate measurement of left ventricular function and dyssynchrony; (3) our development of PET tools to quantify myocardial hibernation and viability; (4) our development of 3-dimensional displays and the use of these displays as a platform for image fusion of perfusion and computed tomography angiography; and (5) the use of expert systems for decision support. ECTb is an important tool for extracting quantitative parameters from all types of cardiac radionuclide distributions. ECTb should continue to play an important role in establishing cardiac SPECT and PET for flow, function, metabolism, and innervation clinical applications.

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Background We evaluated the incremental diagnostic value of fusion images of coronary computed tomography angiography (CTA) and myocardial perfusion imaging (MPI) over MPI alone or MPI and CTA side-by-side to identify obstructive coronary artery disease (CAD > 50% stenosis) using invasive coronary angiography (ICA) as the gold standard. Methods 50 subjects (36 men; 56 ± 11 years old) underwent rest-stress MPI and CTA within 12-26 days of each other. CTAs were performed with multi-detector CT-scanners (31 on 64-slice; and 19 on 16-slice). 37 patients underwent ICA while 13 subjects did not because of low (<5%) pre-test likelihood (LLK) of disease. Three blinded readers scored the images in sequential sessions using (1) MPI alone (2) MPI and CTA side-by-side, (3) fused CTA/MPI images. Results One or more critical stenoses during ICA were found in 28 patients and non-critical stenoses were found in 9 patients. MPI, side-by-side MPI-CTA, and fused CTA/MPI showed the same normalcy rate (NR:13/13) in LLK subjects. The fusion technique performed better than MPI and MPI and CTA side-by-side for the presence of CAD in any vessel (overall area under the curve (AUC) for fused images: 0.89; P = .005 vs MPI, P = .04 vs side-by-side MPI-CTA) and for localization of CAD to the left anterior descending coronary artery (AUC: 0.82, P < .001 vs MPI; P = .007 vs side-by-side MPI-CTA). There was a non-significant trend for better detection of multi-vessel disease with fusion. Conclusions Using ICA as the gold standard, fusion imaging provided incremental diagnostic information compared to MPI alone or side-by-side MPI-CTA for the diagnosis of obstructive CAD and for localization of CAD to the left anterior descending coronary artery.

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The use of myocardial perfusion 82 Rb PET/CT studies continues to increase but its accuracy using database quantification methods for the diagnosis of coronary artery disease (CAD) has not been established. Methods: A sex-independent normal database and criteria for abnormality for rest-stress 82 Rb PET/CT myocardial perfusion imaging were developed and validated by evaluation of 281 patients (136 females: mean age 6 SD, 63.3 6 13.3 y; 145 males: mean age 6 SD, 63.9 6 12.8 y) who underwent a rest-adenosine stress 82 Rb PET/CT study. These patients were divided into 3 groups: (a) healthy group: 30 patients, with ,5% likelihood of CAD (low likelihood [LLK]) based on sequential Bayesian analysis; these patients were used to generate the normal distribution; (b) pilot group: 174 patients; these patients were used to determine the optimal criteria for detecting and localizing the perfusion abnormality; and (c) validation group: 76 patients (23 with LLK of CAD and 53 who underwent coronary angiography; these patients were used for prospective validation. Results: Of the 53 patients who underwent coronary angiography, 8 had ,50% stenosis and 45 patients had at least one stenosis $50% in one major artery. Fifteen patients had single-vessel disease, 17 had double-vessel disease, and 13 had triple-vessel disease. The prospective validation shows a normalcy rate of 78% (18/23) for global CAD. The analyses by individual arteries show a normalcy rate of 96% (22/23) for the left anterior descending coronary artery, 96% for the left circumflex coronary artery (22/23), and 100% for the right coronary artery (23/23). The overall sensitivity for detection of CAD ($50% stenosis) was 93% (42/45). The overall specificity for detection of the absence of CAD (#50% stenosis) was 75% (6/8). Also, the positive predictive value for global CAD was 95% (42/44), the negative predictive value was 67% (6/9), and the accuracy was 91% (48/53). Conclusion: The quantitative 82 Rb PET/CT database created and validated in this study is highly accurate for the detection and localization of CAD. Physicians should consider using the quantitative output of these algorithms as decision support tools to aid with image interpretation. Rest -stress 82 Rb myocardial perfusion PET is widely regarded as a clinically accurate imaging modality for diagnosing and managing patients with coronary artery disease (CAD) (1,2). The reasons given for this high diagnostic performance are (a) the kinetic properties of 82 Rb, (b) the high sensitivity of a ring PET system, (c) the high-contrast resolution of PET scanners, and (d) the accurate attenuation correction used in PET (1-4). With the advent and wide dissemination of PET/CT scanners for cardiac imaging, high-quality transmission scans are generated by the CT scanner for attenuation correction.Although these PET/CT scanners yield high imaging performance, misregistration of the CT transmission and PET emission scans is often seen because of the different temporal resolution of the 2 modalities. Moreover, the transmi...