title: Evaluation of pulse sequences used for magnetic resonance sialography.
abstract: OBJECTIVE
  To determine the most appropriate sequences for the visualization of small parotid ducts in MR sialography.
  
  
  METHODS
  MR images of a phantom consisting of distilled water in polyethylene tubes were obtained with turbo-spin echo (TSE), single-shot turbo-spin echo (SSTSE), half-fourier acquisition, single-shot turbo-spin echo (HASTE) and turbo gradient-spin echo (TGSE) pulse sequences and compared visually and quantitatively. MR sialograms obtained from healthy volunteers and patients with Sjögren's syndrome (SS) were obtained using the same four sequences.
  
  
  RESULTS
  In the phantom, TSE images were best and the contrast-noise ratio (CNR) highest. In the volunteers, the main ducts were especially clearly visualized with TSE and in SSTSE; however, the majority of secondary and/or tertiary parotid ducts were not depicted by any of the sequences used. In SS patients, images of small main ducts and small pseudocysts were clearer using TSE. However, TSE could not depict the narrow main ducts or peripheral ducts or very small pseudocysts.
  
  
  CONCLUSIONS
  TSE is considered the most suitable MR sequence for assessing small parotid gland ducts. However, further improvement is needed since it does not always visualize them sufficiently.
authors.affiliation: Department of Oral Diagnosis & Radiology, Tohoku University Graduate School of Dentistry, Sendai, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Sakamoto
authors.forename: T
authors.initials: T
authors.lastname: Sasano
authors.forename: S
authors.initials: S
authors.lastname: Higano
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Nagasaka
authors.forename: I
authors.initials: I
authors.lastname: Yanagawa
authors.forename: Y
authors.initials: Y
authors.lastname: Hosogai
authors.forename: H
authors.initials: H
authors.lastname: Tamura
authors.forename: M
authors.initials: M
authors.lastname: Iikubo
authors.forename: N
authors.initials: N
authors.lastname: Shoji
mesh_terms: D000328:Adult; D016477:Artifacts; D003560:Cysts / Q000175:diagnosis / Q000473:pathology; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010305:Parotid Diseases / Q000175:diagnosis / Q000473:pathology; D010306:Parotid Gland / Q000473:pathology*; D019047:Phantoms, Imaging; D020959:Polyethylene; D018987:Salivary Ducts / Q000473:pathology*; D012815:Signal Processing, Computer-Assisted; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000473:pathology; D014867:Water
chemical_list: D014867:Water; D020959:Polyethylene