title: MR measurement of blood flow in the parotid gland without contrast medium: a functional study before and after gustatory stimulation.
abstract: OBJECTIVE
  To investigate the feasibility of blood flow imaging in the parotid gland using the arterial spin labeling (ASL) technique for assessment of functional changes in the parotid gland after gustatory stimulation.
  
  
  METHODS
  Anatomical and ASL imaging of the parotid gland was performed in eight healthy volunteers before and after gustatory stimulation over a period of 17 min. All measurements were carried out in a 1.5 T whole-body MR unit. ASL and data recording were performed with an adapted FAIR TrueFISP (flow-sensitive alternating inversion-recovery true fast imaging with steady precession) technique. Maps of estimated tissue blood inflow in both parotid glands were derived using a simplified model and the extended Bloch equations.
  
  
  RESULTS
  Delineation of the parotid glands was possible on FAIR TrueFISP images in all cases. In the 160 s period immediately after stimulation, a significant (P < 0.01) mean increase of 62% in the estimated parotid blood flow was observed. Estimated baseline blood flow before gustatory stimulation ranged from 226 to 500 mL/min/100 g (mean +/- SD 335 +/- 86). These rates increased in the 160 s immediately after stimulation to 404-772 mL/min/100 g (mean 542 +/- 108). In all volunteers, blood flow returned to near baseline values within the observation period. No statistically significant difference between the right and left parotid was observed in baseline and peak blood flow.
  
  
  CONCLUSIONS
  ASL FAIR TrueFISP is feasible for functional characterization of the parotid glands. Assessment of changes in blood flow in the parotid gland could serve as a diagnostic tool in patients suffering from xerostomia.
authors: Section on Experimental Radiology, Eberhard-Karls University, Tübingen, Germany. nina.schwenzer@med.uni-tuebingen.de
authors: Nina F
authors: NF
authors: Schwenzer
authors: Christina
authors: C
authors: Schraml
authors: Petros
authors: P
authors: Martirosian
authors: Andreas
authors: A
authors: Boss
authors: Claus D
authors: CD
authors: Claussen
authors: Fritz
authors: F
authors: Schick
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010306:Parotid Gland / Q000098:blood supply* / Q000502:physiology*; D012472:Salivation / Q000502:physiology*
chemical_list: D003287:Contrast Media