title: MRI-guided percutaneous cryoablation of renal tumors: use of external manual displacement of adjacent bowel loops.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  MRI-guided percutaneous cryoablation of renal tumors adjacent to bowel can be done safely and effectively using external hand compression to displace bowel loops.
authors.affiliation: Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women's Hospital, Boston, MA 02115, USA. ktuncali@partners.org
authors.forename: Kemal
authors.initials: K
authors.lastname: Tuncali
authors.forename: Paul R
authors.initials: PR
authors.lastname: Morrison
authors.forename: Servet
authors.initials: S
authors.lastname: Tatli
authors.forename: Stuart G
authors.initials: SG
authors.lastname: Silverman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003452:Cryosurgery / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D007422:Intestines; D007680:Kidney Neoplasms / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*