Accuracy and usefulness of fusion imaging between three-dimensional coronary sinus and coronary veins computed tomographic images with projection images obtained using fluoroscopy

Coronary sinus (CS) and coronary veins are not delineated by fluoroscopy. The study evaluates the feasibility and accuracy of cardiac tomography (CT) image registration of CS anatomy on fluoroscopic image. Eighteen consecutive patients underwent contrast-enhanced, ECG-gated CT scanning. Coronary sinus, coronary veins, superior vena cava, the distal portion of the trachea, and of the two main bronchi were reconstructed. These images were then fused over the CS fluoroscopic angiogram. Registration accuracy was verified by assessing the overlap of CS borders both in the CT- and in the fluoroscopy-derived images. The mean distance between the centrelines of the CS was 0.73 mm, with a maximum distance of 2.22 mm. For the first-order branches, mean distance was 0.80 mm with a maximum distance of 2.64 mm. High Lin concordance correlation coefficients were computed (> 0.95) for the CS and first-order branch diameters, although the Bland and Altman limits were large. The agreement between the number of vessels identified was moderate with kappa = 0.43. Fusion imaging processing of two different imaging modalities (CT and fluoroscopy) may be feasible and accurate for guiding CRT implantation as it allows constant comprehensive display of CS body and branches. Prospective studies are needed for assessing clinical implications.