title: Imaging of tophi with an extremity-dedicated MRI system.
abstract: OBJECTIVE
  To describe the MRI features of gout tophi in the soft-tissues or joints of the limbs by low-field extremity-dedicated MRI.
  
  
  METHODS
  Nine consecutive patients, 8M/1W, affected by chronic tophaceous gout were studied. Mean patients' age was 71.3±11.5 years, mean disease duration 98.1±44.9 months, and mean serum uric acid concentration 9.2±2.8 mg/L. Diagnosis was based on the ACR classification criteria for gout, and by identification of MSU crystals in the tophi and synovial fluid. Conventional radiograms and MRI with an extremity-dedicated system were obtained of the joint areas involved by tophi.
  
  
  RESULTS
  At T1 weighted MRI images, all tophi showed a homogeneous intermediate signal intensity, similar to that of muscle. Conversely, in T2 weighted images, a wide spectrum of signal intensity patterns was observed. The pattern of contrast enhancement was variable from intense homogeneous to peripheral and heterogeneous. Capsulo-ligamentous structures were often thickened and degenerated and, on occasion, could be recognised as inhomogeneous, hypointense ribbon-shaped elements in the context of the tophus. In only two cases, tendons were infiltrated by tophaceous matter. Bone marrow oedema (BME) and erosions were seen in 8 out of 10 bones adjacent to tophi.
  
  
  CONCLUSIONS
  The MRI appearance of gout tophi using an extremity-dedicated machine is similar to that described in the literature using whole body machines. BME adjacent to the tophus was a frequent finding. This technique may occasionally help in the differential diagnosis of nodules and in the follow-up of the disease. It also represents a useful tool to investigate the pathogenesis of gout and to better understand its clinical progression.
authors: Sezione di Diagnostica per Immagini, Dipartimento di Medicina Interna, Università di Genova, Italy.
authors: F
authors: F
authors: Paparo
authors: G
authors: G
authors: Zampogna
authors: E
authors: E
authors: Fabbro
authors: M
authors: M
authors: Parodi
authors: R
authors: R
authors: Andracco
authors: G
authors: G
authors: Ferrero
authors: G
authors: G
authors: Garlaschi
authors: M A
authors: MA
authors: Cimmino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000473:pathology; D001855:Bone Marrow Diseases / Q000175:diagnosis / Q000473:pathology; D003937:Diagnosis, Differential; D004487:Edema / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006073:Gout / Q000097:blood / Q000175:diagnosis* / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014527:Uric Acid / Q000097:blood
chemical_list: D014527:Uric Acid