title: Communication between cochlear perilymph and cerebrospinal fluid through the cochlear modiolus visualized after intratympanic administration of Gd-DTPA.
abstract: OBJECTIVE
  Intratympanic injection of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) has been reported as a procedure to visualize endolymphatic hydrops of Meniere's disease. We frequently noted that cerebrospinal fluid (CSF) in the internal auditory canal (IAC) was also enhanced after this procedure. The purpose of this study was to evaluate how frequently this occurs and to investigate the specific features of patients who lack this communication.
  
  
  METHODS
  A total of 25 patients with clinically suspected endolymphatic hydrops underwent the procedure. After 24 h, three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) and 3D constructive interference in steady state (3D-CISS) were performed. The presence of contrast enhancement in the CSF space of the fundus of the IAC was evaluated.
  
  
  RESULTS
  The contrast ratio between CSF of the IAC fundus and cerebellar white matter on the injected side was 1.49 +/- 0.65, and that of the noninjected side was 0.32 +/- 0.16 (P < 0.01). Enhancement of the CSF space in the IAC fundus was seen in all but two subjects: one had enlarged endolymphatic duct and sac syndrome (EEDS), and the other had cochlear nerve agenesis. In these two patients, the cochlear modiolus seemed to be normal.
  
  
  CONCLUSIONS
  Intratympanic Gd-DTPA administration can reveal permeability of the modiolus and might facilitate evaluation of functional abnormalities of the modiolus not detected by conventional imaging tests.
authors.affiliation: Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Shouwa-ku, Nagoya, Japan. naganawa@med.nagoya-u.ac.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Naganawa
authors.forename: Hiroko
authors.initials: H
authors.lastname: Satake
authors.forename: Shingo
authors.initials: S
authors.lastname: Iwano
authors.forename: Michihiko
authors.initials: M
authors.lastname: Sone
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakashima
mesh_terms: D000328:Adult; D000368:Aged; D003051:Cochlea / Q000473:pathology*; D003287:Contrast Media; D018159:Endolymphatic Hydrops / Q000134:cerebrospinal fluid* / Q000175:diagnosis*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010498:Perilymph; D014432:Tympanic Membrane / Q000473:pathology*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA