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Proton change of parotid glands after gustatory stimulation examined by magnetic resonance imaging
Author(s) -
Liu YiJui,
Lee YiHsiung,
Chang HingChiu,
Chiu HuiChu,
Chiu TaWei,
Hsu Kang,
Pen ChengMing,
Hsu HsianHe,
Juan ChunJung
Publication year - 2018
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3885
Subject(s) - magnetic resonance imaging , wilcoxon signed rank test , stimulation , nuclear medicine , parotid gland , statistical significance , nuclear magnetic resonance , chemistry , medicine , pathology , physics , mann–whitney u test , radiology
The aim of this study was to investigate proton changes of the parotid gland after gustatory stimulation by semi‐quantitative parameters and an empirical mathematical model (EMM) using high‐temporal‐resolution, double‐echo, echo‐planar imaging (EPI). Approved by a local institutional review board, this study examined 20 parotid glands from 10 healthy volunteers (male:female = 6: 4; age ± standard deviation =35.1 ± 14.1 years) with written informed consent obtained. All participants underwent 1.5‐T, double‐echo EPI with gustatory stimulation. Semi‐quantitative parameters, including maximal drop ratio (MDR), time to peak (TTP), drop slope (DS), recovery slope (RS) and recovery ratio (RR), were calculated. The effect of temporal resolution on parotid functional parameters was evaluated. An EMM comprising an output function ( S o t = A o e − k o t + B ) and an input function ( S in t = A in1 − e − k in t) was also applied to fit all dynamic curves. Kruskal–Wallis test, Wilcoxon test, linear regression analysis and goodness of fit were used for statistical analysis. p < 0.05 was considered to be statistically significant. The signal intensity dropped significantly after gustatory stimulation on the proton density (PD) image ( p < 0.01). MDR was 8.26% in the PD image. MDR and RR were negatively associated with time interval, whereas DS and TTP were significantly positively associated with time interval (all p < 0.05). EMM parametric values derived from PD–time curves of parotid glands were 12.04 ± 6.81%, 6.43 ± 4.23 min –1 , 88.73 ± 6.18%, 8.41 ± 4.86 min –1 and 1.09 ± 1.35 for A o , k o , B , A in and k in , respectively. Semi‐quantitative functional parameters and EMM parameters using high‐temporal‐resolution, double‐echo EPI allow the quantification of parotid proton changes after gustatory stimulation.