title: Semi-quantification of endolymphatic size on MR imaging after intravenous injection of single-dose gadodiamide: comparison between two types of processing strategies.
abstract: OBJECTIVE
  Many inner ear disorders, including Ménière's disease, are believed to be based on endolymphatic hydrops. We evaluated a newly proposed method for semi-quantification of endolymphatic size in patients with suspected endolymphatic hydrops that uses 2 kinds of processed magnetic resonance (MR) images.
  
  
  METHODS
  Twenty-four consecutive patients underwent heavily T2-weighted (hT2W) MR cisternography (MRC), hT2W 3-dimensional (3D) fluid-attenuated inversion recovery (FLAIR) with inversion time of 2250 ms (positive perilymph image, PPI), and hT2W-3D-IR with inversion time of 2050 ms (positive endolymph image, PEI) 4 hours after intravenous administration of single-dose gadolinium-based contrast material (IV-SD-GBCM). Two images were generated using 2 new methods to process PPI, PEI, and MRC. Three radiologists contoured the cochlea and vestibule on MRC, copied regions of interest (ROIs) onto the 2 kinds of generated images, and semi-quantitatively measured the size of the endolymph for the cochlea and vestibule by setting a threshold pixel value.
  
  
  RESULTS
  Each observer noted a strong linear correlation between endolymphatic size of both the cochlea and vestibule of the 2 kinds of generated images. The Pearson correlation coefficients (r) were 0.783, 0.734, and 0.800 in the cochlea and 0.924, 0.930, and 0.933 in the vestibule (P<0.001, for all). In both the cochlea and vestibule, repeated-measures analysis of variance showed no statistically significant difference between observers.
  
  
  CONCLUSIONS
  Use of the 2 kinds of generated images generated from MR images obtained 4 hours after IV-SD-GBCM might enable semi-quantification of endolymphatic size with little observer dependency.
authors.affiliation: Department of Radiology, Nagoya University Graduate School of Medicine.
authors.forename: Shinji
authors.initials: S
authors.lastname: Naganawa
authors.forename: Kojiro
authors.initials: K
authors.lastname: Suzuki
authors.forename: Rei
authors.initials: R
authors.lastname: Nakamichi
authors.forename: Kiminori
authors.initials: K
authors.lastname: Bokura
authors.forename: Tadao
authors.initials: T
authors.lastname: Yoshida
authors.forename: Michihiko
authors.initials: M
authors.lastname: Sone
authors.forename: Georg
authors.initials: G
authors.lastname: Homann
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakashima
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Ikeda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003287:Contrast Media / Q000008:administration & dosage; D004710:Endolymph / Q000166:cytology*; D004711:Endolymphatic Duct / Q000473:pathology*; D018159:Endolymphatic Hydrops / Q000473:pathology*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA