title: Effects of regions of interest methods on apparent coefficient measurement of the parotid gland in early Sjögren's syndrome at 3T MRI.
abstract: BACKGROUND
  The apparent diffusion coefficient (ADC) has been used to assess parotid gland abnormalities in Sjögren's syndrome (SS) patients; however, few data exist on the influence of region of interest (ROI) methods on ADC measurements.
  
  
  OBJECTIVE
  To assess the influence of ROI methods on ADC measurement, and their diagnostic ability in detecting parotid gland abnormalities in early SS patients.
  
  
  METHODS
  Thirteen early SS patients underwent parotid gland diffusion-weighted imaging scans at a 3.0 T MR unit. Two readers independently measured the parotid gland ADC value using three different ROIs (whole-gland [WG], single-slice [SS], and reader-based circular [RBC]). The ADC value based on three different ROIs (ADC-ROIWG, ADC-ROISS, ADC-ROIRBC) were compared between the SS group and a matched healthy control (HC) group (n = 19). Receiver operating characteristic (ROC) curves and intra-class correlation coefficients (ICC) were used to determine the diagnostic ability and reproducibility of the parameters.
  
  
  RESULTS
  The ADC-ROIWG, ADC-ROISS, and ADC-ROIRBCin the SS group were all significantly higher than those in HC group (all P < 0.05). The ADC-ROIWGshowed better diagnostic ability than did ADC-ROIRBC(P = 0.0200), while no significant difference was found between ADC-ROIWGand ADC-ROISS(P = 0.4636). The ROIWGmethod showed the best inter- and intra-reader agreement (ICC, 0.902 and 0.928, respectively), followed by ROISSand ROIRBC.
  
  
  CONCLUSIONS
  The ROI methods can influence the parotid gland ADC measurements and their diagnostic ability. Considering our results, we suggest using in clinical practice single-slice ROIs to measure the ADC of the parotid gland.
authors.affiliation: Department of Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China.
authors.forename: Xiaoquan
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China.
authors.forename: Guoyi
authors.initials: G
authors.lastname: Su
authors.affiliation: Department of Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China.
authors.forename: Hao
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Rheumatology, First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China.
authors.forename: Xunning
authors.initials: X
authors.lastname: Hong
authors.affiliation: Department of Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China.
authors.forename: Haibin
authors.initials: H
authors.lastname: Shi
authors.affiliation: Department of Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, PR China wfy_njmu@163.com.
authors.forename: Feiyun
authors.initials: F
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010306:Parotid Gland / Q000000981:diagnostic imaging*; D010309:Parotitis / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012859:Sjogren's Syndrome / Q000000981:diagnostic imaging*
keywords: Magnetic resonance imaging (MRI); Sjögren’s syndrome; apparent diffusion coefficient (ADC); diffusion-weighted imaging (DWI); parotid gland; region of interest