Figure 4. Image integration: the registration process. (A) During the catheter ablation procedure, segmented multislice CT (MSCT) of the left atrium and pulmonary veins (PVs) is used. (B) With the use of algorithms that minimize the distance between the 2 structures, the MSCT image and the electroanatomical map are fused. Subsequently, the anatomy derived from the MSCT scan can be used to visualize the PV ostia. An endo-view of the right-sided PVs is shown.