Imaging strategy for focal nodular hyperplasia in children: long-term experience from two specialist European centres.

BACKGROUND: Focal nodular hyperplasia (FNH) in children is a rare but benign tumour, which must be differentiated from malignant entities to avoid unnecessary treatment, leading to potential morbidity. OBJECTIVES: To provide data on imaging findings of these lesions with a suggested algorithm for diagnosis, sampling and follow-up. MATERIALS AND METHODS: This retrospective review evaluated imaging of all patients diagnosed with FNH in two tertiary referral centres in Europe between 1975 and 2018. RESULTS: One hundred and four patients with 137 tumours were reviewed. The mean age at presentation was 8.2 years. The median tumour size was 5 cm (range: 0.3-29 cm). Multiple lesions were seen in 16.3% of patients. The male-to-female ratio was 1:2. CONCLUSION: FNH with typical features on imaging can be safely followed up once the diagnosis has been established. The use of contrast-enhanced ultrasound and magnetic resonance imaging allows accurate characterisation in most cases. Histological sampling is only advised when there is diagnostic doubt. Atypical arterial enhancement of FNH should prompt the search for a congenital portosystemic shunt.

Sonographic features of umbilical catheter-related complications.

Umbilical catheters are commonly used in the neonatal period for blood sampling or for administering medication or parenteral nutrition. The position of the catheter is usually confirmed with radiography. However, many complications associated with the use of umbilical catheters, such as liver collections from extravasation or vascular thrombosis, are not apparent on radiographs but can be easily diagnosed with ultrasound. This pictorial review illustrates the sonographic findings of complications that should be excluded in the sick neonate with an indwelling catheter.

Biliary atresia: US diagnosis.

PURPOSE: To evaluate prospectively the sensitivity of ultrasonography (US) in the diagnosis of biliary atresia (BA), with surgery as the reference standard. MATERIALS AND METHODS: After institutional ethical approval and with informed parental consent, 90 consecutive fasting infants with conjugated hyperbilirubinemia underwent detailed US studies performed by a single operator with a 7.5-MHz curvilinear transducer and a 13.5-MHz linear-array transducer. The following features were prospectively recorded: gallbladder morphology, triangular cord sign, presence of a common bile duct, liver size and echotexture, splenic appearance, and vascular anatomy. The operator was blinded to results of other investigations. Sensitivity, specificity, and positive and negative predictive values were calculated for each US variable. BA and non-BA groups were compared by means of the Fisher exact test for categorical variables and an unpaired t test for continuous variables. RESULTS: Thirty infants (13 male, 17 female) had surgically confirmed BA, and 60 (35 male, 25 female) had other documented causes of neonatal jaundice; the mean ages at US assessment were 48.5 and 52.4 days, respectively (P>.5). Eight US features showed a significant difference between BA and non-BA groups (P<.001, Fisher exact test). The features with the greatest individual sensitivity and specificity, respectively, in the diagnosis of BA were triangular cord sign (73% and 100%), abnormal gallbladder wall (91% and 95%) and shape (70% and 100%), and an absent common bile duct (93% and 92%). The hepatic artery diameter was significantly larger in infants with BA than in those without BA (mean+/-standard deviation, 2.2 mm+/-0.59 vs 1.6 mm+/-0.40, P<.001), but portal vein diameters were not significantly different. By means of all these US features, 88 of 90 infants were correctly classified as having or not having BA, for an overall accuracy of 98%. CONCLUSION: BA can be distinguished with US from other causes of conjugated hyperbilirubinemia in 98% of infants if multiple US features are carefully evaluated.

Reproducibility of measurements of hepatic artery and portal vein diameter and flow velocity in paediatric liver transplant recipients.

BACKGROUND: Hepatic blood flow is critical for successful liver transplantation. To reliably calculate flow, vessel cross-sectional area and mean flow velocities must be reproducibly measurable. OBJECTIVE: To assess the reproducibility of sonographic measurements of portal vein (PV) and hepatic artery (HA) diameters and mean flow velocities in children after transplantation. MATERIALS AND METHODS: Ten children were scanned by two operators 5 or 7 days after transplantation. Each scanned the same patient twice measuring the diameter and the time-averaged velocity (TAV) in the PV and HA. Operators were blinded to all measurements. Agreement and repeatability were analysed statistically. RESULTS: The interobserver variation in PV and HA diameters and TAVs were expressed as mean differences between operators and plotted against the mean value for each. This showed relatively poor agreement for PV diameter (mean difference 1.23 +/- 0.96 mm), but better agreement for HA diameter (mean difference 0.18 +/- 0.6 mm). Intraobserver differences were of similar magnitude. TAVs showed better agreement and repeatability. CONCLUSION: This study demonstrates substantial inter- and intraobserver variation in sonographic measurements of vessel diameters and TAV after paediatric liver transplantation. Estimates of volume of blood flow to the transplant derived from these measurements are poorly reproducible.