title: Application of DTI and ARFI imaging in differential diagnosis of parotid tumours.
abstract: OBJECTIVE
  To explore the utility of diffusion tensor imaging (DTI) and acoustic radiation force impulse (ARFI) imaging in the diagnosis of parotid tumours.
  
  
  METHODS
  51 patients with parotid tumours were examined with DTI on 3.0-T MRI and ARFI imaging on an ultrasound scanner before surgery. Values of apparent diffusion coefficient (ADC), fractional anisotropy (FA) and shear-wave velocity (SWV) were calculated and analyzed with independent samples Wilcoxon-Mann-Whitney test. Cut-off values, sensitivity and specificity were calculated with receiver-operating characteristic (ROC) curve analysis. The value of combination was calculated through parallel test for the cut-off value of ADC, FA and SWV (combination = 0 or 1); then, ROC analysis was performed with pathological results as the gold standard to calculate the sensitivity and specificity for the combination of the three parameters distinguishing benign and malignant parotid tumours. Pathological diagnosis for every patient was made post-operatively from the tumour tissue taken during operation.
  
  
  RESULTS
  There was a significant difference between benign and malignant tumours in the values of ADC, FA and SWV (p = 0.032, p = 0.011 and p < 0.0001); a significant difference in the values was also found between pleomorphic adenoma and malignant tumour (p = 0.0012, p < 0.0001 and p = 0.0002). The diagnosis cut-off points between benign and malignant tumours for ADC, FA and SWV were 1.02 × 10(-3) mm(2) s(-1), 0.24 and 2.76 m s(-1), respectively; the sensitivity for ADC, FA and SWV was 87.50, 62.50 and 68.75%; the specificity was 45.71, 82.86 and 97.14%. Analysis of the combination of the three parameters increased the sensitivity, specificity, Youden index and area under the ROC curve compared with analysis of each parameter alone for distinguishing benign and malignant tumours.
  
  
  CONCLUSIONS
  The diagnostic value of the combination of the three parameters for distinguishing benign and malignant parotid tumours is the best; SWV is the preferred indicator. Parameters of DTI and ARFI may reflect the histological characteristics of parotid tumours and predict benignancy and malignancy and could provide quantitative information about the tumour. Combination of DTI with ARFI imaging had obvious advantage for the diagnosis of parotid tumours than each alone.
authors.affiliation: 1 Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China.|2 Traditional Chinese Medical Hospital, Zhangqiu, Shandong, China.
authors.forename: Jinfen
authors.initials: J
authors.lastname: Yu
authors.affiliation: 3 Liaocheng People's Hospital, Liaocheng, Shandong, China.
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Du
authors.affiliation: 2 Traditional Chinese Medical Hospital, Zhangqiu, Shandong, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Lu
authors.affiliation: 4 Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China.
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhang
authors.affiliation: 4 Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Zhang
authors.affiliation: 1 Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China.
authors.forename: Guangbin
authors.initials: G
authors.lastname: Wang
authors.affiliation: 1 Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, China.
authors.forename: Chuanting
authors.initials: C
authors.lastname: Li
mesh_terms: D000235:Adenolymphoma / Q000175:diagnosis / Q000000981:diagnostic imaging; D008949:Adenoma, Pleomorphic / Q000175:diagnosis / Q000000981:diagnostic imaging; D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy / Q000379:methods; D002648:Child; D003937:Diagnosis, Differential; D056324:Diffusion Tensor Imaging / Q000379:methods* / Q000706:statistics & numerical data; D054459:Elasticity Imaging Techniques / Q000379:methods* / Q000706:statistics & numerical data; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010307:Parotid Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D012372:ROC Curve; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: MRI; acoustic radiation force impulse; diffusion tensor imaging; parotid tumour; ultrasound