APPORT DU COUPLAGE ANTENNE ENDORETALE-ANTENNE PHASED-ARRAY DANS LE STAGING PREOPERATOIRE DES CANCERS DE PROSTATE PAR L'IRM

PARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Development and Evaluation of a CT Pulmonary Angiography Protocol Dedicated to Pregnant and Postpartum Women

International audienceIntroduction: This study presents and evaluates a CT pulmonary angiography protocol dedicated to pregnant women. The specific feature of this protocol is to place the region of interest (ROI) (bolus detection) in the superior vena cava. The objective is to evaluate the performances of this method.Materials and methods: The protocol uses a iodine-based contrast agent at 300mgI/mL and an injection rate of 5 to 6 mL/sec for an injection volume of 50 mL of iodine contrast agent followed by 40 mL of NaCl. The ROI is positioned on the superior vena cava, with a 100 Hounsfield units (HU) threshold, and the acquisition is performed at 100 kVp. This protocol was evaluated retrospectively on a large population (n = 105: group 1) and compared with a control group that did not benefit from this protocol (n = 55: group 2). Both groups were studied on the same device in the same center. Each examination was evaluated and classified into 3 groups: optimal, suboptimal, and noncontributory. Dose length products (DLP) values were also recorded. Statistical tests were applied to the data collected.Results: The rate of noncontributory examinations increased from 43.1% for the control group to 4.8% for the new protocol group. The reference enhancement level in the pulmonary trunk is 250 UH. The mean enhancement in the pulmonary trunk of the new protocol group (332 HU (±71 HU (±71 HU)) is significantly greater than the reference value of 250 HU (P .05), which has a mean enhancement of 239 HU (±87 HU). The control group had a mean DLP of 225 mGy.cm (±81 mGy.cm), and the new-protocol group had a mean DLP of 189 mGy.cm (±75 mGy.cm).Discussion: Our noncontributory examination rate is the lowest rate described in the literature. Our protocol contradicts standard practices of placing an ROI in the pulmonary trunk for bolus detection of iodinated contrast media.Conclusion: The results of this study showed that this protocol reduces the number of noncontributory examinations while reducing the dose delivered to patients. This robust protocol is applicable to other devices and meets perfectly radiation-safety requirements and injected contrast media volume limitation

Stability of the standard incus coupling of the Carina middle ear actuator after 1.5T MRI.

Limited data is available concerning the safety of active middle ear implants (AMEI) during Magnetic Resonance Imaging (MRI). Measurements in temporal bones are the gold standard for preclinical assessment of device safety. In this study the coupling stability of an actuator as used in a fully implantable AMEI was determined in temporal bones. Eleven temporal bones were implanted with the actuator according to the manufacturer's surgical guidelines. The actuator was coupled on the incus short process as recommended for sensorineural hearing loss. Temporal bones were exposed 10 times to the MRI magnetic field by entering the MRI suite in a clinically relevant way. Computed Tomography (CT) images were acquired before and after the experiment to investigate the risk of actuator dislocation. Based on the electrical impedance of the actuator, the loading of the actuator to the incus was confirmed. Relative actuator displacement was determined on the CT images by comparing the initial with the final actuator position in 3D space. Impedance curves were analyzed after each exposure to check the loading of the actuator to the ossicles. Analysis of CT images with a 0.30.6 mm in-plane resolution indicate no actuator displacement. The maximum detected change in impedance for all actuators was 8.43 Ω at the actuator's resonance frequency. Impedance curves measured when the actuator was retracted from the short process after the experiment still indicate the presence of a clear resonance peak. No actuator displacement or dislocation could be detected in the analysis of CT images and the measured impedance curves. Impedance curves obtained when the actuator was retracted from the incus short process still show a clear resonance peak, indicating the device is still functional after the MRI exposures

Stability of the standard incus coupling of the Carina middle ear actuator after 1.5T MRI

Limited data is available concerning the safety of active middle ear implants (AMEI) during Magnetic Resonance Imaging (MRI). Measurements in temporal bones are the gold standard for preclinical assessment of device safety. In this study the coupling stability of an actuator as used in a fully implantable AMEI was determined in temporal bones. Eleven temporal bones were implanted with the actuator according to the manufacturer’s surgical guidelines. The actuator was coupled on the incus short process as recommended for sensorineural hearing loss. Temporal bones were exposed 10 times to the MRI magnetic field by entering the MRI suite in a clinically relevant way. Computed Tomography (CT) images were acquired before and after the experiment to investigate the risk of actuator dislocation. Based on the electrical impedance of the actuator, the loading of the actuator to the incus was confirmed. Relative actuator displacement was determined on the CT images by comparing the initial with the final actuator position in 3D space. Impedance curves were analyzed after each exposure to check the loading of the actuator to the ossicles. Analysis of CT images with a 0.30.6 mm in-plane resolution indicate no actuator displacement. The maximum detected change in impedance for all actuators was 8.43 Ω at the actuator’s resonance frequency. Impedance curves measured when the actuator was retracted from the short process after the experiment still indicate the presence of a clear resonance peak. No actuator displacement or dislocation could be detected in the analysis of CT images and the measured impedance curves. Impedance curves obtained when the actuator was retracted from the incus short process still show a clear resonance peak, indicating the device is still functional after the MRI exposures.status: Published onlin

Posture‐related stiffness mapping of paraspinal muscles

International audienceThe paraspinal compartment acts as a bone–muscle composite beam of the spine. The elastic properties of theparaspinal muscles play a critical role in spine stabilization. These properties depend on the subjects’ posture, andthey may be drastically altered by low back pain. Supersonic shear wave elastography can be used to providequantitative stiffness maps (elastograms), which characterize the elastic properties of the probed tissue. The aimof this study was to challenge shear wave elastography sensitivity to postural stiffness changes in healthyparaspinal muscles. The stiffness of the main paraspinal muscles (longissimus, iliocostalis, multifidus) wasmeasured by shear wave elastography at the lumbosacral level (L3 and S1) for six static postures performed byvolunteers. Passive postures (rest, passive flexion, passive extension) were performed in a first shear waveelastography session, and active postures (upright, bending forward, bending backward) with rest posture forreference were performed in a second session. Measurements were repeated three times for each posture. Sixteenhealthy young adults were enrolled in the study. Non-parametric paired tests, multiple analyses of covariance, andintra-class correlations were implemented for analysis. Shear wave elastography showed good to excellentreliability, except in the multifidus at S1, during bending forward, and in the multifidus at L3, during bendingbackward. Yet, during bending forward, only poor quality was recorded for nine volunteers in the longissimus.Significant intra- and inter-muscular changes were observed with posture. Stiffness significantly increased for theupright position and bending forward with respect to the reference values recorded in passive postures. Inconclusion, shear wave elastography allows reliable assessment of the stiffness of the paraspinal muscles except inthe multifidus at S1 and longissimus, during bending forward, and in the multifidus at L3, during bendingbackward. It reveals a different biomechanical behaviour for the multifidus, the longissimus, and the iliocostalis

Recommandations ESUR sur l’utilisation des produits de contraste : enquête de pratique, revue et commentaire par le CJN, le FIRN et la SFNDT

International audienceContrast media administration is classically considered to cause or worsen kidney failure. Recent data may moderate this assertion. The European Society of Urogenital Radiology recently published guidelines re-evaluating the precautions before administering contrast media. The present work evaluates the practice of French nephrologists, and provides a commentary on these recommendations based on an updated review of the literature. We conducted survey among French nephrologists, using an electronic questionnaire distributed by the Societe Francophone de Nephrologie, Dialyse et Transplantation, the French Intensive care Renal Network and the Club des Jeunes Nephrologues. 266 responses were collected. The European Society of Urogenital Radiology guidelines are poorly known among the panel of nephrologists. Their practices differ from the guidelines by the more frequent and earlier implementation of measures to prevent renal failure post contrast media. In accordance with the guidelines, hydration is prescribed as a first-line preventive measure, mainly with saline and bicarbonate. Inhibitors of the renin-angiotensin-aldosterone system are frequently discontinued before an injection of contrast media, contrary to what is recommended. In conclusion, the European Society of Urogenital Radiology guidelines, which the working group endorses, but which are still too little known and applied in clinical nephrology in France, prompt nephrologists to lift some of the restrictions on the use of PCI as well as on the continuation of ARS inhibitors before injecting PCI. (C) 2020 Societe francophone de nephrologie, dialyse et transplantation.L’injection d’un produit de contraste iodé est classiquement considérée comme un facteur de l’apparition ou de l’aggravation d’une insuffisance rénale. Des données récentes viennent cependant tempérer cette opinion. L’European Society of Urogenital Radiology a récemment publié des recommandations réévaluant les précautions à prendre avant l’administration de produits de contraste. Ce travail propose une évaluation des pratiques des néphrologues français et un commentaire de ces recommandations fondé sur une revue de la littérature. Nous avons mené une enquête de pratique par voie électronique, par l’intermédiaire d’un questionnaire électronique diffusé par la société francophone de néphrologie, dialyse et transplantation, le French Intensive care Renal Network et le club des jeunes néphrologues. Nous avons obtenu 266 réponses. Les recommandations de l’European Society of Urogenital Radiology sont peu connues du panel de néphrologues interrogés. Les pratiques rapportées diffèrent de ces recommandations par la mise en place plus fréquente, et pour un stade moins avancé d’insuffisance rénale chronique, de mesures de prévention de l’insuffisance rénale post-produit de contraste iodé. Conformément aux recommandations, l’hydratation est utilisée en première intention, principalement par soluté salé isotonique et bicarbonate de sodium. Les inhibiteurs du système rénine-angiotensine-aldostérone sont fréquemment arrêtés avant une injection de produit de contraste, contrairement à ce qui est préconisé. En conclusion, les nouvelles recommandations de l’European Society of Urogenital Radiology, que le groupe de travail fait siennes, mais qui sont encore trop peu connues et appliquées en néphrologie clinique en France, incitent les néphrologues à lever certaines des restrictions à l’utilisation des produits de contraste iodés ainsi qu’à la poursuite des inhibiteurs du système rénine-angiotensine-aldostérone avant l’injection des produits de contraste iodés

Kidney and contrast media: Common viewpoint of the French Nephrology societies (SFNDT, FIRN, CJN) and the French Radiological Society (SFR) following ESUR guidelines

International audienceContrast medium administration is classically considered to cause or worsen kidney failure, but recent data may moderate this assertion. The European Society of Urogenital Radiology recently published guidelines re-evaluating the precautions before administering contrast media. Kidney injury does not constitute a contra-indication to the administration of iodinated contrast medium, as long as the benefit-risk ratio justifies it. Intravenous hydration with 0.9% NaCl or 1.4% sodium bicarbonate is the only validated measure for the prevention of post-iodine contrast nephropathy. This is necessary for intravenous or intra-arterial administration of iodinated contrast agent without first renal pass when the glomerular filtration rate is less than 30 mL/min/1.73 m(2), for intra-arterial administration of iodinated contrast agent with first renal passage when the glomerular filtration rate is less than 45 mL/min/1.73 m(2), or in patients with acute renal failure. The use of iodinated contrast medium should allow the carrying out of relevant examinations based on an analysis of the benefit-risk ratio and the implementation of measures to prevent toxicity when necessary. (C) 2021 Societe francaise de radiologie