DIAGNOSTIC ACCURACY OF COMPUTED TOMOGRAPHY CORONARY ANGIOGRAPHY FOR EVALUATION OF CORONARY ARTERY DISEASE IN HIGH RISK PATIENTS: A COMPARISON BETWEEN HIGH (0.23 MM) VERSUS STANDARD (0.625 MM) SPATIAL RESOLUTION SCANNER

Purpose: To compare the image quality, evaluability, diagnostic accuracy and radiation exposure of high spatial resolution computed tomographic coronary angiography (HD-CCTA) versus standard spatial resolution 64-slice scanner (SD-CCTA) in high-risk patients for coronary artery disease (CAD) by using invasive coronary angiography (ICA) as the reference method. Material and Methods: Written informed consent was obtained from all patients and the study protocol was approved by the institutional ethical committee. One-hundred-eighty-four consecutive high risk patients for CAD and scheduled for ICA were randomly studied by SD-CCTA (n=91) or HD-CCTA (n=93) before ICA. To compare the two groups, Student’s test or Wilcoxon’s test were used to evaluate differences of continuous variables, the Chi-square test or Fisher’s exact test when appropriate were used regarding to categorical data and McNemar’s test was used to compare the diagnostic performance of CCTA versus ICA in each group. Results: HD-CCTA showed a higher image quality score (3.7 vs 3.4, p:0.0001) and evaluability (97% vs 92%, p<0.002). In a segment-based analysis, HD-CCTA showed a higher specificity, positive predictive value and accuracy in comparison with SD-CCTA (98%, 91% and 99% vs 95%, 80% and 95%, respectively, p<0.0001). Moreover, HD-CCTA showed a better agreement versus ICA for calcified plaques in comparison with SD-CCTA (83% vs 53%, p<0.0001). In a patient-based analysis HD-CCTA showed a higher specificity and accuracy in comparison with SD-CCTA (91% and 98% vs 46% and 92%, respectively, p<0.01). No differences were found in terms of radiation exposure between the two groups. Conclusions: Improved evaluability and accuracy mainly is seen in calcified coronary artery lesions in HD-CCTA in comparison with SD-CCTA suggesting a potential role of this technology in high-risk CAD patients .