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Coronary artery disease (CAD) is the number one killer of adults in the United States, claiming one-half million deaths annually. Early detection and prevention strategies clearly remain a top priority for health care providers in order to reduce the high mortality rate of heart disease. As an unequivocal reflection of arteriosclerosis, coronary arterial calcium (CAC) may provide a means to qualitatively assess the overall disease severity and likewise serve as a means to assess risk for CHD. It is known that patients with heavy calcium burdens have more advanced CAD, a concomitantly a higher likelihood of coronary stenoses, and a concomitant higher risk for acute cardiac events. Computed tomography has been shown to be an accurate, non-invasive method to quantify coronary calcification burden in patients. Evidence shows that calcium measurements by CT correlate well with histological plaque analyses, and that CAC measurements accurately reflect disease severity and can be useful to assess individual risk for CHD. The purpose of this article is to summarize the currently available evidence that has attempted to validate CAC screening as a screening exam and risk predictor for coronary heart disease.

As an unequivocal biomarker for arteriosclerosis, the presence of coronary calcium serves as a qualitative reflection of the severity of coronary artery disease (CAD). Greater calcium burdens correlate with more advanced disease, a higher likelihood of coronary stenoses, and a higher risk for coronary heart disease (CHD). Empirically, the quantification of coronary calcium not only provides an accurate reflection of disease severity, but also has great potential as a screening tool for CHD. Computed tomography (CT) has been shown to be capable of providing accurate, noninvasive measurements of coronary calcification. Evidence shows that calcium measurements by CT correlate well with histological plaque analyses, and that calcium burdens accurately reflect disease severity and can be used to assess individual risk for CHD. The purpose of this review article is to examine the accumulated evidence that has attempted to validate CT as a diagnostic tool for CAD and as a screening exam for CHD., (Copyright 2004 Wiley-Liss, Inc.)

Purpose: To compare coronary artery calcium scores from a multi-detector row helical computed tomographic (CT) scanner with those from an electron-beam CT scanner, with emphasis on subjects with calcium scores less than 400., Materials and Methods: Seventy-eight asymptomatic subjects (37 women, 41 men; age range, 39-78 years; mean age, 54.2 years) underwent multi-detector row CT and electron-beam CT. Volume and Agatston scores were calculated with a workstation. Statistical analyses included assessment of association between calcium scores from two scanners, calculation of percent absolute difference to assess score variability between scanners, equivalence analysis, construction of Bland-Altman plots to assess agreement between scores, and assessment of changes in score grouping and risk criteria based on score differences between scanners., Results: Electron-beam CT calcium scores were higher than multi-detector row CT scores. Linear association between calcium scores obtained from paired scans was significant (r = 0.96-0.99, P <.001). Mean percent absolute differences were 67.9% and 65.0% for volume and Agatston scores, respectively (48.6% and 46.3% for corresponding natural log-transformed scores). In subjects with a score of 11 or greater, mean percent absolute differences between electron-beam CT and multi-detector row CT scores ranged from 15% to 30% (<10% for natural log-transformed calcium scores). With a 20% equivalence limit, calcium scores from the two scanners were statistically equivalent (P <.05). Score grouping would have been subject to change in 12 (11 increased and one decreased; six with scores of 11 or greater), and possible risk management decisions would have been subject to change in eight (16%) of 51 subjects who underwent electron-beam CT versus multi-detector row CT scanning., Conclusion: Multi-detector row CT appears to be comparable to electron-beam CT for coronary calcification screening, except in subjects with a calcium score less than 11., (Copyright RSNA, 2004)

The value of a coronary artery disease prediction algorithm, the Framingham risk score (score), for detecting coronary artery calcium (CAC) was examined in 385 men and 472 women, aged 29 to 43 years. Scores were compared in subjects with and without CAC and were also used to predict presence of CAC. Receiver-operating characteristic curves were computed to compare different prediction models. The score model was compared with age only, natural logarithm of body mass index (lnBMI) only, and score plus lnBMI models. CAC was detected in 30% of men and 16% of women. The mean score was significantly higher in men and women with CAC. For every 2-point increase in the score, the odds of CAC increased by 30% in women and 20% in men. Significant associations between CAC status and risk factors were observed for age in women, and high- density lipoprotein cholesterol and blood pressure in men and women. The area under the receiver-operating characteristic curve for the score was 0.67 and 0.57 for women and men, respectively. When lnBMI was added to the score model, the area increased to 0.76 in women (lnBMI p <0.0001, score p <0.005). For men, the area increased from 0.57 to 0.67, and the score was no longer significant (p >0.60) in the model with lnBMI (p <0.0001). Score predicts CAC in asymptomatic young adults. Inclusion of lnBMI in the score model adds significantly to the prediction of CAC in women and men. The lnBMI model has a greater predictive value than the score in this young population.

Coronary arterial calcification has unequivocally been shown to be a marker of atherosclerosis. To date, much research interest has been generated regarding the quantification of coronary calcification by electron beam computed tomography, and how best to use such measurements to identify and predict those at greatest risk for an adverse cardiac event. This article represents an attempt to provide an objective review of the literature regarding the potential role electron beam computed tomography (EBCT) has as an accurate and cost effective screening modality for coronary arterial disease, as well as a predictor for coronary heart disease.

Coronary artery calcification is a marker for atherosclerotic disease. The calcifications frequently occur early in the disease process and often before the development of luminal narrowing or cardiac events. Electron beam CT has a high accuracy in detecting calcifications, and thus has prognostic value in predicting luminal narrowing and future cardiac events.

Objectives: This study was designed to estimate the prevalence of coronary artery calcification in young adult men and women and to examine the association between the presence of coronary artery calcification and coronary risk factors measured in childhood and young adult life., Background: Electron beam computed tomography is a sensitive, noninvasive method for detecting coronary artery calcification, a marker of the atherosclerotic process. Coronary artery calcification is associated with coronary risk factors in older adults., Methods: Subjects (197 men, 187 women) had coronary risk factors measured in childhood (mean age 15 years) and twice during young adult life (mean ages 27 and 33 years). Each underwent an electron beam computed tomographic study at their second young adult examination., Results: The prevalence of coronary artery calcification was 31% in men and 10% in women. Increased body size, increased blood pressure and decreased high density lipoprotein (HDL) cholesterol levels were the coronary risk factors that showed the strongest association with coronary artery calcification. Significant odds ratios for coronary artery calcification, using standardized risk factor measurements at a mean age of 33 years in men and women, respectively, were 6.4 and 13.6 for the highest decile of body mass index, 6.4 and 6.4 for the highest decile of systolic blood pressure and 4.3 and 4.7 for the lowest decile of HDL cholesterol., Conclusions: Coronary artery calcification is more prevalent in men in this young adult population. Coronary risk factors measured in children and young adults are associated with the early development of coronary artery calcification. Increased body mass index measured during childhood and young adult life and increased blood pressure and decreased HDL cholesterol levels measured during young adult life are associated with the presence of coronary artery calcification in young adults.

Coronary artery calcification is a recognized marker for coronary atherosclerosis; however, the relationship between calcification and the success of balloon angioplasty at a calcification site has not been determined. The purpose of this study was to evaluate whether the presence of coronary artery calcification, as detected by electron bean computed tomography (EBCT), was predictive of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Site- specific coronary calcification was determined by EBCT in 20 patients with 24 lesions before, immediately after, and 2 to 18 month after PTCA. Calcification was scored using >130 Hounsfield units and >1.02-mm2 area criteria. Coronary calcium at the PTCA site was significantly greater in restenosed versus nonrestenosed patients (109.16 +/- 198.16 mm2 v 4.39 +/- 9.50 mm2) (P < .025). The amount of coronary calcium did not change as a result of the PTCA procedure (+2.72 +/- 22.31 mm2 v -4.81 +/- 7.82 mm2) (P = NS). The rate of progression of calcification was not greater in restenosed versus nonrestenosed patients (1.78 +/- 3.32 mm2/month v 0.09 +/- 0.19 mm2/mo) (P = NS). Site-specific coronary calcification as determined by EBCT appeared to be predictive of patients with an increased likelihood to restenose after PTCA. Further studies are needed to verify these observations in a considerably larger patient population.

Coronary artery disease affects 1,500,000 Americans each year; 500,000 of these will die. The earliest detectable lesion of coronary atherosclerosis is the fatty streak. Later, crescent-shaped lipid plaques occur, which may rupture and produce either progressive stenosis or sudden occlusion with myocardial infarction. Calcium is deposited early in the formation of the atherosclerotic plaque, and calcification can be used as a marker of the atherosclerotic process. Many imaging techniques can be used to detect calcification of coronary arteries. The most promising are fluoroscopy, ultrafast CT, and intravascular sonography. Detection of calcification is most valuable in persons less than 40 years old in whom modification of risk factors may be important. In addition, the progression and possible regression of calcification can be used as an indicator of the atherosclerotic process. The absence of calcification in coronary arteries may diminish the need for further testing.