Ultrasound-guided Liver Biopsies in Children: A Single-center Experience and Risk Factors for Minor Bleeding.

OBJECTIVES: The aim of the study was to analyze the institution's experience in ultrasound-guided liver biopsies performed on children and identify risk factors for complications, following a previous study performed in our institution. METHODS: Retrospective analysis of a consecutive series of ultrasound-guided pediatric liver biopsies, between 2011 and 2016. Demographic and anthropometric data, biopsy indications, international normalized ratio (INR) and platelet count, biopsy technique, complications, and pathologic outcomes were recorded. RESULTS: A total of 228 procedures were performed on 203 children with a median age of 9.25 years (range: 0.08-18.42): 107 girls (47%) and 121 boys (53%). One hundred twenty-seven biopsies were performed on transplanted livers (55.7%) and 101 on native livers (44.3%). There were 27 cases with immediate complications (11.84%), all due to minor bleeding. There were no major complications. Increasing needle passes were shown to be a reliable predictor for bleeding (P = 0.0023), whereas transplanted livers predicted protection against bleeding (P = 0.0007). Age younger than 3 years, bodyweight <16 kg, platelet count <70 g/L and INR >1.25 revealed association with increased bleeding incidence, but no predictive value. CONCLUSION: Ultrasound-guided liver biopsies in pediatric age are a safe procedure with a high diagnostic yield. Increasing the number of needle passes predicts a higher incidence of minor bleeding. Other factors to account for minor bleeding risk may include age younger than 3 years, bodyweight <16 kg, platelet count <70 G/L, and INR >1.25. Transplanted livers present a lower bleeding risk.

Acoustic radiation force impulse imaging in paediatric patients: normal liver values.

OBJECTIVES: The objective of this study was to obtain a normal value for liver shear wave velocities (SWVs) in healthy paediatric patients and to investigate variations concerning age, sex, and different approaches, depths, and lobes of measurements. METHODS: A total of 150 healthy children (2 months-17 years) were examined with acoustic radiation force impulse (ARFI) technology by an experienced paediatric radiologist, after receiving an informed consent. Measurements obtained were divided according to group age (n = 50, 0-5 years; n = 50, 6-11 years; n = 50, 12-17 years); sex (male-female); lobe (right-left lobe); approach (intercostal-subcostal), and depth of measurements (1-5 and 5-6 cm for the youngest group; 2-6 to 6-8 cm for the 2 other groups). Comparative analyses were performed with measurements obtained at right and left lobes, with different depths and approaches. Differences between age and sex were also analysed. RESULTS: Mean SWV in the right liver lobe was 1.07 ± 0.10 m/s. No significant differences were found according to sex or among different probe locations. SWVs were, however, significantly higher within left lobe in comparison with right liver lobe (1.07 ± 0.10 m/s, right; 1.21 ± 0.16 m/s, left). Depth of measurements also influenced SWV values obtained, being slightly lower at deeper locations. Regarding the age significant differences were found for children <6 years old compared with other age groups. CONCLUSIONS: ARFI analysis seems to be influenced by age, depth, and lobe of measurements. A mean SWV value of 1.07 ± 0.10 m/s for healthy paediatric population with the possibility of reaching 1.12 m/s in the case of younger children was found. ARFI values were more consistently obtained analysing right liver lobe and depths lower than 5 to 6 cm.

Comparison of acoustic radiation force impulse/serum noninvasive markers for fibrosis prediction in liver transplant.

OBJECTIVES: Fibrosis, related to several causes, can be diagnosed in children and adolescents' liver grafts that are >1 year old. At present, liver biopsy is the gold standard for assessing liver damage in the posttransplant setting. We aimed to evaluate the accuracy of noninvasive biomarkers of fibrosis, namely, acoustic radiation force impulse (ARFI), aspartate-to-platelet ratio index, and aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio index, either alone or in combination, for predicting fibrosis in pediatric patients submitted to liver transplantation. METHODS: We prospectively assessed liver fibrosis in 30 children/adolescents with liver transplant through biopsy (liver transplant follow-up during 12 months). ARFI with Virtual Touch Software (Acuson 2000) was performed, and blood samples were taken to determine liver function and platelet count. Two groups were analyzed according to the histopathologic stage of fibrosis, namely, none/mild (F0-F1) versus significant fibrosis (F2-4). RESULTS: The mean age of the 30 patients was 11 years (3-18 years), with a mean posttransplant period of assessment of 6.5 years. Twenty-four patients (80%) presented stage F0-F1 fibrosis and 6 patients (20%) presented stage F2-4. The area under the curve using receiver operating characteristic analysis for ARFI, aspartate-to-platelet ratio index, and AST/ALT ratio index for significant fibrosis was 0.76 (P = 0.052), 0.74 (P = 0.066), and 0.69 (P = 0.162), respectively. Through multivariate logistic regression analysis, the only independent predictor of significant fibrosis was ARFI (odds ratio 10.7, 95% confidence interval 1.2-95.7; P = 0.045). The combination of ARFI and AST/ALT ratio index presented a good diagnostic accuracy of fibrosis (area under the curve of 0.83; P = 0.013). CONCLUSIONS: ARFI may serve as a potential method for assessing significant fibrosis in pediatric patients with liver transplant, particularly in combination with AST/ALT ratio index.