title: Experimental Fusion of Contrast Enhanced High-Field Magnetic Resonance Imaging and High-Resolution Micro-Computed Tomography in Imaging the Mouse Inner Ear.
abstract: OBJECTIVE
  Imaging cochlear, vestibular, and 8th cranial nerve abnormalities remains a challenge. In this study, the membranous and osseous labyrinths of the wild type mouse inner ear were examined using volumetric data from ultra high-field magnetic resonance imaging (MRI) with gadolinium contrast at 9.4 Tesla and high-resolution micro-computed tomography (µCT) to visualize the scalae and vestibular apparatus, and to establish imaging protocols and parameters for comparative analysis of the normal and mutant mouse inner ear.
  
  
  METHODS
  For in vivo MRI acquisition, animals were placed in a Milleped coil situated in the isocenter of a horizontal 9.4 T Varian magnet. For µCT examination, cone beam scans were performed ex vivo following MRI using the µCT component of a nanoScan PET/CT in vivo scanner.
  
  
  RESULTS
  The fusion of Gd enhanced high field MRI and high-resolution µCT scans revealed the dynamic membranous labyrinth of the perilymphatic fluid filled scala tympani and scala vestibule of the cochlea, and semicircular canals of the vestibular apparatus, within the µCT visualized contours of the contiguous osseous labyrinth. The ex vivo µCT segmentation revealed the surface contours and structural morphology of each cochlea turn and the semicircular canals in 3 planes.
  
  
  CONCLUSIONS
  The fusion of ultra high-field MRI and high-resolution µCT imaging techniques were complementary, and provided high-resolution dynamic and static visualization of the complex morphological features of the normal mouse inner ear structures, which may offer a valuable approach for the investigation of cochlear and vestibular abnormalities that are associated with birth defects related to genetic inner ear disorders in humans.
authors.affiliation: Neurology Department, Harvard University Biological Laboratories, Cambridge, MA 02138, USA.
authors.forename: S Allen
authors.initials: SA
authors.lastname: Counter
authors.affiliation: Karolinska Experimental Research Imaging Center, Karolinska Universitetssjukhuset Solna, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Damberg
authors.affiliation: Karolinska Experimental Research Imaging Center, Karolinska Universitetssjukhuset Solna, Sweden.
authors.forename: Sahar Nikkhou
authors.initials: SN
authors.lastname: Aski
authors.affiliation: Karolinska Experimental Research Imaging Center, Karolinska Universitetssjukhuset Solna, Sweden.
authors.forename: Kálmán
authors.initials: K
authors.lastname: Nagy
authors.affiliation: Department of CLINTEC Karolinska Institutet, 171 76 Stockholm, Sweden.
authors.forename: Cecilia Engmér
authors.initials: CE
authors.lastname: Berglin
authors.affiliation: Department of Surgical Sciences Uppsala University, Uppsala, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Laurell
keywords: Cochlea; Gadolinium; Magnetic Resonance Imaging; Micro Computed Tomography; Vestibular