title: Spinal subdural enhancement after suboccipital craniectomy.
abstract: OBJECTIVE
  To characterize transient intraspinal subdural enhancement (potentially mimicking the subarachnoid spread of tumor) seen on MR images in some children after suboccipital craniectomy for posterior fossa tumor resection.
  
  
  METHODS
  Radiologic and medical records of 10 consecutive children who had MR imaging for spinal staging after resection of posterior fossa tumor during a 9-month period were reviewed retrospectively. In addition, one case with similar findings of intraspinal enhancement on spinal staging MR images obtained at another institution was included in the review.
  
  
  RESULTS
  Intraspinal enhancement thought to be subdural was seen in four of 10 patients undergoing spinal staging MR imaging 6 to 12 days after surgery. In these four patients, MR studies 50 to 18 days later, without intervening treatment, showed resolution of the abnormal enhancement. A fifth patient (from another institution) with similar intraspinal enhancement underwent CT myelography 4 days later, which showed no subarachnoid lesions. No metastases have developed in any of these five patients during the 2.5- to 3.5-year follow-up period. conclusions: From analysis of the MR appearance and on the basis of prior myelographic experience, we suggest an extraarachnoid, probably subdural, location of this enhancement. Awareness of this phenomenon will reduce the rate of false-positive diagnoses of metastatic disease. Preoperative spinal staging should be considered for patients undergoing suboccipital craniectomy.
authors.affiliation: Department of Radiology, University of Washington, Seattle, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Shaw
authors.forename: E
authors.initials: E
authors.lastname: Weinberger
authors.forename: D K
authors.initials: DK
authors.lastname: Brewer
authors.forename: J R
authors.initials: JR
authors.lastname: Geyer
authors.forename: M S
authors.initials: MS
authors.lastname: Berger
authors.forename: S I
authors.initials: SI
authors.lastname: Blaser
mesh_terms: D002648:Child; D002675:Child, Preschool; D003388:Cranial Fossa, Posterior; D003937:Diagnosis, Differential; D006801:Humans; D007223:Infant; D009361:Neoplasm Invasiveness; D009777:Occipital Bone / Q000601:surgery*; D011184:Postoperative Period; D012189:Retrospective Studies; D012888:Skull Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D013355:Subdural Space / Q000473:pathology*