title: Magnetic resonance imaging-guided laser thermal ablation of renal tumours.
abstract: OBJECTIVE
  To test the hypothesis that magnetic resonance imaging (MRI)-guided laser thermal ablation (LTA) of inoperable renal tumours is a safe, tolerable and potentially effective treatment.
  
  
  METHODS
  Nine patients (aged 56-81 years) with malignant renal tumours underwent percutaneous LTA under MRI guidance in a 0.5 T open magnet. Real-time colour thermal mapping was used to monitor tumour ablation, and the follow-up was with gadolinium-enhanced MRI at 6 weeks and (where appropriate) 3-4 months after the procedure. Tumour volume and percentage tumour enhancement before and after ablation were compared. The percentage of tumour ablated on real-time T1-weighted thermal maps was compared with that on gadolinium-enhanced follow-up MRI.
  
  
  RESULTS
  The mean (range) follow-up was 16.9 (3-32) months after the first ablation. The mean tumour size did not change significantly, but the mean percentage of viable tumour decreased significantly from 73.7% before to 29.5% after ablation (P = 0.012, Wilcoxon signed-ranks test). Thermal maps correlated moderately well with follow-up MRI in predicting the extent of tumour ablation (Pearson correlation coefficient 0.55). There were two minor and one major complication.
  
  
  CONCLUSIONS
  In this pilot study of patients unsuitable for surgery, MRI-guided LTA of renal tumours was safe, feasible (being well tolerated by the patient) and significantly reduced enhancing tumour volume by a mean of 45%.
authors.affiliation: Department of International MR and Urology, St Mary's Hospital, London, UK.
authors.forename: E A
authors.initials: EA
authors.lastname: Dick
authors.forename: R
authors.initials: R
authors.lastname: Joarder
authors.forename: M G
authors.initials: MG
authors.lastname: De Jode
authors.forename: P
authors.initials: P
authors.lastname: Wragg
authors.forename: J A
authors.initials: JA
authors.lastname: Vale
authors.forename: W M W
authors.initials: WM
authors.lastname: Gedroyc
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000175:diagnosis / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000601:surgery*; D053685:Laser Therapy / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D016896:Treatment Outcome