title: Contrast-enhanced MRI of the inner ear after intratympanic injection of meglumine gadopentetate or gadodiamide hydrate.
abstract: CONCLUSIONS
  The degree of contrast enhancement of the cochlea after intratympanic administration of meglumine gadopentetate (Gd-DTPA) or gadodiamide hydrate (Gd-DTPA-BMA) varies widely among patients with inner ear diseases. There was no morphological change in the stria vascularis after Gd-DTPA or Gd-DTPA-BMA was placed on the round window of guinea pigs.
  
  
  OBJECTIVE
  We investigated the degree of contrast enhancement of the inner ear after intratympanic administration of ionized and nonionized gadolinium (Gd) contrast agents in patients with inner ear diseases. The inner ear toxicities of these agents were investigated in guinea pigs.
  
  
  METHODS
  3D-FLAIR MRI was conducted 1 day after the intratympanic injection of eightfold-diluted Gd-DTPA or Gd-DTPA-BMA in 73 patients with inner ear diseases. Gd enhancement of the basal turn of the cochlea was evaluated as the signal intensity (SI) ratio between the affected and nonaffected sides. In guinea pigs, nondiluted Gd-DTPA, Gd-DTPA-BMA or saline was placed on the round window for 1 h and the stria vascularis was observed using electron microscopy.
  
  
  RESULTS
  The SI ratio ranged from 1.5 to 16.5 in the Gd-DTPA group and from 2.5 to 21 in the Gd-DTPA-BMA group. Electron microscopy showed no significant differences in the stria vascularis of guinea pigs in any of the groups.
authors.affiliation: Department of Otorhinolaryngology, Nagoya University, Graduate School of Medicine, Nagoya, Japan. suzuki-hrkz@med.nagoya-u.ac.jp
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Suzuki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Teranishi
authors.forename: Shinji
authors.initials: S
authors.lastname: Naganawa
authors.forename: Seiichi
authors.initials: S
authors.lastname: Nakata
authors.forename: Michihiko
authors.initials: M
authors.lastname: Sone
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakashima
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D003051:Cochlea / Q000473:pathology*; D003287:Contrast Media / Q000008:administration & dosage; D004432:Ear, Middle; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006168:Guinea Pigs; D006801:Humans; D021621:Imaging, Three-Dimensional; D007267:Injections; D007759:Labyrinth Diseases / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA