Multi-phase postmortem CT angiography: recognizing technique-related artefacts and pitfalls

Background and purpose: Multi-phase postmortem CT angiography (MPMCTA) is increasingly being recognized as a valuable adjunct medicolegal tool to explore the vascular system. Adequate interpretation, however, requires knowledge about the most common technique-related artefacts. The purpose of this study was to identify and index the possible artefacts related to MPMCTA. Material and methods: An experienced radiologist blinded to all clinical and forensic data retrospectively reviewed 49 MPMCTAs. Each angiographic phase, i.e. arterial, venous and dynamic, was analysed separately to identify phase-specific artefacts based on location and aspect. Results: Incomplete contrast filling of the cerebral venous system was the most commonly encountered artefact, followed by contrast agent layering in the lumen of the thoracic aorta. Enhancement or so-called oedematization of the digestive system mucosa was also frequently observed. Conclusion: All MPMCTA artefacts observed and described here are reproducible and easily identifiable. Knowledge about these artefacts is important to avoid misinterpreting them as pathological finding

Compositional variation and 226Ra-230Th model ages of axial lavas from the southern Mid-Atlantic Ridge, 8°48′S

We present geological observations and geochemical data for the youngest volcanic features on the slow-spreading Mid-Atlantic Ridge at 8°48'S that shows seismic evidence for a thickened crust and excess magma formation. Young lava flows with high sonar reflectivity cover about 14 km2 in the axial rift and were probably erupted from two axial volcanic ridges each of about 3 km in length. Three different lava units occur along an about 11 km long portion of the ridge, and lavas from the northern axial volcanic ridge differ from those of the southern axial volcanic ridge and surrounding lava flows. Basalts from the axial rift flanks and from a pillow mound within the young flows are more incompatible element depleted than those from the young volcanic field. Lavas from this volcanic area have 226Ra-230Th disequilibria model ages of 1,000 and 4,000 years whereas the older lavas from the rift flank and the pillow mound, but also some of the lava field, are older than 8,000 years. Glasses from the northern and southern ends of the southern lava unit indicate up to 100°C cooler magma temperatures than in the center and increased assimilation of hydrothermally altered material. The compositional heterogeneity on a scale of 3 km suggests small magma batches rising vertically from the mantle to the surface without significant lateral flow and mixing. The observations on the 8°48'S lava field support the model of low frequency eruptions from single ascending magma batches that has been developed for slow-spreading ridges

Enseignement de la sécurité numérique : De la sensibilisation à l'expertise

Avec l’avènement de l’internet des objets, les dispositifs électroniques sont omniprésents dans nos vies. Cette omniprésence implique une augmentation des failles de sécurité (vol de données ou d’identité, prise de contrôle d’équipements sensibles…). Pour parer à ces vulnérabilités, deux méthodes complémentaires doivent être mises en place en parallèle. Il est nécessaire de sensibiliser les utilisateurs afin d’éviter les comportements à risque mais aussi de créer des objets plus sécurisés en formant les ingénieurs de demain à ces problématiques. Dans ce contexte, le pôle CNFM de Montpellier a mis en place un programme de formation en sécurité numérique. Ce programme est composé de 4 formations s’adressant à des étudiants du lycée au doctorat en passant par la formation continue. Ce papier présente ces 4 formations qui nous ont permis de former plus de 800 étudiants depuis 2014

Post-mortem magnetic resonance imaging angiography after multiphase computed tomography angiography. Feasibility based on two cases. [Postmortale Magnetresonanztomographie-Angiographie nach Multiphasen-Computertomographie-Angiographie : Machbarkeitsnachweis anhand von zwei Fällen.]

In recent years, forensic imaging has seen impressive developments; however, few studies exist concerning post-mortem magnetic resonance imaging (PMMRI) or post-mortem magnetic resonance angiography (PMMRA). In this article two cases (one traumatic and one natural death) are described in which PMMRA was performed after multi-phase post-mortem computed tomography angiography (MPMCTA) and before the medico-legal autopsy. The results show that most of the contrast medium used and especially almost all findings were visible in MPMCTA as well as in PMMRA

Vegetation models used to retrieve geophysical parameters from passive microwave measurements

National audienc

Oleic Acid (OA), A Potential Dual Contrast Agent for Postmortem MR Angiography (PMMRA): A Pilot Study.

Choosing proper perfusates as contrast agents is an important aspect for postmortem magnetic resonance angiography (PMMRA). However, in this emerging field, the number of suitable kinds of liquid is still very limited. The objective of this research is to compare MR images of oleic acid (OA) with paraffin oil (PO) in vitro and in ex situ animal hearts, in order to evaluate the feasibility to use OA as a novel contrast agent for PMMRA. In vitro, OA, PO and water (control) were introduced into three tubes separately and T <sub>1</sub> weighted-spin echo (T <sub>1</sub> w-SE) and T <sub>2</sub> w-SE images were acquired on a 1.5T MR scanner. In the second experiment, OA and PO were injected into left coronary artery (LCA) and left ventricle (LV) of ex situ bovine hearts and their T <sub>1</sub> w-SE, T <sub>2</sub> w-SE, T <sub>1</sub> w-multipoint Dixon (T <sub>1</sub> w-mDixon) and 3DT <sub>2</sub> w-mDixon images were acquired. The overall results indicate that OA may have a potential to be used as a dual (T <sub>1</sub> and T <sub>2</sub> based) contrast agent for PMMRA when proper sequence parameters are utilized. However, as the pilot study was based on limited number of animal hearts, more researches using OA in cadavers are needed to validate our findings

Research on the feasibility of applying magnetic nanoparticle ferrofluid(MNPF) to postmortem MR angiography (PMMRA)

Objective To explore the feasibility of applying magnetic nanoparticle ferrofluid(MNPF) to postmortem magnetic resonance angiography(PMMRA). Methods MNPF of concentrations ranging from 0 to 1000μg/ml was prepared by modifying nanoparticle γ-Fe2 O3(30 nm) with oleic acid(OA) and then dispersing it in paraffin oil(PO). MNPF was transferred into tubes which were then sealed and properly fixed on the MR table. To acquire image data, a serial of MR sequences were employed, including T1 w-SE, T2 w-SE and 3 DT2*w-GR and characteristics of these images were analyzed. MNPF of γ-Fe2 O3 0μg/ml, 25μg/ml and 1000μg/ml was injected into ex situ bovine hearts, T1 w-SE and T2 w-SE sequences were used and characteristics of the acquired images were analyzed. Results When the concentration of γ-Fe2 O3 lies between 0μg/ml to 100μg/ml, MNPF has hyperintensities on T1 w images and hypointensities on T2 w images. On T2*w images, the signals of MNPF tend to decrease and then disappear when the concentration of γ-Fe2 O3 increases from 0μg/ml to 100μg/ml. When the concentration surpasses 100μg/ml, it may lead to the production of magnetic sensitive artifacts, which leads to improper application of MNPF to PMMRA. Conclusion Oily MNPF with a certain concentration range of γ-Fe2 O3 has the potential to be used as T1-positive and T2*-signal-adjustable contrast agent