title: MR patterns of involvement of humeral head osteonecrosis.
abstract: OBJECTIVE
  To characterize osteonecrosis of the humeral head on coronal and axial MR images.
  
  
  METHODS
  We retrospectively reviewed MR examinations in patients with humeral head osteonecrosis. The angle of the entire affected articular surface at three levels was measured and an angle subtended by the margins of osteonecrosis was also measured.
  
  
  RESULTS
  The appearance of osteonecrosis is identical to that in the femoral head with signal abnormality (13/13), double-line sign (7/13), and subchondral fractures (3/13). The superior aspect of the humeral head was the most common location of osteonecrosis. The MR staging resulted as follows: stage II (6/13), stage IIIA (1/13), stage IIIB (1/13), and stage IV (5/13). The maximum percentage of involvement of the articular surface demonstrated the following distribution: 0% to 25%, 0/11; 25% to 50%, 1/13; 50% to 75%, 5/13; and 75% to 100%, 7/13.
  
  
  CONCLUSIONS
  Quantitative analysis of the percentage of involvement of the humeral head was performed and indicates that in most cases, 75% to 100% of the articular surface at the levels measured was involved.
authors.affiliation: Department of Radiology, The Ohio State University Medical Center, Columbus, Ohio, USA. jonathonalee@yahoo.com
authors.forename: Jonathon A
authors.initials: JA
authors.lastname: Lee
authors.forename: Shella
authors.initials: S
authors.lastname: Farooki
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Ashman
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Yu
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006811:Humerus / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000473:pathology*; D012189:Retrospective Studies