Dimensions of the trapezium bone: a cadaver and CT study.

PURPOSE: The primary purpose of this study was to define the size of the trapezium bone through measurements on cadaver specimens and CT scans of living subjects. The secondary purpose of this study was to determine if any correlation existed between the size of the trapezium and local anatomical parameters. METHODS: The radio-ulnar length (L), dorsopalmar width (ℓ) and height (h) of the distal surface of the trapezium were measured by two independent observers on 20 cadaver specimens. The same measurements were carried out by two other observers on anonymized CT scans from 18 patients. The inter- and intra-observer agreement was determined using the intraclass correlation coefficient. RESULTS: In the cadavers, the mean length, width and height of the trapezium were 22.8, 15.5 and 15.2 mm, respectively. On the CT scans, these same dimensions were 19.2, 11.4 and 11.6 mm. Inter-observer agreement was statistically significant in both parts of the study. DISCUSSION: The dimensions of the trapezium bone were about 3.33 mm larger in cadavers than on CT scans. These differences can be explained partially by a systematic under-sizing error on the CT scans and the fact that the cartilage layer cannot be directly visualized. CONCLUSION: This study was able to define the dimensions of the trapezium bone. It may be possible to predict the trapezium height from the length of the forearm or the width of the radial epiphysis. Our data can be used to adjust the size of trapezium implants to the dimensions of the patient's bone.

Depistage echographique de la maladie luxante de hanche : qu'en est-il de la gemellite comme facteur de risque ?

Objectif : Le depistage echographique de la maladie luxante de hanche repond a des indications particulieres; dont l'existence de facteurs de risque. La gemellite fait partie de ces facteurs derisque. Le but de cette etude etait d'apprecier l'incidence reelle de la grossesse gemellaire dans la survenue de la maladie luxante de hanche. Materiels et Methodes : Nous avons realise une etude retrospective; de fevrier 1991 a mars 2004; de 316 dossiers d'echographies de hanche; realisees de maniere systematique chez des jumeaux; par une equipe pratiquant la methode morphologique de GRAF. Resultats : L'age moyen des nourrissons au premier examen etait de 2 mois en moyenne (de 1 a 3;4 mois). Dans 81 des cas; l'examen echographique initial etait normal. Les enfants presentant une hanche de type IIa etaient ages de 1;7 mois en moyenne. Ces hanches de type IIa; controlees dans un delai moyen de 1;8 mois; se sont normalisees dans 98;4 des cas. Seulement deux nourris- sons ont ete traites; un pour une hanche de type IIb unilateral; l'autre pour des hanches de type IIc bilateral. Ces deux nourrissons etaient nes en presentation de siege des cas. Seulement deux nourrissons ont ete traites; un pour une hanche de type IIb unilateral; l'autre pour des hanches de type IIc bilateral. Ces deux nourrissons etaient nes en presentation de siege

[Kidney trauma in children: state of the art medical imaging]. / Traumatisme du rein de l'enfant: bonnes pratiques en imagerie médicale.

Traumatic renal lesions have some particularities in the pediatric age group, especially for anatomic reasons. Imaging is very important for diagnosis and staging. Ultrasonography with Doppler is the first line examination performed in children and frequently allows initial diagnosis. From the Doppler-ultrasonographic results and the type of trauma, renal Computed Tomography (CT) is complementary performed. The association of these imaging techniques allows comprehensive work-up of traumatic renal lesions, and also of associated or pre-existing lesions. Conservative management is the rule in most cases. Interventional imaging techniques are sometimes used for therapeutic care of renal pedicular vascular lesions or lesions of the collecting system. Far from the traumatic event, imaging allows to follow up the morphologic and functional evolution of major renal lesions, in particular lesions of excretory renal ducts.

[Imaging of the pediatric pancreas: state of the art]. / Imagerie du pancréas de l'enfant en 2005.

The use of high frequency (7-12 MHz) transducers on state of the art US units equipped with Doppler imaging provides excellent evaluation of the pediatric pancreas that compares to other cross-sectional imaging techniques. The availability of multidetector CT imaging reduces the need for sedation but requires additional review of the indications and protocols to avoid unnecessary radiation exposure. Evaluation of pancreatitis and tumors remains the main indication. Advances in MR imaging and MRCP has lead to very good results in children. Storage diseases of the pancreas can be diagnosed at MRI. The length of the examinations, the need for sedation and the limited spatial resolution remain the main pitfalls of MR imaging of the pancreas in pediatric patients.

[Immature hemangiomas in infants: MR and Doppler-US imaging features]. / Sémiologie IRM et écho-Doppler des hémangiomes immatures du nourrisson: à propos de 12 cas.

PURPOSE: To determine the MR imaging features of immature hemangiomas. To discuss the value of MR imaging compared to Doppler ultrasonography (US). MATERIALS AND METHODS: We performed a retrospective study of clinical, Doppler US and MRI data of 12 immature hemangiomas in 11 children. The mean age was 2 months and 21 days. The mean clinical follow up was 22 months and 7 days. RESULTS: MRI was performed for non-diagnosed lesions (4 cases) or to further define lesion extension (8 cases). The lesions either involved the head and neck (8 cases) or the extremities (4 cases). At MR imaging, all immature hemangiomas corresponded to well defined homogeneous T2W hyperintense masses. On T1-weighted images, 11 immature hemangiomas were isointense with intense homogeneous enhancement. Eleven tumors contained linear low signal intensity flow voids. Ten lesions had superficial cutaneous and/or subcutaneous extension whereas 2 lesions had intra-muscular extension. At Doppler US, immature hemangiomas were highly vascularized masses, with well defined margins, often compressibles, homogeneous isoechoic or heterogeneous with nodular hypoechoic foci, relative to subcutaneous fat. A diagnosis of immature hemangioma was confirmed either by pathology (2 cases) or clinical follow up (10 cases). CONCLUSION: In our study, the MR imaging features of immature hemangiomas were reproducible and similar to reports from the literature. MRI is a useful tool to better define the extent of immature hemangiomas, which can be difficult to assess at US. The sensitivity and specificity of MR imaging for this pathology remain to be defined.

[Non-traumatic abdominal emergencies in paediatric practice]. / Les urgences abdominales non traumatiques de l'enfant.

Do advances in MR imaging and Computed Tomography have encroached upon the private territory of Ultrasound-Doppler imaging on paediatric practice? Do the enthusiasm promoted by the use of CT on non traumatic acute abdomen in adult has contaminated the indomitable village of paediatric radiologist? Undoubtfully, Ultrasound-Doppler stayed the first imaging modality to perform. However, the habits are less crystallised than a few years ago. The goal of this article is to describe the ultrasound findings and the potential indications for MRI or CT in the major non traumatic abdominal paediatric emergencies.

A real-time flat-panel X-ray pixel imaging system for low-dose medical diagnostics and craniofacial applications.

The aim of this study was to evaluate on-line performance of a real-time digital imaging system based on amorphous silicon technology and to compare it with conventional film-screen equipment. The digital detecting imager consists of (1) a converter, which transforms the energy of the incident X rays into light; (2) a real-time digital detecting system, capable of producing as many as 10 pictures per second using a large-area pixel matrix (20 x 20 cm2) based on solid-state amorphous silicon sensor technology with a pitch of 400 microns; and (3) appropriate computer tools for control, real-time image treatment, data representation, and off-line analysis. Different phantoms were used for qualitative comparison with the conventional film-screen technique, with images obtained with both systems at the normal dose (used as a reference), as well as with dose reduction by a factor of 10 to 100. Basic image quality parameters evaluated showed that the response of the detector is linear in a wide range of entrance air kerma; the dynamic range is higher compared with the conventional film-screen combination; the spatial resolution is 1.25 lp per millimeter, as expected from the pixel size; and good image quality is ensured at doses substantially lower than for the film-screen technique. The flat-panel X-ray imager based on amorphous silicon technology implemented in standard radiographic equipment permits acquisition of real-time images in radiology (as many as 10 images per second) of diagnostic quality with a marked reduction of dose (as much as 100 times) and better contrast compared with the standard film technique. Preliminary results obtained with a 100-micron pitch imager based on the same technology show better quality but a less substantial dose reduction. Applications in craniofacial surgery look promising.