Relationship of Coronary Calcium on Standard Chest CT Scans With Mortality

Abstract

STRUCTURED ABSTRACT Objectives We aimed to determine the correlation between coronary artery calcium (CAC) scores on 3mm ECG-gated computed tomography (CT) scans and standard 6mm chest CT scans, and to compare relative strength of associations of CAC on each scan type with mortality risk. Background Coronary artery calcification predicts cardiovascular disease (CVD) and all-cause mortality, and is typically measured on ECG-gated 3mm CT scans. Patients undergo standard 6mm chest CTs for various clinical indications much more frequently, but CAC is not usually quantified. To better understand the usefulness of standard chest CTs to quantify CAC, we conducted a case-control study among persons who had both scan types. Methods Between 2000–03, 4,544 community-living individuals self- or physician-referred for “whole body” CT scans, had 3mm ECG-gated CTs and standard 6mm chest CTs, and were followed for mortality through 2009. In this nested case-control study, we identified 157 deaths and 494 controls frequency matched (1:3) on age and gender. The Agatston method quantified CAC on both scan types. Unconditional logistic regression determined associations with mortality, accounting for CVD risk factors. Results Participants were 68±11 years old and 63% male. The Spearman correlation of CAC scores between the two scan types was 0.93 (p<0.001); median CAC scores were lower on 6mm CTs compared to 3mm CTs (22 vs.104 Agatston units, p<0.001). Adjusted for traditional CVD risk factors, each SD higher CAC score on 6mm CTs was associated with 50% higher odds of death (OR=1.5; 1.2–1.9), similar to 50% higher odds on the 3mm ECG-gated CTs (OR=1.5, 1.1–1.9). Conclusions CAC scores on standard 6mm chest CTs are strongly correlated with 3mm ECG-gated CTs and similarly predict mortality in community-living individuals. Chest CTs performed for other clinical indications may provide an untapped resource to garner CVD risk information without additional radiation exposure or expense.

2016 SCCT/STR guidelines for coronary artery calcium scoring of noncontrast noncardiac chest CT scans: A report of the Society of Cardiovascular Computed Tomography and Society of Thoracic Radiology

“…In the gated 3mm versus nongated 6mm study discussed above, 64 each SD higher CAC yielded identically increased OR for all cause mortality of 1.5. Compared to 0 CAC, the OR for the 1e100, 101e300 and > 300 categories were 1.9, 2.3 and 2.6 respectively for the 6mm nongated scans, and 2.1, 2.9 and 3.2 for the 3mm gated scans respectively, in models fully adjusted for risk factors.…”

“…63 Most recently, 4544 subjects underwent both 3mm gated CAC scans and 6 mm standard nongated chest CT scans by electron beam computed tomography, with a 6 year follow up for all cause mortality. 64 There were 157 deaths, matched 1:3 to 494 survivor controls. There was excellent correlation between the 2 scans in the 651 subjects (r ¼ 0.93, p < 0.001); the median CAC scores were lower on the 6 mm scan (22 versus 104 Agatston units, p < 0.001), consistent with the decreased sensitivity of thicker slices to detect CAC.…”

High pitch third generation dual-source CT: Coronary and cardiac visualization on routine chest CT

“…Prior results have shown good correlation of the calcium score on non-gated CT compared to dedicated ECG gated calcium CT scoring 2, 20 . Although a high calcium score is predictive of coronary artery disease, the calcium score is understood as a marker of disease, rather than direct visualization of coronary stenosis.…”

“…However, even using older generation CT scans, coronary artery calcification scores can be obtained from routine non-contrast chest CT (i.e., CT performed for non-cardiac indications) 2 . These calcium score findings may be “incidental” to the primary indication for the chest CT, but may be important to patient care 3 .…”

Coronary artery calcification is common on nongated chest computed tomography imaging

“…One prior lung cancer screening study showed that visual estimation of coronary calcification found on non‐gated chest CT are comparably predictive of cardiovascular events compared to Agatston scoring . The incidental identification of coronary calcification itself can be predictive of future cardiovascular events, and these results emphasize the importance of identifying these higher‐risk patients to provide preventive care …”