title: Chordomas of the skull base: dynamic MRI.
abstract: OBJECTIVE
  To investigate the role of dynamic MRI in the diagnosis of chordomas at the skull base.
  
  
  METHODS
  Six patients with surgically proven chordomas of the skull base were examined with spin-echo technique (repetition time/echo time 200 ms/15 ms). Serial imaging was performed every 30 s for 240 s after a rapid injection of gadopenetate dimeglumine (0.1 mmol/kg). The contrast material enhancement ratio (CER) was analyzed. The CER was obtained for each region of interest as follows (Sn - So) x 100/Smax - So, where Sn indicates signal intensity at each dynamic phase; So, signal intensity on the image obtained before administration of contrast material; and Smax, maximum signal intensity of all dynamic imaging.
  
  
  RESULTS
  All chordomas showed very slow but steady increase of contrast enhancement with no peak within 240 s. The CERs of six cases at 30 s are 13 to 40 (mean value +/- standard deviation: 22.8 +/- 10.2).
  
  
  CONCLUSIONS
  Dynamic MRI may be helpful in differentiating between chordomas and other tumors of the skull base.
authors.affiliation: Department of Radiology, Kumamoto University School of Medicine, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Ikushima
authors.forename: Y
authors.initials: Y
authors.lastname: Korogi
authors.forename: T
authors.initials: T
authors.lastname: Hirai
authors.forename: S
authors.initials: S
authors.lastname: Hamatake
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: Y
authors.initials: Y
authors.lastname: Ushio
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000175:diagnosis*; D002817:Chordoma / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012888:Skull Neoplasms / Q000175:diagnosis*