MRI-guided percutaneous cryoablation of renal tumors: use of external manual displacement of adjacent bowel loops.

PURPOSE: We sought to investigate retrospectively the safety and effectiveness of using external hand compression to displace adjacent bowel loops during MRI-guided percutaneous cryoablation of renal tumors. MATERIALS AND METHODS: Fourteen patients (six women, eight men; mean age: 72 years) with 15 renal tumors (mean diameter: 2.4 cm; range: 1.4-4.6 cm) adjacent to bowel were treated with MRI-guided percutaneous cryoablation during which bowel was displaced manually. Bowel loop of concern was ascending colon (n=5), descending colon (n=8), descending colon and small bowel (n=1), ascending colon and small bowel (n=1). To analyze effectiveness of the maneuver, mean distance between tumor margin and bowel before and after the maneuver were compared and analyzed using paired Student\u27s t-test. Minimum distance between iceball edge and adjacent bowel with external manual displacement during freezing was also measured. Safety was assessed by analyzing post-procedural MR imaging for adjacent bowel wall thickening and focal fluid collections as well as patients\u27 clinical and imaging follow-up. RESULTS: Mean distance between tumor margin and closest adjacent bowel increased from 0.8 cm (range: 0-2 cm) before external manual compression to 2.6 cm (range: 1.6-4.1 cm) with manual displacement (p CONCLUSION: MRI-guided percutaneous cryoablation of renal tumors adjacent to bowel can be done safely and effectively using external hand compression to displace bowel loops