Quantitative Evaluation of Neonatal Brain Elasticity Using Shear Wave Elastography.

OBJECTIVES: To demonstrate the feasibility of 2-dimensional brain ultrasound shear wave elastography (SWE) and to define the average elasticity values of the gray and white matter in term neonates. METHODS: This work was a prospective observational single-center study including 55 healthy term neonates consecutively recruited in the maternity ward between the second and third postnatal days. All were successfully evaluated with a cerebral SWE examination performed with a multifrequency 4-9-MHz transducer. Bilateral sagittal planes of the thalamus and corona radiata were used to measure stiffness using a quantitative SWE method. Several elastograms with 5 to 15 nonoverlapping areas were obtained from the 2 different anatomic locations. The 5 most central measurements were averaged as representative values. RESULTS: The 55 neonates ranged from 37 to 40 weeks' gestation. The estimated mean velocity values of the thalamus (1.17 m/s; 95% confidence interval, 1.13, 1.22 m/s) and corona radiata (1.60 m/s; 95% confidence interval, 1.57, 1.64 m/s) were statistically different (P < .001). There was no significant influence of laterality, gestational age, cephalic perimeter, sex, length, or type of delivery on the stiffness measurements. CONCLUSIONS: Brain ultrasound SWE is feasible and allows measurements of neonatal brain elasticity. The elasticity of the thalamus and corona radiata at the frontal white matter in healthy term neonates is different. The knowledge of normal SWE ranges in term neonates allows comparative studies under pathologic conditions.

Tracheobronchomegaly following intrauterine tracheal occlusion for congenital diaphragmatic hernia.

BACKGROUND: Fetuses with severe congenital diaphragmatic hernia (CDH) and pulmonary hypoplasia may benefit from fetal endoluminal tracheal occlusion (FETO). Enlargement of the main bronchi and trachea appears to be a common complication of FETO. OBJECTIVE: To retrospectively evaluate the trachea and main bronchi of infants who underwent FETO for CDH and compare diameters with age-matched references. MATERIAL AND METHODS: Postnatal and follow-up chest radiographs were performed in seven children with unilateral CDH treated by FETO. Additional CT was performed in six of these (one neonate died before CT could be performed). Images were acquired from 3 days to 23 months of age. For each child, radiographs and CT images with optimal visualisation of the airways were selected for retrospective analysis. Tracheal and bronchial morphology was assessed by two experienced paediatric radiologists, and the diameters of these structures measured and compared with age-matched references. RESULTS: Mean diameters of the trachea and main bronchi were above the age-matched normal range in all patients, regardless of the side of the hernia or the degree of lung hypoplasia. CONCLUSION: Enlargement of the trachea and main bronchi appears following FETO and persists at least to the age of 5 years.

White hemithorax in children.

The aim of this pictorial review is to introduce the radiologist to the differential diagnosis of a white hemithorax in children, to provide significant information on the diagnostic work-up, and to promote radiation-free techniques whenever possible. There are many causes of white hemithorax in children and it can be due to a variety of chest disorders. In most cases, plain chest radiographs and ultrasound will suffice. However, additional information provided by, e.g., CT or MRI is sometimes required.

Extrarenal rhabdoid tumours outside the central nervous system in infancy.

BACKGROUND: Malignant rhabdoid tumours (RT) are increasingly recognized in young children, probably as a consequence of advances in accurate histological diagnosis rather than a true increase in frequency. Although typically presenting as renal tumours in infancy, extrarenal tumours outside the central nervous system (CNS) in children less than 12 months of age are now well recognized, but previous literature on their imaging features is very limited. OBJECTIVE: To demonstrate the imaging features of extrarenal RTs outside the CNS. MATERIALS AND METHODS: A retrospective database review was made from 1989 to 2007 of patients diagnosed with extrarenal RT in infancy, i.e. below 12 months of age. RESULTS: There were nine patients (six boys and three girls). The age at presentation varied from 1 to 11 months (average 6 months). Tumours were located in the thorax/mediastinum (n=3), liver (n=3), neck (n=1), shoulder (n=1) and axilla (n=1). The imaging modalities used included US (n=8), CT (n=7) and MRI (n=6). Bone scan was positive in one patient, while metastases at the time of diagnosis occurred in four patients. On MRI the tumours tended to show nonspecific hypointensity on T1-W images and heterogeneous hyperintensity on T2-W images, with heterogeneous enhancement. CONCLUSION: This is the largest radiological series of extrarenal RTs outside the CNS in infancy. In our series no imaging features were found specific to the diagnosis. A tendency towards large size and mediastinal/paravertebral location were noted. A hypodense solid component on CT and a heterogeneous hyperintensity on T2-W MR images suggest that this tumour should be considered in the routine differential diagnosis of soft-tissue tumours in infancy, in addition to rhabdomyosarcoma.