Diagnosis of anomalous origin and course of coronary arteries using non-contrast cardiac CT scan and detection features.

Background: Anomalous origin and course of coronary arteries (AOCA) is a potential cause of sudden cardiac death. Coronary CT angiography (coronary CTA) enables detailed 3-dimensional visualization of AOCA. Data are limited about the diagnostic performance of noncontrast cardiac CT obtained during coronary calcium scan for detecting AOCA.

Objective: We assessed the feasibility of using noncontrast cardiac CT for detecting AOCA.

Methods: Participants had noncontrast cardiac CT and coronary CTA performed (2005-2010). Cases had AOCA as diagnosed with coronary CTA. Controls were without AOCA. Noncontrast cardiac CT images were independently evaluated for AOCA by a cardiologist and a radiologist blinded to prior AOCA diagnosis. Detection features to assist AOCA diagnosis on noncontrast cardiac CT were evaluated.

Results: The study enrolled 54 cases and 155 controls. Sensitivity and specificity for detecting AOCA were 82% (95% CI, 69%-90%) and 90% (95% CI, 85%-94%) for observer 1, respectively, and 82% (95% CI, 69%-90%) and 85% (95% CI, 79%-90%) for observer 2, respectively. Average sensitivity and specificity were 82% and 88%, respectively. Interobserver agreement (Cohen κ) was κ = 0.65 (95% CI, 0.53-0.76). Inability to visualize the right coronary artery (RCA) origin at the right sinus significantly predicted RCA anomaly. Inability to visualize the left main coronary artery branching point into the left anterior descending coronary artery and the left circumflex coronary artery significantly predicted left coronary artery anomaly.

Conclusion: Noncontrast cardiac CT in conjunction with detection features has the potential for use in the diagnosis of AOCA. A prospective study is needed for validation and to determine the modality's accuracy for detecting AOCA.