1,721,075 research outputs found
Cardio-respiratory mechanical simulator for in vitro testing of impedance minute ventilation sensors in cardiac pacemakers
No full textWe developed a Cardio-Respiratory Mechanical Simulator (CRMS), a system able to reproduce both the cardiac and respiratory movements, intended to be used for in vitro testing of impedance Minute Ventilation (iMV) sensors in cardiac pacemakers. The simulator consists of two actuators anchored to a human thorax model and a software interface to control the actuators and to acquire/process impedance signals. The actuators can be driven separately or simultaneously to reproduce the cardiac longitudinal shortening (LS) at a programmable heart rate (HR) and the diaphragm displacement (DD) at a programmable respiratory rate (RR). A standard bipolar pacing lead moving with the actuators and a pacemaker case fixed to the thorax model have been used to measure impedance (Z) variations during the simulated cardio-respiratory movements. The software is able to discriminate the low-frequency component due to respiration (ZR) from the high-frequency ripple due to cardiac effect (ZC). iMV is continuously calculated from ZR and RR. From preliminary tests the CRMS proved to be a reliable simulator for in vitro evaluation of iMV sensors. ZR recordings collected during cardio-respiratory movements reproduced by the CRMS were comparable in morphology and amplitude with in vivo assessments of transthoracic impedance variations
An Implantable Sensorized Lead for Continuous Monitoring of Cardiac Apex Rotation
Full text linkChanges in the pattern or amplitude of cardiac rotation have been associated with important cardiovascular diseases, including Heart Failure (HF) which is one of the major health problems worldwide. Recent advances in echocardiographic techniques have allowed for non-invasive quantification of cardiac rotation; however, these examinations do not address the continuous monitoring of patient status. We have presented a newly developed implantable, transvenous lead with a tri-axis (3D) MEMS gyroscope incorporated near its tip to measure cardiac apex rotation in the three-dimensional space. We have named it CardioMon for its intended use for cardiac monitoring. If compared with currently proposed implantable systems for HF monitoring based on the use of pressure sensors that can have reliability issues, an implantable motion sensor like a gyroscope holds the premise for more reliable long term monitoring. The first prototypal assembly of the CardioMon lead has been tested to assess the reliability of the 3D gyroscope readings. In vitro results showed that the novel sensorized CardioMon lead was accurate and reliable in detecting angular velocities within the range of cardiac twisting velocities. Animal experiments will be planned to further evaluate the CardioMon lead in in vivo environments and to investigate possible endocardial implantation sites
Gaze Trajectory Index (GTI): A novel metric to quantify saccade trajectory deviation using eye tracking
No full textBackground: Many different indexes have been proposed to quantify saccade curvature based on geometric properties of the saccade trajectory projected on the 2D plane. We introduce the Gaze Trajectory Index (GTI), a novel metric to quantify saccade trajectory deviation based on calculation of the rotational eye movements performed in 3D space while following a 2D saccade trajectory recorded with eye tracking (ET). Methods: We provided a description of GTI calculation. In 13 subjects with normal binocular vision we assessed GTI in single-target tests, then we evaluated GTI against previously proposed metrics (Maximum Deviation,MD; Area Curvature,AC; Quadratic Curvature,QC; Initial Direction,ID) using a distractor paradigm that elicited two types of saccade deviations, i.e.“inner-curved” and “outer-curved” saccades. Results: In single-target tests GTI showed that saccade curvature was significantly higher for oblique than for vertical saccades (0.86°±0.32 vs 0.55°±0.60,p < 0.05) and higher for vertical than for horizontal saccades (0.55°±0.60 vs 0.23°±0.17,p < 0.05), in accordance with previous studies. In distractor-based tests, for inner-curved saccades, GTI strongly correlated with MD (r = 0.965,p < 0.01), AC (r = 0.940,p < 0.01), QC (r = 0.866,p < 0.01), and Principal Component Analysis (PCA) confirmed that all these metrics reflect the same underlying phenomenon. For outer-curved trajectories, GTI showed poor correlation with MD and AC (r = 0.291 and 0.416,p < 0.01), however PCA included the three metrics in the same first component group. For outer-curved trajectories, GTI was the only metric showing strong correlation (r = 0.950,p < 0.05) with the overshoot degree of the trajectory. Conclusion: The novel GTI seems to have adjunctive potential, particularly for outer-curved trajectories, in the estimation of the absolute amount of saccade trajectory deviation
Augmented reality for orthopedic and maxillofacial oncological surgery: a systematic review focusing on both clinical and technical aspects
Full text linkThis systematic review offers an overview on clinical and technical aspects of augmented reality (AR) applications in orthopedic and maxillofacial oncological surgery. The review also provides a summary of the included articles with objectives and major findings for both specialties. The search was conducted on PubMed/Medline and Scopus databases and returned on 31 May 2023. All articles of the last 10 years found by keywords augmented reality, mixed reality, maxillofacial oncology and orthopedic oncology were considered in this study. For orthopedic oncology, a total of 93 articles were found and only 9 articles were selected following the defined inclusion criteria. These articles were subclassified further based on study type, AR display type, registration/tracking modality and involved anatomical region. Similarly, out of 958 articles on maxillofacial oncology, 27 articles were selected for this review and categorized further in the same manner. The main outcomes reported for both specialties are related to registration error (i.e., how the virtual objects displayed in AR appear in the wrong position relative to the real environment) and surgical accuracy (i.e., resection error) obtained under AR navigation. However, meta-analysis on these outcomes was not possible due to data heterogenicity. Despite having certain limitations related to the still immature technology, we believe that AR is a viable tool to be used in oncological surgeries of orthopedic and maxillofacial field, especially if it is integrated with an external navigation system to improve accuracy. It is emphasized further to conduct more research and pre-clinical testing before the wide adoption of AR in clinical settings
Semantic Image Synthesis for Realistic Image Generation in Robotic Assisted Partial Nephrectomy
No full textWith the continuous evolution of robotic-assisted surgery, the integration of advanced technologies into the field becomes pivotal for improving surgical outcomes. The lack of labelled surgical datasets limits the range of possible applications of deep learning techniques in the surgical field. As a matter of fact, the annotation process to label datasets is time consuming. This paper introduces an approach for realistic image generation in the context of Robotic Assisted Partial Nephrectomy (RAPN) using the Semantic Image Synthesis (SIS) technique. Leveraging descriptive semantic maps, our method aims to bridge the gap between abstract scene representation and visually compelling laparoscopic images. It is shown that our approach can effectively generate photo-realistic Minimally Invasive Surgery (MIS) synthetic images starting from a sparse set of annotated real images. Furthermore, we demonstrate that synthetic data can be used to train a semantic segmentation network that general izes on real data reducing the annotation time needed
Understanding How Different Visual Aids for Augmented Reality Influence Tool-Patient Alignment in Surgical Tasks: A Preliminary Study
No full textThis study explores the impact of several visual aids on the accuracy of tool-patient alignment in augmented reality (AR) assisted surgical tasks. AR has gained prominence across surgical specialties, integrating virtual models derived from patient anatomy into the surgical field. This opens avenues for innovative visual aids and feedback which can facilitate surgical operations. To assess the influence of different visual aids on surgeon performance, we conducted a tool-patient alignment test on a 3D-printed frame, involving 12 surgical residents. Each participant inserted 12 toothpicks with a release tool into predefined target positions on the frame simulating patient targets, under AR visualization through a Magic Leap 2 Head-Mounted-Display. As visual aids, four holographic solutions were employed, with two of them offering graphical feedback upon the correct alignment to the target. Linear and angular positioning errors were measured, alongside participant responses to a satisf action questionnaire. The tests maintained a consistent tracking system for estimating target and tool poses in the real-world, ensuring evaluation stability. Preliminary results indicated statistically significant differences among the proposed visual aids, suggesting the need for further exploration in the realm of their usability in relation to the specific surgical task and the expected overall surgical accuracy
CathROB: A Highly Compact and Versatile Remote Catheter Navigation System
Full text linkSeveral remote catheter navigation systems have been developed and are now commercially available. However, these systems typically require specialized catheters or equipment, as well as time-consuming operations for the system set-up. In this paper, we present CathROB, a highly compact and versatile robotic system for remote navigation of standard tip-steerable electrophysiology (EP) catheters. Key features of CathROB include an extremely compact design that minimizes encumbrance and time for system set-up in a standard cath lab, a force-sensing mechanism, an intuitive command interface, and functions for automatic catheter navigation and repositioning. We report in vitro and in vivo animal evaluation of CathROB. In vitro results showed good accuracy in remote catheter navigation and automatic repositioning (1.5 ± 0.6 mm for the left-side targets, 1.7 ± 0.4 mm for the right-side targets). Adequate tissue contact was achieved with remote navigation in vivo. There were no adverse events, including absence of cardiac perforation or cardiac damage, indicative of the safety profile of CathROB. Although further preclinical and clinical studies are required, the presented CathROB system seems to be a promising solution for an affordable and easy-to-use remote catheter navigation
A Novel Sensorized Heart Valve Prosthesis: Preliminary In Vitro Evaluation
Full text linkBackground: Recent studies have shown that subclinical valve thrombosis in heart valve prosthesis (HVP) can be responsible for reduced leaflet motion detectable only by advanced imaging diagnostics. We conceived a novel sensorized HVP able to detect earlier any thrombus formation that may alter the leaflets motion using an electric impedance measurement, IntraValvular Impedance (IVI). Methods: For IVI measurement, dedicated electrodes are embedded in the structure of the HVP to generate a local electric field that is altered by the moving valve leaflets during their cyclic opening/closing. We present preliminary in vitro results using a first prototype of sensorized mechanical heart valve connected to an external impedance measurement system. The prototype was tested on a circulatory mock loop system and the IVI signals were recorded during both normal dynamics and experimentally induced altered working of the leaflets. Results: Recordings showed a very repetitive and stable IVI signal during the normal cyclic opening/closing of the HVP. The induced alterations in leaflet motion were reflected in the IVI signal. Conclusions: The novel sensorized HVP has great potential to give early warning of possible subclinical valve thrombosis altering the valve leaflet motion, and to help in tailoring the anticoagulation therapy
Multi-Sense CardioPatch: A Wearable Patch for Remote Monitoring of Electro-Mechanical Cardiac Activity
No full textThis study describes the conceptual design and the first prototype implementation of the Multi-Sense CardioPatch, a wearable multi-sensor patch for remote heart monitoring aimed at providing a more detailed and comprehensive heart status diagnostics. The system integrates multiple sensors in a single patch for detection of both electrical (electrocardiogram, ECG) and mechanical (heart sounds, HS) cardiac activity, in addition to physical activity (PA). The prototypal system also comprises a microcontroller board with a radio communication unit and it is powered by a Li-Ion rechargeable battery. Results from preliminary evaluations on healthy subjects have shown that the prototype can successfully measure electro-mechanical cardiac activity, providing useful cardiac indexes. The system has potential to improve remote monitoring of cardiac function in chronically diseased patients undergoing home-based cardiac rehabilitation programs
Basic Hemodynamic Parameters
No full textThis chapter deals with the complex evaluation of hemodynamic performance of the cardiovascular system, which should take into account the pump function, the heart, and the system of transport, distribution, and collection of blood, comprising arteries and veins, both for the systemic and the pulmonary circulation. We aim to explain the physiological basis of hemodynamic parameters and the clinical utility of their use
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