Gabriel Kalifa

Evaluation of a new low-dose digital X-ray device: first dosimetric and clinical results in children

Background. A new low-dose digital X-ray device, based on Charpaks Nobel prize-winning multiwire chamber, enables the production of images at very low doses. Objectives. To present the first dosimetric and clinical results. Materials and methods. The analysis was performed on 93 children with scoliosis and 47 undergoing pelvic radiography. The comparative study between conventional X-ray and the new technique focused on three points: (1) the dose delivered by each system (2) the diagnostic information provided by each system and (3) comparison of image quality criteria with European guidelines. Results. The mean ratio of conventional dose to that of the low-dose technique was 13.1 for the spinal examination and 18.8 for the pelvis. There was no significant difference in diagnostic information available from each modality, but there was a slight difference in quality criteria in favour of the conventional technique. Conclusion. This new device allows spectacular dose reduction, consistent with adequate clinical information. Improvements of the prototype will lead to extension of potential indications and industrial development.

Sedation in children undergoing CT scan or MRI: effect of time-course and tolerance of rectal chloral hydrate

The aim of this paper was to describe the time‐course of the sedative effect of rectal chloral hydrate (75 mg/kg) in children undergoing CT scan or MRI. Twenty children (2.13 ± 1.43 years old) were administered 75 mg/kg chloral hydrate rectally (chloralhydrat‐rectiole rectal formulation, Dr Mann‐Pharma Lab, Berlin, Germany), before a CT scan or an NMR imaging. Sedation was measured at specific times using a sedation score of 1–6. Patients were continuously monitored for respiratory and heart rate, systolic and diastolic blood pressures, and oxygen saturation. About 82.35 and 94.11% of the patients had a score of sedation ≥ 3 within 15 and 30 min, respectively. The mean time to effective sedation (score ≥ 3) was of 0.30 ± 0.14 h (median time, 0.25 h). The mean duration of effective sedation (score ≥ 3) was 1.29 ± 1.05 h (median duration, 0.75 h). A total of 93.1% of the X‐ray sections were obtained without artifact and sedation was considered by radiologists to be efficient for 83.3% of the procedures. This sedation procedure appeared efficient and safe during ambulatory CT scan and NMR imaging. The long‐term effect of chloral hydrate, however, remains to be evaluated.

Aortic dilatation in Turner syndrome: the role of MRI in early recognition

Background: Aortic dilatation and dissection are rare but important complications of Turner syndrome that increase the risk of sudden death in young patients. Objective: To assess the value of aortic MRI in patients with Turner syndrome; in particular to demonstrate early aortic dilatation. Materials and methods: A total of 21 patients with Turner syndrome underwent MRI of the thoracic aorta with measurement of vessel diameter at four levels. Results: Measurements were normal for age in 15 cases, two patients presented with values at the upper limit of normal and four had obvious dilatation of the ascending aorta. All were symptom free. Conclusions: MRI allows the non-invasive demonstration of early aortic dilatation, which may lead to earlier surgery in asymptomatic individuals.

Bilateral dysplasia epiphysealis hemimelica: report of two cases

Dysplasia epiphysealis hemimelica is a rare congenital disorder characterised by unilateral bone overgrowth from large joints, mainly the ankle or knee. We present two cases with bilateral lesions; only two similar cases with bilateral involvement have been reported hitherto. The differential diagnosis is considered.

Fibrodysplasia ossificans progressiva and synovial chondromatosis.

Two cases of an unusual association — fibrodysplasia ossificans progressiva and synovial chondromatosis — in non-related children are presented. This association does not seem coincidental and raises several questions about the pathogenesis. A genetic hypothesis related to G proteins is proposed. This is supported by the fact that such abnormalities have been demonstrated in pseudohypoparathyroidism and fibrous dysplasia; these diseases can also be associated with fibrodysplasia ossificans progressiva.

Traumatismes du rachis chez l'enfant

Resume Les traumatismes du rachis chez l’enfant sont graves surtout par l’instabilite qu’ils peuvent entrainer, car le risque essentiel est l’atteinte neurologique. Si l’examen clinique reste fondamental, le bilan comporte un cliche standard de face et un cliche de profil a rayon horizontal complete au moindre doute par un scanner et surtout une IRM. Au niveau du rachis cervical, les lesions siegent frequemment au niveau des trois premieres vertebres.Spine injuries in the pediatric population can lead to instability and subsequent neurological damage. Initial work up includes frontal and lateral cross-table spine radiographs, completed by CT and MRI when any doubt exists about possible injury. At the cervical level, injuries frequently involve the first three segments.

Imagerie cérébrale de la sclérose tubéreuse de bourneville chez l’enfant

Resume La sclerose tubereuse de Bourneville (STB) est une phacomatose frequente, de transmission autosomique dominante. Le diagnostic repose sur une liste de criteres (2 criteres majeurs ou 1 critere majeur + 2 criteres mineurs). L’IRM cerebrale est fondamentale au diagnostic en montrant les signes majeurs des la periode fœtale : nodules sous ependymaires, tubers et tumeurs a cellules geantes. Chez le grand enfant, les sequences FLAIR sont les plus performantes alors que chez le fœtus, le nouveau ne et le nourrisson, les sequences en T1 sont les plus contributives, du fait du processus de myelinisation.

The AP diameter of the pelvis: a new criterion for continence in the exstrophy complex?

Abstract.Objective: Reconstructive surgery of bladder exstrophy remains a challenge. By using CT of the pelvis, we suggest a new pre- and post-operative investigative procedure to define the AP diameter (APD) as a predictive criterion for continence in this anomaly. Patients and methods: Three axial CT slices were selected in nine children with exstrophy who had undergone neonatal reconstructive surgery. The three levels selected were the first sacral plate, the mid acetabular plane and the superior pubic spine. We used combined slices to measure: • APD = distance between the first sacral vertebra and the pubic symphysis. • Pubic diastasis (PD) • Three angles defined on the transverse plane of the first sacral vertebra – iliac wing angle, sacropubic angle and acetabular version. Results: In exstrophy, the angles demonstrate opening of the iliac wings and the pubic ramus, and acetabular retroversion compared to controls. Comparisons between controls, continent and incontinent patients reveal that in continent patients, APD increases with growth and seems to be a predictive criterion for continence, independent of diastasis of the pubic symphysis. Conclusions: We believe that CT of the pelvis with measurements of the APD should be performed in all neonates with bladder exstrophy before reconstructive surgery and for better understanding of the malformation. The APD seems to be predictive and may be a major criterion for continence, independent of PD.

Ischio-vertebral dysplasia: a distinct entity

Background. Kyphoscoliosis is a complication of some bone dysplasias, including cleidocranial dysplasia. Objectives. We report a distinct disorder with defective ossification of the ischial rami, severe kyphoscoliosis and normal clavicles. Early recognition of this syndrome allows prevention of complications. Materials and methods. All patient cases (aged 1 day to 33 years) were selected according to the above criteria, with special attention to radiological findings, family history and follow-up (5–30 years). Results. In all eight patients, we observed the following: (a) Severe thoracic scoliosis of early onset and rapid progression, leading to rotatory dislocation. Spinal cord compression occurred in four cases with respiratory problems related to chest deformity. (b) Bilateral and symmetrical incomplete ossification of the ischial rami. (c) Peculiar facies with retrognathia. (d) Normal clavicles. Three patients were from the same family (grandmother, mother and daughter). Conclusion. Ischio-vertebral dysplasia seems to represent a true entity, with radiological and genetic findings that make it distinct from cleidocranial dysostosis. The association of kyphoscoliosis and these pelvic abnormalities is specific for this condition. Neurological and respiratory complications can be avoided if the condition is recognised early and early treatment is instituted.

Évaluation des doses d’irradiation aux organes en scanographie pédiatrique

Resume Objectifs Determiner la dose organe delivree pour les scanners pediatriques courants du tronc et proposer une reduction des doses. Materiel et methode Une etude sur fantome correspondant au corps d’un enfant de 5 ans a ete menee afin de mesurer la dose delivree aux gonades, a la moelle osseuse (sternum T12) et a la thyroide pour les scanners thoraciques, abdominaux, du bassin et du rachis. On a tente d’optimiser les doses en reduisant les parametres. Resultats Les doses organes delivrees sont assez significatives pour un scanner thoracique, aux seins et aux sites hematopoietiques, la dose aux ovaires est importante pour les scanners abdomino-pelviens et le scanner du rachis est tres irradiant pour la thyroide ainsi que pour la moelle rouge. L’optimisation peut se faire sans degradation de la qualite de l’image en diminuant KV et mAs dans des limites raisonnables. Cette etude doit servir de base a l’evaluation des doses delivrees par les scanners nouvelle generation.