title: MR findings of necrotic lesions and the extralesional area of osteonecrosis of the femoral head.
abstract: OBJECTIVE
  To investigate the MR findings of necrotic lesions and the extralesional area of osteonecrosis of the femoral head (ONFH) for each of the radiological stages.
  
  
  METHODS
  Forty-nine hips in 29 patients (15 female, 14 male; mean age 38 years, range 17-59 years) were imaged using a 1.0-T superconducting magnet. T2-weighted spin echo pulse sequences (T2WI), spoiled gradient recalled echo pulse sequences (SPGR) and fat suppression SPGR (FS-SPGR), followed by Gd-DTPA enhanced fat suppression SPGR (Gd-FS-SPGR), were all obtained with the aid of a TORSO surface coil.
  
  
  CONCLUSIONS
  While a normal fat intensity area with a low-intensity band on SPGR (band pattern) was seen in 16 of 16 stage 1 (100%), nine of 11 stage 2 (82%), four of 17 stage 3 (24%), and none of five stage 4 hips, all hips showed peripheral rim enhancement on Gd-FS-SPGR (100%). This enhancement band on Gd-FS-SPGR corresponded to histological findings of necrotic trabecular bone, repaired marrow, and fibrous reparative tissue. Bone marrow edema was also clearly demonstrated as a diffuse, high-intensity area outside this enhancement band on Gd-FS-SPGR in two stage 2 (18%), 12 stage 3 (71%), and one stage 4 hip (20%). In cases at stage 2 or more advanced stages with homogeneous or inhomogeneous low intensity on nonenhanced MRI, the reparative process both inside and outside the necrotic lesion, including bone marrow edema, was detected clearly on contrast-enhanced MRI.
authors.affiliation: Department of Orthopedic Surgery, Osaka University Medical School, Suita, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sakai
authors.forename: N
authors.initials: N
authors.lastname: Sugano
authors.forename: T
authors.initials: T
authors.lastname: Nishii
authors.forename: K
authors.initials: K
authors.lastname: Haraguchi
authors.forename: T
authors.initials: T
authors.lastname: Ochi
authors.forename: K
authors.initials: K
authors.lastname: Ohzono
mesh_terms: D000293:Adolescent; D000328:Adult; D003287:Contrast Media; D005260:Female; D005270:Femur Head / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000175:diagnosis* / Q000473:pathology
chemical_list: D003287:Contrast Media