Real‐time 3D target tracking in MRI guided focused ultrasound ablations in moving tissues

Magnetic resonance imaging‐guided high intensity focused ultrasound is a promising method for the noninvasive ablation of pathological tissue in abdominal organs such as liver and kidney. Due to the high perfusion rates of these organs, sustained sonications are required to achieve a sufficiently high temperature elevation to induce necrosis. However, the constant displacement of the target due to the respiratory cycle render continuous ablations challenging, since dynamic repositioning of the focal point is required. This study demonstrates subsecond 3D high intensity focused ultrasound‐beam steering under magnetic resonance‐guidance for the real‐time compensation of respiratory motion. The target is observed in 3D space by coupling rapid 2D magnetic resonance‐imaging with prospective slice tracking based on pencil‐beam navigator echoes. The magnetic resonance‐data is processed in real‐time by a computationally efficient reconstruction pipeline, which provides the position, the temperature and the thermal dose on‐the‐fly, and which feeds corrections into the high intensity focused ultrasound‐ablator. The effect of the residual update latency is reduced by using a 3D Kalman‐predictor for trajectory anticipation. The suggested method is characterized with phantom experiments and verified in vivo on porcine kidney. The results show that for update frequencies of more than 10 Hz and latencies of less then 114 msec, temperature elevations can be achieved, which are comparable to static experiments. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

Three-dimensional reconstructions for asymptomatic and cerebral palsy children's lower limbs using a biplanar X-ray system: A feasibility study

The aim of this study is to explore the feasibility of 3D subject-specific skeletal reconstructions of lower limb in children using stereoradiography, and to assess uncertainty of clinical and anatomical parameters for children with cerebral palsy and for healthy children. The stereoradiography technique, using the EOS^® system (Eos-imaging^®), is based on the acquisition of two simultaneous digital anteroposterior and lateral X-rays, from head to feet in standing position and at low radiation dose. This technique allows subject-specific skeletal 3D reconstructions. Five children with cerebral palsy (CP) and 5 typically developing children (TD) were included in the study. Two operators performed the lower limb reconstructions twice. Tridimensional reconstructions were feasible for children over the age of 5 years. The study of reproducibility of anatomical parameters defining skeletal alignment showed uncertainties under 3° for the neck shaft angle, the femoral mechanical angle, and for the femoral and tibial torsions. The maximum degree of uncertainty was obtained for the femoral tibial rotation (4° for healthy children and 3.5° for children with CP).     

Clinical study of 40 cases of incontinentia pigmenti

OBJECTIVE: To analyze the distribution of manifestations in a pediatric cohort and define guidelines for follow-up of incontinentia pigmenti (IP). DESIGN: Retrospective study of 47 children referred to the Department of Pediatric Dermatology with a diagnosis of IP between 1986 and 1999. SETTING: The private or institutional practice of participating dermatologists and pediatricians. MAIN OUTCOME MEASURES: Evaluation of IP clinical diagnosis using the Landy and Donnai criteria. RESULTS: Because hyperpigmentation following the Blaschko lines may be observed in several pigmented disorders, 7 patients were found misdiagnosed. During the neonatal period, erythema, vesicles, and hyperkeratotic le sions were rarely absent in the patients with IP. Ocular and neurological abnormalities were frequent (20% and 30%, respectively) but rarely severe (8% and 7.5%, respectively). CONCLUSIONS: Clinical diagnosis is the first main step for a correct phenotype/genotype correlation, which remains indispensable to better understand the pathological mechanisms of IP and develop new therapies. In doubtful cases, molecular analysis is helpful but characteristic histological features must be added as major criteria for IP diagnosis. Multidisciplinary follow-up is needed, particularly during the first year of life, to detect possible ophthalmologic and neurological complications. Neuroimaging ought to be performed in the case of abnormal neurological examination results or when vascular retinopathy is detected.     

Postoperative pain in retinal detachment surgery

Postoperative pain in retinal detachment surgery is frequent but it is often underestimated. The aim of this study was to determine the incidence of postoperative pain after retinal detachment surgery and to identify its predictive factors in a longitudinal study. We included 106 patients operated for retinal detachment surgery using an endo-ocular or exo-ocular approach with general anesthesia. Postoperative monitoring for 24 h evaluated the intensity of pain using a numerical scale. The possible predictive factors of this pain were studied: ocular antecedents, premedication, total amount of morphine used, type of surgery, duration of surgery, and vomiting. The incidence of postoperative pain was 57.5%, 56% of which was intense pain. Postoperative pain was greatest during the first 4 h. The predictive factors of this pain revealed by bivariate analysis of the data were the type of surgery and vomiting. The incidence and intensity of postoperative pain after retinal detachment surgery remain high. Pain management requires postoperative treatment of vomiting as well as the development of the endo-ocular surgery and locoregional anesthesia techniques.     

Le cancer de la tête du pancréas vu aux urgences: aspects cliniques et thérapeutiques

Objectives

In this work, the authors present their experiment of cancer of the head of the pancreas seen to the emergency concerning 85 cases admitted to the service of the surgical emergency during a 6-year period (2000–2006).

Materials and methods

This is a retrospective study spread out over one period, from January 1^st 2000 to June 30^th 2006 at the service of the visceral surgical urgencies dealt with 85 patients carrying the cancer of the head of the pancreas diagnosed on the data from the imagery or peroperative observations.

Result

The mean age of our patients at the time of the diagnosis is of 60 years. It concerns 54 men and 31 women. The jaundice was the first sign leading the patient to consult. The majority of our patients were admitted to in a table of angiocholite (57.7%), with an often-faded general state. Abdominal echography brought the diagnosis of cancer of the head of the pancreas among 45 patients (52.9%). The abdominal tomodensitometry was produced among all our patients, and it showed a tumour of the head of the pancreas in the majority of the cases (98%), of which 55% had a tumour, which size was between 3 and 6 cm. On the therapeutic level, there were seven cases of surgical abstentions (8.2%), eight exploring laparotomies (9.4%), 48 (55.3%) biliary derivations and 17 (20%) cephalic duodenopancreatectomy; the immediate postoperative continuations were marked by the appearance of complications among six patients. In addition, postoperative death rate was of 9.7% (seven cases).

Conclusion

The cancer of the head of the pancreas is an affection of bad prognosis, because its diagnosis is often late where any gesture of excision surgical is impossible. The surgery remains the only potentially curative treatment.     

Papers Please - Predictive Factors of National and International Attitudes Toward Immunity and Vaccination Passports: Online Representative Surveys

BackgroundIn response to the COVID-19 pandemic, countries are introducing digital passports that allow citizens to return to normal activities if they were previously infected with (immunity passport) or vaccinated against (vaccination passport) SARS-CoV-2. To be effective, policy decision-makers must know whether these passports will be widely accepted by the public and under what conditions. This study focuses attention on immunity passports, as these may prove useful in countries both with and without an existing COVID-19 vaccination program; however, our general findings also extend to vaccination passports.ObjectiveWe aimed to assess attitudes toward the introduction of immunity passports in six countries, and determine what social, personal, and contextual factors predicted their support.MethodsWe collected 13,678 participants through online representative sampling across six countries—Australia, Japan, Taiwan, Germany, Spain, and the United Kingdom—during April to May of the 2020 COVID-19 pandemic, and assessed attitudes and support for the introduction of immunity passports.ResultsImmunity passport support was moderate to low, being the highest in Germany (775/1507 participants, 51.43%) and the United Kingdom (759/1484, 51.15%); followed by Taiwan (2841/5989, 47.44%), Australia (963/2086, 46.16%), and Spain (693/1491, 46.48%); and was the lowest in Japan (241/1081, 22.94%). Bayesian generalized linear mixed effects modeling was used to assess predictive factors for immunity passport support across countries. International results showed neoliberal worldviews (odds ratio [OR] 1.17, 95% CI 1.13-1.22), personal concern (OR 1.07, 95% CI 1.00-1.16), perceived virus severity (OR 1.07, 95% CI 1.01-1.14), the fairness of immunity passports (OR 2.51, 95% CI 2.36-2.66), liking immunity passports (OR 2.77, 95% CI 2.61-2.94), and a willingness to become infected to gain an immunity passport (OR 1.6, 95% CI 1.51-1.68) were all predictive factors of immunity passport support. By contrast, gender (woman; OR 0.9, 95% CI 0.82-0.98), immunity passport concern (OR 0.61, 95% CI 0.57-0.65), and risk of harm to society (OR 0.71, 95% CI 0.67-0.76) predicted a decrease in support for immunity passports. Minor differences in predictive factors were found between countries and results were modeled separately to provide national accounts of these data.ConclusionsOur research suggests that support for immunity passports is predicted by the personal benefits and societal risks they confer. These findings generalized across six countries and may also prove informative for the introduction of vaccination passports, helping policymakers to introduce effective COVID-19 passport policies in these six countries and around the world.     

Development of a Kinetic Model for the Redox Reactions of Co2.4Ni0.6O4 and SiO2/Co2.4Ni0.6O4 Oxides for Thermochemical Energy Storage

One of the possible solutions for the transition of the actual energetic model is the use of thermal energy storage technologies. Among them, thermochemical energy storage based on redox reactions involving metal oxides is very promising due to its high energy density. This paper deals with the development of the kinetic study based on data extracted from the thermogravimetric analysis of a cobalt-nickel mixed oxide (Co_2.4Ni_0.6O₄) without and with the addition of SiO₂ particles to improve the cyclability. The results show that in the reduction reaction the activation energy is not affected by the addition of SiO₂ particles while in the oxidation reaction an increase in the activation energy is observed. The theoretical models fitting with the experimental data are different for each material in the reduction reaction. The mixed oxide is controlled by a nucleation and growth mechanism for conversion ratios higher than 0.5, while the added material is controlled by diffusion mechanisms. In the oxidation reaction, the two materials are controlled by a nucleation and growth mechanism for conversion ratios higher than 0.5.