Multiparametric ultrasound findings in acute kidney failure due to rare renal cortical necrosis

Renal cortical necrosis (RCN) is a rare cause of acute kidney failure and is usually diagnosed on the basis of characteristic enhancement patterns on cross-sectional imaging. Contrast-enhanced ultrasound (CEUS) offers benefits in patients with kidney failure in the clinical setting including the use of a nonnephrotoxic intravascular contrast agent and the fact that it can be performed at the bedside in critical cases. Therefore, the aim of this study is to investigate whether CEUS can reliably identify typical imaging features of RCN. We retrospectively analyzed 12 patients with RCN examined in our department and confirmation of the diagnosis by either histopathology, other contrast-enhanced cross-sectional imaging tests, and/or CEUS follow-up. Assessed parameters in conventional US were reduced echogenicity, loss of corticomedullary differentiation, length and width of kidney, hypoechoic rim, resistance index and in CEUS delayed wash-in of contrast agent (>20 s), reverse rim sign, maximum nonenhancing rim and additional renal infarction. Furthermore, imaging features in RCN were compared with the findings in renal vein thrombosis (RVT), among them echogenicity, corticomedullar differentiation, hypoechoic rim, RI value, delayed cortical enhancement, total loss of cortical perfusion and enhancement of renal medulla. All 12 patients showed the reverse rim sign, while a hypoechogenic subcapsular rim was only visible in four patients on B-mode ultrasound. A resistance index (RI) was available in 10 cases and was always less than 1. RI was a strong differentiator in separating RVT from RCN (RI>1 or not measurable due to hypoperfusion as differentiator, p=0.001). CEUS showed total loss of medullary enhancement in all cases of RVT. With its higher temporal resolution, CEUS allows dynamic assessment of renal macro- and microcirculation and identification of the typical imaging findings of RCN with use of a nonnephrotoxic contrast agent

Crustal structure of Guadeloupe Islands and the Lesser Antilles Arc from a new gravity and magnetic synthesis

Guadeloupe Island (West French Indies) is one of the twenty islands that compose the Lesser Antilles Arc, which results from the subduction of the Atlantic Ocean plate beneath the Caribbean one. The island lies in a complex volcano-tectonic system and the need to understand its geological context has led to numerous on- and offshore geophysical investigations. This work presents the compilation and processing of available, on-land, airborne and marine, gravity and magnetic data acquired during the last 40 years on Guadeloupe Islands and at the scale of the Lesser Antilles Arc. The overall dataset provides new Bouguer and reduced to the pole magnetic anomaly maps at the highest achievable resolution. Regionally, the main central negative gravity trend of the arc allows defining two subsident areas. The first one is parallel to the arc direction (~N160°E) to the north, whereas the second unexpected southern one is oriented parallel to oceanic ridges (N130°E). Along the Outer Arc, the long wavelength positive anomaly is interpreted, at least along the Karukera Spur, as an up-rise of the volcanic basement in agreement with the seismic studies. To the NE of Guadeloupe, the detailed analysis of the geophysical anomalies outlines a series of structural discontinuities consistent with the main bathymetric morphologies, and in continuity of the main fault systems already reported in this area. Based on geophysical evidences, this large scale deformation and faulting of the Outer Arc presumably primarily affects the Atlantic subducting plate and secondarily deforms the upper Caribbean plate and the accretion prism. At the scale of Guadeloupe Island, joined gravity and magnetic modeling has been initiated based on existing interpretation of old seismic refraction profiles, with a general structure in three main layers. According to our geophysical anomalies, additional local structures are also modeled in agreement with geological observations: i) the gravity and magnetic signals confirm an up-rise of the volcanic basement below the limestone platforms outcropping on Grande-Terre Island ; ii) the ancient volcanic complexes of Basse-Terre Island are modeled with high density and reverse magnetized formations; iii) the recent volcanic centre is associated with formations consistent with the low measured density and the underlying hydrothermal system. The EW models coherently image a NNW-SSE depression structure in half-graben beneath Basse-Terre Island, its western scarp following the arc direction in agreement with bathymetric and seismic studies to the north of the island. The so-defined depressed area, and particularly its opening in half-graben toward the SW, is interpreted as the present-day front of deformation of the upper plate associated with the recent volcanic activity on and around Guadeloupe. Based on this regional deformation model, perspectives are given for further integrated investigation of key targets to address the internal structure and evolution of the Lesser Antilles Arc and Guadeloupe volcanic system

Viscoelastic testing reveals normalization of the coagulation profile 12 weeks after severe COVID-19

COVID 19 is associated with a hypercoagulable state and frequent thromboembolic complications. For how long this acquired abnormality lasts potentially requiring preventive measures, such as anticoagulation remains to be delineated. We used viscoelastic rotational thrombelastometry (ROTEM) in a single center cohort of 13 critical ill patients and performed follow up examinations three months after discharge from ICU. We found clear signs of a hypercoagulable state due to severe hypofibrinolysis and a high rate of thromboembolic complications during the phase of acute illness. Three month follow up revealed normalization of the initial coagulation abnormality and no evidence of venous thrombosis in all thirteen patients. In our cohort the coagulation profile was completely normalized three months after COVID-19. Based on these findings, discontinuation of anticoagulation can be discussed in patients with complete venous reperfusion

Metabolische Untersuchung mittels ex-vivo Protonen magic-angle-spinning magnetische Resonanzspektroskopie (1H-MAS-MRS) in einem experimentellen Autoimmunmyokarditis-Rattenmodell zur Identifikation von Myokardschäden

Background. Myocarditis is an inflammatory disease of the myocardium that can lead to dilated cardiomyopathy (DCM) and heart failure (HF). Experimental autoimmune myocarditis (EAM) in rodents is an accepted model of myocarditis and DCM. Altered cellular metabolism is thought to play an important role in the pathogenesis of DCM and generally in HF. Study of the metabolism may provide new diagnostic information and insights into the mechanisms of myocarditis and HF. As yet, proton magnetic resonance spectroscopy (1H-MRS) has not been used to study the changes occurring in myocarditis and subsequent HF. 1H-MRS allows to quantify metabolites and to correlate them to heart function data obtained by magnetic resonance imaging (MRI). We aimed to explore the diagnostic potential of 1H-MRS for detecting and monitoring metabolic changes in the course of myocarditis. Methods. Myocardial function of male young Lewis rats with EAM was quantified by performing left ventricular ejection fraction (LVEF) analysis in short axis cine images covering the whole heart. Inflammatory cellular infiltrate was assessed by immunohistochemistry. Myocardial tissue was analyzed using ex-vivo proton magic angle spinning MRS (1H-MAS-MRS) by placing standardized pieces of a mid ventricular short axis slice of myocardium into a 4 mm zirconium rotor and spinning at 4kHz at 293K. Water presaturation was applied to obtain the proton spectrum. Results. Inflammation was confirmed histologically in myocarditis samples by the presence of an inflammatory cellular infiltrate and CD68 positive staining. A significant increase in the metabolic ratio of taurine/creatine (Tau/Cr) obtained by MRS was observed in myocarditis compared to healthy controls (21 d acute EAM: 4.38 (±0.23), 21 d control: 2.84 (±0.08), 35 d chronic EAM: 4.47 (±0.83) and 35 d control: 2.59 (±0.38), P<0.001). LVEF was reduced in diseased animals (myocarditis: 55.2% (±11.3%), control: 72.6% (±3.8%), P<0.01) and correlated with Tau/Cr ratio (R=0.937, P<0.001). Conclusions. Metabolic alterations occur acutely with the development of myocarditis. Myocardial Tau/Cr ratio as detected by proton MRS is able to differentiate between healthy myocardium and myocardium from rats with EAM and correlates with functional parameters.Einleitung. Experimentelle-Autoimmun-Myokarditis (EAM) in Nagern ist ein bekanntes Tiermodell für Myokarditis und dilatierte Kardiomyopathie (DCM). Ein veränderter Stoffwechsel spielt möglicherweise eine wichtige Rolle in der Pathogenese einer DCM und einer daraus resultierenden Herzinsuffizienz. Weitere Untersuchungen des Stoffwechsels könnten sowohl neue diagnostische Informationen liefern, als auch helfen mechanistische Abläufe während einer Myokarditis und bei Herzinsuffizienz besser zu verstehen. Magnetische Resonanzspektroskopie mit Protonen (1H-MRS) wurde bisher noch nicht zur Untersuchung von Veränderungen während einer Myokarditis und der daraus folgenden Herzinsuffizienz verwendet. Unser Ziel war es Unterschiede im Kreatinmetabolismus zwischen Ratten mit EAM und gesunden Tieren zu identifizieren. Methoden. Die Herzfunktion von jungen männlichen Lewis-Ratten mit EAM wurde durch Bestimmung der linksventrikulären Ejektionsfraktion (LVEF) in Kurzachsen Cine-Bildern quantifiziert. Inflammatorische zelluläre Infiltrate wurden durch immunhistologische Aufarbeitung von Myokardschnitten analysiert. Myokardgewebe wurde mit ex-vivo Protonen Magic Angle Spinning MRS (1H-MAS-MRS) untersucht. Ergebnisse. Eine Myokarditis konnte histologisch durch inflammatorische Zellinfiltrate und durch ein positives CD68 in der Immunhistologie bestätigt werden. Ein signifikanter Anstieg des Metaboliten- Verhältnis von Tau/Cr (Taurin/Kreatin) konnte in den 1H-MAS-MRS Messungen in den Myokarditis-Tieren gegenüber den gesunden Kontrollen beobachtet werden (21 d acute EAM, 4.38 (±0.23); 21 d control, 2.84 (±0.08); 35 d chronic EAM, 4.47 (±0.83); 35 d control, 2.59 (±0.38); P < 0.001). Die LVEF war in den kranken Tieren reduziert (EAM, 55.2% (±11.3%); control, 72.6% (±3.8%); P < 0.01) und korrelierte mit dem Tau/Cr Verhältnis (R = 0.937, P < 0.001) der entsprechenden Ratten. Schlussfolgerung. Metabolische Veränderungen treten bereits in der akuten Phase einer Myokarditis auf. Es konnte gezeigt werden, dass das myokardiale Verhältnis von Tau/tCr aus den 1H-MRS Messungen mit der Myokard-Funktion korreliert und zwischen Myokardgewebe aus gesunden Ratten und Tieren mit EAM unterscheiden kann

Turbinage d’eau potable

Ce projet a pour objectif d’estimer le potentiel hydroélectrique du réseau d’eau potable des Mayens de Sarreyer situés dans le Val de Bagnes. Les contraintes techniques, topographiques ainsi qu’économiques devront être prises en compte afin de concevoir une installation optimale ainsi que respectueuse de l’environnement. La rentabilité est également un point clé de ce projet

Identification of fog Particle Size Distribution by a radiative transfer equation inversion

We investigate the identification problem of the fog Droplet Size Distribution (DSD) by an inverse method of the 1D radiative transfer equation thanks to spectral radiation measurements in the range 350 nm-2500 nm. This distribution together with Lorenz-Mie scattering theory allow to compute the optical properties (scattering coefficient, absorption coefficient, and phase function). We prove the well-posedness of the underlying inverse problem then we perform some numerical experiments using synthetic data. The numerical results suggest that the method allows to identify the DSD with different modellings of the radiative transfer (Beer-Lambert, isotropic and anisotropic collision operator)

Identification par méthode inverse des propriétés optiques d’un milieu diffusant: Application à l’impact du brouillard sur la perception artificielle

National audienceutilisés dans différents domaines d’application (avionique, véhicules routiers intelligents, etc.). Le Cerema, au travers de sa plateforme PAVIN Brouillard-Pluie, mène des évaluations de ces capteurs dans des conditionscontrôlées de brouillard [3]. Dans une perspective de disposer d’un jumeau numérique de la plateforme, ilest nécessaire de développer des modélisations robustes de propagation des ondes électromagnétiques dans lebrouillard.La propagation est régie par les phénomènes de diffusion et d’absorption des photons au contact des gouttelettesde brouillard. La distribution N des tailles de ces gouttes est un paramètre clé des modèles de propagation.Nous proposons d’exposer une méthodologie pour identifier cette distribution en inversant l’équation de transfertradiatif à partir de mesures expérimentales