Severe aortic arch calcification depicted on chest radiography strongly suggests coronary artery calcification

OBJECTIVE: To evaluate the association between aortic arch calcifications (AAC) on chest radiography and coronary artery calcium (CAC) score determined by CT.

METHODS: A total of 128 patients (75 men; 69.3 ± 14.7 years) who underwent chest radiography and CAC scoring at CT were included in this retrospective analysis. The extent of AAC on chest radiography was evaluated independently by two blinded observers using a semi-quantitative four-point scale (0-3). Intra- and interobserver agreement was assessed by weighted ĸ statistics. Amount of AAC determined on radiography was correlated with CAC and ROC analyses performed to characterise the diagnostic performance of AAC grading.

RESULTS: Excellent intraobserver (ĸ = 0.82) and good interobserver (ĸ = 0.75) agreement of AAC grading was noted. Moderate agreement (ĸ = 0.46, 95 % CI 0.36-0.56) with a linear trend (P < 0.0001) between AAC grades and CAC scores was found. Cut-off between AAC grades 0-2 and 3 had a sensitivity of 38.6 %, specificity of 96.4 %, PPV of 85.0 %, NPV of 75.0 % and accuracy of 76.6 % for the correct identification of CAC scores greater than 400.

CONCLUSION: Semi-quantitative AAC grading on chest radiography is reliable and positively associated with CAC scoring. We propose to report the extent of AAC in comprehensive radiological reports as "not present", "moderate" or "severe", as severe AAC strongly suggests coronary artery calcification.

KEY POINTS: • Semi-quantitative aortic arch calcification (AAC) grading on plain chest radiography appears reliable. • AAC grading is positively associated with CT coronary artery calcium scoring. • AAC grading has a high specificity for ruling out CAC scores greater than 400. • We propose the reporting of the extent of AAC grade in chest X-ray (CXR) reports.