title: Tuberculous infection of the wrist: MRI features.
abstract: OBJECTIVE
  The objective of our study was to define the MRI features of tuberculous infection of the wrist.
  
  
  METHODS
  We present the MRI findings of eight patients with tuberculous infection of the wrist. Spin-echo T1-weighted, gradient-echo T2(*)-weighted, and fast spin-echo T2-weighted sequences were performed for all patients. Gadolinium-enhanced MR images were obtained in seven patients. All images were evaluated for the characteristics of tuberculous infection of the wrist, including the presence of synovial thickening around the joints and tendons, signal intensity of the thickened tenosynovium and synovium on the T2-weighted images, synovial fluid collection in the tendon sheath, small low-signal and nonenhanced foci in the synovial fluid, bone erosion, osteomyelitis, and encasement of the median nerve.
  
  
  RESULTS
  The tuberculous infection involved the right (n = 6) and left (n = 2) wrists. All patients had synovial thickening around the flexor and extensor tendons with synovial fluid collection in the tendon sheath. The thickened tenosynovium and synovium revealed low signal intensity on T1-weighted images, intermediate to low signal intensity on T2- and T2(*)-weighted images, and enhancement on contrast-enhanced MR images. The synovial fluid showed intermediate to low signal on T1-weighted images and homogeneous or heterogeneous high signal intensity on T2- and T2(*)-weighted images. Multiple small foci of low signal intensity and nonenhancement scattered in the synovial fluid were present in seven patients. Bone erosion occurred in seven patients, osteomyelitis was seen in six patients, and encasement of the median nerve was found in three patients.
  
  
  CONCLUSIONS
  Characteristic MRI findings of tuberculous infection of the wrist include synovial thickening around the flexor and extensor tendons and synovial fluid collection that contains small low-signal and nonenhanced foci in the tendon sheath. Bone erosion, osteomyelitis, and median nerve encasement are also frequently present. These characteristic manifestations are helpful in diagnosing this disease entity.
authors.affiliation: Department of Medical Imaging, National Taiwan University Hospital, 7, Chung-Shan S. Rd. Taipei, Taiwan.
authors.forename: Chao-Yu
authors.initials: CY
authors.lastname: Hsu
authors.forename: Hsueh-Chieh
authors.initials: HC
authors.lastname: Lu
authors.forename: Tiffany Ting-Fang
authors.initials: TT
authors.lastname: Shih
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014394:Tuberculosis, Osteoarticular / Q000175:diagnosis*; D014955:Wrist Joint