الفهرس 
IntroductionOnly 14 pages are availabe for public view
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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 CTCA based on a functional assessment of myocardial blood flow. The integration of anatomic and functional information may provide additional information for the clinician by the improved diagnostic accuracy of integrated techniques. Patients at low risk for CAD can be selected for primary prevention, and patients at high risk for CAD can be directly selected for coronary angiography (CAG). The remaining group of patients at intermediate risk for CAD can be sub stratified into lower- and higher-risk categories based on the presence or absence of stress-induced ischemia on SPECT-MPI and CTCA.
The most significant results from the present study are as follows: First, CTCA has a high accuracy for the detection of significant coronary artery stenosis. Second, SPECT-MPI has PPV which is higher than that of CTCA. Third, combining CTCA and SPECT-MPI has consistently resulted in considerable improvements of the diagnostic performance, PPV and NPV over the use of either imaging alone.
In conclusion:
CTCA and SPECT-MPI provide different and complementary information on CAD, namely, detection of atherosclerosis versus detection of ischemia, correlating lesion location with functional significance, factors which are extremely important for the decision-making process.
Both CTCA and SPECT-MPI have advantages and limitations. Compared with the latter, the former has a superior ability to exclude disease and does not miss high-risk CAD. However, it is limited by the possibility of overestimation the severity of CAD. On the other hand, SPECT-MPI has the possibility of false-positive findings.
So the combination between CTCA and SPECT-MPI are recommended in diagnosis of coronary artery diseases as this combination allow a precise non-invasive identification of coronary lesions without need to invasive coronary angiography.