Contour Adjustment Research Articles

Bedside right ventricle quantification using three-dimensional echocardiography in children with congenital heart disease: A comparative study with cardiac magnetic resonance imaging

BackgroundAccurate quantification of right ventricular (RV) volumes and function is crucial for the management of congenital heart diseases. AimsWe aimed to assess the feasibility and accuracy of bedside analysis using new RV quantification software from three-dimensional transthoracic echocardiography in children with or without congenital heart disease, and to compare measurements with cardiac magnetic resonance imaging. MethodsWe included paediatric patients with congenital heart disease (106 patients) responsible for RV volume overload and a control group (30 patients). All patients underwent three-dimensional transthoracic echocardiography using a Vivid E95 ultrasound system. RV end-diastolic and end-systolic volumes and RV ejection fraction were obtained using RV quantification software. Measurements were compared between RV quantification and cardiac magnetic resonance imaging in 27 patients. ResultsBedside RV quantification analysis was feasible in 133 patients (97.8%). Manual contour adjustment was necessary in 126 patients (93%). The mean time of analysis was 62±42s. RV end-diastolic and end-systolic volumes were larger in the congenital heart disease group than the control group: median 85.0 (interquartile range 29.5) mL/m2 vs 55.0 (interquartile range 20.5) mL/m2 for RV end-diastolic volume and 42.5 (interquartile range 15.3) mL/m2 vs 29.0 (interquartile range 11.8) mL/m2 for RV end-systolic volume, respectively. Good agreement for RV end-diastolic and end-systolic volumes and RV ejection fraction was found between RV quantification and magnetic resonance imaging measurements. RV quantification software underestimated RV end-diastolic volume/body surface area by 3mL/m2 and RV ejection fraction by 2.1%, and overestimated RV end-systolic volume/body surface area by 0.2mL/m2. ConclusionsWe found good feasibility and accuracy of bedside RV quantification analysis from three-dimensional transthoracic echocardiography in children with or without congenital heart disease. RV quantification could be a reliable and non-invasive method for RV assessment in daily practice, facilitating appropriate management and follow-up care.

Artificial intelligence-generated targets and inter-observer variation in online adaptive radiotherapy of bladder cancer

Background and purposeDaily target re-delineation in online adaptive radiotherapy (oART) introduces uncertainty. The aim of this study was to evaluate artificial intelligence (AI) generated contours and inter-observer target variation among radiotherapy technicians in cone-beam CT (CBCT) guided oART of bladder cancer. Materials and methodsFor each of 10 consecutive patients treated with oART for bladder cancer, one CBCT was randomly selected and retrospectively included. The bladder (CTV-T) was AI-segmented (CTV-TAI). Seven radiotherapy technicians independently reviewed and edited CTV-TAI, generating CTV-TADP. Contours were benchmarked against a ground truth contour (CTV-TGT) delineated blindly from scratch. CTV-TADP and CTV-TAI were compared to CTV-TGT using volume, dice similarity coefficient, and bidirectional local distance. Dose coverage (D99%>95 %) of CTV-TGT was evaluated for treatment plans optimized for CTV-TAI and CTV-TADP with clinical margins. Inter-observer variation among CTV-TADP was assessed using coefficient of variation and generalized conformity index. ResultsCTV-TGT ranged from 48.7 cm3 to 211.6 cm3. The median [range] volume difference was 4.5 [−17.8, 42.4] cm3 for CTV-TADP and −15.5 [−54.2, 4.3] cm3 for CTV-TAI, compared to CTV-TGT. Corresponding dice similarity coefficients were 0.87 [0.71, 0.95] and 0.84 [0.64, 0.95]. CTV-TGT was adequately covered in 68/70 plans optimized on CTV-TADP and in 6/10 plans optimized on CTV-TAI with clinical margins. The median [range] coefficient of variation was 0.08 [0.05, 0.11] and generalized conformity index was 0.78 [0.71, 0.88] among CTV-TADP. ConclusionsTarget re-delineation in CBCT-guided oART of bladder cancer demonstrated non-isotropic inter-observer variation. Manual adjustment of AI-generated contours was necessary to cover ground truth targets.

LVSnake: Accurate and robust left ventricle contour localization for myocardial infarction detection

Background and Objective:Localization of the left ventricle (LV) in echocardiography is important for the diagnosis of cardiovascular diseases. Previous deep learning approaches leverage semantic segmentation models to perform LV or myocardium segmentation and extract important LV parameters from the binary segmentation masks. Although these algorithms yield promising segmentation results, their per-pixel classification characteristic and complex postprocessing process of the binary masks compromise their robustness and speed. Methods:In this paper, inspired by the DeepSnake algorithm in the computer vision community, we develop a deep learning model called LVSnake for left ventricle localization. Our model generates the initial contour by connecting three key landmarks of the left ventricle output by our model including the start point, the apex point, and the end point of the endocardium. Then, a contour adjustment module is designed to refine the initial contour coordinates so as to obtain the final position of the endocardium. The extracted endocardium coordinates are used to perform Myocardial Infarction (MI) detection. Results:Experiment results on the HMC-QU dataset indicate that our model performs more favorably against previous approaches in terms of localization accuracy and robustness. The overall Endpoint-Error (EPE) of our model reaches 3.4 pixels. Using ventricular endocardium location extracted by our method to perform MI detection, the classification accuracy reaches 83.1% which exceeds that of existing studies (79.2%). Conclusions:Our proposed LVSnake can robustly and accurately extract LV positions from echocardiography, which can be used for MI detection.

MILENIAL SISTEM PENYIRAMAN OTOMATIS DI PERKEBUNAN TOMAT MENGGUNAKAN ANDROID BERBASIS APLIKASI APP INVERTOR

In today's life, we need something simple, fast and effective. Humans are required to be efficient in time in various things and activities. The agricultural sector is no exception. Difficulty in caring for and managing plants is one of the factors in the lack of greenery around community settlements. Water content and adjustment of soil contours also make maintenance difficult, because tomato plants have different water and humidity requirements for each type of plant. Tomato plantations are all activities that cultivate certain tomato plants on soil or other planting media in an appropriate ecosystem, to process and market goods and services produced from these plants, with the assistance of technology, capital and management to create prosperity for tomato plantation business actors. and society. Tomato plants are vegetables that we consume in this life and tomatoes can nourish our bodies. To produce quality tomato plants, good tomato plant maintenance is needed. The irrigation system that has been used so far is manual. Therefore, an automatic watering system was created using an Invertor-based Android application so that we can control watering and make it easier for tomato garden owners when they are out of town and then we can control it from Android and become more time efficient so that they can do other things. In today's life, we need something simple, fast and effective. Humans are required to be efficient in time in various things and activities. The agricultural sector is no exception. Difficulty in caring for and managing plants is one of the factors in the lack of greenery around community settlements. Water content and adjustment of soil contours also make maintenance difficult, because tomato plants have different water and humidity requirements for each type of plant. Tomato plantations are all activities that cultivate certain tomato plants on soil or other planting media in an appropriate ecosystem, to process and market goods and services produced from these plants, with the assistance of technology, capital and management to create prosperity for tomato plantation business actors. and society. Tomato plants are vegetables that we consume in this life and tomatoes can nourish our bodies. To produce quality tomato plants, good tomato plant maintenance is needed. The irrigation system that has been used so far is manual. Therefore, an automatic watering system was created using an Invertor-based Android application so that we can control watering and make it easier for tomato garden owners when they are out of town and then we can control it from Android and become more time efficient so that they can do other things.

In-Silico Trial of Simulation-Free Hippocampal-Avoidance Whole Brain Radiotherapy Using Diagnostic MRI-Based and Online Adaptive Planning

<h3>Purpose/Objective(s)</h3> Hippocampal-avoidance whole brain radiotherapy (HA-WBRT) has been shown to better preserve cognitive function with no difference in intracranial progression-free and overall survival. One limiting factor for its wider implementation is the plan complexity and considerably longer planning time required. We hypothesized that, <i>in silico,</i> a simulation-free workflow using diagnostic magnetic resonance (MR)-based radiation planning and online adaptation to account for differences in head position would expedite time to HA-WBRT delivery without compromising plan quality. <h3>Materials/Methods</h3> Seven patients treated for brain tumors who had cone beam computed tomography (CBCT) imaging available that sufficiently visualized the brainstem and ventricles were selected for this <i>in silico</i> study. Structures were contoured on the diagnostic brain MR, and a baseline HA-WBRT plan was generated. Then, to mimic simulation-free first fraction treatment, contours were transferred onto a daily setup CBCT for each patient. Within a commercially available, CT-based adaptive platform, contours were manually adjusted for anatomical differences; differences in head tilt between the diagnostic brain MR and CBCT were accounted for by triangulating with the brainstem, ventricles, and cranium and by online adaptation. Constraints were based on CC-001 protocol. Workflow tasks were timed, and baseline and adapted plans were compared using paired t-test on statistical software. <h3>Results</h3> All plans required adaptation at first fraction to account for head tilt differences and to meet constraints. An adaptive hippocampal avoidance planning template was applied to each patient with no modifications resulting in all objectives being met in the initial plan and adaptive plan. Structures that benefitted the most from first-fraction adaptation included hippocampi and optic chiasm; 71% and 57% of cases, respectively, required adaptation to meet constraints at first fraction. On pairwise comparison, there was a significant improvement in all dosimetric parameters for target coverage and with limiting hotspots in the hippocampal avoidance zone after adaptation (<i>p≤</i> .02); planning target volume (PTV) coverage increased by a median of 5% (IQR: 4%). Median duration of tasks was as follows: structure propagation and alignment on CBCT (8.5 min); contour adjustment (22.4 min); dose calculation (12.4 min); plan evaluation (0.9 min); total process time was 44.2 min. <h3>Conclusion</h3> Simulation-free HA-WBRT plans were successfully created using diagnostic brain MR imaging and first-fraction online adaptation to account for positional differences between diagnostic and on-table imaging. A Phase I clinical trial (NCT05096286) evaluating the feasibility and safety of simulation-free HA-WBRT using this methodology is underway.

Accuracy of new transthoracic 3D echocardiographic automated algorithm for right ventricle quantification in children with congenital heart disease

Management of many congenital heart diseases (CHD) depends on right ventricle (RV) assessment for which cardiac magnetic resonance (CMR) remains the gold standard. The objective of this study was to assess feasibility and reproducibility of a new semi-automated algorithm to quantify RV (4D auto RVQ) from 3D transthoracic echocardiography (3D TTE) in a pediatric population, and to compare measurements with those obtained from CMR. In all, 90 infants were prospectively included (age 7.5 years, 3–18). Fifteen healthy infants and 75 patients with CHD (30 repaired TOF, 25 ASD, 8 dilated pulmonary valve stenosis, 7 tricuspid regurgitation, 3 APVR, and 2 repaired TAC). All patients underwent 2D and 3D TTE (Vivid E95, GE Healthcare). RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), RV ejection volume (RVEV) and RV ejection fraction (RVEF) were analyzed by 4D auto RVQ and compared with measurements from 18 patients who underwent CMR exams for the follow up of their cardiopathy. 4D auto RVQ was feasible in 87 infants (96.7%). In 3 patients 4D auto RVQ was unable to detect RV contouring due to inadequate image quality. Manual contour adjustment was necessary in 81 cases (80%). Mean time of analysis including the time of manual adjustment was 62 seconds. RV was enlarged in 65 of 75 patients with CHD (mean 95 ml/m 2 , 62–165 ml/m 2 ). Good correlation for RVEDV, RVESV, RVEV and RVEF was found between 4D auto RVQ and CMR (r = 0.89–0.99, all P < 0.0001). 4D auto RVQ underestimated RVEDV/BSA of 8 ml/m 2 and RVEF by 6%, and overestimated RVESV/BSA of 9 ml/m 2 . Intraobserver and interobserver variability were low (4.7% and 8.9% respectively) ( Fig. 1 ). 4D auto RVQ is a promising tool for assessment of RV volume and function in children. Such simple and non-invasive exam could reduce the practice of CMR imaging during the follow up of children with CHD.

Three-dimensional echocardiographic assessment of left ventricular volume in different heart diseases using a fully automated quantification software.

BACKGROUNDHeartModel (HM) is a fully automated adaptive quantification software that can quickly quantify left heart volume and left ventricular function. This study used HM to quantify the left ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV) of patients with dilated cardiomyopathy (DCM), coronary artery heart disease with segmental wall motion abnormality, and hypertrophic cardiomyopathy (HCM) to determine whether there were differences in the feasibility, accuracy, and repeatability of measuring the LVEDV, LVESV, LV ejection fraction (LVEF) and left atrial end-systolic volume (LAESV) and to compare these measurements with those obtained with traditional two-dimensional (2D) and three-dimensional (3D) methods.AIMTo evaluate the application value of HM in quantifying left heart chamber volume and LVEF in clinical patients.METHODSA total of 150 subjects who underwent 2D and 3D echocardiography were divided into 4 groups: (1) 42 patients with normal heart shape and function (control group, Group A); (2) 35 patients with DCM (Group B); (3) 41 patients with LV remodeling after acute myocardial infarction (Group C); and (4) 32 patients with HCM (Group D). The LVEDV, LVESV, LVEF and LAESV obtained by HM with (HM-RE) and without regional endocardial border editing (HM-NE) were compared with those measured by traditional 2D/3D echocardiographic methods to assess the correlation, consistency, and repeatability of all methods.RESULTS(1) The parameters measured by HM were significantly different among the groups (P < 0.05 for all). Compared with Groups A, C, and D, Group B had higher LVEDV and LVESV (P < 0.05 for all) and lower LVEF (P < 0.05 for all); (2) HM-NE overestimated LVEDV, LVESV, and LAESV with wide biases and underestimated LVEF with a small bias; contour adjustment reduced the biases and limits of agreement (bias: LVEDV, 28.17 mL, LVESV, 14.92 mL, LAESV, 8.18 mL, LVEF, -0.04%). The correlations between HM-RE and advanced cardiac 3D quantification (3DQA) (rs = 0.91-0.95, P < 0.05 for all) were higher than those between HM-NE (rs = 0.85-0.93, P < 0.05 for all) and the traditional 2D methods. The correlations between HM-RE and 3DQA were good for Groups A, B, and C but remained weak for Group D (LVEDV and LVESV, rs = 0.48-0.54, P < 0.05 for all); and (3) The intraobserver and interobserver variability for the HM-RE measurements were low.CONCLUSIONHM can be used to quantify the LV volume and LVEF in patients with common heart diseases and sufficient image quality. HM with contour editing is highly reproducible and accurate and may be recommended for clinical practice.

Left Heart Chamber Volumetric Assessment by Automated Three-Dimensional Echocardiography in Heart Transplant Recipients.

BackgroundRecently, a new automated software (Heart Model) was developed to obtain three-dimensional (3D) left heart chamber volumes. The aim of this study was to verify the feasibility and accuracy of the automated 3D echocardiographic algorithm in heart transplant (HTx) patients. Conventional manual 3D transthoracic echocardiographic (TTE) tracings and cardiac magnetic resonance (CMR) images were used as a reference for comparison.MethodsThis study enrolled 103 healthy HTx patients prospectively. In protocol 1, left ventricular end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), left atrial max volume (LAVmax), LA minimum volume (LAVmin) and LV ejection fraction (LVEF) were obtained using the automated 3D echocardiography (3DE) and compared with corresponding values obtained through the manual 3DE. In protocol 2, 28 patients’ automated 3DE measurements were compared with CMR reference values. The impacts of contour edit and surgical technique were also tested.ResultsHeart Model was feasible in 97.1% of the data sets. In protocol 1, there was strong correlation between 3DE and manual 3DE for all the parameters (r = 0.77 to 0.96, p<0.01). Compared to values obtained through manual measurements, LV volumes and LVEF were overestimated by the automated algorithm and LA volumes were underestimated. All the biases were small except for that of LAVmin. After contour adjustment, the biases reduced and all the limits of agreement were clinically acceptable. In protocol 2, the correlations for LV and LA volumes were strong between automated 3DE with contour edit and CMR (r = 0.74 to 0.93, p<0.01) but correlation for LVEF remained moderate (r = 0.65, p < 0.01). Automated 3DE overestimated LV volumes but underestimated LVEF and LA volumes compared with CMR. The limits of agreement were clinically acceptable only for LVEDV and LAVmax.ConclusionSimultaneous quantification of left heart volumes and LVEF with the automated Heart Model program is rapid, feasible and to a great degree it is accurate in HTx recipients. Nevertheless, only LVEDV and LAVmax measured by automated 3DE with contour edit seem applicable for clinical practice when compared with CMR. Automated 3DE for HTx recipients is a worthy attempt, though further verification and optimization are needed.

Fully automated quantification of LV regional wall motion from echocardiograms to detect myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Ultromics Ltd Background Myocardial wall motion analysis from echocardiography allows precise assessment of cardiac contractile function. Strain, which assesses myocardial deformation, has been shown to enable earlier detection of myocardial disease [1]. Current analysis software packages [2] use semi-automated methods to compute strain, which frequently require manual endocardial delineation and iterative contour adjustment based on tracking results, respectively, causing significant variability. Purpose We present a fully automated pipeline for tracking left ventricular (LV) wall motion to quantify global and segmental longitudinal strain from 2D echocardiograms, and go on to validate the pipeline with an openly available myocardial infarction (MI) dataset. Methods We applied our existing deep learning-based automated contouring method [3] to delineate the endocardial border in the A4C, A2C and A3C views and combined this with spline-based elastic image registration to track LV motion through time. We sampled points from a region of interest initiated from the endocardial border at the end-diastolic (ED) frame, and tracked subsequent motion by recomputing updated positions of all sample points based on each frame‘s displacement field, enabling us to both track the myocardium throughout the cardiac cycle and calculate longitudinal strain relative to the ED frame. The automated endocardial contour was used to regularise the process. The pipeline was independently tested on the HMC-QU dataset [4] which was downloaded from Kaggle and consists of a single cardiac cycle from the A4C view from 160 patients who were diagnosed with an acute MI and underwent echocardiography either prior to percutaneous coronary intervention or within 24 hours of undergoing the procedure; the dataset includes the labels of ED and end-systolic (ES) frames, as well as the presence of an MI in 6 segments excluding the apical cap (Fig 1a), as determined by the consensus of cardiologists from HMC Hospital in Qatar. The Wilcoxon signed-rank test was used to compare peak strain between the MI and non-MI segments; ROC curves were computed to compare the performance of the automatically derived peak longitudinal strain against the MI labels. Results Fig 1b shows ROC curves of peak segmental longitudinal strain for detecting MI, with the best performance in the mid-anterolateral segment (AUC 0.84), and a lower performance for basal segments than mid and apical segments, consistent with known variation in clinical practice [5]. Fig 2 shows that peak longitudinal strain computed from our pipeline was statistically significantly more positive in segments with an MI. Conclusions We present a fully automated pipeline for calculating segmental strain across a cardiac cycle to identify infarcted segments without any observer variability. Clinical application of this method has the potential to identify and monitor regional myocardial function and benefit patient management. Abstract Figure. Fig1. ROC of peak longitudinal strains Abstract Figure. Fig2.Boxplot of peak longitudinal strain

Active contour model based on local intensity fitting and atlas correcting information for medical image segmentation

Intensity inhomogeneity and noises often occur in real medical images, which present a large degree of challenge to image segmentation. At the same time, most of the existing image segmentation algorithms are sensitive to initial conditions and model parameters. This paper presents an accurate and robust active contour model to solve the above problems. Inspired by the idea of the region-scalable fitting (RSF) model, we first define a local atlas fitting term transformed by the segmentation contour of the coherent local intensity clustering (CLIC) model. Then, we define a new energy functional by merging the atlas term into the energy functional of the RSF model. The advantage of this operation is that it makes full use of the existing segmentation features and advantages of the two models and avoids cumbersome adjustment of model parameters and initial contours. The experimental results clearly show that the improved model not only has better segmentation results than the RSF model and other active contour models such as the LINC, REGAC and SMAP models, but also solves the problem of sensitivity to initial contours, parameters adjustment and noise.

Analysis of patient-specific quality assurance for Elekta Unity adaptive plans using statistical process control methodology.

The Elekta Unity MR‐linac utilizes daily magnetic resonance imaging (MRI) for online plan adaptation. In the Unity workflow, adapt to position (ATP) and adapt to shape (ATS) treatment planning options are available which represent a virtual shift or full re‐plan with contour adjustments respectively. Both techniques generate a new intensity modulated radiation therapy (IMRT) treatment plan while the patient lies on the treatment table and thus adapted plans cannot be measured prior to treatment delivery. A statistical process control methodology was used to analyze 512 patient‐specific IMRT QA measurements performed on the MR‐compatible SunNuclear ArcCheck with a gamma criterion of 3%/2 mm using global normalization and a 10% low dose threshold. The lower control limit (LCL) was determined from 68 IMRT reference plan measurements, and a one‐sided process capability ratio (Cp,l) was used to assess the pass rates from 432 measured ATP and 80 measured ATS plans. Further analysis was performed to assess differences between SBRT or conventional fractionation pass rates and to determine whether there was any correlation between the pass rates and plan complexity. The LCL of the reference plans was determined to be a gamma pass rate of 0.958, and the Cp,l of the measured ATP plans and measured ATS plans were determined to be 1.403 and 0.940 for ATP and ATS plans, respectively, while a Cp,l of 0.902 and 1.383 was found for SBRT and conventional fractionations respectively. For plan complexity, no correlation was found between modulation degree and gamma pass rate, but a statistically significant correlation was observed between the beam‐averaged aperture area and gamma pass rate. All adaptive plans passed the TG‐218 guidelines, but the ATS and SBRT plans tended to have a smaller beam‐averaged aperture area with slightly lower gamma pass rates.

Application of a machine learning contouring tool for the evaluation of left ventricular strain in clinical practice

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): AK has been funded by the Egyptian cultural centre and educational bureau of the Egyptian embassy in London and the Ministry of higher education in Egypt. SEP acknowledges support from the “SmartHeart” EPSRC programme grant (www.nihr.ac.uk; EP/P001009/1) and the London Medical Imaging and AI Centre for Value-Based Healthcare. This new centre is one of the UK Centres supported by a £50m investment from the Data to Early Diagnosis and Precision Medicine strand of the government’s Industrial Strategy Challenge Fund, managed and delivered by UK Research and Innovation (UKRI). SEP acknowledges support from the CAP-AI programme, London’s first AI enabling programme focused on stimulating growth in the capital’s AI Sector. CAP-AI is led by Capital Enterprise in partnership with Barts Health NHS Trust and Digital Catapult and is funded by the European Regional Development Fund and Barts Charity. SEP also acts as a paid consultant to Circle Cardiovascular Imaging Inc., Calgary, Canada and Servier onbehalf Barts Heart Centre, St Bartholomew’s Hospital, Barts Health NHS Trust, West Smithfield, London, UK Background Manual contouring of cardiovascular magnetic resonance (CMR) cine images remains common practice and the reference standard for left ventricular (LV) volumes and mass evaluation. However, it is time-consuming and machine learning (ML) may significantly reduce the time required for contouring. Accurate LV contours are the basis for reliable LV strain analysis using tissue tracking. Purpose To assess the impact of a ML contouring tool alone versus expert adjusted contours on LV strain. Methods We retrospectively selected 402 CMR studies with diagnoses of myocardial infarction (n = 108), myocarditis (n = 130) and healthy controls (n = 164) from the Barts BioResource between January 2015 to June 2018. CMR examinations were obtained using 1.5T and 3T scanners (Siemens Healthineers, Germany). We excluded 32 cases due to phase inconsistency between short (SAX) and long axes (LAX) cine images or suboptimal cine image quality. For the remaining 370 cases, steady state free precession cine images for LAX and SAX were analysed by the ML contouring tool (using CVI42 research prototype software 5.11). Manual expert adjustment for the contours was done for each case if considered suboptimal for strain analysis in the reference end-diastolic phase. Strain results from ML and expert adjusted ML methods were compared for strain agreement. Times taken by these methods were recorded and compared against the time taken for standard manual contouring. Results SAX and LAX derived strains by ML and expert adjusted ML methods showed good agreement by Bland-Altman analysis (Figure 1) with excellent coefficient of concordance using Kendall W which is 0.98 for global SAX, radial and circumferential strains (mean difference(MD) = -1.7% (lower and upper limits of agreement (UL,LL) -6.6,3.2), MD = 0.5% (-1.0,2.1)) and is 0.95 for global LAX derived strain (radial and longitudinal, MD = 0.7% (UL,LL -8.7 ,7.4),MD= 0.2% (-1.9,2.5), respectively). Time taken for adjustment of ML contours was significantly shorter than manual contouring (1.35 minutes vs 8.0 minutes, around 590% time saving in ML adjusted method). Conclusions ML contouring compared to expert manual adjustment has a clinically reasonable agreement when used for measuring LV strain. Also, using the ML tool with expert adjustment shows significant time saving for analysis and reporting time compared to entirely manual analysis, favouring its application in routine clinical practice. Abstract Figure.

A method of transferring the subgingival contour of interim restorations to definitive restorations by using zirconia copings customized with casting wax

Establishing continuous and symmetric gingival levels is essential to achieving optimal gingival esthetics. Adjustment of the subgingival contour of the interim prosthesis is useful for managing gingival levels. This article illustrates how to accurately and predictably transfer the adjusted subgingival contour of interim restorations to the definitive restorations by using zirconia copings customized with casting wax.

CONTROL OF VALVE ELECTRIC DRIVE COORDINATES OF AUTOMATED WELDING EQUIPMENT FEED MECHANISMS

Goal. Finding ways to improve the quality of operation of the electrode wire feeder in terms of increasing the frequency of undistorted pulse feed with controlled characteristics, in particular its speed, as well as developing methods to simplify the adjustment of regulators of fast-acting electric drive to improve the results of the arc welding and surfacing process. Methodology. In the work, methods of analysis of existing technical solutions were used to increase the speed of operation of electric drives for a specific purpose with the choice of the most rational solution based on the use of the method of synthesis of a control system based on the concept of inverse problems of dynamics with subsequent computer simulation, confirming the adequacy of the applied method of synthesis of high-speed systems. Results. The authors considered the possibilities of increasing the speed of control systems for gearless computerized electric drives in a system with modern designs of valve electric drives for electrode wire feeding systems. A mathematical model of a rectifier motor has been developed with some assumptions that significantly influenced the simulation results. The new possibilities are based on the use of an original synthesis method based on the use of the concept of the inverse problem of dynamics with the subsequent study of the operation of the automatic control system for pulse wire feed, which was performed with aperiodic adjustment of the velocity contour by different methods. This approach made it possible to obtain the necessary laws of electric drive control without the traditional solution of the optimization problem. The developed control system for the electrode wire feed with pulsed motion algorithms provided the required linear movement of the wire at a pulse repetition rate of 100 Hz. The carried out computer simulation of the new control system confirmed the results of the study. It was found that an increase in the pulse time duration over 50 % of the pulse repetition period for given feed frequencies leads to an increase in the wire movement in the pulse, as well as to a decrease in the worked out frequency of the wire linear displacement feed. It was not possible to provide the required wire movement in the impulse feed mode for aperiodic adjustment of the speed loop with a P-controller for the same system parameters. Originality. The development was carried out for a specific application in the electrode wire feed systems of mechanized and automatic equipment for consumable electrode arc welding with obtaining certain algorithms of pulse motion. To effectively solve the complex problem of increasing the frequency of feed pulses with the provision of a displacement step, an original technique of the concept of inverse dynamic problems with confirmation of the result by mathematical modeling by practical results was used. Practical significance. The use of standard settings of the valve electric drive of mechanized and automatic welding equipment provides the frequency of undistorted electrode wire feed in the pulse mode of the feed mechanisms up to 50 Hz. New possibilities of settings made it possible to increase the frequency of wire feed, which makes it possible to raise the quality indicators of welded products - the formation of a welded joint, a decrease in electrode metal losses, an increase in the mechanical properties of a welded joint.

Abstract 13708: Right Ventricular Strain Comparison Between Quantification Software in Pediatric Normal and Pulmonary Hypertension Patients

Background: Right ventricular (RV) free wall longitudinal strain (FWLS) is a functional assessment in pediatric pulmonary hypertension (PH). RV FWLS analysis requires study transfer to an offline software which can hinder clinical use. Autostrain RV (AS-RV) uses an automatic recognition and speckle tracking that allows for an efficient tool in routine clinical use. We evaluated the feasibility and reproducibility of AS-RV FWLS in controls and PH patients, and compared the timing of AS-RV to the offline analysis. Methods: Two and 3-dimensional echocardiography 4-chamber RV images were obtained in 32 PH patients and 33 controls. RV FWLS was analyzed by AS-RV software on the EPIQ machines and offline by TomTec 4D RV strain software. AS-RV timing with and without RVFW adjustments were compared to TomTec. Adjusted AS-RV and TomTec RVFWLS were compared between controls and PH patients using paired T-tests, Intraclass correlation (ICC), and Bland-Altman. Results: Controls and PH patients were not statistically different in age, body surface area, or heart rate. PH patients had decreased RV FWLS than controls (-24.1 ± 5.2 vs -28.3 ± 3.6; p&lt;0.001). AS-RV was feasible in all controls and 31/32 PH patients. However, 72% of controls and 75% of PH patients required contour adjustments for accurate tracking. There were significant differences in timing between AS-RV, adjusted AS-RV, and TomTec in controls (4.3 ± 1.0 seconds, 26.5 ± 25.7 seconds, 50.4 ± 6.9 seconds; p&lt;0.0001 respectively) and PH patients (4.4 ± 1.3 seconds, 42.4 ± 29.7 seconds, 52.7 ± 5.5; p&lt;0.0001). ICC of adjusted AS-RV and TomTec showed strong correlation in controls and PH patients (0.70 and 0.78 respectively). Bland-Altman analysis shown in Figure 1. Conclusion: RV FWLS evaluation is feasible and reproducible using AS-RV, but frequent adjustments need to be made for data accuracy. Adjusted AS-RV can be incorporated into clinical use with less time, making quantification of RV easier in clinical practice.

Integration of the function generation synthesis into the design of a multi-leaf collimator

Throughout recent history, medical robots have gained a lot of popularity in robotic assisted radiotherapy. Integration of robot manipulators into the field of radiotherapy has improved the chances of patient recovery by increasing system precision, operation reliability and treatment efficiency. In order to prevent healthy tissues from radiation exposures during treatments, linear accelerators of radiotherapy robots have been enhanced by the implementation of active collimator designs. Addition of collimator mechanisms to these systems has also increased possibilities of treatments by allowing adjustable beam geometries on the targets. However, as the collimator leaves are additional obstacles on the path of the beam, beam scattering has become one of the most crucial issues waiting to be improved for these systems. In order to propose a solution for this problem, current paper tries to implement function generation synthesis into a multi-leaf active collimator design, where the individual collimator blocks are stacked vertically. This study demonstrates the proposed approach by utilizing two single degree of freedom planar systems positioned side by side for a point beam source. Throughout the study, kinematic synthesis approach was introduced to design these planar systems to adjust beam contour geometries on a single axis. At the end of the study, proposed procedure was verified by a numerical example and the results were used to design four degrees of freedom collimator that is able to adjust beam contour geometries on the plane. The prototype of the system was also modelled in order to ensure the realization of the collimator design for contour adjustments.

Analysis of the interaction process during laser transmission welding of multilayer polymer films with adapted laser wavelength by numerical simulation and thermography

The field of application of multilayer polymer films ranges from the packaging of food and other goods to medical technology and the encapsulation of organic electronics. The layer structure of the polymer films is adapted to the respective areas of application. Usually, polymer film systems contain several individual layers. A trend toward more flexible production and batch sizes down to one can be identified in all the above-mentioned areas of application. This requires new production processes. Laser transmission welding with adapted laser beam sources represents a promising approach for this. It is characterized by a contactless and a locally limited energy position. A very high degree of format flexibility is also possible, thanks to a purely numerical adjustment of the welding contour. In many applications, it is desired to keep the polymer film as it is available on the market. If two multilayer polymer films should be welded with laser radiation in an overlapping arrangement, sufficient absorption of the laser radiation in the material is required. Each individual polymer layer has wavelength-dependent material-specific optical properties. Due to the vibrations of polymer chains, polymers have absorption peaks in the near infrared range. If a suitable laser beam source is now used for the welding process, the energy can be deposited directly in the material without modifying it beforehand. The energy input should be the highest at the point of contact or in the sealing layers of the two polymer films so that it is locally heated and melted. The surrounding film layers are also thermally influenced by heat conduction processes. In addition, the optical properties of the other layers influence the propagation of the laser radiation through the multilayer polymer film. For a comprehensive understanding of the process, it is imperative to examine these processes in detail. Therefore, the interaction process is considered in depth and, especially, the propagation of the temperature field within the material, which is not directly accessible for real measurements, is analyzed exactly. For this purpose, on the one hand, a numerical temperature model is set up, which depicts the real experimental setup and takes into account the optical properties and heat conduction variables of the individual layers. The numerical model allows the temporal resolution of interaction processes within the multilayer polymer film to be viewed from different angles. On the other hand, thermographic images of the real samples are taken during the welding process. For this purpose, the emitted heat radiation of the polymer films is measured off-axis. The data obtained are evaluated and compared with each other. For the final discussion of the results, additional analyses of the weld specimens microscopy and thin sections are used.

Optimising adjacent membrane segmentation and parameterisation in multicellular aggregates by piecewise active contours

In fluorescence microscopy imaging, the segmentation of adjacent cell membranes within cell aggregates, multicellular samples, tissue, organs, or whole organisms remains a challenging task. The lipid bilayer is a very thin membrane when compared to the wavelength of photons in the visual spectra. Fluorescent molecules or proteins used for labelling membranes provide a limited signal intensity, and light scattering in combination with sample dynamics during in vivo imaging lead to poor or ambivalent signal patterns that hinder precise localisation of the membrane sheets. In the proximity of cells, membranes approach and distance each other. Here, the presence of membrane protrusions such as blebs; filopodia and lamellipodia; microvilli; or membrane vesicle trafficking, lead to a plurality of signal patterns, and the accurate localisation of two adjacent membranes becomes difficult. Several computational methods for membrane segmentation have been introduced. However, few of them specifically consider the accurate detection of adjacent membranes. In this article we present ALPACA (ALgorithm for Piecewise Adjacent Contour Adjustment), a novel method based on 2D piecewise parametric active contours that allows: (i) a definition of proximity for adjacent contours, (ii) a precise detection of adjacent, nonadjacent, and overlapping contour sections, (iii) the definition of a polyline for an optimised shared contour within adjacent sections and (iv) a solution for connecting adjacent and nonadjacent sections under the constraint of preserving the inherent cell morphology. We show that ALPACA leads to a precise quantification of adjacent and nonadjacent membrane zones in regular hexagons and live image sequences of cells of the parapineal organ during zebrafish embryo development. The algorithm detects and corrects adjacent, nonadjacent, and overlapping contour sections within a selected adjacency distance d, calculates shared contour sections for neighbouring cells with minimum alterations of the contour characteristics, and presents piecewise active contour solutions, preserving the contour shape and the overall cell morphology. ALPACA quantifies adjacent contours and can improve the meshing of 3D surfaces, the determination of forces, or tracking of contours in combination with previously published algorithms. We discuss pitfalls, strengths, and limits of our approach, and present a guideline to take the best decision for varying experimental conditions for in vivo microscopy.

Process Development for Tip Repair of Complex Shaped Turbine Blades with IN718

One of the most common defects during the operation of turbine blades is wear of the blade tip, which can lead to scrap of the blades. Additive Manufacturing (AM) offers the possibility to avoid a cost-intensive replacement of the complete blade with repair processes via Laser Material Deposition (LMD, also known as Direct Energy Deposition, DED) processes. Due to the industrial relevance of the application, only limited information regarding the exact deposition strategy and the process parameters used for the LMD process is available. The blade geometry used in this study is characterized by the variation of the profile cross-sections over the height of the blade. In addition, the profiles are rotated around the center of their skeleton line, which is known as twist. Furthermore, the profiles are shifted along their tendon line towards the leading edge, which is referred to as the forward sweep. First, a suitable set of process parameters is determined with which pore- and crack-free basic probes with IN718 can be manufactured. In order to transfer these parameters to the turbine blade, various process strategies are investigated which take into account both the sensitive blade geometry and the kinematics of the production system used. These strategies include the adjustment of contour and hatch tracks, design of suitable fly-in and fly-out strategies, as well as measures for the production of the overhang. The shape accuracy after the process is assessed by comparing the repaired blade with its target geometry with optical measurements. In summary, the three-dimensional build-up strategy used enables a stable reproduction of the twist and forward sweep and achieves a sufficient oversize for machining. Thus, the developed process represents a basic solution for the near-net-shape repair of blade tip damage of complex blade geometries, which can be applied to other blade geometries.

Protocolised way to cope with anatomical changes in head & neck cancer during the course of radiotherapy.

During a course of radiotherapy for head-and-neck-cancer (HNC), non-rigid anatomical changes can be observed on daily Cone Beam CT (CBCT). To objectify responses to these changes, we use a decision support system (traffic light protocol). Action levels orange and red may lead to re-planning. The purpose of this study was to evaluate how often re-planning was done for non-rigid anatomical changes, which anatomical changes led to re-planning and in which subgroups of patients treatment adaptation was deemed necessary. A consecutive series of 388 HNC patients were retrospectively selected using the digital log of CBCT scans. The logs were analyzed for the number of new plans on an original planning CT scan (O-pCT) or a new pCT scan (N-pCT). Reasons for re-planning were categorized into: target volume increase/decrease, body contour decrease/increase and local shift of target volume. Subgroup analysis was performed to investigate relative differences of re-planning between treatment modalities. For 33 patients the treatment plan was adapted due to anatomical changes, resulting in 37 new plans in total. Re-planning on a N-pCT with complete re-delineation was done 22 times. In fifteen cases a new plan was created after adjustment of contours on the O-pCT. Main reasons for re-planning were target volume increase, body contour decrease and local shifts of target volume. Most re-planning (23%) was seen in patients treated with chemoradiotherapy. Visual detection of anatomical changes on CBCT during treatment of HNC, results in re-planning in 1 out of 10 patients.