Influence of coronary calcification on the diagnostic accuracy of 64-slice computed tomography coronary angiography: a systematic review and meta-analysis

Abstract

To determine via meta-analysis the diagnostic accuracy of 64-slice computed tomography coronary angiography (CTA) for assessment of significant obstructive coronary artery stenosis at different coronary artery calcium score (CACS) levels. Data of 12,053 versus 5,890 segments, 906 versus 758 arteries and 1,120 versus 514 patients in low versus high CACS subgroups from 19 eligible studies were compared. The per-patient prevalence of coronary artery disease was 48% versus 68%, respectively. Subgroups were stratified by different CACS thresholds ranging from 100 to 400. Meta-analyses of per-patient data comparing overall low versus high CACS subgroups resulted in a sensitivity of 97.5 (95.5-99)% versus 97 (94.5-98.5)%, specificity of 85 (82-88)% versus 66.5 (58-74.5)%, diagnostic odds ratio of 153 (81-290) versus 40 (20-83), positive predictive value of 85 (82-87)% versus 86 (84-88)%, negative predictive value of 97.5 (95-99)% versus 91 (88-94)% and overall accuracy of 91% versus 89% with 95% confidence interval, respectively. The drop in specificity was significant (P = 0.035), while the sensitivity and overall accuracy were insignificantly changed (P > 0.05). Meta-analyses of independent subgroups at CACS levels ≤10 and ≤100 demonstrated high specificities of 90 (94-100)% and 88.5 (81-91.5)%, whereas at CACS levels ≥400 the specificity declined significantly to 42 (28-56)% but with consistently retained high sensitivity of 97.5 (94-99)%. The specificity of CTA decreases with increasing CACS, while the sensitivity remains high independent of that. The suggested CACS thresholds are arbitrary and do not necessarily warrant cancelling angiography. Diagnostic studies are needed to explore whether a specific CACS threshold may serve as a pre-angiographic gatekeeper to prevent likely equivocal angiographies.

Coronary artery calcium score and coronary computed tomography angiography for patients with asymptomatic polyvascular (non-coronary) atherosclerosis

“…The presence of calcium in the coronary arteries (in particular, CACS ≥ 400 or CACS ≥ 600) significantly reduces the specificity of CCTA. (36) On the basis of this finding and the results obtained from our study, in which patients with double-and triple-vessel disease obtained a higher CACS, we confirmed that CCTA has a negative predictive value, as widely described in the scientific literature. (37) It has been widely demonstrated that the sensitivity of CCTA in identifying severe stenosis is very high; on the contrary, the specificity tends to be lower due to the tendency of CCTA to overestimate stenosis, especially in calcified plaques.…”

“…Second, the absence of a high value of CACS does not completely rule out the possibility of CAD and, conversely, CACS cannot assess those plaques that are non-calcified or partially calcified. (36) For this reason, a major limitation regarding the diagnostic accuracy of CCTA is coronary calcifications. The presence of calcium in the coronary arteries (in particular, CACS ≥ 400 or CACS ≥ 600) significantly reduces the specificity of CCTA.…”

Image quality in coronary CT angiography: challenges and technical solutions

“…26,27 Even with 64-slice and newer CT systems, the sensitivity and specificity of coronary CTA for significant stenosis remains high in the presence of severe calcifications. 28 Because motion further intensifies calcium-related artefacts, 26 patients should be screened for compliance to breath-hold and HR stability.…”

Computed tomography segmental calcium score (SCS) to predict stenosis severity of calcified coronary lesions

“…Bulky calcifications can be expected in 10 % of coronary segments in patients with intermediate pre-test likelihood of coronary artery disease, and of these one in four are associated with significant stenoses [19]. Bulky calcifications typically lead to overestimation of lesion severity (false positive diagnosis) [19][20][21][22] related to limited spatial resolution of CCTA and the resulting visual impression known as the 'blooming effect'. Whether focal segmental calcifications can help predict the probability of underlying coronary stenosis was the research question addressed by this study.…”