title: Effects of gender, age, and body mass index on fat contents and apparent diffusion coefficients in healthy parotid glands: an MRI evaluation.
abstract: OBJECTIVE
  To establish standard apparent diffusion coefficient (ADC) and the fat content as a function of age, gender and body mass index (BMI) in healthy parotid glands, and to address the influences of fat suppression on ADC measurements.
  
  
  METHODS
  A total of 100 healthy adults (gender and age evenly distributed) were prospectively recruited, with parotid fat content measured from gradient-echo images with fat-water separated using iterative decomposition with echo asymmetry and least squares (IDEAL). The ADCs were estimated using both fat-saturated and non-fat-saturated diffusion-weighted imaging via a periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) technique.
  
  
  RESULTS
  Parotid fat content was larger in men than in women by about 10 percentage points (P < 0.005), and positively associated with BMI and age for both genders (mostly with P < 0.001). ADCs estimated with non-fat-saturated PROPELLER were significantly lower in men than in women (P < 0.005), but showed no gender difference if measured using fat-saturated PROPELLER (P = 0.840). The negative association between parotid ADC and age/BMI/fat (P < 0.001) showed greater regression slopes in non-fat-saturated PROPELLER than in fat-saturated data.
  
  
  CONCLUSIONS
  Parotid fat content in healthy adults correlates positively with both age and BMI; the correlation with age is gender-dependent. Parotid ADC measurements are strongly influenced by fat saturation.
  
  
  CONCLUSIONS
  Parotid fat content in healthy adults correlates positively with age and BMI. The rate of aging-related increase in fat contents is gender-dependent. Parotid ADC measurements are strongly influenced by fat saturation.
authors: Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.
authors: Hing-Chiu
authors: HC
authors: Chang
authors: Chun-Jung
authors: CJ
authors: Juan
authors: Hui-Chu
authors: HC
authors: Chiu
authors: Cheng-Chieh
authors: CC
authors: Cheng
authors: Su-Chin
authors: SC
authors: Chiu
authors: Yi-Jui
authors: YJ
authors: Liu
authors: Hsiao-Wen
authors: HW
authors: Chung
authors: Hsian-He
authors: HH
authors: Hsu
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D000367:Age Factors; D000369:Aged, 80 and over; D015992:Body Mass Index; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000033:anatomy & histology*; D011446:Prospective Studies; D012016:Reference Values; D012737:Sex Factors