title: Application of MRI movie for observation of articulatory movement during a fricative /s/ and a plosive /t/.
abstract: OBJECTIVE
  To use an accurate method of tooth visualization in magnetic resonance imaging (MRI) movie for the observation of spatio-temporal relationships among articulators.
  
  
  METHODS
  The subjects were two volunteers. Each subject repeated a vowel-consonant-vowel syllable (ie, /asa/; /ata/), and the run was measured using a gradient echo sequence. A custom-made clear retainer filled with the jelly form of ferric ammonium citrate was then fit onto the dental arch, and a T1-weighted turbo-spin-echo sequence was taken. Landmarks were used for superimposition of the incisor boundary onto sequential images of MRI movie. Tracings were conducted to observe the spatio-temporal relationships among articulators.
  
  
  RESULTS
  The incisor boundary was clearly visible in the magnetic resonance images. After superimposition, the contact distance of the tongue to palate/incisor was found to be longer during /t/-articulation than during /s/-articulation. There were prominent differences in images with and without tooth superimposition in the front oral cavity.
  
  
  CONCLUSIONS
  The method could distinctly extract a tooth boundary in MRI. Detailed configurational relationships between the tongue and tooth were observed during the production of a fricative and a plosive in MRI movie using this method.
authors.affiliation: Tokyo Medical and Dental University, Japan.
authors.forename: I W
authors.initials: IW
authors.lastname: Ng
authors.forename: T
authors.initials: T
authors.lastname: Ono
authors.forename: M S
authors.initials: MS
authors.lastname: Inoue-Arai
authors.forename: E
authors.initials: E
authors.lastname: Honda
authors.forename: T
authors.initials: T
authors.lastname: Kurabayashi
authors.forename: K
authors.initials: K
authors.lastname: Moriyama
mesh_terms: D000328:Adult; D003287:Contrast Media; D005260:Female; D006801:Humans; D007180:Incisor / Q000502:physiology; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008297:Male; D021362:Palate, Hard / Q000502:physiology; D019047:Phantoms, Imaging; D010700:Phonetics; D013068:Speech Production Measurement / Q000379:methods*; D014059:Tongue / Q000502:physiology
chemical_list: D003287:Contrast Media