Standard value of ultrasound elastography using acoustic radiation force impulse imaging (ARFI) in healthy liver tissue of children and adolescents.

PURPOSE: Ultrasound elastography by acoustic radiation force impulse imaging (ARFI) is used in adults for non invasive measurement of liver stiffness, indicating liver diseases like fibrosis. To establish ARFI in children and adolescents we determined standard values of healthy liver tissue and analysed potentially influencing factors. MATERIALS AND METHODS: 132 patients between 0 and 17 years old were measured using ARFI. None of them had any liver disease or any other disease that could affect the liver secondarily. All patients had a normal ultrasound scan, a normal BMI and normal liver function tests. The mean value of all ARFI measurements was calculated and potentially influencing factors were analysed. RESULTS: The mean value of all ARFI elastography measurements was 1.16 m/sec (SD ±â€Š0.14 m/sec). Neither age (p = 0.533) nor depth of measurement (p = 0.066) had no significant influence on ARFI values, whereas a significant effect of gender was found with lower ARFI values in females (p = 0.025), however, there was no significant interaction between age groups (before or after puberty) and gender (p = 0.276). There was an interlobar difference with lower values in the right liver lobe compared to the left (p = 0.036) and with a significantly lower variance (p < 0.001). Consistend values were measured by different examiners (p = 0.108), however, the inter examiner variance deviated significantly (p < 0.001). CONCLUSION: ARFI elastography is a reliable method to measure liver stiffness in children and adolescents. In relation to studies which analyse liver diseases, the standard value of 1.16 m/sec (±â€Š0.14 m/sec) allows a differentiation of healthy versus pathological liver tissue.

Application of ultrasound in callus distraction of the hypoplastic mandible: an additional method for the follow-up.

Mandibular callus distraction was performed on 14 patients. In addition to established radiological methods, sonography was performed to monitor the clinical progress. Ultrasound shows a precise picture of all interesting items in distraction treatment. Although the value of radiographs is not obsolete completely, sonography was found to be a meaningful supplement in the clinical monitoring of callus distraction. Furthermore the method is capable of early recognition of complications and it can reduce X-ray exposure.