CT angiography (CTA) and SPECT myocardial perfusion imaging (MPI) are complementary imaging techniques to assess coronary artery disease (CAD). Spatial integration and combined visualization of SPECT MPI and CTA data may facilitate correlation of myocardial perfusion defects and subtending coronary arteries and thus offer additional diagnostic value over either stand-alone or side-byside interpretation of the respective datasets from the 2 modalities. In this study, we investigated the additional diagnostic value of a software-based CTA/SPECT MPI image fusion system over conventional side-by-side analysis in patients with suspected CAD. Methods: Seventeen symptomatic patients who underwent both CTA and SPECT MPI within a 90-d period were included in our study; 7 of them also underwent invasive coronary angiography (ICA). The potential benefits of the synchronized multimodal heart visualization (SMARTVis) system in assessing CAD were investigated through a case study involving 4 experts from 2 medical centers, in which we performed, first, a side-by-side analysis using structured CTA and SPECT reports and, second, an integrated analysis using the SMARTVis system in addition to the reports. Results: The fused interpretation led to a more accurate diagnosis, reflected in an increase in the individual observers' sensitivity and specificity to correctly refer for invasive angiography eventually followed by revascularization. For the first, second, third, and fourth observers, the respective sensitivities improved from 50%, 60%, 80%, and 80% to 70%, 80%, 100%, and 90% and the respective specificities from 100%, 94%, 83%, and 83% to 100%, 100%, 94%, and 83%. Additionally, the interobserver diagnosis agreement increased from 74% to 84%. The improvement was primarily found in patients presenting with CAD in more vessels than the number of reported perfusion defects. Conclusion: Integrated analysis of cardiac CTA and SPECT MPI using the SMARTVis system results in an improved diagnostic performance. Cor onary artery disease (CAD) is a major cause of death worldwide (1). Invasive coronary angiography (ICA) is regarded as the reference standard imaging technique for diagnosing CAD (2); it enables determination of the location, extent, and severity of vessel obstructions. CT angiography (CTA) is rapidly gaining clinical acceptance (3); it noninvasively provides high-resolution images of the cardiac and coronary artery anatomy and allows assessment of the presence, extent, and type of coronary stenoses. Still, neither CTA nor ICA provides information on the functional implications of detected stenoses; a functional test may therefore be required to evaluate the presence and extent of myocardial ischemia. SPECT myocardial perfusion imaging (MPI) is widely used to noninvasively assess reversible myocardial ischemia. In conventional side-by-side analysis, integration of CTA and SPECT MPI findings is mentally performed by using a standardized myocardial segmentation model that allocates each myocardial segment to 1 of the 3 main coronary arteries (4,5). However, individual coronary anatomy does not always correspond to the standardized myocardial distribution (6). In a study of 50 patients, demonstrated that only 9 of the 17 American Heart Association segments are fed by a single coronary artery and that the other 8 segments may be fed by more than one coronary artery. Spatial integration and combined visualization of anatomic and functional data may facilitate correlation of myocardial perfusion defects and subtending coronary arteries and thus offer additional diagnostic value over either stand-alone or side-by-side interpretation of the respective datasets (7-17). The concept of 3-dimensional (3D) fusion imaging to improve
In other work, Kirişli et al. REF also evaluated their system to fuse coronary anatomy from CT and myocardial perfusion from single-photon emission computed tomography, and documented that the fused interpretation led to a more accurate diagnosis.
Additional Diagnostic Value of Integrated Analysis of Cardiac CTA and SPECT MPI Using the SMARTVis System in Patients with Suspected Coronary Artery Disease
Journal of nuclear medicine : official publication, Society of Nuclear Medicine
Journal of nuclear medicine : official publication, Society of Nuclear Medicine
Medicine