Non-invasive diagnosis of non-alcoholic fatty liver disease in children: role of shear-wave elastography and steatometry

Abstract

Background. The ability of certain forms of non-alcoholic fatty liver disease (NAFLD), namely non-alcoholic steatohepatitis (NASH), to rapid progression and the formation of advanced liver fibrosis and cirrhosis raises the need for early diagnosis of NAFLD, long-term monitoring, timely therapeutic intervention already in the childhood. Routine grey scale ultrasound is currently considered unsuitable for screening of children for NAFLD due to the low level of sensitivity and specificity in detecting the initial stages of steatosis, significant subjectivity of visual assessment, so innovative methods of visualization with the possibility of quantitative assessment of liver fibrosis and steatosis have taken the lead in recent years. The purpose of the study: to determine the diagnostic value of sonographic markers obtained by 2D shear wave elastography and hepatic steatometry in NAFLD in children compared to the data of transient elastography. Materials and methods. The study included 170 children aged 6 to 17 years. The mean age of the patients was 12.15 ± 2.51 years. The presence of hepatic steatosis was determined by transient elastography (Fibroscan®, Echosens, France) with the measurement of a controlled attenuation parameter. According to the presence of steatosis, steatohepatitis, and obesity, patients were divided into 4 groups: group 1 — 37 children with NASH and obesity, group 2 — 53 people with simple steatosis and obesity, group 3 — 65 children with obesity without steatosis, group 4 (control) consisted of 15 individuals with normal weight without steatosis. The liver parenchyma stiffness was assessed by multidimensional shear wave elastography (2D-SWE) using an ultrasound system Soneus P7 (Ultrasign, Ukraine-Switzerland) in real time. Liver steatometry with the determination of the ultrasound attenuation coefficient (UAC) was performed using an ultrasound scanner Soneus P7 (Ultrasign, Ukraine-Switzerland). To evaluate the diagnostic accuracy of the threshold values, receiver operating characteristic (ROC) analysis was conducted with the determination of the area under the ROC curve (AUC). Results. The average values of UAC in children of groups 1 and 2 were 2.19 [1.99; 2.33] and 2.18 [2.04; 2.33] dB/cm, respectively, which significantly distinguished them from patients of groups 3 and 4. The median value of the liver parenchyma stiffness in children with NASH was 5.61 [5.14; 6.51] kPa that significantly distinguished these patients from those of groups 2–4 (p < 0.05). Comparison of steatometry and 2D-SWE results with transient elastography data using ROC analysis showed high performance (AUC 0.789, p < 0.0001) of the threshold value of UAC 2.03 dB/cm for the diagnosis of NAFLD (sensitivity 83.3 %, specificity 62.9 %), the highest level of performance (AUC 0.907, p < 0.0001) of the threshold value of the liver parenchyma stiffness 5.28 kPa for the diagnosis of NASH (sensiti­vity 84.6 %, specificity 77.1 %). Conclusions. Modern ultrasound-associated imaging techniques — steatometry and multidimensio­nal shear wave elastography — demonstrate high levels of sensiti­vity, specificity, and performance in the diagnosis of hepatic steatosis and fibrosis; therefore, within the framework of multiparametric ultrasound examination, they can be used for screening diagnosis of NAFLD and differential diagnosis of simple steatosis and NASH.

Keywords

• ultrasound attenuation coefficient
• shear wave elastography
• non-alcoholic fatty liver disease
• children