Diagnosing Heart Disease with Cardiac Computed Tomography (original) (raw)
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International Journal of Cardiovascular Imaging
The correlation between formal coronary artery calcium scoring (CACS) determined by multi-detector CT (MDCT) and the presence of coronary calcium on standard non-gated CT chest examinations was evaluated. In 163 consecutive healthy participants, we performed screening same-day standard non-gated, non-enhanced CT chest exams followed by high-resolution, ECG-synchronized MDCT exams for CACS. For the standard CT examinations, a scoring system (Weston score, range 0–12) was developed assigning a score (0–3) for each coronary vessel including the left main trunk. Overall, 30% and 39% of patients had CAC on standard CT and MDCT exams, respectively (P = 0.13). CAC on standard CT was highly correlated to the Agatston CACS on the MDCT (Spearman correlation coefficient 0.83, P < 0.001). Absence of calcium on the standard CT exam was associated with a very low CACS (mean Agatston 0.5, range 0–19). A Weston score >2 identified a CACS > 100 with an area under the curve of 0.976, sensitivity of 100%, and specificity of 85%. A Weston score >7 identified a CACS > 400 with an area under the curve of 0.991, sensitivity of 100%, specificity of 98%. The intra-observer variability was low as was the inter-observer variability between a cardiac specialized radiologist and a non-specialized reader. A visual coronary artery scoring system on standard, non-gated CT correlates well with traditional methods for CACS. Further, a non-expert cardiac radiologist performed equally well to a cardiac expert. This information suggests that a visual scoring system, at least in a descriptive manner can be utilized for a general statement about coronary artery calcification seen on standard CT imaging to guide clinicians in risk stratification.
Journal of Cardiovascular and Thoracic Research
Introduction Cardiovascular diseases, including coronary artery disease (CAD), are among the most common causes of death in the elderly population. According to the World Health Organization (WHO), cardiovascular diseases take nearly 18 million lives annually. 1 The lifetime risk of developing CAD is estimated to be 49 percent in men and 32 percent in women. 2 Therefore, identifying people at risk and early diagnosis is important. Older age, male gender, hypertension, diabetes, dyslipidemia, obesity, smoking, and low physical activity are among the most established risk factors for cardiovascular diseases. 3,4 Recent studies have found that coronary artery calcium (CAC) is a strong independent predictor of CAD. 5-8 Calcification of the coronary arteries has an important role in the pathophysiology of atherosclerosis. CAC can be easily measured by noninvasive imaging methods, including electron-beam tomography (EBT) or multidetector computed tomography (CT). 9 CAC score (CACS) measured by noncontrast cardiac CT scan is a low-radiation and relatively cheap test that provide a quantitative assessment of the overall coronary atherosclerotic burden. 10 Growing evidence suggests that CACS is a useful test for risk stratification of both symptomatic and asymptomatic individuals. 11-13 Higher CACSs has been shown to be associated with a higher risk of major cardiovascular events and all-cause mortality. 5,14,15 Several studies have claimed that there are some associations between CACS and cardiac risk factors. 16-18 However, there were great inconsistencies between the reported results. Here we aimed to investigate the association between CACS and demographic, clinical, laboratory, and CT angiographic findings in patients with suspected CAD. We also evaluated the predictive value of
International Journal of Cardiovascular Imaging, 2009
Present guidelines discourage the use of CT coronary angiography (CTCA) in symptomatic angina patients. We examined the relation between coronary calcium score (CS) and the performance of CTCA in patients with stable and unstable angina in order to understand under which conditions CTCA might be a gate-keeper to conventional coronary angiography (CCA) in such patients. We included 360 patients between 50 and 70 years old with stable and unstable angina who were clinically referred for CCA irrespective of CS. Patients received CS and CCTA on 64-slice scanners in a multicenter cross-sectional trial. The institutional review board approved the study. Diagnostic performance of CTCA to detect or rule out significant coronary artery disease was calculated on a per patient level in pre-defined CS categories. The prevalence of significant coronary artery disease strongly increased with CS. Negative CTCA were associated with a negative likelihood ratio of <0.1 independent of CS. Positive CTCA was associated with a high positive likelihood ratio of 9.4 if CS was <10. However, for higher CS the positive likelihood ratio never exceeded 3.0 and for CS >400 it decreased to 1.3. In the 62 (17%) patients with CS <10, CTCA reliably identified the 42 (68%) of these patients without significant CAD, at no false negative CTCA scans. In symptomatic angina patients, a negative CTCA reliably excludes significant CAD but the additional value of CTCA decreases sharply with CS >10 and especially with CS >400. In patients with CS <10, CTCA provides excellent diagnostic performance.
Plos One, 2014
Aims: To investigate the value of coronary calcium scoring (CCS) as a filter scan prior to coronary computed tomography angiography (CCTA). Methods and Results: Between February 2008 and April 2011, 732 consecutive patients underwent clinically indicated CCTA. During this 'control phase', CCS was performed in all patients. In patients with CCS$800, CCTA was not performed. During a subsequent 'CCTA phase' (May 2011-May 2012) another 200 consecutive patients underwent CCTA, and CCS was performed only in patients with increased probability for severe calcification according to age, gender and atherogenic risk factors. In patients where CCS was not performed, calcium scoring was performed in contrast-enhanced CCTA images. Significant associations were noted between CCS and age (r = 0.30, p,0.001) and coronary risk factors (x 2 = 37.9; HR = 2.2; 95%CI = 1.7-2.9, p,0.001). Based on these associations, a #3% pre-test probability for CCS$800 was observed for males ,61 yrs. and females ,79 yrs. According to these criteria, CCS was not performed in 106 of 200 (53%) patients during the 'CCTA phase', including 47 (42%) males and 59 (67%) females. This resulted in absolute radiation saving of ,1 mSv in 75% of patients younger than 60 yrs. Of 106 patients where CCS was not performed, estimated calcium scoring was indeed ,800 in 101 (95%) cases. Non-diagnostic image quality due to calcification was similar between the 'control phase' and the 'CCTA' group (0.25% versus 0.40%, p = NS). Conclusion: The value of CCS as a filter for identification of a high calcium score is limited in younger patients with intermediate risk profile. Omitting CCS in such patients can contribute to further dose reduction with cardiac CT studies.
European Heart Journal, 2016
To compare the effectiveness and safety of a cardiac computed tomography (CT) algorithm with functional testing in patients with symptoms suggestive of coronary artery disease (CAD). Methods and results Between April 2011 and July 2013, 350 patients with stable angina, referred to the outpatient clinic of four Dutch hospitals, were prospectively randomized between cardiac CT and functional testing (2 : 1 ratio). The tiered cardiac CT protocol included a calcium scan followed by CT angiography if the Agatston calcium score was between 1 and 400. Patients with test-specific contraindications were not excluded from study participation. By 1 year, fewer patients randomized to cardiac CT reported anginal complaints (P ¼ 0.012). The cumulative radiation dose was slightly higher in the CT group (6.6 + 8.7 vs. 6.1 + 9.3 mSv; P , 0.0001). After 1.2 years, event-free survival was 96.7% for patients randomized to CT and 89.8% for patients randomized to functional testing (P ¼ 0.011). After CT, the final diagnosis was established sooner (P , 0.0001), and additional downstream testing was required less frequently (25 vs. 53%, P , 0.0001), resulting in lower cumulative diagnostic costs (E369 vs. E440; P , 0.0001). Conclusion For patients with suspected stable CAD, a tiered cardiac CT protocol offers an effective and safe alternative to functional testing. Incorporating the calcium scan into the diagnostic workup was safe and lowered diagnostic expenses and radiation exposure.
Proceedings of Singapore Healthcare, 2011
Screening for coronary artery disease (CAD), using CT coronary angiography, coronary artery calcium scoring and myocardial perfusion imaging, seems an attractive idea. However, there is considerable uncertainty whether the overall potential benefits outweigh the risks. In a situation where the prevalence of disease is very low, the positive predictive value of any test will tend to be low, and false positive results frequent, requiring a large number of individuals to undergo further testing to confirm disease in a small number of patients. Even when disease is detected, the benefits of revascularisation are uncertain in asymptomatic populations. There is considerable uncertainty about the risks from radiation as a result of imaging tests such as CT scans. Based on available data, the actual risks of malignancy for most individuals appear to be small and of limited concern in a symptomatic patient with a moderate likelihood of disease. However, in a low risk population as in the con...