Validation of Coronary Calcium Subtraction to Improve Diagnostic Accuracy of Coronary CT Angiography (C-Sub320)

• Diagnostic accuracy of Coronary Subtraction Coronary CT angiography [ Time Frame: Within 90 days of ICA and CCTA ] [ Designated as safety issue: No ]
  Sensitivity, Specificity, Negative and Positive predictive value of Coronary Subtraction CT angiography by visual assessment to identify a >50% coronary stenosis as defined by invasive coronary angiography on a patient by patient level.
  
  

• Coronary CT angiography reader confidence [ Time Frame: Within 90 days of ICA and CCTA ] [ Designated as safety issue: No ]
  Coronary CT angiography reader confidence by a 3 level visual scale assessed on CT images without and with Coronary Calcium Subtraction
  
  
• Coronary stenosis severity in non-diagnostic or partially diagnostic segments by conventional CCTA [ Time Frame: Within 90 days of ICA and CCTA ] [ Designated as safety issue: No ]
  In coronary segments deemed non-diagnostic or partially diagnostic due to calcification or coronary stents by conventional CCTA concordance of stenosis severity by Coronary Subtraction CT angiography and invasive quantitative coronary angiography is assessed
  
  
• Coronary revascularization [ Time Frame: Within 30 days after CCTA ] [ Designated as safety issue: No ]
  On a patient by patient level the ability of CCTA to predict need for coronary revascularization (PCI or CABG) is assessed using CCTA without and with coronary calcium subtraction
  
  

CCTA is a very important clinical method for the clinical evaluation of patients with chest pain of potential cardiac ischemic origin. However Coronary calcification and/or previously implanted coronary stents may limit the diagnostic accuracy of CCTA. A novel approach - coronary calcium subtraction - has been developed to potentially overcome this limitation.

• Study Objective: To assess diagnostic accuracy using coronary calcium subtraction coronary CT angiography (CCTA) as compared to conventional CCTA.
• Material and Methods: A total of 200 patients with suspected or known coronary artery disease (CAD) who have been referred for invasive coronary angiography (ICA) will prior to ICA undergo additional research CCTA with the newly developed coronary calcium subtraction protocol. Based on the coronary calcium scan (CS), coronary calcium score will be calculated according to the Agatston score. Conventional contrast enhanced CCTA studies will be analyzed for image quality and the presence and extent of coronary stenosis. Using a dedicated algorithm, subtraction will be performed on all datasets to obtain CCTA subtraction images. Subtracted images will be analyzed similar to the conventional CCTA images. ICA will serve as the gold standard. Image quality will be compared between conventional and subtracted CCTA. In addition, diagnostic accuracy in the evaluation of coronary stenosis as determined on ICA will be compared. Finally, factors influencing the performance of coronary calcium subtraction will be evaluated.