Figure 2.

Workflow of image fusion for CBCT. Patient with von Hippel-Lindau disease, multiple lesions and a new enhancing renal lesion are seen on MRI (A) the previous MRI is imported into the workstation and the lesion is segmented. (B-C) the MR is registered to the procedural CBCT. (D) The number of probes and their trajectory is planned by the operator, taking advantages of the information available on CBCT and preprocedural MRI. In this case, 2 lesions are seen (blue and green circles). The 3D reconstruction of the CBCT is displayed. Two probes were needed to ensure complete coverage of the inferior lesion. The data can be examined in the axial, coronal, and sagittal planes as well. (E) The operator advances the ablation following the virtual planned path displayed on live fluoroscopy. Both needles are planned on the same CBCT; however during navigation 1 virtual path is displayed at a time. The segmented tumor is seen. (F) Once the target is reached, a CBCT image is obtained to confirm needle positioning. Registration with preprocedural imaging is automatically updated. (G-H) After cryoablation, the iceball is segmented. The post-CBCT is registered to the pre-CBCTand the ablation is examined to ensure complete coverage. (Color version of figure is available online.)