Post mortem magnetic resonance imaging in the fetus, infant and child: A comparative study with conventional autopsy (MaRIAS Protocol)

<p>Abstract</p> <p>Background</p> <p>Minimally invasive autopsy by post mortem magnetic resonance (MR) imaging has been suggested as an alternative for conventional autopsy in view of the declining consented autopsy rates. However, large prospective studies rigorously evaluating the accuracy of such an approach are lacking. We intend to compare the accuracy of a minimally invasive autopsy approach using post mortem MR imaging with that of conventional autopsy in fetuses, newborns and children for detection of the major pathological abnormalities and/or determination of the cause of death.</p> <p>Methods/Design</p> <p>We recruited 400 consecutive fetuses, newborns and children referred for conventional autopsy to one of the two participating hospitals over a three-year period. We acquired whole body post mortem MR imaging using a 1.5 T MR scanner (Avanto, Siemens Medical Solutions, Enlargen, Germany) prior to autopsy. The total scan time varied between 90 to 120 minutes. Each MR image was reported by a team of four specialist radiologists (paediatric neuroradiology, paediatric cardiology, paediatric chest & abdominal imaging and musculoskeletal imaging), blinded to the autopsy data. Conventional autopsy was performed according to the guidelines set down by the Royal College of Pathologists (UK) by experienced paediatric or perinatal pathologists, blinded to the MR data. The MR and autopsy data were recorded using predefined categorical variables by an independent person.</p> <p>Discussion</p> <p>Using conventional post mortem as the gold standard comparator, the MR images will be assessed for accuracy of the anatomical morphology, associated lesions, clinical usefulness of information and determination of the cause of death. The sensitivities, specificities and predictive values of post mortem MR alone and MR imaging along with other minimally invasive post mortem investigations will be presented for the final diagnosis, broad diagnostic categories and for specific diagnosis of each system.</p> <p>Clinical Trial Registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT01417962">NCT01417962</a></p> <p><b>NIHR Portfolio Number: </b>6794</p

IDENTIFICATION DE PRÉCIPITÉS DE NITRURE D'ALUMINIUM DANS DES ÉCHANTILLONS DE FER

La spectroscopie de pertes d'énergie d'électrons à haute tension (1 MV) a été utilisée pour confirmer la composition chimique de fins précipités de nitrure d'aluminium qui apparaissent dans les aciers faiblement alliés. La technique a permis de bien mettre en évidence un enrichissement en aluminium des zones contenant les précipités. Elle confirme que ceux-ci sont consitués de nitrure d'aluminium.Electron Energy Loss Spectroscopy at high voltage (1 MV) has been used to establish the chemical composition of thin precipitates observed in low-carbon steel samples which show a poor ductibility at high temperature, 750 - 1100°C. The technique has allowed to confirm that the precipitates correspond to Al N formation

MICRO-ANALYSE DE CRISTAUX EN CROISSANCE SUR UNE SURFACE DE SILICIUM

Sur une surface de silicium, préalablement polie, chauffée dans un microscope électronique, nous avons fait croître des cristaux que nous avons observés et analysés.Crystals were grown on a polished silicon surface by heating in an electron microscope column. These crystals and their growths were studied by TEM and analysed by EELS, revealing structure and composition

Transmission Electron Microscopy Studies of (AIN-Si3N4) Codeposits Obtained by LPCVD

Several (Al,Si,N) compounds have been obtained by LPCVD in a vertical hot-wall reactor using aluminium trichloride, silicon tetrachloride and ammonia as source gases, with nitrogen as the carrier gas. In order to determine both their structure and local chemical composition, several deposits have been examined by analytical transmission electron mimscopy combining electron diffraction (ED), high resolution electron microscopy (HREM) and electron energy loss spectroscopy (EELS). It has been confirmed that the chemical composition of the materials as well as the size of the "nanocrystals" observed in the deposits are strongly dependent on the temperature and the reactive gas flow. It has also been shown that for the range of temperature (1273 K-1373 K) used in this work these "nanocrystals" have the wurtzite structure of aluminium nitride

EELS ANALYSIS OF A PRECIPITATE IN V3Si BY STEM AND HVEM

Nous avons effectué l'analyse d'un précipité dans V3Si (structure A15) par spectroscopie de pertes d'énergie en microscopie électronique classique à haute tension (1000 kV) et à balayage (100 kV), par transmission. Compte tenu du diagramme de phases du système binaire V-Si, l'analyse a permis de penser qu'il s'agissait de V5Si3. Ce résultat a été confirmé par microdiffraction électronique en faisceau convergent.The analysis of a precipitate in V3Si (A15 structure) has been performed by transmission EELS with a HVEM (1000 kV) and with a STEM (100 kV). Taking into account the phase diagram of the V-Si system, the composition V5Si3 is anticipated. This result has been confirmed by convergent beam electron microdiffraction

LPCVD of SiC layers in a hot-wall reactor using TMS precursor

Sic polycrystalline layers were grown by LPCVD in a hot wall reactor using tetramethylsilane (TMS) diluted in hydrogen as precursor. The morphology and the structure of the films were analyzed in terms of deposition temperature, total pressure in the reactor and TMS flow rate. The layers have been characterized using various techniques : SEM, X-ray diffraction and TEM (HREM and EELS)

AES, XPS AND TEM CHARACTERIZATION OF BORON NITRIDE DEPOSITED UNDER CHEMICAL VAPOR INFILTRATION (CVI) CONDITIONS

Des dépôts de nitrure de bore, élaborés à partir de mélanges gazeux BF3-NH3 dans des conditions CVI et déposés dans des préformes fibreuses ou sur des substrats plans de carbure de silicium ont été caractérisés par XRD, AES, XPS et TEM. Ces dépôts sont non stoechiométriques et possèdent du bore en excès (N:B at = 0,6 - 0,8) ainsi qu'une quantité non négligeable d'oxygène. L'unité structurale de base se compose d'hexagones quasi parfaits. L'arrangement des couches est typiquement turbostratique (d002 = 3,64 Å ; Lc = 28 Å). Ces empilements sont aléatoirement orientés au sein du dépôt mais tendent à s'orienter parallèlement à l'interface proche du substrat. Le dépôt comporte des pores submicroscopiques, une faible densité (1,6 - 1,9 g.cm-3) et une certaine nanoporosité (8 - 22 %). La microstructure est semblable à celle du pyro-carbone élaboré dans des conditions similaires.BN-films deposited, from BF3-NH3 mixtures under CVI-conditions, either within porous SiC fiber preforms or on plan sintered SiC substrates, have been characterized, at a submicron scale, by XRD, AES, XPS and TEM. The deposits are non-stoichiometric with an excess of boron (N:B at. = 0.6 - 0.8) and contain a significant amount of oxygen. The basic structural unit is an almost perfect hexagonal ring. The stacking of the hexagonal layers is turbostratic (d002 = 3.64 Å ; Lc = 28 Å). The BN layers are randomly orientated in the bulk of the deposit but tend to be aligned parallel to the interface near the substrate surface. The deposit contains numerous submicroscopic pores. It has a low density (1.6 - 1.9 g.cm-3) and a significant nanoporosity (8 - 22 %). The main features of the microstructure are similar to those of pyrocarbon deposits