title: Extraforaminal with or without foraminal disk herniation: reliable MRI findings.
abstract: OBJECTIVE
  The purpose of our study was to evaluate spinal MR images for extraforaminal disk herniation with or without foraminal disk herniation to determine the reliable MRI findings.
  
  
  METHODS
  Thirty-five patients with extraforaminal with or without foraminal disk herniation confirmed at radiculography or surgery between March 2005 and July 2007 underwent spinal MRI. We assessed the morphologic features of the disk, changes in nerve root thickness, epidural fat obliteration surrounding the nerve root, and displacement of the nerve root in the foraminal and extraforaminal zones.
  
  
  RESULTS
  Mixed disk herniation was found in 23 patients, and purely extraforaminal herniation was found in 12 patients. Focal eccentricity of the disk contour was identified in 32 patients (91%). Change in the nerve root thickness was found in 30 patients (86%). The nerve roots were displaced in 22 patients (63%), and the original location was maintained in nine patients (26%). Differentiation between the disk and the nerve root was poor in four of the 35 patients (11%). Obliteration of the epidural fat surrounding the nerve root was present in all patients.
  
  
  CONCLUSIONS
  The presence of extraforaminal with or without foraminal disk herniation should be ascertained on the basis of the following MRI findings: focal eccentricity of the disk contour, obliteration of epidural fat surrounding the nerve root, change in the thickness of the nerve root, and displacement of the nerve root.
authors.affiliation: Department of Radiology, School of Medicine, Pusan National University, Medical Research Institute, 1-10 Ami-Dong, Seo-Gu, Busan, Republic of Korea.
authors.forename: In Sook
authors.initials: IS
authors.lastname: Lee
authors.forename: Hak Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jung Sub
authors.initials: JS
authors.lastname: Lee
authors.forename: Tae-Yong
authors.initials: TY
authors.lastname: Moon
authors.forename: Ung Bae
authors.initials: UB
authors.lastname: Jeon
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000473:pathology*; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged