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

Abstract

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's 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’ 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 < 0.01). Mean minimum distance between iceball edge and closest adjacent bowel during the procedures was 1.6 cm (range: 0.5–3.5 cm). No evidence of bowel injury was encountered. Twelve of 15 tumors had follow-up (mean: 10 months) that showed no tumor recurrence. 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.