Heart Phantom Research Articles

Cardiac visceral fat volume estimation from low-dose chest computed tomography: a study with a designed beating heart phantom

Background: Since 2017, a pilot project for lung cancer screening by chest low dose computed tomography (LDCT) has been implemented in Moscow. Patients to be included into the screening have risk factors for ischemic heart disease (IHD). The association between epicardial adipose tissue (EAT) volume and coronary artery atherosclerosis, IHD, and atrial fibrillation has been demonstrated previously.Aim: To demonstrate the feasibility of LDCTbased EAT volumetry using a dynamic (contracting) heart phantom.Materials and methods: The study was performed with the designed dynamic heart phantom and chest phantom in two stages. At stage I, two adipose tissue pieces were scanned inside and outside the chest phantom using CT and LDCT. At stage II, the dynamic heart phantom was scanned outside and inside the chest phantom. In addition, we scanned the heart phantom with a coronary calcium phantom. The contracting heart phantom was developed within three months. All scans of the phantom were performed within one day. We determined the adipose tissue thresholds in LDCT and the EAT volumetric error with both chest CT and LDCT. Measurements of the adipose tissue volumes were performed by the radiologist twice with semi-automatic software.Results: The results of stage I helped to identify optimal density thresholds for LDCT-based adipose tissue volumetry in lung cancer screening, ranging from -250 HU to -30 HU. The stage II results showed that for all heart phantom scanning variants, the average EAT volumetry error did not exceed 5%, except for the case of contracting heart phantom with added coronary calcium in a chest phantom with body mass index (BMI) 29 (-5.92%). Adding the coronary calcium phantom to the heart phantom in LDCT increased the error by an average of 4% in BMI 23 and BMI 29 chest phantoms.Conclusion: LDCT-based EAT volumetry with fat density threshold from -250 HU to -30 HU is feasible in lung cancer screening, including patients with coronary calcium. However, considering the phantom design, further patient studies, and correlation of EAT volumes between LDCT for lung cancer screening and сoronary CT angiography are required.

Deep learning-driven catheter tracking from bi-plane X-ray fluoroscopy of 3D printed heart phantoms

Minimally invasive surgery (MIS) has changed not only the performance of specific operations but also the more effective strategic approach to all surgeries. Expansion of MIS to more complex surgeries demands further development of new technologies, including robotic surgical systems, navigation, guidance, visualizations, dexterity enhancement, and 3D printing technology. In the cardiovascular domain, 3D printed modeling can play a crucial role in providing improved visualization of the anatomical details and guide precision operations as well as functional evaluation of various congenital and congestive heart conditions. In this work, we propose a novel deep learning-driven tracking method for providing quantitative 3D tracking of mock cardiac interventions on custom-designed 3D printed heart phantoms. In this study, the position of the tip of a catheter is tracked from bi-plane fluoroscopic images. The continuous positioning of the catheter relative to the 3D printed model was co-registered in a single coordinate system using external fiducial markers embedded into the model. Our proposed method has the potential to provide quantitative analysis for training exercises of percutaneous procedures guided by bi-plane fluoroscopy.

Estimation of optimal number of gates in dual gated 18F-FDG cardiac PET

Gating of positron emission tomography images has been shown to reduce the motion effects, especially when imaging small targets, such as coronary plaques. However, the selection of optimal number of gates for gating remains a challenge. Selecting too high number of gates results in a loss of signal-to-noise ratio, while too low number of gates does remove only part of the motion. Here, we introduce a respiratory-cardiac motion model to determine the optimal number of respiratory and cardiac gates. We evaluate the model using a realistic heart phantom and data from 12 cardiac patients (47–77 years, 64.5 on average). To demonstrate the benefits of our model, we compared it with an existing respiratory model. Based on our study, the optimal number of gates was determined to be five respiratory and four cardiac gates in the phantom and patient studies. In the phantom study, the diameter of the most active hot spot was reduced by 24% in the dual gated images compared to non-gated images. In the patient study, the thickness of myocardium wall was reduced on average by 21%. In conclusion, the motion model can be used for estimating the optimal number of respiratory and cardiac gates for dual gating.

Development of a Hybrid Training Simulator for Structural Heart Disease Interventions

To address the expanding needs to acquire the necessary skill sets for managing a wide array of transcatheter interventions, a 3D visualization system that integrates into the training platform would significantly enhance the trainee's capacity to comprehend the spatial relationships of various cardiac structures and facilitate the learning process. In addition to procedural training, the same technology may potentially help formulate treatment strategies in preprocedural planning especially in complex anatomy. Herein, a hybrid simulator for structural heart disease interventions is demonstrated by using the combination of a mixed reality (MR) display and 3D printing. The system consists of a 3D printed phantom heart model, a catheter with real‐time tracking using electromagnetic sensors, and the stand‐alone MR display for rendering 3D positions of the catheter within the heart model, along with quantitative feedback. The phantom heart model is generated by 3D printing technology using a segmented geometry from a human cardiac computed tomography (CT) scan. The catheter is coupled with electromagnetic sensors that allow real‐time tracking of their 3D positions and orientations. Custom software and algorithms to coregister and display the catheter's position relative to the phantom heart model are developed to interface with commercial software provided with the tracking sensors and MR display such that updates occur seamlessly in real time. Prespecified target crossings in the fossa ovalis during a transcatheter septal puncture procedure are demonstrated in the training scene. This hybrid training system will be used for training and educating transcatheter septal puncture procedure and other structural heart interventions.

Loküle transuda

The association between heart failure and phantom tumor has been well known for years. Because drainage mechanism exists in parietal pleura, phantom tumors generally localize between fissures. Loculated transudate in peripheral lung areas is extremely rare. We present an interesting case of encapsulated transudative pleural effusion associated with pneumonia. The pleural fissures, formed by a double layer of visceral pleura, represent extensions of the pleural space between lobes of the lungs. Localized transudative effusion between fissures, known as phantom tumor or vanishing tumor, can be seen during fluid overload. Because most pleural fluid drainage occurs through parietal pleural lymphatics , effusions tend to localize in visceral site rather than parietal pleura. We found only two reports of loculated transudates in peripheral lung regions . Encapsulated transudative effusion was affected right upper region in one paper and in our patient. The predilection of this area may be due to higher negativity in the intrapleural pressure or pleural adhesions caused by repeated thoracentesis. In conclusion, loculated transudate strongly suggests an unstable cardiac event, and it can present with atypical localization.

Design, Implementation, and Validation of a Pulsatile Heart Phantom Pump

The developments in Computed Tomography (CT) and Magnetic Resonance allow visualization of blood flow in vivo using these techniques. However, validation tests are needed to determine a gold standard. For the validation tests, controllable systems that can generate pulsatile flow are needed. In this study, we aimed to develop an affordable pulsatile pump and an artificial circulatory system to simulate the blood flow for validation purposes. Initially, the prerequisites for the phantom were pulsating flow output equal to that of the human cardiac pulse pattern; the flow pattern of the mimicked cardiac output should be equal to that of a human, a variable stroke volume (40–120 ml/beat), and a variable heart rate (60–170 bpm). The developed phantom setup was tested with CT scanner. A washout profile was created based on the image intensity of the selected slice. The test was successful for a heart rate of 70 bpm and a stroke volume of 68 ml, but the system failed to work at various heartbeats and stroke volumes. This was due to the problems with software of the microcontroller. As conclusion in this study, we present a proof of concept for a pulsatile heart phantom pump that can be used in validation tests.

Ultrasound-based prediction of interventricular septum positioning during left ventricular support-an experimental study.

The implantation of left ventricular assist devices (LVADs) is often complicated by arrhythmias and right ventricular failure (RVF). Today, the pump speed is titrated to optimize device support using single observations of interventricular septum (IVS) positioning with echocardiographic ultrasound (US). The study demonstrates the applicability of three integrated US transducers in the LVAD cannula to monitor IVS positioning continuously and robustly in real time. In vitro, the predictor of the IVS shift shows an overall prediction error for all volume states of less than 20% and provides a continuous assessment for 99% of cases in four differently sized heart phantoms. The prediction of IVS shift depending on the cannula position is robust for azimuthal and polar deviations of ± 20° and ± 8°, respectively. This intracardiac US concept results in a viable predictor for IVS positioning and represents a promising approach to continuously monitor the IVS and ventricular loading in LVAD patients. Graphical abstract.

Evaluation of a Patient-Specific, Low-Cost, 3-Dimensional–Printed Transesophageal Echocardiography Human Heart Phantom

Currently available 3-dimensional (3D) modeling and printing techniques allow for the creation of patient-specific models based on 3D medical imaging data. The authors hypothesized that a low-cost, patient-specific, cardiac computed tomography-based phantom, created using desktop 3D printing and casting, would have comparable image quality, accuracy, and usability to an existing commercially available echocardiographic phantom. Blinded comparative study. Simulation laboratory at a single academic institution. Voluntary cardiac anesthesiologists at a single academic institution. Stage 1 of the study consisted of an online questionnaire in which a set of basic transesophageal echocardiography (TEE) views obtained from the 3D printed phantom and commercial phantom were presented to participants, who had to identify the views and evaluate their fidelity to clinical images on a Likert scale. In stage 2, participants performed an unblinded basic TEE examination on both phantoms. The time needed to acquire each basic view was recorded. Overall usability of the phantoms was assessed through a questionnaire. The participants could recognize most of the views. Fidelity ratings for both phantoms were similar (p < 0.05), with the exception of a midesophageal 2-chamber view that was observed better on the 3D printed phantom. The time required to obtain the views was shorter for the 3D printed phantom, although not statistically significant for most views. The overall user experience was better for the 3D phantom for all categories examined (p < 0.05). The study suggested that a 3D-printed TEE phantom is comparable with the commercially available one with good usability.

Assessment of ejection fraction and heart perfusion using myocardial perfusion single-photon emission computed tomography in Finland and Estonia: a multicenter phantom study.

Myocardial SPECT/CT imaging is frequently performed to assess myocardial perfusion and dynamic parameters of heart function, such as ejection fraction (EF). However, potential pitfalls exist in the imaging chain that can unfavorably affect diagnosis and treatment. We performed a national cardiac quality control study to investigate how much SPECT/CT protocols vary between different nuclear medicine units in Finland, and how this may affect the heart perfusion and EF values. Altogether, 21 nuclear medicine units participated with 27 traditional SPECT/CT systems and two cardiac-centered IQ-SPECT systems. The reproducibility of EF and the uniformity of perfusion were studied using a commercial dynamic heart phantom. SPECT/CT acquisitions were performed and processed at each participating unit using their own clinical protocol and with a standardized protocol. The effects of acquisition protocols and analysis routines on EF estimates and uniformity of perfusion were studied. Considerable variation in EF estimates and in the uniformity of perfusion were observed between the units. Uniformity of perfusion was improved in some units after applying the higher count-statistic standard acquisition protocol. EF estimates varied more due to differences in analysis routines than as a result of different acquisition protocols. The results obtained with the two IQ-SPECT systems differed substantially from the traditional multipurpose cameras. On average, the EF and heart perfusion were accurately estimated by SPECT/CT, but high errors could be produced if the acquisition and analysis routines were poorly optimized. Eight of the 21 participants altered their imaging protocol after this quality control tour.

Dynamic Left Atrioventricular Phantom Test Bed Emulating Mitral Valve Motion

Abstract Novel catheter-based medical procedures targeting heart valve structures are currently under development. These techniques entail installing a prosthetic implant on valves inside a beating heart. The development of these approaches requires a simple and effective validation test bed. Current early process testing methods rely on both static and dynamically pressurized excised porcine hearts. The variability between excised-tissue mechanical properties poses problems of reproducibility. In addition, these test beds do not emulate annulus motion, which affects the implant installation. A reproducible phantom of the left atrioventricular chambers was developed. The system consists of a hydraulic constant flow arrangement and a polyvinyl alcohol phantom heart with material properties that mimic passive myocardium mechanical properties and annulus motion. The system was then used to emulate blood flow through an actual heart. The building process starts by obtaining an accurate computer-aided design (CAD) model of a human heart, from which, a mold is produced using a novel rapid-freezing prototyping method and computer numerical control machining. The phantom is then cast-out of polyvinyl alcohol (PVA), a hydrogel, whose mechanical properties are set by subjecting the phantom to freeze and thaw cycles. Subsequently, blood flow is emulated at a constant volumetric rate at the atrial pressure observed in a healthy adult human heart at rest. The annulus motion is implemented by suturing the outside of the phantom to a one-degree-of-freedom cam-follower mechanism reproducing valve motion. Such test beds could play a significant role in future development of medical devices.

Details preserved unsupervised depth estimation by fusing traditional stereo knowledge from laparoscopic images.

Depth estimation plays an important role in vision-based laparoscope surgical navigation systems. Most learning-based depth estimation methods require ground truth depth or disparity images for training; however, these data are difficult to obtain in laparoscopy. The authors present an unsupervised learning depth estimation approach by fusing traditional stereo knowledge. The traditional stereo method is used to generate proxy disparity labels, in which unreliable depth measurements are removed via a confidence measure to improve stereo accuracy. The disparity images are generated by training a dual encoder–decoder convolutional neural network from rectified stereo images coupled with proxy labels generated by the traditional stereo method. A principled mask is computed to exclude the pixels, which are not seen in one of views due to parallax effects from the calculation of loss function. Moreover, the neighbourhood smoothness term is employed to constrain neighbouring pixels with similar appearances to generate a smooth depth surface. This approach can make the depth of the projected point cloud closer to the real surgical site and preserve realistic details. The authors demonstrate the performance of the method by training and evaluation with a partial nephrectomy da Vinci surgery dataset and heart phantom data from the Hamlyn Centre.

Development of a phantom network for optimization of coronary artery disease imaging using computed tomography

Computed Tomography provides a practical means of diagnosing coronary artery disease in patients, but requires improvements in image quality through optimization of scan parameters and development of new image reconstruction software. In this work, the design of an anthropomorphic phantom coronary artery network with appropriate CT attenuation and mechanical properties is described. The static and dynamic mechanical properties of fresh porcine coronary arteries are characterized at physiological loading conditions through uniaxial tensile testing and dynamic mechanical analysis. The Young’s modulus was determined to be 0.16 ± 0.04 MPa, and the storage and loss moduli at 1.25 Hz were 0.02 ± 0.01 MPa and 0.004 ± 0.002 MPa. The static and dynamic mechanical properties and CT attenuations of a platinum-cured silicone rubber, a tin-cured silicone rubber, a polyurethane rubber, and latex rubber previously used in soft tissue phantom applications were investigated and compared to those of coronary arteries. The platinum-cured silicone rubber was found to be the most suitable material for simulation of the arterial walls, with a physiological Young’s modulus of 0.13 ± 0.03 MPa (19% lower than that of the coronary arteries), storage modulus of 0.07 ± 0.03 MPa (273% higher), and loss modulus of 0.005 ± 0.002 MPa (43% higher). The CT Number of the platinum-cured silicone rubber was found to best suit the required range of values representative of the arterial walls. To manufacture the phantom coronary arteries, moulds of the arterial lumen were 3D printed on a commerical SLA printer, onto which the platinum-cured silicone rubber was dip/brush coated. The phantom coronary arteries were attached to a phantom heart model, filled with an iodine contrast and CT scanned. The average CT number of the phantom artery wall was found to be 65 HU, which is in agreement with the accepted range. The work presented in this study demonstrates the feasibility of in-house manufacturing of imaging phantoms.

A Conformational Anastomotic Device for Heart Transplantation

Purpose Automated donor to recipient anastomosis has the potential to reduce procedural & ischemic times . A major impediment to automated anastomosis is creating the hemostatic end to end anastomosis without luminal compromise. We present our design of a conformational felt sandwich anastomotic device. Methods An adjustable anastomotic platform with a calibrated railing system (diameter: 10-100mm) was designed and tested in-vitro with a biomimetic heart phantom. Felt-incorporated two circular platforms, anvil and staple cartridge respectively, can be circumferentially tightened and released. Staples are deployed in an interlocking triangular pattern for hemostasis . Results A one cm cuff is created for both donor and recipient heart structure to be anastomosed. A modular anvil with incorporated conformational felt was then clasped around the structure to be anastomosed and the wall was everted on to the anvil and engaged in the spikes (Figure). The positional pins were then engaged, with a clockwise movement accurate apposition was achieved. The handle was depressed to discharge a specially arranged staple to achieve a hemostatic seal. The automated anastomosis obtains a hemostatic seal with a conformational felt on the outside of the vessel wall (Figure). The system also works well with bovine pericardium . Conclusion An automated donor to recipient anastomosis can improve the operational ease and reduce procedural/ischemic times while obtaining reproducible results.

Influence of Bowtie Filter and Patient Positioning on In-plane Dose Distribution and Image Quality in ECG-gated CT

In electrocardiographic (ECG)-gated computed tomography (CT) for diagnosis of cardiac diseases, radiation dose and image quality are optimized by limiting field of view (FOV) and centering on the heart. However, it is necessary to set wide FOV with large bowtie filter depending on patient positioning or various diagnoses such as aortic diseases. The purpose of this study is to clarify influence of bowtie filter and patient positioning on in-plane dose distribution, organ-absorbed dose, image quality in ECG-gated CT. In-plane dose distribution and organ-absorbed dose were evaluated with radio photoluminescence glass dosimeters, and signal-to-noise ratio (SNR) were measured for evaluation of image quality. The bowtie filter was used small (S) and large (L). With automatic exposure control, volume computed tomography dose index was 55.3 mGy at S and 71.8 mGy at L. The phantom was positioned on the heart of phantom (Heart) and the center of phantom (Body). In Heart-L compared with Heart-S, organ-absorbed dose was 1.29 times at breasts. In Heart-S compared with Body-S, in-plane dose distribution was increased 25% at left anterior and decreased 20% at right posterior. In SNR, S and L were decreased from 50 mm off-center. To set appropriate bowtie filter and positioning was reduced radiation dose and improved image quality in ECG-gated CT.

Influence of Heart Rate and Innovative Motion-Correction Algorithm on Coronary Artery Image Quality and Measurement Accuracy Using 256-Detector Row Computed Tomography Scanner: Phantom Study.

ObjectiveTo investigate the efficacy of motion-correction algorithm (MCA) in improving coronary artery image quality and measurement accuracy using an anthropomorphic dynamic heart phantom and 256-detector row computed tomography (CT) scanner.Materials and MethodsAn anthropomorphic dynamic heart phantom was scanned under a static condition and under heart rate (HR) simulation of 50–120 beats per minute (bpm), and the obtained images were reconstructed using conventional algorithm (CA) and MCA. We compared the subjective image quality of coronary arteries using a four-point scale (1, excellent; 2, good; 3, fair; 4, poor) and measurement accuracy using measurement errors of the minimal luminal diameter (MLD) and minimal luminal area (MLA).ResultsCompared with CA, MCA significantly improved the subjective image quality at HRs of 110 bpm (1.3 ± 0.3 vs. 1.9 ± 0.8, p = 0.003) and 120 bpm (1.7 ± 0.7 vs. 2.3 ± 0.6, p = 0.006). The measurement error of MLD significantly decreased on using MCA at 110 bpm (11.7 ± 5.9% vs. 18.4 ± 9.4%, p = 0.013) and 120 bpm (10.0 ± 7.3% vs. 25.0 ± 16.5%, p = 0.013). The measurement error of the MLA was also reduced using MCA at 110 bpm (19.2 ± 28.1% vs. 26.4 ± 21.6%, p = 0.028) and 120 bpm (17.9 ± 17.7% vs. 34.8 ± 19.6%, p = 0.018).ConclusionMotion-correction algorithm can improve the coronary artery image quality and measurement accuracy at a high HR using an anthropomorphic dynamic heart phantom and 256-detector row CT scanner.

Ultrasonic sensor concept to fit a ventricular assist device cannula evaluated using geometrically accurate heart phantoms.

Future left ventricular assist devices (LVADs) are expected to respond to the physiologic need of patients; however, they still lack reliable pressure or volume sensors for feedback control. In the clinic, echocardiography systems are routinely used to measure left ventricular (LV) volume. Until now, echocardiography in this form was never integrated in LVADs due to its computational complexity. The aim of this study was to demonstrate the applicability of a simplified ultrasonic sensor to fit an LVAD cannula and to show the achievable accuracy in vitro. Our approach requires only two ultrasonic transducers because we estimated the LV volume with the LV end-diastolic diameter commonly used in clinical assessments. In order to optimize the accuracy, we assessed the optimal design parameters considering over 50 orientations of the two ultrasonic transducers. A test bench was equipped with five talcum-infused silicone heart phantoms, in which the intra-ventricular surface replicated papillary muscles and trabeculae carnae. The end-diastolic LV filling volumes of the five heart phantoms ranged from 180 to 480 mL. This reference volume was altered by ±40 mL with a syringe pump. Based on the calibrated measurements acquired by the two ultrasonic transducers, the LV volume was estimated well. However, the accuracies obtained are strongly dependent on the choice of the design parameters. Orientations toward the septum perform better, as they interfere less with the papillary muscles. The optimized design is valid for all hearts. Considering this, the Bland-Altman analysis reports the LV volume accuracy as a bias of ±10% and limits of agreement of 0%-40% in all but the smallest heart. The simplicity of traditional echocardiography systems was reduced by two orders of magnitude in technical complexity, while achieving a comparable accuracy to 2D echocardiography requiring a calibration of absolute volume only. Hence, our approach exploits the established benefits of echocardiography and makes them applicable as an LV volume sensor for LVADs.

Precise image fusion standardization for separated modalities using dedicated multimodal heart phantom

ABSTRACTThe standardization of images derived from different medical modalities should be ensured when image fusion brings essential information and hybrid scanners are not available. The aim of this study was to show that precise image fusion standardization can be obtained using special and unique multimodal heart phantom (MHP) which is compatible with all applied diagnostic methods. MHP was designed and constructed according to International Commission on Radiological Protection reports, scanners requirements and personal experience. Three different types of acquisitions were done: physiological perfusion, myocardial ischaemia and intestines artefacts. The measurements were done using different modalities (single photon emission computed tomography (SPECT), positron emission tomography (PET), MRI, CT) as well as hybrid scanners (PET/CT, SPECT/CT). It was shown that MHP can be used not only for improvement of image fusion standardization protocol but also for verification of proper implementation of the fusion protocol in hybrid scanners.

Dynamic tests of multi-detector radiometric system on central blood circulation phantom

Phantoms of organs and biological systems are widely used for verification of radioisotope protocols. The construction and operation of the heart and circulation phantom is described. The present model was designed for experimental testing of multi-detector radiometric system, prototype of which was designed in Ural Federal University as an extension and alternative to Anger camera and single-photon-emission tomography radionuclide diagnostics. The model represents vital dynamic properties of the single-chamber pulsing heart and circulation, featuring adjustable heart rate, blood volume, ejection fraction and flowrate. The trial experiments were performed with 99mTc-pertechnetate to obtain time-activity curves and the ejection fraction was thus measured basing on first-pass radio angiography technique.

Heart phantom with electrical properties of heart muscle tissue

Abstract The weakened heart is supported by a left ventricular assist device (LVAD) to supply the heart muscle with oxygenated blood. In case the heart muscle recovers during LVAD therapy, the patient has to be weaned from the device. To date, there is no adequate method to detect heart muscle recovery in LVAD therapy. In order to establish a novel method based on the measurement of electric conductivity, this study presents a silicone model of a ventricle mock-up to simulate the electrical properties of cardiac muscle tissue. Previously, it has been shown that the electrical properties of myocardial tissue change during ischemia, so that these changes are a possible estimate for measuring the condition of myocardial tissue. To this purpose, this study presents a casting process for a ventricle model and describes the materials used to imitate the electrical properties of the heart muscle to obtain conductive material. Initial results showed that the higher the carbon concentration in the silicone, the higher the conductivity of the silicone samples. The measurements were performed at different frequencies and the samples were analyzed for homogenization.

Multiview Three-Dimensional Echocardiography Image Fusion Using a Passive Measurement Arm.

Three-dimensional (3D) echocardiography offers a fast and efficient way to scan and assess the structures and function of the heart. However, due to limitations inherent to 3D echocardiography such as limited field-of-view and low signal-to-noise ratio, 3D assessment of the heart is performed only in a minority of patients who undergo transthoracic echocardiography. One approach for improving the field-of-view and image quality is to scan the heart from multiple locations by moving the transducer and fusing the resulting images into a single volume, which requires 3D alignment of individual volumetric echocardiography scans. Previous approaches relied on optical or electromagnetic trackers for transducer tracking. This study proposes a passive measurement arm system for tracking the position of the ultrasound transducer and thereby aligning multiple echocardiography scans. The proposed system does not suffer from line-of-sight limitation as in the case of an optical tracking based fusion system. Additionally, in contrast to an electromagnetic based tracking system, measurement arm measurements are not affected by other ferromagnetic materials in the vicinity. The proposed approach was tested by scanning a heart phantom and fusing nine echocardiography volumes acquired from different locations. The fusion of all nine scans yielded a percentage field-of-view improvement of 98.5%.