Background: Early diagnosis of coronary artery disease has always been an important clinical issue. Coronary angiography is the gold standard for the diagnosis of coronary artery disease, but it is an invasive test that is only applicable to a small percentage of patients. Clinical diagnosis of most patients still need to rely on non-invasive examination. Conventional electrocardiograms and exercise plate tests have high false-positive and false-negative rates and are more limited in predicting coronary artery disease. The diagnosis of chest pain in female patients remains challenging because women have a lower prevalence of coronary artery disease and a higher incidence of false-positive loading tests. Detection of coronary artery disease in female patients is important, as approximately 40% or more of female deaths in the United States are due to cardiovascular disease. The diagnosis of coronary artery disease in women is problematic for a variety of reasons. Middle-aged and older women have a lower rate of clinical symptom presentation and a greater tendency to have atypical symptoms than men, and women are less likely to receive immediate evaluation and thus delayed diagnosis. Since women are older at the time of diagnosis, then the exercise inability and other disorders associated with old age make exercise load testing less accurate in women than in men. Therefore, the ideal diagnostic tool for women differs from that of men. Calcium deposits within the coronary arteries are the hallmark of intimal atherosclerosis. Coronary artery calcification is also a predictor of the outcome of interventional therapy, e.g., dilatation of calcified lesions by balloons can trigger vascular entrapment and rupture. In 1959 it was. CAC) Blankenhorn and Stern applied fluoroscopy to noninvasively examine coronary artery disease. Later, pathologic studies confirmed that CAC is related to the presence and extent of coronary atherosclerosis.CT can detect CAC much more sensitively than fluoroscopy, and the use of plain CT is limited by motion artifacts. In recent years, more and more quantitative studies of CAC have been performed using spiral CT. Patient selection: Inclusion criteria: female patients, over 45 years of age, with risk factors and a positive cardiac load test, undergoing coronary angiography for typical or atypical chest pain. Also, good CT coronary calcification images. Exclusion criteria: Cases with poor images that could not show the left main trunk, left anterior descending branch near the middle were given exclusion. 2. Coronary angiography: All patients underwent multiple projection position coronary angiography. The results were evaluated by two physicians who were unaware of the patients’ clinical information and CT findings. All luminal stenosis was measured in all three vessels. Normal coronary arteries were defined as the complete absence of any degree of luminal stenosis. Coronary arteries with less than 50% stenosis were considered non-obstructive stenosis, whereas stenosis of more than 50% was called obstructive coronary stenosis. The patients were categorized into 2 groups, one comprising of 41 patients with normal coronary arteries confirmed by coronary angiography and the other group comprising of 67 patients with stenosis on angiography, out of which 12 were non-obstructive and 55 were obstructive stenosis. 3, CT scan: Image acquisition: Chest CT was performed without contrast injection using Simens 64-slice helical CT, and the image selection CT level had the ability to show the left main stem, proximal and middle anterior descending branches, diagonal branches, gyratory branch vessels, or the right coronary. Determination of coronary calcification: by visualization on images. The extent of calcification is indicated by the following: above different sites of calcification, punctate calcification is considered mild, segmental calcification is moderate, and diffuse calcification is considered severe. A, B Figure A shows diffuse calcification of the left anterior descending branch on CT scan in a 68-year-old woman with a three-branch lesion on coronary angiography. Figure B shows a CT scan of the chest of a 70-year-old woman with a left main coronary artery, a left anterior descending branch, and a diagonal branch; the coronary arteries do not appear calcified on CT. The patient had chest pain and a positive plate motion test. Imaging showed normal coronary arteries. 4. Statistical methods: Continuous variables were expressed by mean +- standard deviation, and comparisons between groups were made using the t-test; categorical variables were expressed by percentages and completed using the chi-square test. p<0.05 was considered statistically different. 5.Results: From January 2007-June 2009, approximately 1000 patients were admitted for chest CT examination.The case group consisted of 108 symptomatic females (mean age 50±5; range 45-76 years) with normal coronary angiogram or coronary artery disease.The clinical characteristics of the patients are shown in Table 1.There was no difference between the two groups in terms of mean age, smoking history, diabetes mellitus and positive exercise test. The number of patients with typical chest pain was significantly higher in the CAD group (55/67, 82%) than in the group with normal coronary arteries (5/41, 12%), whereas the number of patients with atypical chest pain was relatively low (12/67, 18% vs. 36/41, 87%).41 The patients with normal coronary arteries on angiography showed no calcification in 26 of them, and in the 15 patients with calcification it appeared to be mildly calcified.67 The number of patients with coronary arterial stenosis was significantly higher than that of patients with normal coronary arteries. Of the patients with coronary stenosis, 31 had target lesions LAD, 18 LCX, 18 RCA, 7 had mild calcification, 39 had moderate calcification, and 21 had diffuse calcification, which was not related to the distribution of target lesions. The severity of calcification was related to the number of diseased vessel branches: 19 with single-branch lesions showed mild calcification in 4 and moderate in 15, 29 with double-branch lesions showed mild calcification in 3, moderate in 18, and severe in 8, and there were 19 with triple-branch lesions, with moderate calcification in 6 and severe calcification in 13). Among the study patients all CAD group patients had coronary calcification while all patients without coronary calcification showed normal coronary angiogram.CT scan without calcification predicted normal coronary arteries in elderly women sensitivity=63.4%, specificity=100%, misdiagnosis rate=0%, missed diagnosis rate=36.6%, overall compliance=24.1+62%=86.1% Discussion: Exercise electrocardiography The diagnostic value of exercise ECG in women has been questioned due to its high number of false positives, with reported data of 40%-80% of patients with a positive exercise test showing normal or mild stenosis on transcoronary angiography. Therefore, the use of more accurate noninvasive means is crucial. Pathologic studies confirm that coronary calcification must accompany coronary artery disease. Calcifications can also be detected using conventional chest X-rays, but the clinical application of their technique is limited by their reduced sensitivity to small calcifications. The advantages of spiral CT over X-ray are increased sensitivity and the ability to differentiate coronary calcifications from those on structures that overlap coronary calcifications on radiography such as vertebrae, cartilage, heart valves, and the aortic wall. Moreover, spiral CT can complete the scan in less than five minutes without the need for contrast injection. The patient can complete it in a single breath-hold, avoiding artifacts caused by breathing. Female patients with normal coronary angiograms were found to have significantly lower calcification scores than those with stenoses on angiograms. The CAC score can clearly correlate with the extent and severity of coronary artery disease, as well as with future cardiac events. Excessive additional testing should be avoided. Most of those experienced in applying CAC quantification consider only cardiac stress testing for the detection of obstructive coronary artery disease in asymptomatic individuals with a CAC of 400 or more.The results of CAC studies may serve as a motivation for patients to comply with lifestyle modification therapy, as the visualization of CAC in the patient's heart is more credible than abstract discussions of preventing heart disease. Needless to say, CAC will increasingly be used as a means of evaluating coronary artery disease. CONCLUSIONS: The current study demonstrates the unlikelihood of stenosis on coronary angiography in middle-aged and elderly women with chest pain and/or a positive exercise test when no coronary calcification is detected on spiral CT. Therefore, it is not necessary to perform coronary angiography in these patients.