title: Acoustic Radiation Force Impulse and Doppler Ultrasonography: Comprehensive Evaluation of Acute Rejection After Liver Transplantation.
abstract: OBJECTIVE
  The aim of our study was to evaluate the clinical application of color Doppler flow imaging (CDFI) and acoustic radiation force impulse (ARFI) for the diagnosis of acute rejection after liver transplantation.
  
  
  METHODS
  B-Mode CDFI and ARFI assessments were performed in 76 patients who underwent biopsy after liver transplantation at our institution, between October 2011 and October 2014. The study group included 56 patients with acute rejection confirmed by biopsy, with 20 patients whose liver function recovered within 1 month of transplantation forming the control group. Anteroposterior diameter of the liver, hemodynamic index (consisting of the portal vein diameter, portal vein flow velocity, and hepatic vein flow waveform), and ARFI shear wave velocity (SWV) were measured. We used logistic regression modeling and receiver operating curve to evaluate between-group differences.
  
  
  RESULTS
  Compared with the control group, patients with acute rejection exhibited increased anteroposterior diameter (P = .035) and change in hemodynamic index (P = .021), including increased portal vein diameter, decreased portal vein flow, and loss of triphasic waveform of hepatic vein flow. Acoustic radiation force impulse SWV was markedly increased in the acute rejection group (P < .001). The correlation r-value of measured parameters to acute rejection diagnosis was 0.253 for anterioposterior diameters, 0.271 for change in hemodynamic index, and 0.721 for increased SWV. Shear wave velocity and change in the hemodynamic index had diagnostic value, with an area under the receiver operating curve of 0.933.
  
  
  CONCLUSIONS
  Combining CDFI with ARFI was useful for the diagnosis of acute rejection after liver transplantation.
authors.affiliation: Department of Ultrasound, Tianjin First Center Hospital, Tianjin, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Ultrasound, Tianjin First Center Hospital, Tianjin, China.
authors.forename: Jingwen
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Ultrasound, Tianjin First Center Hospital, Tianjin, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Ultrasound, Tianjin First Center Hospital, Tianjin, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Ultrasound, Tianjin First Center Hospital, Tianjin, China.
authors.forename: Ningning
authors.initials: N
authors.lastname: Niu
mesh_terms: D000208:Acute Disease; D000328:Adult; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006084:Graft Rejection / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000473:pathology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008099:Liver / Q000000981:diagnostic imaging* / Q000473:pathology; D016031:Liver Transplantation / Q000009:adverse effects*; D008297:Male; D064847:Multimodal Imaging / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler / Q000379:methods*
keywords: acoustic radiation force impulse; acute rejection; color Doppler flow imaging; liver transplantation; logistic regression