Diagnostic performance of coronary CT angiography for stenosis detection according to calcium score: systematic review and meta-analysis.

OBJECTIVES: A systematic review and meta-analysis to assess sensitivity and specificity of coronary CT angiography (CCTA) for significant stenosis at different degrees of coronary calcification.

METHODS: A literature search was performed including studies describing test characteristics of CCTA for significant stenosis, performed with at least 16-MDCT and according to calcium score (CS). Invasive coronary angiography was the reference standard. Pooled sensitivity and specificity of CCTA by CS categories and CT equipment were calculated.

RESULTS: Of 14,121 articles, 51 studies reported on the impact of calcium scoring on diagnostic performance of CCTA and could be included in the systematic review. Twenty-seven of these studies (5,203 participants) were suitable for meta-analysis. On a patient-basis, sensitivity of CCTA for significant stenosis was 95.8, 95.6, 97.6 and 99.0% for CS 0-100, 101-400, 401-1,000 and >1,000 respectively. Specificity was 91.2, 88.2, 50.6 and 84.0% respectively. Specificity of CCTA was significantly lower for CS 401-1,000 due to lack of patients without significant stenosis. Sensitivity and specificity of 16-MDCT were significantly lower compared to more modern CT systems.

CONCLUSIONS: Even in cases of severe coronary calcification, sensitivity and specificity of CCTA for significant stenosis are high. With 64-MDCT and newer CT systems, a CS cut-off for performing CCTA no longer seems indicated.

KEY POINTS: Decisions about performing coronary CT angiography (CCTA) sometimes depend on calcium scoring. CCTA is highly sensitive for coronary stenosis. With 16-MDCT, however, heavy calcification reduces specificity for significant stenosis. For 64-MDCT (and above), CCTA has high specificity, even with severe coronary calcification.