title: Ecchordosis physaliphora and its variants: proposed new classification based on high-resolution fast MR imaging employing steady-state acquisition.
abstract: OBJECTIVE
  To propose a new classification for ecchordosis physaliphora (EP) using fast imaging employing steady-state acquisition (FIESTA).
  
  
  METHODS
  We evaluated 974 consecutive patients and selected for further study 78 (8.0 %) who manifested an excrescence on the dorsal surface of the clivus (DSC) and/or clivus lesions. Lesions were defined as "classical EP" when they appeared as a hyperintense excrescence (cyst-like component) on DSC. Other lesions were defined as "possible EP".
  
  
  RESULTS
  Of the 78 patients, 17 (22 %) were diagnosed with classical EP, the other 61 with possible EP. The 61 patients with possible EP were further classified into "incomplete EP = EP bud" (n = 55, 90.2 %), characterised by a T2 hypointense protrusion of the clivus, and into "EP variant" (n = 6, 9.8 %), characterised by hyperintense lesions within only clivus. FIESTA findings of incomplete EP were similar to those of classical EP except for lack of the hyperintense excrescence on DSC. Most lesions were located at the level of the Dorello canal at the midline of the craniospinal axis.
  
  
  CONCLUSIONS
  Our results suggest that the magnetic resonance imaging appearance of EP is diverse. Based on our FIESTA results we propose a new classification for EP, i.e. classical EP, incomplete EP (EP bud) and EP variant.
  
  
  CONCLUSIONS
  • Ecchordosis physaliphora (EP) is a rare benign cystic congenital lesion arising from notochord. • The classical type of EP is frequently associated with a T2 hypointense protrusion. • T2 hypointense protrusions without clivus cysts may represent an incomplete type of EP. • Third type of EP variant only harbours lesions within the clivus.
authors.affiliation: Department of Radiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Chihara
authors.forename: Y
authors.initials: Y
authors.lastname: Korogi
authors.forename: S
authors.initials: S
authors.lastname: Kakeda
authors.forename: J
authors.initials: J
authors.lastname: Nishimura
authors.forename: Y
authors.initials: Y
authors.lastname: Murakami
authors.forename: J
authors.initials: J
authors.lastname: Moriya
authors.forename: N
authors.initials: N
authors.lastname: Ohnari
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001932:Brain Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D002817:Chordoma / Q000453:epidemiology* / Q000473:pathology*; D003388:Cranial Fossa, Posterior / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007564:Japan / Q000453:epidemiology; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D055815:Young Adult
references.citation: Eur Radiol. 2004 Feb;14(2):239-42
references.pmid: 14531013
references.citation: Radiology. 1990 May;175(2):545-52
references.pmid: 2326480
references.citation: Histopathology. 2004 Jun;44(6):597-602
references.pmid: 15186275
references.citation: J Neurosurg. 1991 Dec;75(6):976-9
references.pmid: 1941129
references.citation: J Neurosurg. 1983 Sep;59(3):535-7
references.pmid: 6886768
references.citation: Neuroradiology. 1988;30(1):81-3
references.pmid: 3357574
references.citation: AJR Am J Roentgenol. 2011 Mar;196(3):644-50
references.pmid: 21343509
references.citation: No Shinkei Geka. 1996 Nov;24(11):1021-5
references.pmid: 8934471
references.citation: Minim Invasive Neurosurg. 2002 Mar;45(1):36-40
references.pmid: 11932823
references.citation: J Neurosurg. 1998 Nov;89(5):830-4
references.pmid: 9817423
references.citation: AJNR Am J Neuroradiol. 2004 Nov-Dec;25(10):1851-5
references.pmid: 15569763
references.citation: Clin Neuropathol. 1985 Mar-Apr;4(2):77-86
references.pmid: 3995810
references.citation: Clin Neuropathol. 1987 May-Jun;6(3):98-103
references.pmid: 3608292
references.citation: Neurosurgery. 1990 Mar;26(3):515-8; discussion 518-9
references.pmid: 2320221
references.citation: Eur Neurol. 1982;21(2):90-3
references.pmid: 7094956
references.citation: Neuroradiology. 2011 Jun;53(6):413-23
references.pmid: 20668844
references.citation: AJR Am J Roentgenol. 2000 Nov;175(5):1375-80
references.pmid: 11044047
references.citation: Am J Surg Pathol. 2004 Jun;28(6):756-61
references.pmid: 15166667
references.citation: Int J Legal Med. 2008 May;122(3):225-7
references.pmid: 17786464
references.citation: Radiology. 2008 May;247(2):585-8
references.pmid: 18430884