title: The iliac wing sign: an indicator of the presence of bone and/or soft-tissue injury of the pelvis and hips.
abstract: OBJECTIVE
  To prospectively evaluate the feasibility of using the "iliac wing sign (IWS)" as an indicator of bone and/or soft-tissue injury of the pelvis and hips on magnetic resonance (MR) imaging. IWS means edema of the iliacus muscle attachment entering the iliac wing that is visualized as a linear high signal intensity on fat-suppressed T2-weighted MR images.
  
  
  METHODS
  Consecutive 106 patients who complained of hip pain were enrolled in this study. We evaluated the correlation between IWS and bone and/or soft-tissue injury of the pelvis and hips using Fisher's exact test. Further, performance parameters of sensitivity, specificity, accuracy, the positive predictive value (PPV), and negative predictive value (NPV) of IWS were calculated.
  
  
  RESULTS
  Thirty-eight of the 106 (36%) patients had bone and/or soft-tissue injury. Twenty-seven of these 38 (71%) patients with injury showed a positive IWS, while only 11 of 68 (16%) patients without injury showed a positive IWS (p<.0001). IWS, thus, yielded a sensitivity of 71%, specificity of 84%, accuracy of 79%, positive predictive value (PPV) of 71%, and negative predictive value (NPV) of 84%.
  
  
  CONCLUSIONS
  In cases with a positive IWS, the careful interpretation of MR images is needed because injury presence is highly likely, as suggested by the relatively high sensitivity and PPV. IWS absence may mean a low probability of injury because of the high specificity and NPV.
authors: Department of Radiology, Saiseikai Ibaraki Hospital, 2-1-45 Mitsukeyama, Ibaraki, Osaka 567-0035, Japan. t.a.kakigi@dance.ocn.ne.jp
authors: Takahide
authors: T
authors: Kakigi
authors: Makoto
authors: M
authors: Hosono
authors: Taro
authors: T
authors: Shimono
authors: Taizo
authors: T
authors: Hiraoka
authors: Kazumasa
authors: K
authors: Nishimura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000175:diagnosis* / Q000209:etiology; D002648:Child; D005260:Female; D057918:Fiducial Markers; D050723:Fractures, Bone / Q000150:complications / Q000473:pathology*; D025981:Hip Injuries / Q000150:complications / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017695:Soft Tissue Injuries / Q000150:complications / Q000473:pathology*; D055815:Young Adult