ABC | Volume 113, Nº6, December 2019

Original Article Myocardial Perfusion by Coronary Computed Tomography in the Evaluation of Myocardial Ischemia: Simultaneous Stress Protocol with SPECT Wilter dos Santos Ker, 1, 2 Daniel Gama das Neves, 2 Tiago Augusto Magalhães, 3 A lair Augusto Sarmet M. D. dos Santos, 1 Claudio Tinoco Mesquita, 1 Marcelo Souto Nacif 1,2, 3 Hospital Universitário Antonio Pedro, 1 Niterói, RJ – Brazil Universidade Federal Fluminense, 2 Niterói, RJ – Brazil Complexo Hospital de Clínicas da Universidade Federal do Paraná (CHC-UFPR), 3 Curitiba, PR – Brazil Mailing Address: Wilter dos Santos Ker • Rua Aroazes, 180, apto. 903. Postal Code 22775-060, Jacarepaguá, RJ – Brazil E-mail: wiltersker@gmail.com Manuscript received December 24, 2018, revised manuscript February 13, 2019, accepted February 13, 2019 DOI: 10.5935/abc.20190201 Abstract Background: Functional assessment to rule out myocardial ischemia using coronary computed tomography angiography (CCTA) is extremely important and data on the Brazilian population are still limited. Objective: To assess the diagnostic performance of myocardial perfusion by CCTA in the detection of severe obstructive coronary artery disease (CAD) compared with single-photon emission computerized tomography (SPECT). To analyze the importance of anatomical knowledge to understand the presence of myocardial perfusion defects on SPECT imaging that is not identified on computed tomography (CT) scan. Method: A total of 35 patients were evaluated by a simultaneous pharmacologic stress protocol. Fisher’s exact test was used to compare proportions. The patients were grouped according to the presence or absence of significant CAD. The area under the ROC curve was used to identify the diagnostic performance of CCTA and SPECT in perfusion assessment. P < 0.05 values were considered statistically significant. Results: For detection of obstructive CAD, CT myocardial perfusion analysis yielded an area under the ROC curve of 0.84 [a 95% confidence interval (CI95%): 0.67-0.94, p < 0.001]. SPECT myocardial perfusion imaging, on the other hand, showed an AUC of 0.58 (95% CI 0.40 – 0.74, p < 0.001). In this study, false-positive results with SPECT are described. Conclusion: Myocardial perfusion analysis by CTA displays satisfactory results compared to SPECT in the detection of obstructive CAD. CCTA can rule out false-positive results of SPECT. (Arq Bras Cardiol. 2019; 113(6):1092-1101) Keywords: Coronary Artery Disease/physiopathology; Myocardial Ischemia; Tomography, Emission-Computed, Single‑Photon/methods; Myocardial Perfusion Imaging; Cineangiography/methods. Introduction In order to adequately assess coronary artery disease (CAD), both anatomical and functional analysis using myocardial perfusion methods should be considered, since both have prognostic and diagnostic value. Multimodal assessment and the combination of these techniques provide safe information on the anatomical and functional diagnosis of obstructive CAD, enabling better clinical and therapeutic planning. 1,2 In the last years, we have observed several coronary computed tomography angiography (CCTA) studies of patients with moderate stenosis. The patients were referred to perform complementary functional tests, such as pharmacologic stress cardiac magnetic resonance imaging and single photon emission computed tomography (SPECT) to verify the presence of perfusion defects. This approach allows for, with high sensitivity and specificity, the characterization of ischemia in patients with obstructive CAD. 1-3 Myocardial perfusion by CCTA is still little explored. Stress computed tomography (CT) myocardial perfusion imaging is a technique which has shown consistent results in the diagnosis of obstructive CAD. In its turn, myocardial perfusion scintigraphy is a well-established method for detection of CAD. The possibility of integrating anatomy and function in a single exam can enhance stratification of obstructive CAD and ensure better patient management. 3-7 The clinical benefits of CCTA are changing the perspectives of contemporary cardiology, 7 not only for grading stenosis, but also for characterizing the atherosclerotic load and the types of plaques. Recent data in the literature, on the evaluation of significant obstructive CAD (> 50%) by CCTA, have revealed good accuracy, with high sensitivity (82-99%) and specificity (94-98%), when compared to invasive cinecoronariography. 1-6,8 Multicentric studies, published in the last years, have demonstrated the high negative predictive value of CCTA 1092