Heartbeat Motion Research Articles

Respiration and heartbeat motion correction of intraoperative thermographic images in neurosurgery

In this paper, a new respiration and heartbeat motion artifacts correction method for thermographic images in neurosurgery is presented. Aims to solve the ambiguity of the respiration and heartbeat motion artifacts correction of thermographic images in neurosurgery. The proposed method consists of two main steps; firstly, a complex steerable pyramid is employed to separate the local wavelets of the phase for each thermographic image. Thereafter, temporal filtering is carried out to pass respiration and heartbeat frequencies and reject other frequencies outside that range followed by image reconstruction. Secondly, the optimized and adjusted-combined local and global (OA-CLG) method is applied to detect respiration and heartbeat motion artifacts only. Afterwards, a bicubic interpolation is carried out to compensate the estimated motion artifacts. To evaluate the proposed method’s performance and accuracy, 10 clinical thermographic datasets were examined. Results show that with the proposed method respiration and heartbeat motion artifacts can be corrected while preserving the image structures, properties, spatial resolution, and maintaining temperature values.

Position-based dynamics simulator of vessel deformations for path planning in robotic endovascular catheterization.

A major challenge during autonomous navigation in endovascular interventions is the complexity of operating in a deformable but constrained workspace with an instrument. Simulation of deformations for it can provide a cost-effective training platform for path planning. Aim of this study is to develop a realistic, auto-adaptive, and visually plausible simulator to predict vessels' global deformation induced by the robotic catheter's contact and cyclic heartbeat motion. Based on a Position-based Dynamics (PBD) approach for vessel modeling, Particle Swarm Optimization (PSO) algorithm is employed for an auto-adaptive calibration of PBD deformation parameters and of the vessels movement due to a heartbeat. In-vitro experiments were conducted and compared with in-silico results. The end-user evaluation results were reported through quantitative performance metrics and a 5-Point Likert Scale questionnaire. Compared with literature, this simulator has an error of 0.23±0.13% for deformation and 0.30±0.85mm for the aortic root displacement. In-vitro experiments show an error of 1.35±1.38mm for deformation prediction. The end-user evaluation results show that novices are more accustomed to using joystick controllers, and cardiologists are more satisfied with the visual authenticity. The real-time and accurate performance of the simulator make this framework suitable for creating a dynamic environment for autonomous navigation of robotic catheters.

WIDEBAND ENERGY HARVESTING FOR IMPLANTABLE BIOMEDICAL APPLICATIONS

In this paper, a nonresonant electromagnetic micro-generator is proposed. The proposed device is capable of converting nonresonant environmental vibrations to electrical power. The energy harvester could generate output power from heartbeat, human leg and arm motion. The proposed energy harvester uses Frequency up CONVersion technique (FCONV) to improve the bandwidth of the device. The results approve the high bandwidth of the proposed method. The micro-generator is designed by micro-electro-mechanical systems (MEMS) methods. Consequently, the volume of the power harvester is minimized and power density is maximized. The new configuration of energy harvester with imposed motion trigger is proposed. Output power, bandwidth and performance of the designed micro-power harvester are discussed. The proposed micro-generator exhibits higher bandwidth in comparison with resonant, multi-resonant and tunable bandwidth structures. The nonresonant device is designed using FCONV to convert 1–3[Formula: see text]Hz heartbeat mechanical vibrations to output electrical power. The optimum upconverted mechanical vibration frequency is 60[Formula: see text]Hz and the output voltage frequency is 120[Formula: see text]Hz. The peak output electrical power of FCONV is 17.75[Formula: see text][Formula: see text]W. For 1[Formula: see text]Hz, 2[Formula: see text]Hz and 3[Formula: see text]Hz mechanical vibration with imposed motion trigger, average output powers are 1.60[Formula: see text][Formula: see text]W, 3.81[Formula: see text][Formula: see text]W and 5.19[Formula: see text][Formula: see text]W, respectively. The achieved results illustrate that the proposed FCONV method exhibits better and wider frequency response in comparison with different methods. The designed device can be utilized to supply implantable biomedical sensors. Also, the heat generation of the device is studied. The results illustrate that the temperature rise of the micro-generator remains in the normal human body temperature range. Hence, the proposed power harvester is biocompatible.

Your Smart Speaker Can "Hear" Your Heartbeat!

Vital sign monitoring is a common practice amongst medical professionals, and plays a key role in patient care and clinical diagnosis. Traditionally, dedicated equipment is employed to monitor these vital signs. For example, electrocardiograms (ECG) with 3-12 electrodes are attached to the target chest for heartbeat monitoring. In the last few years, wireless sensing becomes a hot research topic and wireless signal itself is utilized for sensing purposes without requiring the target to wear any sensors. The contact-free nature of wireless sensing makes it particularly appealing in current COVID-19 pandemic. Recently, promising progress has been achieved and the sensing granularity has been pushed to millimeter level, fine enough to monitor respiration which causes a chest displacement of 5 mm. While a great success with respiration monitoring, it is still very challenging to monitor heartbeat due to the extremely subtle chest displacement (0.1 - 0.5 mm) - smaller than 10% of that caused by respiration. What makes it worse is that the tiny heartbeat-caused chest displacement is buried inside the respiration-caused displacement. In this paper, we show the feasibility of employing the popular smart speakers (e.g., Amazon Echo) to monitor an individual's heartbeats in a contact-free manner. To extract the submillimeter heartbeat motion in the presence of other interference movements, a series of novel signal processing schemes are employed. We successfully prototype the first real-time heartbeat monitoring system using a commodity smart speaker. Experiment results show that the proposed system can monitor a target's heartbeat accurately, achieving a median heart rate estimation error of 0.75 beat per minute (bpm), and a median heartbeat interval estimation error of 13.28 ms (less than 1.8%), outperforming even some popular commodity products available on the market.

In-Vitro MPI-guided IVOCT catheter tracking in real time for motion artifact compensation.

Using 4D magnetic particle imaging (MPI), intravascular optical coherence tomography (IVOCT) catheters are tracked in real time in order to compensate for image artifacts related to relative motion. Our approach demonstrates the feasibility for bimodal IVOCT and MPI in-vitro experiments. During IVOCT imaging of a stenosis phantom the catheter is tracked using MPI. A 4D trajectory of the catheter tip is determined from the MPI data using center of mass sub-voxel strategies. A custom built IVOCT imaging adapter is used to perform different catheter motion profiles: no motion artifacts, motion artifacts due to catheter bending, and heart beat motion artifacts. Two IVOCT volume reconstruction methods are compared qualitatively and quantitatively using the DICE metric and the known stenosis length. The MPI-tracked trajectory of the IVOCT catheter is validated in multiple repeated measurements calculating the absolute mean error and standard deviation. Both volume reconstruction methods are compared and analyzed whether they are capable of compensating the motion artifacts. The novel approach of MPI-guided catheter tracking corrects motion artifacts leading to a DICE coefficient with a minimum of 86% in comparison to 58% for a standard reconstruction approach. IVOCT catheter tracking with MPI in real time is an auspicious method for radiation free MPI-guided IVOCT interventions. The combination of MPI and IVOCT can help to reduce motion artifacts due to catheter bending and heart beat for optimized IVOCT volume reconstructions.

Heartbeat Signal Detection From Analysis of Airflow in Rat Airway Under Different Depths of Anaesthesia Conditions

We inserted a tubular flow sensor incorporating micro-electro-mechanical systems technologies directly into the rat airway and analyzed the airflow waveforms obtained under different depths of anaesthesia conditions by using discrete Fourier transformation (DFT) to evaluate the heartbeat frequency. The electrocardiogram (ECG) signal was used as the reference heartbeat frequency. The calibration curve of the flow sensor used to measure the oscillating airflow in the rat airway was determined on the basis of King’s law. The airflow waveform at the rat airway caused by only the heartbeat was measured by applying deep anaesthesia; the waveform frequency coincided with the simultaneously measured ECG signal frequency. DFT analysis of the airflow signals measured under deep and shallow anaesthesia conditions verified the fundamental heartbeat frequency values. The airflow components related to heartbeat motion were successfully extracted by using the heartbeat frequency spectrum. The respiration and heartbeat signals were thus successfully detected.

Comprehensive biocompatibility of nontoxic and high-output flexible energy harvester using lead-free piezoceramic thin film

Flexible piezoelectric energy harvesters have been regarded as an overarching candidate for achieving self-powered electronic systems for environmental sensors and biomedical devices using the self-sufficient electrical energy. In this research, we realize a flexible high-output and lead-free piezoelectric energy harvester by using the aerosol deposition method and the laser lift-off process. We also investigated the comprehensive biocompatibility of the lead-free piezoceramic device using ex-vivo ionic elusion and in vivo bioimplantation, as well as in vitro cell proliferation and histologic inspection. The fabricated LiNbO3-doped (K,Na)NbO3 (KNN) thin film-based flexible energy harvester exhibited an outstanding piezoresponse, and average output performance of an open-circuit voltage of ∼130 V and a short-circuit current of ∼1.3 μA under normal bending and release deformation, which is the best record among previously reported flexible lead-free piezoelectric energy harvesters. Although both the KNN and Pb(Zr,Ti)O3 (PZT) devices showed short-term biocompatibility in cellular and histological studies, excessive Pb toxic ions were eluted from the PZT in human serum and tap water. Moreover, the KNN-based flexible energy harvester was implanted into a porcine chest and generated up to ∼5 V and 700 nA from the heartbeat motion, comparable to the output of previously reported lead-based flexible energy harvesters. This work can compellingly serve to advance the development of piezoelectric energy harvesting for actual and practical biocompatible self-powered biomedical applications beyond restrictions of lead-based materials in long-term physiological and clinical aspects.

Motion prediction via online instantaneous frequency estimation for vision-based beating heart tracking

The beating heart tracking based on stereo endoscope remains challenging due to highly dynamic scenes and poor imaging conditions in minimally invasive surgery. This paper proposes a new prediction method for robust tracking of heart motion. The dual time-varying Fourier series is used for modeling the motion of points of interest (POI) on heart surfaces, which is driven jointly by breathing and heartbeat motion. A dual Kalman filtering scheme is used to estimate the frequencies and Fourier coefficients of the model respectively. A novel orthogonal decomposition algorithm is developed to measure the instantaneous frequencies of breathing and heartbeat motion online from the 3D trajectory of the POI. The difference in direction between breathing and heartbeat motion is exploited by using principal component analysis on the past trajectory, and optimal 1D principal component signals are extracted for measuring the corresponding frequencies. The frequencies calculated from the orthogonal subbands are fused based on an additive noise model for optimal frequency measurement. The proposed method is evaluated and compared with other available prediction methods based on the simulated data and the real-measured signals from the videos recorded by the daVinci® surgical robot. The prediction algorithm is finally incorporated into a well-established visual tracking method to handle long-term occlusions.

Motion prediction using dual Kalman filter for robust beating heart tracking.

A novel prediction method for robust beating heart tracking is proposed. The dual time-varying Fourier series is used to model the heart motion. The frequency parameters and Fourier coefficients in the model are estimated respectively by using a dual Kalman filter scheme. The instantaneous frequencies of breathing and heartbeat motion are measured online from the 3D trajectory of the point of interest using an orthogonal decomposition algorithm. The proposed method is evaluated based on both the simulated signals and the real motion signals, which are measured from the videos recorded using the da Vinci surgical system.

Holographic otoscope using dual-shot-acquisition for the study of eardrum biomechanical displacements

Recently an optoelectronic holography system was deployed in the clinic with the purpose of quantifying the tympanic membrane (TM) displacements of various mammal species, the objective being the understanding of their middle ear biomechanics. The optoelectronic holography system has an in-line configuration where the data gathered is decoded using lensless digital holography with the Fresnel approximation. This paper presents quantitative data obtained from an acoustically excited postmortem chinchilla's TM. To achieve this we used a robust customized windowed unwrapping method to unwrap the noisy optical phase obtained by subtracting phase maps of two recorded holograms and the results were compared with those obtained when using the unwrapping branch-cut algorithm. Additionally, phase maps obtained by the phase-stepping technique were compared applying both unwrapping methods. For in vivo applications particular emphasis is made on post-processing dual-shot-acquisition of holograms as one of various acquisition strategies and algorithms to diminish measurement error due to heartbeat, breathing, and patient's head motion as well as environment induced mechanical disturbances present in a noncontrolled environment, such as in a clinic. By recording only two holograms representing a stationary and deformed state of eardrum, respectively, we can increase the acquisition speed of the camera used to record faster events happening on the TM surface.

Development of Master-Slave Surgical Robot System with Heartbeat Synchronization Mechanism (Evaluation of Position Synchronization Performance and Synchronization Suture Operability)

In this paper, a master-slave surgical robot system with heartbeat synchronization mechanism for off-pump CABG suturing operation is developed. This robot system is composed of a master manipulator, a slave manipulator, a heartbeat sensing system and a compact flexible endoscope system. The heartbeat sensing system measures 6 DOF heartbeat motion in real-time. The position of the slave manipulator is controlled as synchronizing with heartbeat. The compact flexible endoscope is fixed to a heart using a soft coupling which is used in medical case, so that the relative position between a heart and the compact flexible endoscope is maintained constant. Moreover, the surgical robot system is controlled in master-slave control method for surgeon's tele-operation. Therefore this system is able to perform surgical procedure while the system synchronizes with the heartbeat. In order to evaluate the performance of the system, the synchronization ability test, the master-slave operation test in vivo, and the performance of suturing operation under synchronization were conducted. In the result of the first test, it was showed that the maximum error between desired position and experimental position in the synchronization control was less than 1mm. In the second test, it was confirmed that the system was able to suture a pericardia, which was not beating. In the third test, it became clear that the maximum error between the desired position and experimental position was less than 1.24 to 2mm and the system was able to suture an isolated tissue which was driven by a robotic heartbeat phantom in 1Hz.

The increase of effective focal spot size by cardiac ballistic impulse

A ballistic movement of the body is caused with each ejection of blood from the heart. The authors have studied the effect of heart beat motion with respect to reduction of resolving power of an X-ray system. A star test pattern was used to measure the effective focal spot size of the polytome unit. Exposures were obtained with the anode rotating and at rest to establish base line values for focal spot size in the anode-cathode axis and perpendicular to it. Patient motion along the anode-cathode axis reduces resolution in a direction perpendicular to the anode-cathode axis but not parallel to it. The effective increase in focal spot size was approximately 0.1 mm in this one direction. Shortening the exposure time catches the body at rest and shows no increase in effective focal spot size.