title: Accuracy of computer-aided ultrasound as compared with magnetic resonance imaging in the evaluation of nonalcoholic fatty liver disease in obese and eutrophic adolescents.
abstract: OBJECTIVE
  To compare the accuracy of computer-aided ultrasound (US) and magnetic resonance imaging (MRI) by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD) in adolescents.
  
  
  METHODS
  This prospective, cross-sectional study evaluated 50 adolescents (aged 11-17 years), including 24 obese and 26 eutrophic individuals. All adolescents underwent computer-aided US, MRI, laboratory tests, and anthropometric evaluation. Sensitivity, specificity, positive and negative predictive values and accuracy were evaluated for both imaging methods, with subsequent generation of the receiver operating characteristic (ROC) curve and calculation of the area under the ROC curve to determine the most appropriate cutoff point for the hepatorenal gradient in order to predict the degree of steatosis, utilizing MRI results as the gold-standard.
  
  
  RESULTS
  The obese group included 29.2% girls and 70.8% boys, and the eutrophic group, 69.2% girls and 30.8% boys. The prevalence of NAFLD corresponded to 19.2% for the eutrophic group and 83% for the obese group. The ROC curve generated for the hepatorenal gradient with a cutoff point of 13 presented 100% sensitivity and 100% specificity. As the same cutoff point was considered for the eutrophic group, false-positive results were observed in 9.5% of cases (90.5% specificity) and false-negative results in 0% (100% sensitivity).
  
  
  CONCLUSIONS
  Computer-aided US with hepatorenal gradient calculation is a simple and noninvasive technique for semiquantitative evaluation of hepatic echogenicity and could be useful in the follow-up of adolescents with NAFLD, population screening for this disease as well as for clinical studies.
authors.affiliation: PhD, MD, Radiologist and Teacher at Instituto Cenecista de Ensino Superior de Santo Ângelo (IESA), Santo Ângelo, RS, Brazil.
authors.forename: José Hermes Ribas
authors.initials: JH
authors.lastname: do Nascimento
authors.affiliation: PhD, Neuroradiologist at Instituto do Cérebro - Pontifícia Universidade Católica do Rio Grande do Sul (InsCer-PUCRS), Porto Alegre, RS, Brazil.
authors.forename: Ricardo Bernardi
authors.initials: RB
authors.lastname: Soder
authors.affiliation: PhD, Coordinator for Pediatrics Internship, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil.
authors.forename: Matias
authors.initials: M
authors.lastname: Epifanio
authors.affiliation: PhD, Coordinator for the Imaging Center of Instituto do Cérebro - Pontifícia Universidade Católica do Rio Grande do Sul (InsCer-PUCRS), Porto Alegre, RS, Brazil.
authors.forename: Matteo
authors.initials: M
authors.lastname: Baldisserotto
keywords: Adolescents; Obesity; Steatosis; Ultrasound