Diagnostic performance of a novel deep learning attenuation correction software for MPI using a cardio dedicated CZT camera. Experience in the clinical practice.

PURPOSE: To evaluate the diagnostic performance of a novel deep learning attenuation correction software (DLACS) for myocardial perfusion imaging (MPI) using a cadmium-zinc-telluride (CZT) cardio dedicated camera with invasive coronary angiography (ICA) correlation for the diagnosis of coronary artery disease (CAD) in a high-risk population. METHODS: Retrospective study of 300 patients (196 males [65%], mean age 68 years) from September 2014 to October 2019 undergoing MPI, followed by ICA and evaluated by means of quantitative angiography software, within six months after the MPI. The mean pre-test probability score for coronary disease according to the European Society of Cardiology criteria was 37% for the whole cohort. The MPI was performed in a dedicated CZT cardio camera (D-SPECT Spectrum Dynamics) with a two-day protocol, according to the European Association of Nuclear Medicine guidelines. MPI was retrospectively evaluated with and without the DLACS. RESULTS: The overall diagnostic accuracy of MPI without DLACS to identify patients with any obstructive CAD at ICA was 87%, sensitivity 94%, specificity 57%, Positive Predictive Value 91% and Negative Predictive Value 64%. Using DLACS the overall diagnostic accuracy was 90%, sensitivity 91%, specificity 86%, Positive Predictive Value 97% and Negative Predictive Value 66%. CONCLUSION: Use of the novel DLACS enhances performance of the MPI using the CZT D-SPECT camera and achieves improved results, especially avoiding artefacts and reducing the number of false positive results.

Efficacy of Oral Anticoagulation in Stroke Prevention among Sinus-Rhythm Patients Who Lack Left Atrial Mechanical Contraction after Cryoablation.

The customary recommendation is that oral anticoagulation be withdrawn a few months after cryoablation for atrial fibrillation, independently of left atrial mechanical contraction in patients in sinus rhythm. Recently, a 5-fold increase in stroke has been described in sinus-rhythm patients who lack atrial mechanical contraction. One aim of this study was to evaluate the efficacy of oral anticoagulation in preventing postoperative stroke in such patients. This prospective study divided 154 sinus-rhythm patients into 2 groups, depending on the presence (108 patients) or absence (46 patients) of left atrial mechanical contraction at 6 months after surgery, and monitored them annually for 5 years. Those without left atrial contraction were maintained on acenocumarol. The primary endpoint was the occurrence of ischemic stroke. The median follow-up period was 29 ± 16 months; 4 patients (2.5%), all belonging to the group with preserved atrial contraction, had ischemic stroke; the group of patients without left atrial contraction had no episodes of stroke during follow-up. Logistic binary regression analyses showed no evidence of factors independently predictive of stroke. Among anticoagulated patients in sinus rhythm without left atrial contraction, we found the incidence of stroke to be zero. In a small, nonrandomized group such as this, we cannot discount the element of chance, yet we suggest that maintaining anticoagulation might lower the incidence of stroke in this population.

Impact of alprazolam in allostatic load and neurocognition of patients with anxiety disorders and chronic stress (GEMA): observational study protocol.

INTRODUCTION: The allostatic load model explains the additive effects of multiple biological processes that accelerate pathophysiology related to stress, particularly in the central nervous system. Stress-related mental conditions such as anxiety disorders and neuroticism (a well-known stress vulnerability factor), have been linked to disturbances of hypothalamo-pituitary-adrenal with cognitive implications. Nevertheless, there are controversial results in the literature and there is a need to determine the impact of the psychopharmacological treatment on allostatic load parameters and in cognitive functions. Gador study of Estres Modulation by Alprazolam, aims to determine the impact of medication on neurobiochemical variables related to chronic stress, metabolic syndrome, neurocognition and quality of life in patients with anxiety, allostatic load and neuroticism. METHODS/ANALYSIS: In this observational prospective phase IV study, highly sympthomatic patients with anxiety disorders (six or more points in the Hamilton-A scale), neuroticism (more than 18 points in the Neo five personality factor inventory (NEO-FFI) scale), an allostatic load (three positive clinical or biochemical items at Crimmins and Seeman criteria) will be included. Clinical variables of anxiety, neuroticism, allostatic load, neurobiochemical studies, neurocognition and quality of life will be determined prior and periodically (1, 2, 4, 8, and 12 weeks) after treatment (on demand of alprazolam from 0.75 mg/day to 3.0 mg/day). A sample of n=55/182 patients will be considered enough to detect variables higher than 25% (pretreatment vs post-treatment or significant correlations) with a 1-ß power of 0-80. t Test and/or non-parametric test, and Pearson's test for correlation analysis will be determined. ETHICS AND DISSEMINATION: This study protocol was approved by an Independent Ethics Committee of FEFyM (Foundation for Pharmacological Studies and Drugs, Buenos Aires) and by regulatory authorities of Argentina (ANMAT, Dossier # 61 409-8 of 20 April 2009), following the law of Habeas Data and psychotherapeutic drug control. TRIAL REGISTRATION NUMBER: GEMA 20811.

Third CoreValve™ insertion for treatment of a severe paravalvular leak after a failed valve-in-valve procedure.

An 83-year-old high-risk gentleman diagnosed with severe symptomatic aortic stenosis was scheduled for TAVR. A 31 mm CoreValve was implanted but severe paravalvular leak was noted. A valve-in-valve procedure was performed. However, the valve frame was partially dislodged into de ascending aorta. We report our strategy to solve this severe leak after a failed valve-in-valve procedure.

Towards a new modality-independent interface for a robotic wheelchair.

This work presents the development of a robotic wheelchair that can be commanded by users in a supervised way or by a fully automatic unsupervised navigation system. It provides flexibility to choose different modalities to command the wheelchair, in addition to be suitable for people with different levels of disabilities. Users can command the wheelchair based on their eye blinks, eye movements, head movements, by sip-and-puff and through brain signals. The wheelchair can also operate like an auto-guided vehicle, following metallic tapes, or in an autonomous way. The system is provided with an easy to use and flexible graphical user interface onboard a personal digital assistant, which is used to allow users to choose commands to be sent to the robotic wheelchair. Several experiments were carried out with people with disabilities, and the results validate the developed system as an assistive tool for people with distinct levels of disability.

Robust human machine interface based on head movements applied to assistive robotics.

This paper presents an interface that uses two different sensing techniques and combines both results through a fusion process to obtain the minimum-variance estimator of the orientation of the user's head. Sensing techniques of the interface are based on an inertial sensor and artificial vision. The orientation of the user's head is used to steer the navigation of a robotic wheelchair. Also, a control algorithm for assistive technology system is presented. The system is evaluated by four individuals with severe motors disability and a quantitative index was developed, in order to objectively evaluate the performance. The results obtained are promising since most users could perform the proposed tasks with the robotic wheelchair.

Surface electromyogram signals classification based on bispectrum.

This paper bispectrum is used to classify human arm movements and control a robotic arm based on upper limb's surface electromyogram signals (sEMG). We use bispectrum based on third-order cumulant to parameterize sEMG signals and classify elbow flexion and extension, forearm pronation and supination, and rest states by an artificial neural network (ANN). Finally, a robotic manipulator is controlled based on classification and parameters extracted from the signals. All this process is made in real-time using QNX ® operative system.

Vision based interface: an alternative tool for children with cerebral palsy.

In this paper a new vision based interface (VBI) for children with cerebral palsy is presented. The VBI is implemented for the interaction between children and computer. The VBI detects and tracks the movement of the hand, foot or head of the user. These movements are translated into movements of the cursor on the screen of the computer. The evaluation of system user-VBI is based on HAAT model. The experimental results show four vase studies of children, when they carried out different tasks with the computer.

SLAM algorithm applied to robotics assistance for navigation in unknown environments.

BACKGROUND: The combination of robotic tools with assistance technology determines a slightly explored area of applications and advantages for disability or elder people in their daily tasks. Autonomous motorized wheelchair navigation inside an environment, behaviour based control of orthopaedic arms or user's preference learning from a friendly interface are some examples of this new field. In this paper, a Simultaneous Localization and Mapping (SLAM) algorithm is implemented to allow the environmental learning by a mobile robot while its navigation is governed by electromyographic signals. The entire system is part autonomous and part user-decision dependent (semi-autonomous). The environmental learning executed by the SLAM algorithm and the low level behaviour-based reactions of the mobile robot are robotic autonomous tasks, whereas the mobile robot navigation inside an environment is commanded by a Muscle-Computer Interface (MCI). METHODS: In this paper, a sequential Extended Kalman Filter (EKF) feature-based SLAM algorithm is implemented. The features correspond to lines and corners -concave and convex- of the environment. From the SLAM architecture, a global metric map of the environment is derived. The electromyographic signals that command the robot's movements can be adapted to the patient's disabilities. For mobile robot navigation purposes, five commands were obtained from the MCI: turn to the left, turn to the right, stop, start and exit. A kinematic controller to control the mobile robot was implemented. A low level behavior strategy was also implemented to avoid robot's collisions with the environment and moving agents. RESULTS: The entire system was tested in a population of seven volunteers: three elder, two below-elbow amputees and two young normally limbed patients. The experiments were performed within a closed low dynamic environment. Subjects took an average time of 35 minutes to navigate the environment and to learn how to use the MCI. The SLAM results have shown a consistent reconstruction of the environment. The obtained map was stored inside the Muscle-Computer Interface. CONCLUSIONS: The integration of a highly demanding processing algorithm (SLAM) with a MCI and the communication between both in real time have shown to be consistent and successful. The metric map generated by the mobile robot would allow possible future autonomous navigation without direct control of the user, whose function could be relegated to choose robot destinations. Also, the mobile robot shares the same kinematic model of a motorized wheelchair. This advantage can be exploited for wheelchair autonomous navigation.

Robust EMG sensing system based on data fusion for myoelectric control of a robotic arm.

BACKGROUND: Myoelectric control of a robotic manipulator may be disturbed by failures due to disconnected electrodes, interface impedance changes caused by movements, problems in the recording channel and other various noise sources. To correct these problems, this paper presents two fusing techniques, Variance Weighted Average (VWA) and Decentralized Kalman Filter (DKF), both based on the myoelectric signal variance as selecting criterion. METHODS: Tested in five volunteers, a redundant arrangement was obtained with two pairs of electrodes for each recording channel. The myoelectric signals were electronically amplified, filtered and digitalized, while the processing, fusion algorithms and control were implemented in a personal computer under MATLAB environment and in a Digital Signal Processor (DSP). The experiments used an industrial robotic manipulator BOSCH SR-800, type SCARA, with four degrees of freedom; however, only the first joint was used to move the end effector to a desired position, the latter obtained as proportional to the EMG amplitude. RESULTS: Several trials, including disconnecting and reconnecting one electrode and disturbing the signal with synthetic noise, were performed to test the fusion techniques. The results given by VWA and DKF were transformed into joint coordinates and used as command signals to the robotic arm. Even though the resultant signal was not exact, the failure was ignored and the joint reference signal never exceeded the workspace limits. CONCLUSION: The fault robustness and safety characteristics of a myoelectric controlled manipulator system were substantially improved. The proposed scheme prevents potential risks for the operator, the equipment and the environment. Both algorithms showed efficient behavior. This outline could be applied to myoelectric control of prosthesis, or assistive manipulators to better assure the system functionality when electrode faults or noisy environment are present.

[Usefulness of rapid bedside assay of cardiac troponin I and creatine phosphokinase-MB in acute ischemic coronary syndromes]. / Utilidad de la determinación cualitativa de troponina I y creatinfosfocinasa isoenzima MB en los síndromes isquémicos coronarios agudos.

Recently, a rapid bedside assay for quantitative determination of cTI and CPK-MB has been developed that provides a positive or negative result in 10 to 15 minutes allowing for a better therapeutic approach. The objective of our study was to validate the diagnostic usefulness of cardiac troponin I in patients with chest pain. We determined sensitivity, specificity, positive and negative predictive values in 40 patients that arrived to the hospital with chest pain. These patients were assigned to four different groups: Group A: Patients with acute myocardial infarction. Group B: Patients with unstable angina and normal ECG. Group C: Patients with atypical chest pain and normal ECG. Group D: Control. Eighteen (45%) patients were woman and 22 (55%) were men; age 54.1 +/- 26, range 32 to 85 years. In Group A, sensitivity, specificity, positive and negative predictive values for cTI were 95%, for CPK-MB, they were 40, 50, 90, 7.1%. For Group B, cTI: 64, 90, 90, 64%; CPK-MB: 50, 90, 87, 56%. Group C, cTI and CPK MB 25, 95, 50, 86%. Group D, cTI and CPK-MB: 50, 95, 50, 95%. This study suggests that the rapid bedside qualitative test through cardiac troponin I assessment is a test with higher predictive value for early diagnosis of acute myocardial infarction than CPK-MB.

Utilidad de la determinación cualitativa de troponina I y creatinfosfocinasa isoenzima MB en los síndromes isquémicos coronarios agudos / Usefulness of rapid bedside assay of cardiac troponin I and creatine phosphokinase-MB in acute ischemic coronary syndromes

Recently, a rapid bedside assay for quantitative determination of cTI and CPK-MB has been developed that provides a positive or negative result in 10 to 15 minutes allowing for a better therapeutic approach. The objective of our study was to validate the diagnostic usefulness of cardiac troponin I in patients with chest pain. We determined sensitivity, specificity, positive and negative predictive values in 40 patients that arrived to the hospital with chest pain. These patients were assigned to four different groups: Group A: Patients with acute myocardial infarction. Group B: Patients with unstable angina and normal ECG. Group C: Patients with atypical chest pain and normal ECG. Group D: Control. Eighteen (45%) patients were woman and 22 (55%) were men; age 54.1 +/- 26, range 32 to 85 years. In Group A, sensitivity, specificity, positive and negative predictive values for cTI were 95%, for CPK-MB, they were 40, 50, 90, 7.1%. For Group B, cTI: 64, 90, 90, 64%; CPK-MB: 50, 90, 87, 56%. Group C, cTI and CPK MB 25, 95, 50, 86%. Group D, cTI and CPK-MB: 50, 95, 50, 95%. This study suggests that the rapid bedside qualitative test through cardiac troponin I assessment is a test with higher predictive value for early diagnosis of acute myocardial infarction than CPK-MB.

Influencia de algunos preservativos conservadores sobre la efectividad de una vacuna contra la enfermedad del Newcastle / Influence of some conservative preservative on the efficiency of a vaccine against Newcastle disease

La estructura viral puede verse afectada por la presencia de ciertos compuestos químicos. Se demuestra un aumento en el tiempo de mortalidad de embriones de pollo que recibieron virus expuestos a conservadores como el fenol o el metil y el propil parabeno, lo que indica una disminución significativa en el número de partículas virales viables capaces de causar infección. Por hemoaglutinación también se demuestra un incremento relativamente pequeño y lento en el número de virus, en función de un tiempo determinado, en el líquido alaitoideo de embriones inoculados con virus expuestos a fenol y parabenos, a diferencia de otros embriones que recibieron vacunas expuestas a conservadores como la penicilina y estreptomicina con o sin tampón fosfato. El uso de vacunas tratadas con fenol o parabenos, previo a su administración en pollitos, dieron títulos serológicos de inhibición de la hemoaglutinación bastante bajos, demostrando también la importancia del uso adecuado de conservadores apropiados en una formulación vacunal

Seguridad de la vacuna Cerdovirac como preventiva de la peste porcina clásica / Safety of the Cerdovirac vaccine as preventive of classical hog swine plague

La peste porcina clásica es una enfermedad viral, específica de los cerdos, la cual sólo puede ser prevenida por vacunación. Este trabajo reporta sobre la seguridad de administrar virus vivo modificado por lapinización como profiláctico contra infecciones experimentales homólogas. De las mediciones de temperatura, antes o después de la vacunación y confrontación, en combinación con los resultados histopatológicos, se reporta la incapacidad de los virus modificados, a diferencia de la cepa virulenta de confrontación, de ocasionar infección patológica visualizada por el aparecimiento de fiebre y microcoagulaciones sistémicas con daños endoteliales de los vasos sanguíneos e infiltración linfoplasmocitaria en los tejidos. A esto se suma la habilidad de estos virus para proteger totalmente contra dosis letales cuando se administran a individuos sanos con pesos alrededor de 9.5 kg o más. La resistencia humoral parece ser importante según los resultados de la administración de suero realizada temprano a los 3 días de la infección; caso contrario, los efectos del virus de confrontación resultaron ser mortalmente irreversibles