Publications by authors named "Gerard O"

33 Publications

Mitral Annulus Segmentation Using Deep Learning in 3-D Transesophageal Echocardiography.

IEEE J Biomed Health Inform 2020 04 12;24(4):994-1003. Epub 2019 Dec 12.

3D Transesophageal Echocardiography is an excellent tool for evaluating the mitral valve and is also well suited for guiding cardiac interventions. We introduce a fully automatic method for mitral annulus segmentation in 3D Transesophageal Echocardiography, which requires no manual input. One hundred eleven multi-frame 3D transesophageal echocardiography recordings were split into training, validation, and test sets. Each 3D recording was decomposed into a set of 2D planes, exploiting the symmetry around the centerline of the left ventricle. A deep 2D convolutional neural network was trained to predict the mitral annulus coordinates, and the predictions from neighboring planes were regularized by enforcing continuity around the annulus. Applying the final model and post-processing to the test set data gave a mean error of 2.0 mm - with a standard deviation of 1.9 mm. Fully automatic segmentation of the mitral annulus can alleviate the need for manual interaction in the quantification of an array of mitral annular parameters and has the potential to eliminate inter-observer variability.
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http://dx.doi.org/10.1109/JBHI.2019.2959430DOI Listing
April 2020

Quality of life trajectories in survivors of acute myocardial infarction: a national longitudinal study.

Heart 2020 01 7;106(1):33-39. Epub 2019 Nov 7.

Leeds Institute of Cardiovascular and Metabolic Medicine/Leeds Institute of Data Analytics, University of Leeds, Leeds, UK.

Aim: To define trajectories of perceived health-related quality of life (HRQoL) among survivors of acute myocardial infarction (AMI) and identify factors associated with trajectories.

Methods: Data on HRQoL among 9566 survivors of AMI were collected from 77 National Health Service hospitals in England between 1 November 2011 and 24 June 2015. Longitudinal HRQoL was collected using the EuroQol five-dimension questionnaire measured at hospitalisation, 1, 6 and 12 months post-AMI. Trajectories of perceived HRQoL post-MI were determined using multilevel regression analysis and latent class growth analysis (LCGA).

Results: One or more percieved health problems in mobility, self-care, usual activities, pain/discomfort and anxiety/depression was reported by 69.1% (6607/9566) at hospitalisation and 59.7% (3011/5047) at 12 months. Reduced HRQoL was associated with women (-4.07, 95% CI -4.88 to -3.25), diabetes (-2.87, 95% CI -3.87 to -1.88), previous AMI (-1.60, 95% CI -2.72 to -0.48), previous angina (-1.72, 95% CI -2.77 to -0.67), chronic renal failure (-2.96, 95% CI -5.08 to -0.84; -3.10, 95% CI -5.72 to -0.49), chronic obstructive pulmonary disease (-3.89, 95% CI -5.07 to -2.72) and cerebrovascular disease (-2.60, 95% CI -4.24 to -0.96). LCGA identified three subgroups of HRQoL which we labelled: improvers (68.1%), non-improvers (22.1%) and dis-improvers (9.8%). Non-improvers and dis-improvers were more likely to be women, non-ST-elevation myocardial infarction (NSTEMI) and have long-term health conditions, compared with improvers.

Conclusions: Quality of life improves for the majority of survivors of AMI but is significantly worse and more likely to decline for women, NSTEMI and those with long-term health conditions. Assessing HRQoL both in hospital and postdischarge may be important in determining which patients could benefit from tailored interventions.

Trial Registration: NCT01808027 and NCT01819103.
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http://dx.doi.org/10.1136/heartjnl-2019-315510DOI Listing
January 2020

An image fusion tool for echo-guided left ventricular lead placement in cardiac resynchronization therapy: Performance and workflow integration analysis.

Echocardiography 2019 10 19;36(10):1834-1845. Epub 2019 Oct 19.

Center for Cardiological Innovation, Oslo, Norway.

Background: The response rate to cardiac resynchronization therapy (CRT) may be improved if echocardiographic-derived parameters are used to guide the left ventricular (LV) lead deployment. Tools to visually integrate deformation imaging and fluoroscopy to take advantage of the combined information are lacking.

Methods: An image fusion tool for echo-guided LV lead placement in CRT was developed. A personalized average 3D cardiac model aided visualization of patient-specific LV function in fluoroscopy. A set of coronary venography-derived landmarks facilitated registration of the 3D model with fluoroscopy into a single multimodality image. The fusion was both performed and analyzed retrospectively in 30 cases. Baseline time-to-peak values from echocardiography speckle-tracking radial strain traces were color-coded onto the fused LV. LV segments with suspected scar tissue were excluded by cardiac magnetic resonance imaging. The postoperative augmented image was used to investigate: (a) registration accuracy and (b) agreement between LV pacing lead location, echo-defined target segments, and CRT response.

Results: Registration time (264 ± 25 seconds) and accuracy (4.3 ± 2.3 mm) were found clinically acceptable. A good agreement between pacing location and echo-suggested segments was found in 20 (out of 21) CRT responders. Perioperative integration of the proposed workflow was successfully tested in 2 patients. No additional radiation, compared with the existing workflow, was required.

Conclusions: The fusion tool facilitates understanding of the spatial relationship between the coronary veins and the LV function and may help targeted LV lead delivery.
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http://dx.doi.org/10.1111/echo.14483DOI Listing
October 2019

Transcatheter heart valve interventions: where are we? Where are we going?

Eur Heart J 2019 02;40(5):422-440

Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, RC Leiden, The Netherlands.

Transcatheter heart valve interventions have transformed the outcomes of patients with valvular heart disease (VHD) who are unfavourable candidates for surgery. Technological advances have allowed extension of these interventions to younger or lower risk patients and those with other forms of VHD and may in the future permit earlier treatment of VHD in less symptomatic patients or those with moderate disease. The balance of risks and benefits is likely to differ between lower and higher risk patients, and more evidence is needed to evaluate the net benefit of transcatheter technology in these groups. As academic researchers, clinicians, industry, and patient stakeholders collaborate to research these broader indications for transcatheter valve interventions, it is essential to address (i) device durability and deliverability, (ii) specific anatomical needs (e.g. bicuspid aortic valves, aortic regurgitation, mitral and tricuspid valve disease), (iii) operator training, and (iv) the reinforced importance of the multidisciplinary Heart Team.
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http://dx.doi.org/10.1093/eurheartj/ehy668DOI Listing
February 2019

Adaptive Color Gain for Vena Contracta Quantification in Valvular Regurgitation.

Ultrasound Med Biol 2018 08 18;44(8):1770-1777. Epub 2018 May 18.

GE Vingmed Ultrasound, Oslo, Norway; Department of Informatics, University of Oslo, Oslo, Norway; Department of Cardiology, Center for Cardiological Innovation, Oslo University Hospital, Rikshospitalet, Norway.

Severe valvular regurgitation can lead to pulmonary hypertension, atrial fibrillation and heart failure. Vena contracta width is used to estimate the severity of the regurgitation. Parameters affecting visualization of color Doppler have a significant impact on the measurement. We propose a data-driven method for automated adjustment of color gain based on the peak power of the color Doppler signal in the vicinity of the vena contracta. A linear regression model trained on the peak power was used to predict the orifice diameter. According to our study, the color gain should be set to about 6 dB above where color Doppler data completely disappears from the image. Based on our method, orifices with reference diameters of 4, 6.5 and 8.5 mm were estimated with relative diameter errors within 18%, 12% and 14%, respectively.
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http://dx.doi.org/10.1016/j.ultrasmedbio.2018.04.002DOI Listing
August 2018

Children and screens: Groupe de Pédiatrie Générale (Société française de pédiatrie) guidelines for pediatricians and families.

Arch Pediatr 2018 Feb 1;25(2):170-174. Epub 2018 Feb 1.

Pediatricians of the Groupe de pédiatrie générale (GPG), GPG CH Versailles, 1, rue Richaud, 78000 Versailles, France.

The Groupe de Pédiatrie Générale (General Pediatrics Group), a member of the Société française de pédiatrie (French Pediatrics Society), has proposed guidelines for families and doctors regarding children's use of digital screens. A number of guidelines have already been published, in particular by the French Academy of Sciences in 2013 and the American Academy of Pediatrics in 2016. These new guidelines were preceded by an investigation into the location of digital screen use by young children in France, a survey of medical concerns on the misuse of digital devices, and a review of their documented benefits. The Conseil Supérieur de l'Audiovisuel (Higher Council on Audiovisual Technology) and the Union Nationale de Associations Familiales (National Union of Family Associations) have taken part in the preparation of this document. Five simple messages are proposed: understanding without demonizing; screen use in common living areas, but not in bedrooms; preserve time with no digital devices (morning, meals, sleep, etc.); provide parental guidance for screen use; and prevent social isolation.
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http://dx.doi.org/10.1016/j.arcped.2017.12.014DOI Listing
February 2018

Left atrial volumetric assessment using a novel automated framework for 3D echocardiography: a multi-centre analysis.

Eur Heart J Cardiovasc Imaging 2017 Sep;18(9):1008-1015

Lab. on Cardiovascular Imaging and Dynamics, KU Leuven, Leuven, Belgium.

Aims: This study aims at validating a software tool for automated segmentation and quantification of the left atrium (LA) from 3D echocardiography.

Methods And Results: The LA segmentation tool uses a dual-chamber model of the left side of the heart to automatically detect and track the atrio-ventricular plane and the LA endocardium in transthoracic 3D echocardiography. The tool was tested in a dataset of 121 ultrasound images from patients with several cardiovascular pathologies (in a multi-centre setting), and the resulting volumes were compared with those assessed manually by experts in a blinded analysis using conventional contouring. Bland-Altman analysis showed good agreement between the automated method and the manual references, with differences (mean ± 1.96 SD) of 0.5 ± 5.7 mL for LA minimum volume and -1.6 ± 9.7 mL for LA maximum volume (comparable to the inter-observer variability of manual tracings). The automated tool required no user interaction in 93% of the recordings, while 4% required a single click and only 2% required contour adjustments, reducing considerably the amount of time and effort required for LA volumetric analysis.

Conclusion: The automated tool was validated in a multi-centre setting, providing quantification of the LA volume over the cardiac cycle with minimal user interaction. The results of the automated analysis were in agreement with those estimated manually by experts. This study shows that such approach has clinical utility for the assessment of the LA morphology and function, automating and facilitating the time-consuming task of analysing 3D echocardiographic recordings.
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http://dx.doi.org/10.1093/ehjci/jew166DOI Listing
September 2017

Spatiotemporal registration of multiple three-dimensional echocardiographic recordings for enhanced field of view imaging.

J Med Imaging (Bellingham) 2016 Jul 8;3(3):037001. Epub 2016 Jul 8.

KU Leuven , Department of Cardiovasular Sciences, Cardiovascular Imaging and Dynamics Lab, UZ Herestraat 49, Box 7003, Leuven 3000, Belgium.

The use of three-dimensional (3-D) echocardiography is limited by signal dropouts and narrow field of view. Data compounding is proposed as a solution to overcome these limitations by combining multiple 3-D recordings to form a wide field of view. The first step of the solution requires registration between the recordings both in the spatial and temporal dimension for dynamic organs such as the heart. Accurate registration between the individual echo recordings is crucial for the quality of compounded volumes. A temporal registration method based on a piecewise one-dimensional cubic B-spline in combination with multiscale iterative Farnebäck optic flow method for spatial registration was described. The temporal registration method was validated on in vivo data sets with annotated timing of mitral valve opening. The spatial registration method was validated using in vivo data and compared to registration with Procrustes analysis using manual contouring as a benchmark. The spatial accuracy was assessed in terms of mean of absolute distance and Hausdorff distance between the left ventricular contours. The results showed that the temporal registration accuracy is in the range of half the time resolution of the echo recordings and the achieved spatial accuracy of the proposed method is comparable to manual registration.
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http://dx.doi.org/10.1117/1.JMI.3.3.037001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4944392PMC
July 2016

Automated Segmentation of the Right Ventricle in 3D Echocardiography: A Kalman Filter State Estimation Approach.

IEEE Trans Med Imaging 2016 Jan 7;35(1):42-51. Epub 2015 Jul 7.

As the right ventricle's (RV) role in cardiovascular diseases is being more widely recognized, interest in RV imaging, function and quantification is growing. However, there are currently few RV quantification methods for 3D echocardiography presented in the literature or commercially available. In this paper we propose an automated RV segmentation method for 3D echocardiographic images. We represent the RV geometry by a Doo-Sabin subdivision surface with deformation modes derived from a training set of manual segmentations. The segmentation is then represented as a state estimation problem and solved with an extended Kalman filter by combining the RV geometry with a motion model and edge detection. Validation was performed by comparing surface-surface distances, volumes and ejection fractions in 17 patients with aortic insufficiency between the proposed method, magnetic resonance imaging (MRI), and a manual echocardiographic reference. The algorithm was efficient with a mean computation time of 2.0 s. The mean absolute distances between the proposed and manual segmentations were 3.6 ± 0.7 mm. Good agreements of end diastolic volume, end systolic volume and ejection fraction with respect to MRI ( -26±24 mL , -16±26 mL and 0 ± 10%, respectively) and a manual echocardiographic reference (7 ± 30 mL, 13 ± 17 mL and -5±7% , respectively) were observed.
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http://dx.doi.org/10.1109/TMI.2015.2453551DOI Listing
January 2016

Parametric ultrasound and fluoroscopy image fusion for guidance of left ventricle lead placement in cardiac resynchronization therapy.

J Med Imaging (Bellingham) 2015 Apr 13;2(2):025001. Epub 2015 May 13.

Center for Cardiological Innovation , Songsvannsveien 9, Oslo 0372, Norway ; GE Vingmed Ultrasound AS , Strandpromenaden 45, Horten 3183, Norway ; University of Oslo , Department of Informatics, Gaustadalléen 23 B, Oslo 0373, Norway.

Recent studies show that the response rate to cardiac resynchronization therapy (CRT) could be improved if the left ventricle (LV) is paced at the site of the latest mechanical activation, but away from the myocardial scar. A prototype system for CRT lead placement guidance that combines LV functional information from ultrasound with live x-ray fluoroscopy was developed. Two mean anatomical models, each containing LV epi-, LV endo- and right ventricle endocardial surfaces, were computed from a database of 33 heart failure patients as a substitute for a patient-specific model. The sphericity index was used to divide the observed population into two groups. The distance between the mean and the patient-specific models was determined using a signed distance field metric (reported in mm). The average error values for LV epicardium were [Formula: see text] and for LV endocardium were [Formula: see text]. The validity of using average LV models for a CRT procedure was tested by simulating coronary vein selection in a group of 15 CRT candidates. The probability of selecting the same coronary branch, when basing the selection on the average model compared to a patient-specific model, was estimated to be [Formula: see text]. This was found to be clinically acceptable.
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http://dx.doi.org/10.1117/1.JMI.2.2.025001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4478843PMC
April 2015

Enhancing bull sexual behavior using estrus-specific molecules identified in cow urine.

Theriogenology 2015 Jun 10;83(9):1381-8. Epub 2015 Feb 10.

INRA, UMR CNRS/USTL 8576, UGSF, Villeneuve D'Ascq, France.

Deficiencies in bull mating behavior have implications for bovine artificial insemination activities. The aim of this study was to identify the compounds present in fluids emitted by cows during estrus, which could enhance bull libido. Chemical analysis of urine samples from cows led to the characterization of molecules varying specifically at the preestrous and estrous stages. The synthetic counterpart molecules (1,2-dichloroethylene, squalene, coumarin, 2-butanone, oleic acid) were used to investigate the biological effects on male sexual behavior and sperm production. When presented to males, 2-butanone and oleic acid synthetic molecules significantly lowered mounting reaction time and ejaculation time (-33% and 21% after 2-butanone inhalation, respectively, P < 0.05). The "squalene +1,2-dichloroethylene" combination induced a 9% increase of sperm quantity (P < 0.05). This study suggests that the identified estrous-specific molecules could be part of the chemical signals involved in male and female mating behavior and may be used for a wide range of applications. The identification of these molecules may have implications for the cattle breeding industry.
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http://dx.doi.org/10.1016/j.theriogenology.2015.02.004DOI Listing
June 2015

Effect of post-thaw dilution with caffeine, pentoxifylline, 2'-deoxyadenosine and prostatic fluid on motility of frozen-thawed dog semen.

Theriogenology 2010 Jul 23;74(1):153-64. Epub 2010 Mar 23.

Department of Veterinary Clinical Sciences, Faculty of Veterinary Medicine, Agripolis, Legnaro- PD, Italy.

The aim of the experiment was to evaluate the motility pattern of frozen-thawed canine semen to which pentoxifyilline (PTX), caffeine (CAF), 2'-deoxyadenosine (DX), and prostatic fluid (PROST) were added after thawing. Semen evaluations were performed using computer-assisted sperm analysis (CASA) at thawing and during 120min of incubation at 37 degrees C. Three experiments were conducted: 1) to establish which concentrations of stimulants work best; 2) to investigate the interaction between thawing rate and addition of CAF 5mM, PTX 2.5mM and PROST; 3) to evaluate the effect of PTX 7.5mM and DX 5mM on semen motility after thawing. In experiment 1, ALH and VCL were enhanced at thawing by CAF 7.5mM (CAF 7.5: 9.1+/-0.5microm; control: 6.7+/-0.4microm) and DX 5 and 7.5mM (DX 5: 199.1+/-12.8microm/s; DX 7.5: 197.3+/-13.9microm/s; control: 162.5+/-8.4microm/s), while PTX 2.5-5-7.5mM improved TOT after 120min of incubation. In experiment 2, PROST lowered ALH values throughout incubation (P<0.05) with respect to the other treatments, in particular when compared to CAF at Time=30 and at Time=60. In experiment 3, PTX 7.5mM improved VAP (PTX: 101.6+/-6.8microm/s; control: 81.9+/-10.5microm/s), VSL (PTX: 82.9+/-6.4microm/s; control: 65.9+/-9.8microm/s), VCL (PTX: 214.3+/-13.3microm/s; control:167+/-15.7microm/s), ALH (PTX: 10.5+/-0.3; control: 7.3+/-1.4microm), PM (PTX: 11.3+/-4.2%; control: 7.7+/-3.9%) and TOT (PTX: 20.1+/-5.3%; control:15.6+/-5.6%) at Time=120, while DX 5mM influenced VCL at Time=60 (DX: 218.3+/-14.3microm/s; control: 188.5+/-7.5microm/s, P<0.05). Motility stimulants may be useful for enhancing motility of canine frozen-thawed spermatozoa without affecting sperm longevity.
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http://dx.doi.org/10.1016/j.theriogenology.2010.01.026DOI Listing
July 2010

Estimation of genetic parameters and genome scan for 15 semen characteristics traits of Holstein bulls.

J Anim Breed Genet 2009 Aug;126(4):269-77

INRA, UR337 Station de Génétique Quantitative et Appliquée, Jouy-en-Josas, France.

A QTL detection experiment was performed in French dairy cattle to search for QTL related to male fertility. Ten families, involving a total of 515 bulls, were phenotyped for ejaculated volume and sperm concentration, number of spermatozoa, motility, velocity, percentage of motile spermatozoa after thawing and abnormal spermatozoa. A set of 148 microsatellite markers were used to realize a genome scan. First, genetic parameters were estimated for all traits. Semen production traits were found to have moderate heritabilities (from 0.15 to 0.30) while some of the semen quality traits such as motility had high heritabilities (close to 0.60). Genetic correlations among traits showed negative relationships between volume and concentration and between volume and most quality traits such as motility or abnormal sperm while correlations between concentration and these traits were rather favourable. Percentages of abnormal sperm were negatively related to quality traits, especially with motility and velocity of spermatozoa. Three QTL related to abnormal sperm frequencies were significant at p < 0.01. In total, 11 QTL (p < 0.05) were detected. However, the number of QTL detected was within the range of expected false positives. Because of the lack of power to find QTL in this design further analyses are required to confirm these QTL.
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http://dx.doi.org/10.1111/j.1439-0388.2008.00788.xDOI Listing
August 2009

Accuracy of measuring mitral annular velocity by 2D speckle tracking imaging.

J Cardiol 2009 Apr 23;53(2):188-95. Epub 2008 Dec 23.

Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.

Background: Recent developments in 2D speckle tracking imaging allow not only measurements of regional myocardial strain, but also velocities of the mitral annulus. The aim of this study was to determine the accuracy of speckle tracking derived mitral annulus velocity compared with conventional pulsed wave Doppler measurements.

Methods: 2D speckle tracking was acquired from the apical 4-chamber view (QLab, Speckle SQ, Philips, Andover, MA) in 169 subjects. While using texture tracking, two small regions of interest (ROIs) were placed in the septal (IVS) and lateral corners (LAT) of the mitral annulus. The software automatically tracked the ROIs frame-by-frame, yielding regional mean velocity curves of the mitral annulus throughout the cardiac cycle (synthetic pulsed wave Doppler; SPW). From these curves, peak systolic, early- and late-diastolic velocities of the mitral annulus (S'-SPW, E'-SPW, and A'-SPW) were measured. Peak systolic, early- and late-diastolic velocity in the mitral annulus (S', E', and A') by conventional pulsed wave tissue Doppler tracing were also obtained.

Results: Adequate ROI tracking was observed in 150/169 subjects in IVS and 139/169 subjects in LAT of the mitral annulus. All annular velocities derived from SPW were significantly lower than corresponding velocities obtained from conventional method in both IVS and LAT regions of the mitral annulus. However, significant correlation between S' (E', A')-SPW and S' (E', A') was observed. In particular, a good correlation between E'-SPW and E' was noted in both IVS (r=0.89, P<0.001) and LAT (r=0.85, P<0.001) regions of the mitral annulus. If we defined E/E'-SPW in IVS>26 for predicting E/E' in IVS>15, sensitivity, specificity, and accuracy were 83%, 97%, and 94%, respectively. E/E'-SPW in LAT>13 had a 94% sensitivity, 92% specificity, and 93% accuracy for predicting E/E' in LAT>10.

Conclusions: The values of annular velocities by SPW were significantly lower compared to those assessed by traditional tissue velocities. However, new cut-off values of E/E'-SPW for predicting elevated LV filling pressure highly correlated with traditional parameters. 2D speckle tracking imaging provides another strategy for evaluating LV filling pressures.
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http://dx.doi.org/10.1016/j.jjcc.2008.10.009DOI Listing
April 2009

Assessment of subendocardial vs. subepicardial left ventricular rotation and twist using two-dimensional speckle tracking echocardiography: comparison with tagged cardiac magnetic resonance.

Eur Heart J 2009 Mar 19;30(5):608-17. Epub 2008 Nov 19.

Division of Cardiology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium.

Aims: The aim of this article is to evaluate the accuracy and reproducibility of two-dimensional speckle tracking echocardiography (2D-STE) for the estimation of left ventricular (LV) twist, using tagged cardiac magnetic resonance (cMR) as the reference standard, and to assess how much 2D-STE rotational parameters are affected by the level at which measurements are made within the LV.

Methods And Results: Forty-three patients with various heart diseases and 10 healthy volunteers underwent cMR and 2D-STE on the same day. With both methods, basal and apical time-rotation curves were generated at endocardial, midwall, and epicardial levels. By using the most apical cMR short-axis cross-section as a comparator, apical rotation was significantly underestimated by 2D-STE. When 2D-STE and cMR short-axis cross-sections were matched for their internal dimensions, measurements of endocardial, midwall, and epicardial twists no longer differ between cMR and 2D-STE (12.6 +/- 5.9 vs. 12.5 +/- 5.7 degrees , 10.5 +/- 4.6 vs. 9.7 +/- 4.1 degrees , and 8.9 +/- 4.0 vs. 8.4 +/- 3.7 degrees , respectively, all P = ns).

Conclusion: Compared with tagged cMR, 2D-STE underestimates apical rotation and LV twist. This is related to the inability of 2D-STE to image the real LV apex in most of the patients. However, when 2D-STE and cMR data are compared at similar acquisition levels, both techniques provide similar values.
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http://dx.doi.org/10.1093/eurheartj/ehn511DOI Listing
March 2009

Measurement of left ventricular mass by real-time three-dimensional echocardiography: validation against magnetic resonance and comparison with two-dimensional and m-mode measurements.

J Am Soc Echocardiogr 2008 Sep;21(9):1001-5

Second Department of Internal Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.

Background: The recent development of 3-dimensional (3D) surface detection algorithm of the endocardial and epicardial surfaces from real-time 3D echocardiographic (RT3DE) datasets allows direct semiautomated quantification of left ventricular mass (LVM). Our aims were to (1) evaluate the accuracy of RT3DE measurements of LVM using this algorithm against cardiac magnetic resonance (CMR) reference and (2) compare RT3DE LVM with conventional M-mode, 2-dimensional (2D), and RT3DE-guided biplane measurements.

Methods: A total of 205 patients were studied in 2 protocols: (1) RT3DE and CMR imaging was performed on the same day in 55 subjects; (2) in an additional 150 subjects, RT3DE, 2D, and M-mode images were acquired. In both protocols, RT3DE endocardial and epicardial surfaces were semiautomatically identified at end diastole (QLab, Philips Medical Systems, Andover, MA) to calculate LVM. CMR, 2D, and M-mode-derived LVM were obtained using standard techniques.

Results: A significant correlation (r = 0.95) was noted between RT3DE and CMR-derived LVM with a small bias of -2 g. M-mode-derived LVM measurements (175 +/- 64 g) were significantly larger than RT3DE LVM (123 +/- 39 g, bias: 52 g) with moderate correlation (r = 0.76). No significant differences in LVM were noted between 2D (125 +/- 42 g) and RT3DE values (bias: 1.2 g) with good correlation (r = 0.91, P < .001). However, the best correlation was noted between RT3DE and RT3DE-guided biplane LVM values (r = 0.95, P < .001, bias: -4.6 g). Intraobserver, interobserver variability, and test-retest variability of the RT3DE measurements were 9%, 12%, and 6%, respectively.

Conclusion: RT3DE imaging using the 3D surface detection algorithm allows accurate and reproducible measurements of LVM. RT3DE-guided biplane technique can be used as an accurate time-saving alternative in clinical practice.
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http://dx.doi.org/10.1016/j.echo.2008.07.008DOI Listing
September 2008

Assessment of left ventricular mass and volumes by three-dimensional echocardiography in patients with or without wall motion abnormalities: comparison against cine magnetic resonance imaging.

Heart 2008 Aug 1;94(8):1050-7. Epub 2007 Nov 1.

Division of Cardiology, Department of Cardiovascular Diseases, Cliniques Universitaires St Luc, Université Catholique de Louvain, Brussels, Belgium.

Aim: To evaluate if three-dimensional echocardiography (3-DE) is as accurate and reproducible as cine magnetic resonance imaging (cMR) in estimating left ventricular (LV) parameters in patients with and without wall motion abnormalities (WMA).

Methods: 83 patients (33 with WMA) underwent 3-DE and cMR. 3-DE datasets were analysed using a semi-automatic contour detection algorithm. The accuracy of 3-DE was tested against cMR in the two groups of patients. All measurements were made twice by two different observers.

Results: LV mass by 3-DE was similar to that obtained by cMR (149 (SD 42) g vs 148 (45) g, p = 0.67), with small bias (1 (28) g) and excellent interobserver agreement (-2 (31) g vs 4 (26) g). The two measurements were also highly correlated (r = 0.94), irrespective of WMA. End-diastolic and end-systolic LV volumes and ejection fraction by 3-DE and cMR were highly correlated (r = 0.97, 0.98, 0.94, respectively). Yet, 3-DE underestimated cMR end-diastolic volumes (167 (68) ml vs 187 (70) ml, p<0.001) and end-systolic volumes (88 (56) ml vs 101 (65) ml, p<0.001), but yielded similar ejection fractions (50% (14%) vs 50% (16%), p = 0.23).

Conclusion: 3-DE permits accurate determination of LV mass and volumes irrespective of the presence or absence of WMA. LV parameters obtained by 3-DE are also as reproducible as those obtained by cMR. This suggests that 3-DE can be used to follow up patients with LV hypertrophy and/or remodelling.
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http://dx.doi.org/10.1136/hrt.2007.123711DOI Listing
August 2008

Review of myocardial motion estimation methods from optical flow tracking on ultrasound data.

Conf Proc IEEE Eng Med Biol Soc 2006;2006:1537-40

Ecole Nationale Supérieure des Télécommunications, LTCI CNRS UMR 5141, 46 rue Barrault, Paris, France, 75013.

Quantitative analysis of cardiac motion is of great clinical interest in assessment of ventricular function. Ultrasound imaging, especially matrix transducers acquiring real-time three dimensional data, provide valuable information, from which quantitative measures of cardiac function can be extracted via optical flow computation. Such analysis requires tracking of the image brightness patterns with underlying assumptions of visual persistency. We present a review of myocardial motion analysis on cardiac ultrasound, based on optical-flow computation, with phantom and clinical evaluations for segmental wall assessment and motion features quantification.
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http://dx.doi.org/10.1109/IEMBS.2006.259640DOI Listing
March 2008

Integrating functional and anatomical information to facilitate cardiac resynchronization therapy.

Pacing Clin Electrophysiol 2007 Aug;30(8):1021-2

Cardiology Division, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.

Multiple imaging modalities are required in patients receiving cardiac resynchronization therapy. We have developed a strategy to integrate echocardiographic and angiographic information to facilitate left ventricle (LV) lead position. Full three-dimensional LV-volumes (3DLVV) and dyssynchrony maps were acquired before and after resynchronization. At the time of device implantation, 3D-rotational coronary venous angiography was performed. 3D-models of the veins were then integrated with the pre- and post-3DLVV. In the case displayed, prior to implantation, the lateral wall was delayed compared to the septum. The LV lead was positioned into the vein over the most delayed region, resulting in improved LV synchrony.
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http://dx.doi.org/10.1111/j.1540-8159.2007.00803.xDOI Listing
August 2007

Dynamic cardiac information from optical flow using four dimensional ultrasound.

Conf Proc IEEE Eng Med Biol Soc 2005;2005:4465-8

Department of Biomedical Engineering, Columbia University, New York, NY, USA.

Quantitative analysis of cardiac motion is of great clinical interest in assessing ventricular function. Real-time 3-D (RT3D) ultrasound transducers provide valuable three-dimensional information, from which quantitative measures of cardiac function can be extracted. Such analysis requires segmentation and visual tracking of the left ventricular endocardial border. We present results based on correlation of four-dimensional optical flow motion for temporal tracking of ventricular borders in three dimensional ultrasound data. A displacement field is computed from the optical flow output, and a framework for the computation of dynamic cardiac information is introduced. The method was applied to a clinical data set from a heart transplant patient and dynamic measurements agreed with physiological knowledge as well as experimental results.
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http://dx.doi.org/10.1109/IEMBS.2005.1615458DOI Listing
October 2012

Rapid online quantification of left ventricular volume from real-time three-dimensional echocardiographic data.

Eur Heart J 2006 Feb 30;27(4):460-8. Epub 2005 Nov 30.

Noninvasive Cardiac Imaging Laboratory, University of Chicago Hospitals, 5841 S. Maryland Avenue, MC 5084, Chicago, IL 60637, USA.

Aims: Determination of left ventricular (LV) volumes and ejection fraction (EF) from two-dimensional echocardiographic (2DE) images is subjective, time-consuming, and relatively inaccurate because of foreshortened views and the use of geometric assumptions. Our aims were (1) to validate a new method for rapid, online measurement of LV volumes from real-time three-dimensional echocardiographic (RT3DE) data using cardiac magnetic resonance (CMR) as the reference and (2) to compare its accuracy and reproducibility with standard 2DE measurements.

Methods And Results: CMR, 2DE, and RT3DE datasets were obtained in 50 patients. End-systolic and end-diastolic volumes (ESV and EDV) were calculated from the 2DE images using biplane method of disks. ES and ED RT3DE datasets were analysed using prototype software designed to automatically detect the endocardial surface using a deformable shell model and calculate ESV and EDV from voxel counts. 2DE and RT3DE-derived volumes were compared with CMR (linear regression, Bland-Altman analysis). In most patients, analysis of RT3DE data required <2 min per patient. RT3DE measurements correlated highly with CMR (r: 0.96, 0.97, and 0.93 for EDV, ESV, and EF, respectively) with small biases (-14 mL, -6.5 mL, -1%) and narrow limits of agreement (SD: 17 mL, 16 mL, 6.4%). 2DE measurements correlated less well with CMR (r: 0.89, 0.92, 0.86) with greater biases (-23 mL, -15 mL, 1%) and wider limits of agreement (SD: 29 mL, 24 mL, 9.5%). RT3DE resulted in lower intra-observer (EDV: 7.9 vs. 23%; ESV: 7.6 vs. 26%) and inter-observer variability (EDV: 11 vs. 26%; ESV: 13 vs. 31%).

Conclusion: Semi-automated detection of the LV endocardial surface from RT3DE data is suitable for clinical use because it allows rapid, accurate, and reproducible measurements of LV volumes, superior to conventional 2DE methods.
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http://dx.doi.org/10.1093/eurheartj/ehi666DOI Listing
February 2006

Assessment of left ventricular contraction by parametric analysis of main motion (PAMM): theory and application for echocardiography.

Phys Med Biol 2005 Jul 6;50(14):3277-96. Epub 2005 Jul 6.

INSERM, U678, University Pierre et Marie Curie, CHU Pitié-Salpêtrière, 91 Boulevard de l'Hôpital, 75634 Paris Cedex 13, France.

The computerized study of the regional contraction of the left ventricle has undergone numerous developments, particularly in relation to echocardiography. A new method, parametric analysis of main motion (PAMM), is proposed in order to synthesize the information contained in a cine loop of images in parametric images. PAMM determines, for the intensity variation time curves (IVTC) observed in each pixel, two amplitude coefficients characterizing the continuous component and the alternating component; the variable component is generated from a mother curve by introducing a time shift coefficient and a scale coefficient. Two approaches, a PAMM data driven and a PAMM model driven (simpler and faster), are proposed. On the basis of the four coefficients, an amplitude image and an image of mean contraction time are synthesized and interpreted by a cardiologist. In all cases, both PAMM methods allow better IVTC adjustment than the other methods of parametric imaging used in echocardiography. A preliminary database comprising 70 segments is scored and compared with the visual analysis, taken from a consensus of two expert interpreters. The levels of absolute and relative concordance are 79% and 97%. PAMM model driven is a promising method for the rapid detection of abnormalities in left ventricle contraction.
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http://dx.doi.org/10.1088/0031-9155/50/14/006DOI Listing
July 2005

[Insemination: history and state of the art in animals].

Gynecol Obstet Fertil 2004 Oct;32(10):880-6

Département recherche et développement, UNCEIA, 13, rue Jouët, 94704 Maisons-Alfort, France.

Insemination has been used since 1950 in the bovine and since the seventies in other domestic species. The use of insemination varies between the different species in terms of activity and method. The methods depend on the anatomical and physiological characteristics of each species, which lead to different sites of semen deposition and different minimal numbers of inseminated spermatozoa to obtain efficient fertility results. The use of frozen semen influences also the methods of insemination. Intra-uterine insemination is principally used when only small quantities of semen are available and/or to reduce the number of inseminated spermatozoa. Recent results in different species indicate that the use of intra-uterine insemination could be developed in the next years.
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http://dx.doi.org/10.1016/j.gyobfe.2004.08.011DOI Listing
October 2004

3D reconstruction and analysis of the vertebral body line.

Stud Health Technol Inform 2002 ;88:172-6

Laboratoires d'Electronique Philips, 22 Avenue Descartes, 94453 Limeil-Brévannes, France.

Quantitative analysis of 3D spinal deformities includes measurements related to individual vertebrae and measurements related to the overall shape of the spine. For the latter aspect, we propose to build a 3D model of the line that connects all vertebrae centres. We present two methods that allow reconstructing this vertebral body line in a quick and easy way. Various new descriptors of the spinal shape can be automatically computed. A study is under way to assess their clinical relevance and reliability.
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October 2004

Semi-automatic landmark detection in digital X-ray images of the spine.

Stud Health Technol Inform 2002 ;88:132-5

Laboratoire d'Electronique Philips, 22 Avenue Descartes, 94453 Limeil-Brévannes, France.

Quantitative diagnosis of 3D scoliotic deformities depends on a number of dedicated measurements. Existing methods rely on the manual determination of a series of anatomical landmarks in X-ray images. We have developed an automatic method to alleviate the burden of this tedious task. Our method looks for a compromise between local image information and global prior constraints and finds the most probable points using dynamic programming optimization. Remaining errors can be quickly corrected by effective user interaction. The first results are promising.
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October 2004

Angiographic right and left ventricular function in arrhythmogenic right ventricular dysplasia.

Am J Cardiol 2004 Mar;93(6):728-33

Service d'Explorations Fonctionnelles Cardiaques et Respiratoires, Paris, France.

We prospectively documented right ventricular (RV) and left ventricular (LV) volumes and ejection fractions in a large series of patients with arrhythmogenic RV dysplasia/cardiomyopathy (ARVD/C). Eighty-five patients with ARVD/C and 11 controls underwent 2 successive orthogonal right and left monoplane x-ray-digitized cineangiographies. Volumes were calculated using the hemielliptical RV and ellipsoidal LV models. All controls and 58 of 85 patients (ARVD/C-I) had a RV ejection fraction > or =35% and 27 patients had a RV ejection fraction <35% (ARVD/C-II). Tricuspid annulus plane systolic excursion (TAPSE) was lower in ARVD/C-II than in ARVD/C-I patients (6 +/- 3 vs 14 +/- 3 mm) and controls (16 +/- 2 mm) (each p <0.001). In patients with ARVD/C, TAPSE was positively related to RV ejection fraction (r = 0.79) and to crista supraventricularis shortening (r = 0.81) (each p <0.001). Sensitivity and specificity of TAPSE <12 mm in identifying patients with RV ejection fraction <35% were 96% and 78%, respectively. LV ejection fraction was > or =50% in 68 patients, 40% to 49% in 10, and <40% in 7. Diffuse RV outflow tract aneurysm was observed in 9 patients, all belonging to ARVD/C-II, and this sign identified patients with LV ejection fraction <40% with 86% sensitivity and 96% specificity. In conclusion, 68% of ARVD/C patients had normal RV ejection fraction and RV volumes, and 80% of ARVD/C patients had normal LV ejection fraction. Decreased TAPSE <12 mm and a diffuse RV outflow tract aneurysm were sensitive and specific indicators of RV ejection fraction <35% and LV ejection fraction <40%, respectively.
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http://dx.doi.org/10.1016/j.amjcard.2003.11.055DOI Listing
March 2004

Bull semen in vitro fertility after cryopreservation using egg yolk LDL: a comparison with Optidyl, a commercial egg yolk extender.

Theriogenology 2004 Apr;61(5):895-907

Laboratory of Biotechnology and Pathology of Reproduction, National Veterinary School of Nantes, Nantes, France.

Low-density lipoproteins (LDL) have been previously isolated and identified as the cryoprotective fraction of yolk. The effect of LDL on sperm motility after freezing-thawing has been reported, but no study has been made to assess the effect of LDL on bull semen fertility. The aim of this study was to evaluate the fertility of bull semen cryopreserved in the presence of LDL. Motility of semen cryopreserved in LDL was analyzed and compared to semen cryopreserved with Optidyl, a commercial extender containing egg yolk. To evaluate the fertilizing ability of semen, we used in vitro fertilization test, whereas acrosome and plasma membrane integrity were also evaluated. The percentage of motile spermatozoa was two fold higher after freezing in LDL than in Optidyl 54.4% versus 30.2% (P < 0.05). The cleavage rate was significantly higher after fertilization with semen frozen in LDL than with Optidyl 63.0% versus 54.8% (P < 0.05). No significant difference was observed on the blastocyst rate after in vitro culture. Integrity of the acrosome and the plasma membrane were maintained in both extenders. In conclusion, LDL preserve bull semen quality and fertilizing ability, allowing also better semen motility, after the freeze-thaw process.
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http://dx.doi.org/10.1016/s0093-691x(03)00259-0DOI Listing
April 2004

Efficient model-based quantification of left ventricular function in 3-D echocardiography.

IEEE Trans Med Imaging 2002 Sep;21(9):1059-68

Medisys Group, Philips Research France, 51 rue Carnot, 92156 Suresnes, France.

Quantitative functional analysis of the left ventricle plays a very important role in the diagnosis of heart diseases. While in standard two-dimensional echocardiography this quantification is limited to rather crude volume estimation, three-dimensional (3-D) echocardiography not only significantly improves its accuracy but also makes it possible to derive valuable additional information, like various wall-motion measurements. In this paper, we present a new efficient method for the functional evaluation of the left ventricle from 3-D echographic sequences. It comprises a segmentation step that is based on the integration of 3-D deformable surfaces and a four-dimensional statistical heart motion model. The segmentation results in an accurate 3-D + time left ventricle discrete representation. Functional descriptors like local wall-motion indexes are automatically derived from this representation. The method has been successfully tested both on electrocardiography-gated and real-time 3-D data. It has proven to be fast, accurate, and robust.
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http://dx.doi.org/10.1109/TMI.2002.804435DOI Listing
September 2002

Mechanisms of reduced and compensatory growth.

Domest Anim Endocrinol 2000 Aug;19(2):121-32

Nutrition Unit, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Sart-Tilman, Belgium.

Growth is an integrated process, resulting from the response of cells dependent on the endocrine status and nutrient availability. During feed restriction, the production and secretion of growth hormone (GH) by the pituitary gland are enhanced, but the number of GH receptors decreases. Changes of GH binding proteins induce GH resistance and are followed by reduced insulin-like growth factor-I (IGF-I) secretion. On the other hand, high circulating levels of GH enhance the mobilization of fatty acids, which are used to support energy requirements. Thus, when feed restriction in growing animals is moderate, there is mainly protein but barely fat accretion. By contrast, a severe feed restriction enhances the release of catabolic hormones and stimulates, from muscle cells, the liberation of amino acids, which are used by hepatocytes for gluconeogenesis. During refeeding and compensatory growth, the secretion of insulin is sharply enhanced and plasma GH concentrations remain high. This situation probably allows more nutrients to be used for growth processes. The role of plasma IGF-I during compensatory growth is not clear and must be explained in connection with changes of its binding proteins. Thyroxin and 3,5,3'-triiodothyronine seem to have a permissive effect on growth. The simultaneous occurrence of puberty with refeeding can exert a synergistic effect on growth. Initially, compensatory growth is characterized by the deposition of very lean tissue, similar as during feed restriction. This lasts for some weeks. Then, protein synthesis decreases and high feed intake leads to increased fat deposition.
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http://dx.doi.org/10.1016/s0739-7240(00)00072-2DOI Listing
August 2000
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