Image quality of the aortic and mitral valve with CT: relative versus absolute delay reconstruction.

Rationale And Objective: The purpose of this study was to compare image quality and artifacts of 16-detector row CT imaging of the aortic and mitral valve when performing ECG-gated synchronization using relative and absolute reconstructions.

Materials And Methods: Cardiac CT was performed in 22 consecutive patients; 20 data sets per RR interval were reconstructed with relative and absolute reconstructions. Mean and variability of heart rate during data acquisition were noted. Two readers assessed contrast media-related artifacts, calcification-related artifacts, ECG gating-related artifacts, and image quality in parallel and perpendicular planes.

Results: Contrast media-related and calcification-related artifacts similarly occurred with both reconstruction techniques. ECG gating-related artifacts occurred in both valves more often with relative reconstructions than with absolute reconstructions (p = .001). Image quality was significantly better for absolute reconstructions for the open aortic cusp surface (p = .014) and edge (p = .008) in both planes, and of the closed mitral valve leaflets (p = .003) and apposition zone (p = .003) in perpendicular planes. Occurrence of ECG gating-related artifacts in both valves significantly correlated (p = .01) with heart rate variability for relative reconstructions, whereas no correlation was found using the absolute technique.

Conclusion: Absolute reconstructions allow CT imaging of the aortic and mitral valve with fewer artifacts and are less sensitive to heart rate variability as compared to relative reconstructions.