title: MRI evidence of endolymphatic impermeability to the gadolinium molecule in the in vivo mouse inner ear at 9.4 tesla.
abstract: OBJECTIVE
  Previous in vivo experimental magnetic resonance imaging (MRI) investigations of the mammalian inner ear at 4.7 Tesla have indicated that intravenously injected gadolinium (Gd) penetrates the perilymphatic labyrinth, but not the endolymphatic membranous labyrinth. In the present study, high field MRI at 9.4T was used to visualize the in vivo mouse vestibulo-cochlea system, and to determine whether the endolymphatic system is permeable to a Gd complex.
  
  
  METHODS
  A 9.4 T Varian magnet equipped with a 12 cm inner diameter gradient system with maximum gradient strength of 600 mT/m, a millipede coil (Varian design) and a Gd contrast agent were used for image acquisition in the normal C57 BL-6 mouse.
  
  
  RESULTS
  High-resolution 2D and 3D images of the mouse cochlea were acquired within 80 minutes following intravenous injection of Gd. Gd initially permeated the perilymphatic scala tympani and scala vestibuli, and permitted visualization of both cochlear turns from base to apex. The superior, inferior and lateral semicircular canals were subsequently visualized in 3 planes. The membranous endolymphatic labyrinth was impermeable to intravenously injected Gd, and thus showed no apparent uptake of Gd at 9.4T.
  
  
  CONCLUSIONS
  The 9.4T field strength MRI permitted acquisition of high resolution images of anatomical and physiological features of the normal, wild type mouse perilymphatic inner ear in vivo, and provided further evidence that the endolymphatic system is impermeable to intravenously injected Gd.
authors.affiliation: Neurology Department, Harvard University Biological Laboratories, Cambridge, MA 02138,USA.
authors.forename: S Allen
authors.initials: SA
authors.lastname: Counter
authors.forename: Sahar
authors.initials: S
authors.lastname: Nikkhou
authors.forename: Stefan
authors.initials: S
authors.lastname: Brené
authors.forename: Peter
authors.initials: P
authors.lastname: Damberg
authors.forename: Adam
authors.initials: A
authors.lastname: Sierakowiak
authors.forename: Tomas
authors.initials: T
authors.lastname: Klason
authors.forename: Cecilia Engmér
authors.initials: CE
authors.lastname: Berglin
authors.forename: Göran
authors.initials: G
authors.lastname: Laurell
keywords: Magnetic resonance imaging; Tesla.; cochlea; semicircular canals; vestibular
references.citation: Hear Res. 2011 Dec;282(1-2):184-95
references.pmid: 21875659
references.citation: J Comp Neurol. 2007 Oct 10;504(5):519-32
references.pmid: 17701983
references.citation: Neuroreport. 1999 Feb 25;10(3):473-9
references.pmid: 10208574
references.citation: Hear Res. 2010 Jan;259(1-2):36-43
references.pmid: 19818391
references.citation: Neuroreport. 2004 Aug 26;15(12):1927-30
references.pmid: 15305139
references.citation: Magn Reson Med Sci. 2012;11(2):145-50
references.pmid: 22790302
references.citation: Neuroreport. 2000 Dec 18;11(18):3979-83
references.pmid: 11192613
references.citation: Dev Biol. 2004 Aug 1;272(1):161-75
references.pmid: 15242798
references.citation: J Assoc Res Otolaryngol. 2011 Dec;12(6):741-51
references.pmid: 21769689
references.citation: Acta Otolaryngol. 2003 Oct;123(8):910-5
references.pmid: 14606591
references.citation: Neuroreport. 2003 Sep 15;14(13):1707-12
references.pmid: 14512842