title: Acoustic radiation force impulse (ARFI) elastography compared with biopsy for evaluating hepatic fibrosis after liver transplantation: a cross-sectional diagnostic study.
abstract: Biopsies are used after liver transplantation to evaluate fibrosis. This study aimed to evaluate the elasticity of transplanted livers by means of a non-invasive examination, acoustic radiation force imaging (ARFI) elastography, correlating the results with the histological analysis.
  Cross-sectional study in a public university hospital.
  All patients consecutively operated between 2002 and 2010 with an indication for biopsy were evaluated by means of elastography. The radiologist evaluating ARFI and the pathologist doing anatomopathological examinations were blinded to each other's evaluations.
  During the study period, 33 patients were included. The indication for transplantation was cirrhosis due to hepatitis C in 21 cases (63%). Liver biopsies showed absence of fibrosis (F0) in 10 patients, F1 in 11, F2 in 8 and F3 in 4. There were no cases of F4 (cirrhosis). The difference in ARFI values (degree of fibrosis) was 0.26 (95% confidence interval, CI: 0.07-0.52) between the groups F0-F1 and F2-F4 (P = 0.04). An area under the curve of 0.74 (CI: 0.55-0.94) and a cutoff of 1.29 m/s between the groups resulted in the best relationship between sensitivity and specificity. Sensitivity (0.66; CI: 0.50-0.83) was lower than specificity (0.85; CI: 0.72-0.97). There was no significant difference in ARFI between patients with hepatitis C and those with other diseases.
  The values obtained from elastography were not affected by inflammatory reaction or anatomical alterations. A cutoff point of 1.29 m/s separating patients with or without significant fibrosis was identified.
authors.affiliation: MD. Researcher, Instituto de Radiologia (InRad), Hospital das Clínicas (HC), Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, SP, Brazil.
authors.forename: Joel
authors.initials: J
authors.lastname: Schmillevitch
authors.affiliation: MD, PhD. Director, Ultrasonography Service, Instituto de Radiologia (InRad), Hospital das Clínicas (HC), Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo (SP), Brazil.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Chammas
authors.affiliation: MD, PhD. Attending Physician, Liver and Digestive System Organ Transplantation Division, Hospital das Clínicas (HC), Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo (SP), Brazil.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Pugliese
authors.affiliation: MD, PhD. Professor, Department of Infectious and Parasitic Diseases, Hospital das Clínicas (HC), Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo (SP), Brazil.
authors.forename: Edson
authors.initials: E
authors.lastname: Abdala
authors.affiliation: Nurse, Coordinator of the Liver and Digestive System Organ Transplantation Division, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo (SP), Brazil.
authors.forename: Adriana Cortez
authors.initials: AC
authors.lastname: Rizzon
authors.affiliation: MD, PhD. Titular Professor, Department of Pathology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo (SP), Brazil.
authors.forename: Venâncio
authors.initials: V
authors.lastname: Alves
authors.affiliation: MD, PhD. Titular Professor and Director, Liver and Digestive System Organ Transplantation Division, Hospital das Clínicas (HC), Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo (SP), Brazil.
authors.forename: Luiz Augusto
authors.initials: LA
authors.lastname: Carneiro
authors.affiliation: MD, PhD. Titular Professor, Department of Radiology, Universidade de São Paulo (FMUSP), São Paulo (SP), Brazil.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cerri
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy / Q000379:methods*; D003430:Cross-Sectional Studies; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology*; D016031:Liver Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D055815:Young Adult