Robin Azoulay

Ultrasonography of Crohn disease in children.

US is increasingly performed in Crohn disease (CD) in children as a first line imaging modality. It reduces the use of other more invasive examinations such as endoscopy, CT or contrast enema. We describe bowel ultrasonography technique, normal bowel appearances on US and pathological patterns in CD. We discuss the current role and limitations of bowel US in CD in children including diagnosis, extent of disease, assessment of disease activity, follow-up and detection of complications. The diagnostic accuracy of US is discussed according to the literature and compared to other imaging modalities. US is currently used for screening in children with the suspicion of inflammatory bowel disease (IBD) with a good negative predictive value. In follow-up, US has a role in monitoring medical treatment by evaluating disease activity, extent of disease and for detecting complications.

Brain iron levels in attention-deficit/hyperactivity disorder: a pilot MRI study.

Abstract Objective. Brain iron deficiency has been supposed to be involved in the pathophysiology of ADHD. Available studies assessing iron in ADHD are based on serum ferritin, a peripheral marker of iron status. To what extent serum ferritin correlates with brain iron (BI) is unclear. The main aim of this study was to compare BI, estimated with magnetic resonance imaging (MRI) in the putamen, pallidum, caudate, and thalamus, between children with and without ADHD. The secondary aim was to assess the correlation between serum ferritin and BI levels. Methods. Thirty-six children (18 with and 18 without ADHD, the latter including nine healthy controls and nine psychiatric controls) completed MRI and blood sampling. Brain iron levels were estimated by imaging T2*. Results. Children with ADHD showed significantly lower estimated BI in right and left thalamus compared to healthy controls. Estimated BI did not differ significantly between children with ADHD and psychiatric controls. Children with ADHD had significantly lower levels of serum ferritin than healthy as well as psychiatric controls. Serum ferritin and T2* values did not correlate significantly in most regions. Conclusions. Low iron in the thalamus may contribute to ADHD pathophysiology.

Renal transplantation in children: Critical analysis of age related surgical complications

Irtan S, Maisin A, Baudouin V, Nivoche Y, Azoulay R, Jacqz‐Aigrain E, El Ghoneimi A, Aigrain Y. Renal transplantation in children: Critical analysis of age related surgical complications.
Pediatr Transplantation 2010: 14:512–519.

Reliability of cervical lordosis and global sagittal spinal balance measurements in adolescent idiopathic scoliosis

Study designRadiological reproducibility study.PurposeTo assess intra and interobserver reliability of radiographic measurements for global sagittal balance parameters and sagittal spine curves, including cervical spine.Summary of background dataSagittal spine balance in adolescent idiopathic scoliosis (AIS) is a main issue and many studies have been reported, showing that coronal and sagittal deformities often involve sagittal cervical unbalance. Global sagittal balance aims to obtain a horizontal gaze and gravity line at top of hips when subject is in a static position, involving adjustment of each spine curvature in the sagittal plane. To our knowledge, no study did use a methodologically validated imaging analysis tool able to appreciate sagittal spine contours and distances in AIS and especially in the cervical region.MethodsLateral full-spine low-dose EOS radiographs were performed in 75 patients divided in three groups (control subjects, AIS, operated AIS). Three observers digitally analyzed twice each radiograph and 11 sagittal measures were collected for each image. Reliability was assessed calculating intraobserver Pearson’s r correlation coefficient, interobserver intra-class correlation coefficient (ICC) completed with a two-by-two Bland–Altman plot analysis.ResultsThis measurement method has shown excellent intra and interobserver reliability in all parameters, sagittal curvatures, pelvic parameters and global sagittal balance.ConclusionsThis study validated a simple and efficient tool in AIS sagittal contour analysis. It defined new relevant landmarks allowing to characterize cervical segmental curvatures and cervical involvement in global balance.

USPIO (Ferumoxtran-10)-enhanced MRI to visualize reticuloendothelial system cells in neonatal rats: feasibility and biodistribution study.

To investigate whether USPIO‐enhanced magnetic resonance imaging (MRI) detected reticuloendothelial system (RES) cells in newborn normal rats.

Renal parenchymal fibrosis and atrophy are not correlated with upper tract dilatation: Long-term study of partial unilateral ureteral obstruction in neonatal mice

PURPOSE The mechanism underlying the evolution of congenital obstructive hydronephrosis is still unclear. In a previous study, we have shown that it is possible to create renal lesions in newborn mice specific to partial ureteral obstruction. We aimed to study the long-term results of such partial obstruction. METHODS Mice were operated on the third day of life. We created 2 groups: partial unilateral obstruction and control. We studied antero-posterior pelvis diameter, kidney length and volume on magnetic resonance imaging at day 10 and 3 months. We assessed ureteric patency by injecting Patent Blue dye. Kidney weight and fibrosis were histologically assessed. Fibrosis was assessed using Sirius Red staining and morphometry. RESULTS Imaging showed parenchymal atrophy in the partially obstructed kidney and compensatory hypertrophy of the contralateral kidney. Pelvis dilatation was detected at day 10 but remained stable without significant increase at 3 months. The patency test confirmed the absence of total obstruction in the long term. There was no correlation between the degree of dilatation and parenchymal atrophy or the contralateral hypertrophy. Pathological studies at 3 months revealed fibrosis in the parenchyma without significant correlation with pelvis dilatation. CONCLUSIONS Long-term results confirmed that partial ureteral obstruction in newborn mice produces fibrotic lesions of the renal parenchyma, which are not correlated with dilatation of the upper tract. These results could contribute to the clinical management of obstructive uropathy in children, emphasizing that follow up with simple evaluation of upper tract dilatation is insufficient to predict renal deterioration.

Partial Unilateral Ureteral Obstruction in Newborn Mice: Magnetic Resonance Imaging and Pathology Studies

PURPOSE The mechanism underlying the evolution of congenital obstructive hydronephrosis in humans is still unclear. Although partial unilateral ureteral obstruction has been extensively explored in rats, studies in neonatal mice may lead to new insights into underlying cellular mechanisms, especially with the availability of mutant mice. We developed a model of partial unilateral ureteral obstruction in newborn mice. MATERIALS AND METHODS Mice were operated on by the fifth day of life. We created 3 groups, namely partial unilateral ureteral obstruction (embedding the ureter in the psoas muscle), complete unilateral ureteral obstruction (ligating the ureter) and sham (exposing the ureter). We studied pelvis diameter and kidney length on magnetic resonance imaging, and kidney weight, inflammation, apoptosis and fibrosis on histological assessment during the second (early) and fourth weeks (late) postoperatively. RESULTS Magnetic resonance imaging showed enlarged pelvis diameter in late partial unilateral ureteral obstruction, and in early and late complete unilateral ureteral obstruction. Pathological studies revealed parenchyma atrophy in early and late partial unilateral ureteral obstruction. Apoptosis occurred early in partial unilateral ureteral obstruction and decreased later. Macrophage infiltration was enhanced in early and late partial unilateral ureteral obstruction. Fibrosis increased in late partial unilateral ureteral obstruction. All of these results were significantly intermediate between mice with complete unilateral ureteral obstruction and sham operated mice. CONCLUSIONS It is possible to create renal lesions in newborn mice specific to partial ureteral obstruction. Magnetic resonance imaging of morphological changes demonstrated specific features of partial unilateral ureteral obstruction. Being noninvasive, this approach opens the way for further studies to investigate prognostic parameters after partial ureteral obstruction. In the future this model could be used in knockout mice to study the pathogenesis of renal lesions secondary to obstruction.

Imaging strategies in paediatric musculoskeletal trauma

Skeletal trauma is one of the most common reasons for imaging children in the emergency department. Plain radiographs are the leading imaging tool. US, CT and MRI can sometimes be used. Fear of overlooking serious injury has led physicians to ask for a high number of unnecessary radiological examinations, resulting in increased radiation exposure and health care costs. The aim of this review is to outline the guidelines for imaging in musculoskeletal trauma in children and to discuss the indications for different imaging modalities. We will not refer to non-accidental trauma.

RP-WP-32 IRM Osteo-articulaire de l’enfant : apports de l’injection de chelate de gadolinium

Objectifs pedagogiques Connaitre les particularites techniques de l’IRM osteoarticulaire avec injection de chelate de Gadolinium chez l’enfant. Savoir interpreter le rehaussement normal des cartilages de croissance et de la moelle osseuse sur les sequences adaptees. Illustrer les principales indications avec des cas cliniques. Messages a retenir La sequence 3D Tl EG dynamique pendant l’injection est indispensable a l’etude de la vascularisation de la moelle osseuse et est interessante pour l’etude de la vascularisation des cartilages de croissance. La sequence de type 3D Tl EG en saturation de graisse, au temps tardif est adaptee a l’etude des cartilages de croissance.

In vivo assessment of experimental neonatal excitotoxic brain lesion with USPIO-enhanced MR imaging

Purpose:To assess the feasibility of magnetic resonance imaging (MRI) enhanced with ultrasmall superparamagnetic particles of iron oxide (USPIO) for assessing excitotoxic brain lesions in an experimental model of neonatal periventricular white matter (PWM) lesions.Materials and methods:Brain lesions were induced by intracerebral injection of ibotenate in 14 newborn rats. Pre- and post-USPIO T2-weighted MRI was performed in seven of them (group A) and in five control newborns (group C). In seven newborns with induced cerebral lesions, USPIO-enhanced MRI was not performed (group B). We compared the signal intensity of the lesion to the contralateral unaffected brain (lesion-to-brain contrast, LBC) and the lesion signal-to-noise ratio (SNR) before and after USPIO injection. MR imaging was correlated with histology.Results:USPIO injection significantly (P < 0.05) decreased LBC and SNR of brain lesion but induced no changes in normal controls. The densities of macrophages and iron-laden cells were higher on the lesion side than on the contralateral side (P < 0.05). Neither lesion size nor the surrounding macrophage infiltrate was significantly different between groups A and B.Conclusion:Post-USPIO T2-weighted MRI demonstrated negative enhancement of neonatal excitotoxic brain lesion. USPIO injection does not appear to exacerbate brain lesions.