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

ObjectiveTo 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.Materials and MethodsThis 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.ResultsThe 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).ConclusionComputer-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.

Imaging evaluation in metabolic syndrome: beyond steatosis

“…Specifically in cases of steatosis, imaging methods play an important role, as demonstrated by the study developed by Cruz et al ( 12 ) , published in the present issue of Radiologia Brasileira . In such study, the authors have found that the prevalence of liver steatosis in patients referred to undergo abdominal ultrasonography (US) in Aracaju, SE, Brazil, was 29.1% - similar to the prevalence observed in the international literature -, which brings in an interesting discussion on the matter and demonstrates the value of US for initial, noninvasive detection of NAFLD and qualitative grading of steatosis ( 3 , 4 , 6 , 12 ) .…”

“…The Brazilian radiological literature has recently been quite concerned with the relevance of imaging methods in the investigation of liver diseases ( 6 , 11 ) . Specifically in cases of steatosis, imaging methods play an important role, as demonstrated by the study developed by Cruz et al ( 12 ) , published in the present issue of Radiologia Brasileira .…”

Doença Hepática Gordurosa Não Alcoólica: um problema global de caráter reversível

“…O TNF-α induz o recrutamento de células inflamatórias da resposta inata que podem promover a morte celular dos hepatócitos, enquanto a Resistina inibe o transporte de ácidos graxos do tecido adiposo para os hepatócitos, reduzindo a deposição de lipídios neste órgão 15 . Quando existe uma elevada concentração de TNF-α, a Resistina é reduzida, favorecendo a evolução da esteatose, da Doença Hepática Gordurosa Não Alcoólica, da cirrose e do carcinoma 13,15,20 .…”

“…Schild et al 21 O diagnóstico da Doença Hepática Gordurosa Não Alcoólica pode ser feito por meio de exames; entre eles, o mais eficaz e de menor custo é a ultrassonografia abdominal ou a ecografia, que define o grau da doença, porém apresenta limitações visto que, em alguns casos não identifica a cirrose 20,23,24 . A partir de tal exame, adotam-se as classificações de esteatose hepática grau 1 (leve), grau 2 (moderado) e grau 3 (grave) 13 .…”

“…Os exames sanguíneos avaliam os teores das aminotransferases que são importantes marcadores de lesão hepática. O aumento das enzimas alanina aminotransferase (ALT) e aspartato aminotransferase (AST) pode indicar uma lesão no fígado; porém, em alguns casos, permanece com teores normais mesmo em condições de doenças hepáticas 11,20,24 . Um dos fatores que auxiliam na reversão do quadro de Doença Hepática Gordurosa Não Alcoólica é a redução do peso corporal, visto que alguns pacientes com obesidade mórbida ou com um elevado Índice de Massa Corporal (≥35 kg/m 2 ), ao se submeterem a cirurgias bariátricas apresentaram uma melhora significativa de seu quadro clínico 7,21,26 .…”