ABSTRACT
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 1.16âm/sec (SD ±â0.14âm/sec). Neither age (pâ=â0.533) nor depth of measurement (pâ=â0.066) had no significant influence on ARFI values, whereas a significant effect of gender was found with lower ARFI values in females (pâ=â0.025), however, there was no significant interaction between age groups (before or after puberty) and gender (pâ=â0.276). There was an interlobar difference with lower values in the right liver lobe compared to the left (pâ=â0.036) and with a significantly lower variance (pâ<â0.001). Consistend values were measured by different examiners (pâ=â0.108), however, the inter examiner variance deviated significantly (pâ<â0.001). 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 1.16âm/sec (±â0.14âm/sec) allows a differentiation of healthy versus pathological liver tissue.
Subject(s)
Elasticity Imaging Techniques/methods , Elasticity Imaging Techniques/standards , Liver/diagnostic imaging , Adolescent , Age Factors , Child , Child, Preschool , Female , Humans , Infant , Liver Cirrhosis/diagnostic imaging , Male , Predictive Value of Tests , Reference ValuesABSTRACT
PURPOSE: Handling children with trauma is often very difficult, as the signs and the exact location of the fracture are sometimes unclear. The aim of this study was to compare ultrasound and X-ray for the identification of fractures. MATERIALS AND METHODS: In this study 653 patients from newborn to 17 years old (mean age 4.4 years) with nonspecific clinical signs or clinically indistinct fracture location were examined initially with ultrasound. After identification of the fracture by ultrasound, an X-ray exam of the predefined region followed. In cases of negative ultrasound an X-ray exam was performed not focused on a predefined region. RESULTS: Examinations of 726 parts of the body revealed 308 fractures. 266 fractures were identified by both ultrasound and X-ray, 20 exclusively by ultrasound, 21 exclusively by X-ray. One maxillary fracture was missed. The sensitivity was 92.9% for ultrasound and 93.2% for X-ray, and the specificity was 99.5% (ultrasound) and 99.8% (X-ray). Ultrasound was superior to X-ray on the clavicle, but the opposite was true in the lower limb. In 8.4% of the patients ultrasound helped us to reduce the number of X-rays. CONCLUSION: Ultrasound is comparable to X-ray for the detection of fractures. Ultrasound should be the first imaging method in children with trauma and nonspecific clinical signs or indistinct location of pain, followed by X-ray exams of the predefined region.
