Oguro, SotaTuncali, KemalElhawary, HaythamMorrison, PaulHata, NobuhikoSilverman, Stuart2017-09-262010Oguro, Sota, Kemal Tuncali, Haytham Elhawary, Paul R. Morrison, Nobuhiko Hata, and Stuart G. Silverman. 2010. “Image Registration of Pre-Procedural MRI and Intra-Procedural CT Images to Aid CT-Guided Percutaneous Cryoablation of Renal Tumors.” International Journal of Computer Assisted Radiology and Surgery 6 (1) (May 25): 111–117. doi:10.1007/s11548-010-0485-9.1861-6410http://nrs.harvard.edu/urn-3:HUL.InstRepos:33953715Purpose: To determine whether a non-rigid registration (NRR) technique was more accurate than a rigid registration (RR) technique when fusing pre-procedural contrast-enhanced MR images to unenhanced CT images during CT-guided percutaneous cryoablation of renal tumors. Methods: Both RR and NRR were applied retrospectively to 11 CT-guided percutaneous cryoablation procedures performed to treat renal tumors (mean diameter; 23 mm). Pre-procedural contrast-enhanced MR images of the upper abdomen were registered to unenhanced intra-procedural CT images obtained just prior to the ablation. RRs were performed manually, and NRRs were performed using an intensity-based approach with affine and Basis-Spline techniques used for modeling displacement. Registration accuracy for each technique was assessed using the 95% Hausdorff distance (HD), Fiducial Registration Error (FRE) and the Dice Similarity Coefficient (DSC). Statistical differences were analyzed using a two-sided Student’s t-test. Time for each registration technique was recorded. Results: Mean 95% HD (1.7 mm), FRE (1.7 mm) and DSC (0.96) using the NRR technique were significantly better than mean 95% HD (6.4 mm), FRE (5.0 mm) and DSC (0.88) using the RR technique (P < 0.05 for each analysis). Mean registration times of NRR and RR techniques were 15.2 and 5.7 min, respectively. Conclusions: The non-rigid registration technique was more accurate than the rigid registration technique when fusing pre-procedural MR images to intra-procedural unenhanced CT images. The non-rigid registration technique can be used to improve visualization of renal tumors during CT-guided cryoablation procedures.en-USmulti-modality image fusioncryoablationrenal tumorsb-splinenon-rigid registrationJournal Article2017-05-2520112017-09-2610.1007/s11548-010-0485-9