title: Evaluating Instantaneous Perfusion Responses of Parotid Glands to Gustatory Stimulation Using High-Temporal-Resolution Echo-Planar Diffusion-Weighted Imaging.
abstract: OBJECTIVE
  Parotid glands secrete and empty saliva into the oral cavity rapidly after gustatory stimulation. However, the role of the temporal resolution of DWI in investigating parotid gland function remains uncertain. Our aim was to design a high-temporal-resolution echo-planar DWI pulse sequence and to evaluate the instantaneous MR perfusion responses of the parotid glands to gustatory stimulation.
  
  
  METHODS
  This prospective study enrolled 21 healthy volunteers (M/F = 2:1; mean age, 45.2 ± 12.9 years). All participants underwent echo-planar DWI (total scan time, 304 seconds; temporal resolution, 4 s/scan) on a 1.5T MR imaging scanner. T2WI (b= 0 s/mm2) and DWI (b= 200 s/mm2) were qualitatively assessed. Signal intensity of the parotid glands on T2WI, DWI, and ADC was quantitatively analyzed. One-way ANOVA with post hoc group comparisons with Bonferroni correction was used for statistical analysis.P< .05 was statistically significant.
  
  
  RESULTS
  Almost perfect interobserver agreement was achieved (κ ≥ 0.656). The parotid glands had magnetic susceptibility artifacts in 14.3% (3 of 21) of volunteers during swallowing on DWI but were free from perceptible artifacts at the baseline and at the end of scans on all images. Increased ADC and reduced signal intensity of the parotid glands on T2WI and DWI occurred immediately after oral administration of lemon juice. Maximal signal change of ADC (24.8% ± 10.8%) was significantly higher than that of T2WI (-10.1% ± 5.2%,P< .001). The recovery ratio of ADC (100.71% ± 42.34%) was also significantly higher than that of T2WI (22.36% ± 15.54%,P< .001).
  
  
  CONCLUSIONS
  Instantaneous parotid perfusion responses to gustatory stimulation can be quantified by ADC by using high-temporal-resolution echo-planar DWI.
authors.affiliation: From the Departments of Radiology (T.-W.C., C.-W.W., H.-H.H., C.-J.J.).|Department of Medicine (T.-W.C.), Taipei Medical University, Taipei, Taiwan.
authors.forename: T-W
authors.identifier: http://orcid.org/0000-0002-1636-279X
authors.initials: TW
authors.lastname: Chiu
authors.affiliation: Department of Medicine (T.-W.C.), Taipei Medical University, Taipei, Taiwan.
authors.forename: Y-J
authors.identifier: http://orcid.org/0000-0001-5865-6836
authors.initials: YJ
authors.lastname: Liu
authors.affiliation: Department of Diagnostic Radiology (H.-C.C.), The University of Hong Kong, Hong Kong.
authors.forename: H-C
authors.identifier: http://orcid.org/0000-0003-3546-9194
authors.initials: HC
authors.lastname: Chang
authors.affiliation: Department of Medicine (T.-W.C.), Taipei Medical University, Taipei, Taiwan.
authors.forename: Y-H
authors.identifier: http://orcid.org/0000-0003-1010-1131
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery (J.-C.L.), Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.|Department of Biological Science and Technology (J.-C.L., J.-M.Y.), Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan.
authors.forename: J-C
authors.identifier: http://orcid.org/0000-0002-4950-0239
authors.initials: JC
authors.lastname: Lee
authors.affiliation: Dentistry (K.H.), National Defense Medical Center, Taipei, Taiwan.
authors.forename: K
authors.identifier: http://orcid.org/0000-0002-8351-161X
authors.initials: K
authors.lastname: Hsu
authors.affiliation: From the Departments of Radiology (T.-W.C., C.-W.W., H.-H.H., C.-J.J.).|Department of Radiology (C.-W.W., H.-H.H., C.-J.J.), Tri-Service General Hospital, Taipei, Taiwan.
authors.forename: C-W
authors.identifier: http://orcid.org/0000-0002-4288-1729
authors.initials: CW
authors.lastname: Wang
authors.affiliation: Department of Biological Science and Technology (J.-C.L., J.-M.Y.), Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu, Taiwan.
authors.forename: J-M
authors.identifier: http://orcid.org/0000-0002-3205-4391
authors.initials: JM
authors.lastname: Yang
authors.affiliation: From the Departments of Radiology (T.-W.C., C.-W.W., H.-H.H., C.-J.J.).|Department of Radiology (C.-W.W., H.-H.H., C.-J.J.), Tri-Service General Hospital, Taipei, Taiwan.
authors.forename: H-H
authors.identifier: http://orcid.org/0000-0003-4485-8247
authors.initials: HH
authors.lastname: Hsu
authors.affiliation: From the Departments of Radiology (T.-W.C., C.-W.W., H.-H.H., C.-J.J.) peterjuancj@yahoo.com.tw.|Department of Radiology (C.-W.W., H.-H.H., C.-J.J.), Tri-Service General Hospital, Taipei, Taiwan.
authors.forename: C-J
authors.identifier: http://orcid.org/0000-0001-5219-0406
authors.initials: CJ
authors.lastname: Juan