title: Diagnostic performance of 3D standing CT imaging for detection of knee osteoarthritis features.
abstract: OBJECTIVE
  To determine the diagnostic performance of standing computerized tomography (SCT) of the knee for osteophytes and subchondral cysts compared with fixed-flexion radiography, using MRI as the reference standard.
  
  
  METHODS
  Twenty participants were recruited from the Multicenter Osteoarthritis Study. Participants' knees were imaged with SCT while standing in a knee-positioning frame, and with postero-anterior fixed-flexion radiography and 1T MRI. Medial and lateral marginal osteophytes and subchondral cysts were scored on bilateral radiographs and coronal SCT images using the OARSI grading system and on coronal MRI using Whole Organ MRI Scoring. Imaging modalities were read separately with images in random order. Sensitivity, specificity and accuracy for the detection of lesions were calculated and differences between modalities were tested using McNemar's test.
  
  
  RESULTS
  Participants' mean age was 66.8 years, body mass index was 29.6 kg/m(2) and 50% were women. Of the 160 surfaces (medial and lateral femur and tibia for 40 knees), MRI revealed 84 osteophytes and 10 subchondral cysts. In comparison with osteophytes and subchondral cysts detected by MRI, SCT was significantly more sensitive (93 and 100%; p < 0.004) and accurate (95 and 99%; p < 0.001 for osteophytes) than plain radiographs (sensitivity 60 and 10% and accuracy 79 and 94%, respectively). For osteophytes, differences in sensitivity and accuracy were greatest at the medial femur (p = 0.002).
  
  
  CONCLUSIONS
  In comparison with MRI, SCT imaging was more sensitive and accurate for detection of osteophytes and subchondral cysts than conventional fixed-flexion radiography. Additional study is warranted to assess diagnostic performance of SCT measures of joint space width, progression of OA features and the patellofemoral joint.
authors: a 1 Department of Rehabilitation Medicine, The University of Kansas , Kansas City, KS, USA.
authors: Neil A
authors: NA
authors: Segal
authors: Michael C
authors: MC
authors: Nevitt
authors: John A
authors: JA
authors: Lynch
authors: Jingbo
authors: J
authors: Niu
authors: James C
authors: JC
authors: Torner
authors: Ali
authors: A
authors: Guermazi
mesh_terms: D000368:Aged; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000473:pathology; D054850:Osteophyte / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed
keywords: Biomechanics; bone marrow lesions; cartilage loss; cone beam computed tomography; joint loading; knee; osteoarthritis; weight bearing