title: Influence of radiation synovectomy on articular cartilage, synovial thickness and enhancement as evidenced by MRI in patients with chronic synovitis.
abstract: Radiation synovectomy is a safe and effective treatment for chronic synovitis that is refractory to the repetitive, intra-articular application of glucocorticosteroids in patients with rheumatoid or seronegative arthritis. Short-term and long-term effects of radiation synovectomy on articular cartilage, synovial enhancement and thickness were assessed in a prospective, clinical trial by MRI.
  
  
  METHODS
  Thirteen patients (mean age 39+/-13 y) were treated with a median activity of 8.4 GBq 165Dy ferric hydroxide, a radionuclide with favorable physical properties and a well-documented clinical safety and efficacy profile. MRI was performed on a 1.5-T MR unit using a circular polarized knee coil.
  
  
  RESULTS
  After a mean observation period of 13 mo, a marked reduction in synovial enhancement was observed in 10 patients. The mean reduction in baseline synovial thickness (mean 7.6+/-3.0 mm) was 24% (P = 0.03) at 1 wk and 42% (P = 0.01) about 1 y after treatment, respectively. Clinically, 9 of 13 patients (69%) exhibited persistent response to radiation synovectomy. The local clinical score, as defined by the reduction in pain, pannus, joint effusion and by the increase in the range of motion, improved significantly (P = 0.01), from a median of 7 (range 4-10) to a median of 2 (range 0-9). One year after treatment, changes in the local clinical score were related to the decrease in synovial enhancement in MRI (r = 0.7, P = 0.008, n = 12). There were no persistent adverse effects, nor was there evidence for any severe radiation-induced damage to the articular cartilage. On later follow-up images, the structure of the articular cartilage remained unaltered in all but 3 patients, who had new, superficial erosions most likely attributed to an active disease with persistence of inflammation.
  
  
  CONCLUSIONS
  This study suggests that radiation synovectomy with 165Dy-ferric hydroxide is effective in terms of reducing chronic synovitis without causing detectable harm to the articular cartilage, as shown by MRI.
authors.affiliation: Department of Nuclear Medicine, MR Institute, University Hospital of Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Pirich
authors.forename: E
authors.initials: E
authors.lastname: Schwameis
authors.forename: P
authors.initials: P
authors.lastname: Bernecker
authors.forename: M
authors.initials: M
authors.lastname: Radauer
authors.forename: M
authors.initials: M
authors.lastname: Friedl
authors.forename: S
authors.initials: S
authors.lastname: Lang
authors.forename: H
authors.initials: H
authors.lastname: Kritz
authors.forename: A
authors.initials: A
authors.lastname: Wanivenhaus
authors.forename: S
authors.initials: S
authors.lastname: Trattnig
authors.forename: H
authors.initials: H
authors.lastname: Sinzinger
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000473:pathology / Q000532:radiotherapy*; D002358:Cartilage, Articular / Q000473:pathology / Q000528:radiation effects*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D000074402:Synovectomy; D013583:Synovial Membrane / Q000473:pathology; D013585:Synovitis / Q000150:complications / Q000473:pathology / Q000532:radiotherapy*; D014915:Whole-Body Counting