Combined CT coronary angiography and SPECT myocardial perfusion imaging in diagnosis of coronary artery disease.

Abstract

The diagnostic principle of CAD is very different for SPECT-MPI and CTCA. SPECT-MPI has abilities to show the extent and severity of ischemia by visual or semi quantitative method, but it cannot show the morphology and plaques of coronary arteries. CTCA can directly depict the site and severity of coronary lesions. In addition, the length of stenosis, distribution, magnitude, and even composition of plaque can be precisely revealed and classified (calcified versus non-calcified). But CTCA does not directly provide the hemodynamic significance related to the abnormalities of coronary arteries, which is very important in developing the therapeutic strategies for CAD. CTCA and SPECT-MPI provide different information for CAD, thus it is difficult to directly compare CTCA with SPECT-MPI as they show different things. The correlation between CTCA and SPECT-MPI is supplemental rather than substitutional, i.e., the anatomic and functional correlation of CAD. Whereas CTCA has the advantage of detecting coronary atherosclerosis at its earliest stages, thereby allowing initiation of appropriate therapeutic measures well before development of obstructive CAD. SPECT-MPI can clarify the hemodynamic consequences of the anatomic findings on