Objective-To establish the normal criterion of ascending aortic diameter (AAOD) measured by 64 Multi-Detector Computed Tomography (MDCT) and Electron Beam Computed Tomography (EBT) based on gender and age.Methods-1442 consecutive subjects who were referred for evaluation of possible coronary artery disease underwent coronary CT angiography (CTA) and coronary artery calcium scanning (CACS) (55+11 years, 65% male) without known coronary heart disease, hypertension, chronic pulmonary and renal disease, diabetes and severe aortic calcification. The ascending aortic diameter, descending aortic diameter (DAOD), pulmonary artery (PAD) and chest anterioposterior diameter (CAPD), posterior border of sternal bone to anterior border of spine, were measured at the slice level of mid right pulmonary artery by using end systolic trigger image. The volume of four chambers, ejection fraction of left ventricle, and cardiac output were measured in 56% of the patients. Patients demographic information, age, gender, weight, height and body surface area (BSA), were recorded. The mean value and age specific and gender adjusted upper normal limits (mean + 2 standard deviations) were calculated. The linear correlation analysis was done between AAOD and all parameters. The reproducibility, wall thickness and difference between end systole and diastole were calculated.Result-AAOD has significant linear association with age, gender, descending aortic diameter and pulmonary artery diameter (P<0.05). There is no significant correlation between AAOD and body surface area, four chamber volume, LVEF, CO and CAPD. The mean Intra-luminal AAOD was 31.1 ± 3.9mm and 33.6 ± 4.1 mm in females and males respectively. The upper normal limits (mean + 2 standard deviations) of Intra-luminal AAOD, mean+ standard deviation, was 35.6, 38.3 and 40 mm for females and 37.8, 40.5 and 42.6 mm for males in age group 20 to 40, 41 to 60, above 60 year respectively. Intra-luminal should parallel echocardiography and invasive angiography. Traditional cross sectional imaging (with computed tomography and magnetic resonance imaging) includes the vessel wall. The mean total AAOD was 33.5mm and 36.0 mm in females and males respectively. The upper normal limits (mean + 2 standard deviations) of Intra-luminal AAOD, mean+ standard Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conclusion-The ascending aortic diameter increases with age and male gender. Gender specific and age adjusted normals for aortic diameters are necessary to differentiate pathologic atherosclerotic changes in the ascending aorta. Use of intra-luminal or...

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Background. The differential diagnosis of chest pain in women is complex, ranging from atypical angina to chest pain in the absence of coronary artery disease (i.e., Syndrome X). The mechanism of these conditions remains unexplained. The purpose of this study was to examine coronary blood flow based on a new angiographic technique. Methods. Patients with chest pain were enrolled. In the new technique, as the contrast injection stopped, the blood in white color moved in and displaced the black contrast. Characteristics of blood flow could be observed and classified by type and time. The duration of the arterial phase was calculated and compared with the control. Results. Sixty patients were enrolled. Ten patients with normal coronary arteries and ventricular function; without chest pain served as controls. In the control group, the duration of the arterial phase in the RCA was 1.76 sec, while it was 3.76 sec for the syndrome X group (p<0.05). From the mMID segment to the distal segment, syndrome X patients had a much longer delay compared to control subjects (0.81 vs. 0.26 sec) (p<0.05). From the distal segment (bDIS) to the origin of the PDA, syndrome X patients had an average duration of 0.81 sec compared to 0.40 sec in controls (p<0.05). The largest difference was the period of time when the contrast left the PDA until flushed from the distal vasculature, which was 1.66 sec and 0.40 sec in syndrome X vs. control. Syndrome X patients with prolonged myocardial phase (1.89 sec) had dense and prolonged contrast retention at the myocardium. Conclusions. In patients with syndrome X, the prolonged arterial phase deprived the myocardium of highly oxygenated blood and triggered ischemia. This new imaging method allows for a better understanding of the mechanism of ischemia in Syndrome X patients.