Custom Software Research Articles

Feasibility of non-invasive echocardiographic estimates of intraventricular pressure differences by blood speckle tracking in adults

Abstract Introduction Non-invasive estimation of the intraventricular pressure difference (IVPD) in early diastole using high-frame-rate ultrasound-based blood speckle tracking (BST) has been reported in pediatric cardiology of various pathologies. This novel echocardiographic technology has recently become available in probes suitable for the adult population. Purpose We tested the feasibility by analyzing intra- and interobserver variability and investigating if IVPD in the left ventricular inflow exhibited the expected differences in controls vs a group of heart failure patients to indicate the ability of this new index to assess diastolic function. Methods Apical BST images of LV inflow were acquired using a GE Vivid E95 ultrasound scanner and the M5Sc probe in healthy volunteers (n=9) and patients with heart failure and left bundle branch block (LBBB) (n=15) implanted with cardiac resynchronization therapy (CRT) 6±2 months (mean±SD) earlier. Echocardiography was performed both with CRT turned on and off. IVPD was analyzed from the BST acquisitions using custom software (Figure 1). Blinded intra- and interobserver variability analysis were performed on the measurements from the healthy controls with the same observer and two other observers, respectively. Results All the controls and 11 of the 15 patients had BST acquisitions eligible for IVPD-analysis, giving a total feasibility of 83%. Intraobserver reliability was excellent (intraclass correlation coefficient 0.96 [0.85, 0.99], mean and 95% CI) and interobserver reliability was good (intraclass correlation coefficient 0.88 [0.59, 0.97] and 0.84 [0.48, 0.96]) respectively. IVPD was highest in controls (-1.7±0.5 mmHg), and higher with CRT on (-1.3±0.7 mmHg, p=NS vs controls) than off (-0.9±0.5 mmHg, p<0.05 compared to both on and controls) in the patients. Conclusions Estimating the intracavitary pressure difference that accelerates blood into the LV during early filling seems feasible and reproducible in adult hearts by BST. IVPD is reduced in patients with heart failure and LBBB, and increases in patients with LBBB when treated with CRT. IVPD based on BST is a potential new echocardiographic method to evaluate diastolic function. Future improvements of the technology are warranted for widespread use.

Exploring three-dimensional right ventricular shape and function in tetralogy of fallot patients

Abstract Background Tetralogy of Fallot (ToF) accounts for approximately 7 to 10 % of all CHD and is commonly associated with failure of the right ventricle (RV). Parameters providing more insight into the mechanics of RV failure are needed to guide clinical decision making. As advancements in Three-Dimensional (3D) echocardiography (3DE) have enabled more detailed analysis of RV volume and function, the way is paved for new 3D derived parameters. We developed a custom software to assess 3D RV shape and function. Purpose The aim of this study was to evaluate the differences of 3DE derived RV geometry (curvature) and deformation parameters in adults with ToF and controls. Methods In 50 patients with ToF and 50 controls 3DE RV images were acquired. RV geometries from 3D datasets were segmented using commercially available RV analysis software (TomTec 4D-RV function 2.0) and processed using custom software (RV-dynamics) to calculate Curvature, Area Strain (AS) and Longitudinal Strain (LS). Parameters were measured globally and over different segments of the RV (i.e. septal body (SB), inferior free wall (IFW), anterior free wall (AFW), lateral free wall (LFW), apex (Ax), RV inflow tract (RVIT), RV outflow tract (RVOT), anterior boundary (AB) and posterior boundary (PB)). Results Globally and for all independent regions of the RV, AS was significantly reduced in patients with ToF as compared with healthy controls. Except for AFW, global and all regional values of LS were significantly reduced in patients with ToF as compared with healthy controls. Global AS and LS were strongly correlated with RVEF with values for r of -0.9 and -0.6 respectively. RV curvature differed over multiple segments, predominantly in the end-diastolic Ax and end-systolic PB and Ax regions. Conclusion The RV-dynamics software gives the opportunity to analyze 3D RV morphology and RV deformation parameters in the diseased RV in more detail. AS and LS may provide more detailed assessment of the functional condition of the diseased RV in ToF whereas curvature provides an interesting method for the quantification of RV remodeling. Further insight in the different mechanisms of dysfunction of the RV may improve clinical decision making.

Septum displacement implications in the limited cardiac reserve, RV to pc uncoupling and oxygen uptake during exercise in heart failure

Abstract Background Exertional dyspnea is crucial in heart failure (HF) and may be determined by an unfavorable dynamic of ventricular interaction. This concept has been poorly addressed over time and we hypothesized that a careful study of the interventricular septum adaptations during maximal exercise in HF might be implicated in the limited cardiac reserve, uncoupling of right ventricular (RV) to pulmonary circulation (Pc), both yielding to a limited O2 uptake. Aim To address the pathophysiology behind biventricular interaction during exercise in HF, studying the role of l septum displacement during exercise and how and whether it would affect peak exercise oxygen consumption (VO2 peak). Through a limited cardiac output (CO) increase and some degrees of RV to PC uncoupling assessed by TAPSE/PASP. Methods 22 HF underwent a combined cardiopulmonary exercise testing imaging (CPET imaging) with RV 3D-imaging analysis and were compared with a control population. 3D imaging of the RV chamber was examined off-line using the 4D RV TomTec software and obtained 3D mesh of the RV model using custom software to obtain the mean curvature value of IVS in 4 regions of: inflow tract (RVIT), outflow tract (RVOT), apical and body. We acquired measurements of curvature during end-diastole (ED) and at end systole (ES) phases and obtained a parametric curvature map. Results HF patients (mean age 72±12, 27% female) typically exhibited an abnormal septal curve, with a more leftward configuration either at rest and under exercise (rest =−0.01±0.007 at ED, and −0.01±0.009 at ES; peak exercise= −0.01±0.006 at ED, and −0.01±0.007 at ES) compared to controls (rest =−0.02±0.002 at ED, and −0.02±0.006 at ES; peak exercise −0.02±0.0.006 at ED, and −0.02±0.01 at ES, Figure). Notably, the degree of the IVS curvature was found to linearly correlate with an impaired gas exchange performance as showed by a lower peak VO2, a limited CO and impairment of TAPSE/PASP in HF (respectively, r=0.64, p<0.001, r=0.5, p<0.001, r=0.53, p<0.001 at ED during exercise; r=0.61, p<0.001 at ES during exercise; Figure). Conclusions In HF, the occurrence of right to left IVS displacement appears worth of investigation, tightly contributing to a reduced CO response, and RV-PA uncoupling during exercise. These findings clearly point to the utility of assessing how therapeutic strategies may modulate the negative septum displacement and overall cardiac mechanics. RV colorimetric curvature map Septal curvature correlations

In-situ quality monitoring during embedded bioprinting using integrated microscopy and classical computer vision

Despite significant advances in bioprinting technology, current hardware platforms lack the capability for process monitoring and quality control. This limitation hampers the translation of the technology into industrial GMP-compliant manufacturing settings. As a key step towards a solution, we developed a novel bioprinting platform integrating a high-resolution camera forin-situmonitoring of extrusion outcomes during embedded bioprinting. Leveraging classical computer vision and image analysis techniques, we then created a custom software module for assessing print quality. This module enables quantitative comparison of printer outputs to input points of the computer-aided design model's 2D projections, measuring area and positional accuracy. To showcase the platform's capabilities, we then investigated compatibility with various bioinks, dyes, and support bath materials for both 2D and 3D print path trajectories. In addition, we performed a detailed study on how the rheological properties of granular support hydrogels impact print quality during embedded bioprinting, illustrating a practical application of the platform. Our results demonstrated that lower viscosity, faster thixotropy recovery, and smaller particle sizes significantly enhance print fidelity. This novel bioprinting platform, equipped with integrated process monitoring, holds great potential for establishing auditable and more reproducible biofabrication processes for industrial applications.

SONAR VISION: ULTRASONIC RADAR USING ARDUINO

This project explores the design and implementation of an ultrasonic radar system using Arduino to detect and map objects within a specified range. The system employs an ultrasonic sensor (HC- SR04) to measure distance by emitting sound waves and capturing their reflections. A servo motor rotates the sensor to scan the environment, providing angular data. The Arduino microcontroller processes the data and transmits it to a computer for visualization using custom software or the Processing IDE. The radar can identify obstacles in real time, making it suitable for applications like security systems, object detection, and robotics. Its low cost, ease of implementation, and scalability make it a versatile tool for educational and practical purposes. Key Words: ultrasonic radar, Arduino, HC-SR04, distance measurement, servo motor, object detection, real-time scanning, visualization, low cost, robotics.

Kalamari: a representative set of genomes of public health concern.

Kalamari is a resource that supports genomic epidemiology and pathogen surveillance. It consists of representative genomes and common contaminants. Kalamari also contains a custom taxonomy and software for downloading and formatting the data.

Software solution for integration of frozen section quality assurance into daily practice.

Diagnoses rendered using the frozen section (FS) technique during surgical procedures are used to guide intraoperative decisions. Therefore, diagnostic FS errors have the potential to affect patient safety and quality of care. Diagnostic FS errors arise due to both technical and interpretative factors and present a challenge to surgical pathology laboratories to recognize, document, and manage in a timely fashion. Thus, there is a need to monitor discrepancies between FS and permanent diagnoses and effectively communicate with the clinical teams when an error is discovered to ensure an opportunity for timely interventions, if clinically indicated. Our FS practice is complex, with many contributing variables, such as a partially generalized FS pathology practice model among pathology faculty and/or surgeons with specific subspecialty expertise and different physical locations of FS facilities. We implemented a comprehensive frozen section quality assurance (FSQA) program using custom software solutions aimed at improving patient safety by monitoring recognition, increasing documentation, and facilitating communication in cases where there is a discordance between intraoperative and permanent diagnoses. Our FSQA program allows for categorizing frozen section discrepancies according to the source of error, such as interpretive vs technical errors, to understand how errors arise and todevelop appropriate mitigation strategies for reducing errors. Overall, our intervention to improve FSQA has engaged pathology faculty in a uniform and systematic manner, and our data show that our new FSQA program led to a markedly shortened time interval of FSQA, allowing for timely management and resolution of errors.

Transmission-Based Monitoring of Dual-Applicator Microwave Ablation Discriminates Discontiguous from Contiguous Ablation Zones in an In Vivo Porcine Liver Model.

To determine the technical feasibility of discriminating discontiguous from contiguous ablation zones between a pair of microwave ablation (MWA) applicators using broadband microwave transmission signal measurements in an in vivo porcine liver model. Dual applicator 2.45GHz MWA was performed using one directional and one omnidirectional applicator, spaced 3cm apart, under imaging guidance. The study involved 15 hepatic MWAs across four swine, with ablation durations of 200s (n=8) for discontiguous ablation and 600s (n=7), each at 60W; these ablation durations and applied power combinations were selected with the intent of creating discontiguous (200s) and contiguous (600s) ablation zones. A custom software periodically measured transmission signals between the applicators at 46-second intervals. Contrast-enhanced CT, gross pathology, and histopathologic analyses were used to assess the processed transmission signal (PTS). Statistical analyses revealed significant differences between contiguous and discontiguous ablation zones on CECT imaging (volume: 16.9±5.2cm3 vs. 3.9±1.5cm3, p=0.0002), gross tissue sections and histology (area: 10±3.3cm2 and 6.5±1.3cm2, p=0.001 and PTS datasets showed values of 85.1±11% and 37.3±12.9% (p=0.02). PTS values functioned well as predictors of complete vs incomplete ablation (area under curve of the receiver operating characteristic curve = 0.90), with a PTS threshold of 53% being optimal for indicating ablation zone contiguity. Ablation zone contiguity was strongly correlated with PTS (Spearman correlation coefficient 0.86, p<0.0001). This study demonstrated that PTS between dual MWA applicators can distinguish between contiguous and discontiguous ablation zones.

Empowering personalized oncology: evolution of digital support and visualization tools for molecular tumor boards

BackgroundMolecular tumor boards (MTBs) play a pivotal role in personalized oncology, leveraging complex data sets to tailor therapy for cancer patients. The integration of digital support and visualization tools is essential in this rapidly evolving field facing fast-growing data and changing clinical processes. This study addresses the gap in understanding the evolution of software and visualization needs within MTBs and evaluates the current state of digital support. Alignment between user requirements and software development is crucial to avoid waste of resources and maintain trust.MethodsIn two consecutive nationwide medical informatics projects in Germany, surveys and expert interviews were conducted as stage 1 (n = 14), stage 2 (n = 30), and stage 3 (n = 9). Surveys, via the SoSci Survey tool, covered participants' roles, working methods, and support needs. The second survey additionally addressed requirements for visualization solutions in molecular tumor boards. These aimed to understand diverse requirements for preparation, implementation, and documentation. Nine semi-structured expert interviews complemented quantitative findings through open discussion.ResultsUsing quantitative and qualitative analyses, we show that existing digital tools may improve therapy recommendations and streamline MTB case preparation, while continuous training and system improvements are needed.ConclusionsOur study contributes to the field by highlighting the importance of developing user-centric, customizable software solutions that can adapt to the fast-paced environment of MTBs to advance personalized oncology. In doing so, it lays the foundation for further advances in personalized medicine in oncology and points to a shift towards more efficient, technology-driven clinical decision-making processes. This research not only enriches our understanding of the integration of digital tools into MTBs, but also signals a broader shift towards technological innovation in healthcare.

FragMAX Facility for Crystallographic Fragment and Ligand Screening at MAX IV

ABSTRACTThe FragMAX facility at MAX IV Laboratory is a state‐of‐the‐art platform for crystallographic fragment screening, designed to support structure‐based drug and chemical tool compound discovery. This facility offers a comprehensive workflow, from high‐throughput crystal preparation and automated diffraction data collection at the BioMAX beamline to advanced data processing and analysis using custom software tools like FragMAXapp and FragMAXproc. Key components include an extensive relational SQLite database, various fragment libraries, laboratory automation equipment, and a range of bespoke software solutions. FragMAX has conducted numerous successful screening campaigns, serving both academic and industrial users. Users benefit from comprehensive support, and stringent data management. Here, we provide an overview of the different components of the facility and details of their practical implementation.

Inclined distance running at iso-efficient speeds: Effect on joint work

ABSTRACT Runners often reduce their pace during inclined running to maintain a constant metabolic workload, known as iso-efficiency speed (a speed-incline combination with the same metabolic intensity as level running). This study investigates changes in lower extremity (LE) joint work profiles when running on an incline at iso-efficiency speed. Eleven collegiate distance runners completed a treadmill running task under three conditions (0%, 4%, and 8% incline). Running velocity was reduced with increasing incline to ensure a consistent metabolic workload across conditions. An 8-camera motion capture system and an instrumented treadmill collected kinematics and ground reaction forces. Visual 3D was used to calculate ankle, knee, and hip joint powers, while custom software (MATLAB) calculated ankle, knee, and hip joint positive and negative work values. A significant increase in LE total positive work was attributed to greater ankle and hip joint positive work with steeper inclines. Reduced LE total negative work resulted from lower knee and hip joint negative work as incline increased. Results suggest that at iso-efficiency speeds, inclined treadmill running increases eccentric demands on the ankle joint and concentric demands on the ankle and hip joints, benefiting training programmes to optimize cardiorespiratory stimuli while reducing mechanical demand on specific extremity structures.

Automated Measurement of Strabismus Angle Using a Commercial Virtual Reality Headset.

Current clinical measurements of strabismus angles (SAs) are manual and require a skilled examiner and active cooperation by patients. This results in high interexaminer variability, and clinical use is limited by the availability of trained examiners. An objective and automated procedure, independent of the examiner, would be useful. This single-center, prospective, diagnostic feasibility study compared the vertical and horizontal SA of patients, as measured with a commercially available virtual reality headset (VRH) and custom software with the gold standard measurements performed manually with the Harms tangent screen (HW) and the alternate prism cover test (ACT). We implemented the ACT by showing the patient a fixation target on each eye alternatively with the VRH while recording the eye position of the patient. We then processed the data with custom written software to calculate the SA of the patients. These measurements were then compared to the SA measured with HW and the clinical ACT. Thirty-three patients took part in our study. We found good correlation between the VRH method and the HW as well as the clinical ACT. Best correlation was found for horizontal SA in the primary position, with the vertical SA in the primary position also correlating well. Peripheral gaze resulted in a slightly lower correlation due to the overestimation of horizontal SA and underestimation of vertical SA; cyclorotation was not measured with the VRH. Overall, VRH, HW, and clinical ACT correlated similarly well as the published interexaminer correlation for ACT. The automated measurement of strabismus with a VRH is feasible, easily applicable, fast, accurate, and can be run on consumer hardware that is affordable and increasingly available.

Quantitative ultrasound imaging reveals distinct fracture-associated differences in tibial intracortical pore morphology and viscoelastic properties in aged individuals with and without diabetes mellitus - an exploratory study.

Diabetes mellitus (DM) is a chronic metabolic disorder that increases fragility fracture risk. Conventional DXA-based areal bone mineral density (aBMD) assessments often underestimate this risk. Cortical Backscatter (CortBS) ultrasound, a radiation-free technique, non-invasively analyzes cortical bone's viscoelastic and microstructural properties. This study aimed to evaluate CortBS's discriminative performance in DM patients compared to DXA and characterize changes in cortical bone microstructure in Type 1 and Type 2 DM (T1DM, T2DM) patients. This in-vivo study included 89 DM patients (T1DM = 39, T2DM = 48) and 76 age- and sex-matched controls. DXA measured aBMD, while CortBS measurements were taken at the anteromedial tibia using a medical ultrasound scanner with custom software. Multivariate analysis of variance assessed the impact of DM type on CortBS and DXA measurement results. Partial least squares discriminant analyses with cross-validation were used to compare the discrimination performance for vertebral, non-vertebral, and any fragility fractures, adjusting for gender, age, and anthropometric parameters (weight, height, BMI). Fractures occurred in 8/23 T1DM, 17/18 T2DM, and 16/55 controls. DXA parameters were reduced in fracture patients, with significant diabetes impact. T2DM was associated with altered CortBS parameters, reduced scatterer density, and larger pores. CortBS outperformed DXA in discriminating fracture risk (0.61 ≤ AUC(DXA) ≤ 0.63, 0.68 ≤ AUC(CortBS) ≤ 0.69). Both T1DM and T2DM showed altered bone metabolism, with T2DM linked to impaired tissue formation. CortBS provides insights into pathophysiological changes in diabetic bone and provided superior fracture risk assessment in DM patients compared to DXA.

Enhancing Laboratory Efficiency: Implementing Custom Image Analysis Tools for Streamlined Pathology Workflows

In the field of pathology, the efficient analysis and interpretation of diagnostic images are critical for timely and accurate decision-making. Traditional manual methods for image analysis are often time-consuming, error-prone, and resource-intensive, leading to delays in diagnosis and increased workloads for pathologists. To address these challenges, this paper explores the development and implementation of custom image analysis tools to streamline pathology workflows. The integration of machine learning (ML) algorithms, computer vision techniques, and automation technologies into laboratory settings has the potential to significantly enhance the speed and accuracy of image processing tasks. This study examines how tailored image analysis solutions can optimize tasks such as tissue segmentation, feature extraction, and classification of abnormal cells. The use of such tools not only improves the diagnostic workflow but also reduces human error, enhances reproducibility, and facilitates real-time analysis. Additionally, the paper discusses the practical considerations for implementing these technologies, including software customization, integration with existing laboratory information systems, and user training. By leveraging the power of custom-built image analysis solutions, pathology laboratories can improve operational efficiency, reduce turnaround times for results, and ultimately enhance patient outcomes. The research provides insights into the future of digital pathology and offers a roadmap for laboratories looking to adopt cutting-edge technologies to stay at the forefront of diagnostic innovation.

Robust design methodologies to engineer multimaterial and multiscale bioprinters

Commonly used bioprinting technologies (e.g., material extrusion, material jetting) enable the fabrication of complex, multimaterial and multiscale scaffolds with controlled properties for tissue engineering applications. This enables the fabrication of scaffolds that more accurately replicate the structure of natural tissues. Despite the availability of commercial bioprinters, their high cost and lack of customization have driven researchers to modify existing devices or create entirely new platforms. Among all the available examples in literature, there is a strong need for more modular systems which are robustly designed taking into consideration the specific needs of bioprinting. In this context, the aim of this work is to introduce robust engineering methodologies to design and fabricate custom hardware and software for multimaterial and multiscale bioprinting. Firstly, we will identify the main design requirements that should be considered for a bioprinter (e.g., encumbrance, positioning resolution). Based on these requirements, we will then propose an analysis of the key building blocks of a bioprinter, including hardware (i.e., positioning system, toolheads, additional modules for extended functionalities), electronics (i.e., power supply, control boards), and software, introducing for each one the main concepts and equations for its optimal design. Throughout the work, we will use a customized bioprinting platform (namely, the BOOST bioprinter) as an example of the application of the proposed methodologies. Finally, we will present a validation of the methodologies and the bioprinter by fabricating high quality scaffolds through the combination of material extrusion and material jetting. The firmware developed during this work is available online as a support for developing more robust customized bioprinters.

The description of the steps of the Q&A test and detector module assembly of the CBM-STS

The Silicon Tracking System (STS) is the core detector system of the Compressed Baryonic Matter (CBM) experiment at FAIR (Facility for Antiproton and Ion Research). The CBM will study matter at the highest baryonic densities in collisions of nuclear beams with a stationary target. The expected long latency for identification and the changing signature of the events drive us to use self-triggered streaming readout. The CBM data collection will be based on time-stamped detector data into a compute farm. Event reconstruction and physics analysis are performed online at up to 10 MHz collision rates. In the presented work, we will discuss step-by-step how the CBM-STS detector components are rigorously selected and prepared for assembly. It starts with carefully testing the readout ASICs. The various parameters are recorded to select the chip. The next step is to test the micro cable’s TAB (Tape Automated Bonding) bonding quality on the ASIC. Later, the 16-chip cables are bonded to the silicon strip sensor. All test results are stored and available for later use in a specially designed database using custom software applied to each step in the assembly process. After assembly of 1/3 of the modules (896), we will overview the acquired experience.

Determinants of Financial Information Disclosure Online: Empirical Evidence in Portugal

The rapid advancement of information technology, particularly the Internet, has significantly transformed communication and corporate reporting practices. The evolution of the Internet and Information and Communication Technologies (ICT) has enabled companies to disseminate extensive financial and non-financial information quickly and cost-effectively. Typically published on company websites, this information is accessible to users worldwide. Digital financial reporting has evolved to meet the needs of both information users and companies. The Internet is increasingly the primary channel for companies to share financial information, driven by technological advancements and the growing demand for online company data. However, the rise of technology in financial reporting raises concerns about information overload, potentially diminishing the quality and relevance of economic data. Additionally, managing the costs associated with technology, such as website development, customer relationship management systems, hardware, software, and other digital platforms, is crucial. This study aims to determine the extent of online financial information disclosure among the 150 largest Portuguese companies and identify the factors influencing this disclosure. The research methodology involves content analysis of the websites of 52 of the largest and best-performing companies operating in Portugal, as ranked by Revista Exame, using a predefined disclosure index to evaluate the degree of financial information disclosure on the Internet. The objective is to enhance understanding of the financial reporting practices adopted by major Portuguese companies and identify factors determining the level of disclosure. The results confirm that the disclosure index has an average value of 0.52147 and that there is a relationship between company size and sector of activity and the level of internet financial reporting.

Detection of Indian Counterfeit Currency Notes with MATLAB-Based Feature Extraction

Fakes are a major threat to India’s economy hence the need for a solution that will help detect these materials easily and accurately. The detection of counterfeit currency is a major concern for almost all countries, and this research focuses on developing a MATLAB-based counterfeit currency detection system which evaluates a true image of the Indian Currencies with the help of image processing and pattern recognition technique. Benefiting from MATLAB’s powerful image processing resources, the system conducts the necessary preprocessing, feature extraction and classification of vital security elements of currency, such as watermarks, security threads and micro-lettering which play an important role in identifying the genuine currency from the counterfeit. The specific characteristics of edge and texture are statistically and geometrically calculated, and the normal and high-resolution light conditions are at high accuracy with varying resolutions. In order to determine a distinction between actual and fake notes, support vector machine (SVM) classifiers are used. By validating this MATLAB solution, it has been determined to be effective as an easy to use, robust and customizable software that has the potential to work in numerous operations within banking and retail and prevent the spreading of counterfeit money.

Abstract 4139162: Optical coherence tomography measures mechanical contractile properties of the beating murine heart

Introduction: Optical imaging techniques can characterize properties of tissue at high temporal and spatial resolution, offering unique insights into electrically excitable tissues such as nerve and muscle. We hypothesized that the gated high-speed optical coherence tomography (OCT) could profile the contractile properties of mouse myocardial tissue and facilitate investigations of microscale mechanical function in the beating heart. Methods: C57BL/6 male mice (n=6) underwent a sternotomy while anesthetized and ventilated and were imaged at baseline with OCT. Another cohort of C57BL/6 male mice (n=6) were sacrificed and the hearts were ex vivo perfused with crystalloid using a Langendorff system. These hearts were imaged at baseline and after inhibition of contractile function with blebbistatin. OCT was performed using a custom tissue stabilizer and a Thorlabs TEL 321 OCT system, which was synchronized to physiologic signals using custom hardware and software and cardiac pacing protocols (Fig. 1A and 1B). OCT cross-sectional B-scan images (Fig. 1C) were obtained throughout multiple cardiac cycles in both in vivo and ex vivo preparations. Data were processed in MATLAB and ImageJ using the workflow in Fig. 1D. Results: Highly reproducible cross-sectional mean intensity changes were observed over the contractile cycle in vivo and ex vivo (Fig. 1E, left and middle). With mechanical contraction inhibited by blebbistatin, this cyclical intensity extinguished, linking the optical scattering change measured by OCT to myocardial contraction (Fig. 1E, right). B-scan curves averaged over multiple mice and temporally aligned with the ECG waveform (Fig. 1F) demonstrate a signal intensity waveform that reproducibly varies with the contractile cycle for both in vivo and ex vivo preparations. In vivo and ex vivo baseline waveforms both had peak intensity during systole and minimum in end-diastole (Fig. 1F). Reproducibility in ex vivo beating heart preparations without blood perfusion provides evidence that myocardial mechanical properties, not red blood cell flow, generate the intensity changes. Conclusion: Gated high-speed OCT imaging can quantify the mechanical contraction wave in the myocardium. Combined with gated OCT angiography, OCT techniques will provide high resolution imaging of both blood flow and mechanical contractility of the beating heart in small animal models of heart disease.

Abstract 4141469: Left Ventricular Septum Displacement Implications in the Limited Cardiac Reserve, RV to Pc Uncoupling and Oxygen Uptake During Exercise in Heart Failure

Background: Dyspnea on exertion is cardinal symptom in heart failure (HF) and may be caused by an unfavorable dynamic of ventricular interaction. This concept has been poorly addressed over time and we hypothesized that a careful study of the interventricular septum adaptations during maximal exercise in HF might be implicated in the limited cardiac reserve and uncoupling of right ventricular (RV) to pulmonary circulation (Pc), both yielding to a limited O2 uptake. Aim: To study the pathophysiology behind biventricular interaction during exercise in HF, evaluating the role of septum displacement during exercise and how and whether it would affect peak exercise oxygen consumption (VO 2 peak) through a limited cardiac output (CO) increase and some degrees of RV to PC uncoupling assessed by TAPSE/PASP. Methods: 22 HF performed a combined cardiopulmonary exercise testing imaging (CPET imaging) with RV 3D-imaging analysis and were compared with a control population. 3D imaging of the RV chamber was examined off-line using the 4D RV TomTec software and obtained 3D mesh of the RV model using custom software to obtain the mean curvature value of IVS in 4 regions of: inflow tract (RVIT), outflow tract (RVOT), apical and body. We acquired measurements of curvature during end-diastole (ED) and at end systole (ES) phases and obtained a parametric curvature map. Results: HF patients (mean age 72±12, 27% female) typically showed an abnormal septal curve, with a more leftward configuration either at rest and under exercise (rest =−0.01±0.007 at ED, and −0.01±0.009 at ES; peak exercise= −0.01±0.006 at ED, and −0.01±0.007 at ES) compared to controls (rest=−0.02±0.002 at ED, and −0.02±0.006 at ES; peak exercise −0.02±0.0.006 at ED, and −0.02±0.01 at ES, Figure). Notably, the degree of the IVS curvature showed a linear correlation with an impaired gas exchange performance as indicated by a lower peak VO 2 , a limited CO and impairment of TAPSE/PASP in HF (respectively, r=0.64, p&lt;0.001, r=0.5, p&lt;0.001, r=0.53, p&lt;0.001 at ED during exercise; r=0.61, p&lt;0.001 at ES during exercise; Figure). Conclusions: In HF, the evidence of right to left IVS displacement appears worth of investigation, by intervening strictly to a reduced CO response, and RV-PA uncoupling during exercise. These findings clearly point to the utility of assessing how new and current therapeutic strategies may modulate the negative septum displacement and overall cardiac mechanics.