Automatic left-atrial segmentation from cardiac 3D ultrasound: a dual-chamber model-based approach

In this paper, we present an automatic solution for segmentation and quantification of the left atrium (LA) from 3D cardiac ultrasound. A model-based framework is applied, making use of (deformable) active surfaces to model the endocardial surfaces of cardiac chambers, allowing incorporation of a priori anatomical information in a simple fashion. A dual-chamber model (LA and left ventricle) is used to detect and track the atrio-ventricular (AV) plane, without any user input. Both chambers are represented by parametric surfaces and a Kalman filter is used to fit the model to the position of the endocardial walls detected in the image, providing accurate detection and tracking during the whole cardiac cycle. This framework was tested in 20 transthoracic cardiac ultrasound volumetric recordings of healthy volunteers, and evaluated using manual traces of a clinical expert as a reference. The 3D meshes obtained with the automatic method were close to the reference contours at all cardiac phases (mean distance of 0.03 \pm 0.6 mm). The AV plane was detected with an accuracy of -0.6 ± 1.0 mm. The LA volumes assessed automatically were also in agreement with the reference (mean ± 1.96 SD): 0.4 ± 5.3 ml, 2.1 ± 12.6 ml, and 1.5 ± 7.8 ml at end-diastolic, end-systolic and pre-atrial-contraction frames, respectively. This study shows that the proposed method can be used for automatic volumetric assessment of the LA, considerably reducing the analysis time and effort when compared to manual analysis.status: publishe

Left-Atrial Segmentation From 3-D Ultrasound Using B-Spline Explicit Active Surfaces With Scale Uncoupling

Segmentation of the left atrium (LA) of the heart allows quantification of LA volume dynamics which can give insight into cardiac function. However, very little attention has been given to LA segmentation from three-dimensional (3-D) ultrasound (US), most efforts being focused on the segmentation of the left ventricle (LV). The B-spline explicit active surfaces (BEAS) framework has been shown to be a very robust and efficient methodology to perform LV segmentation. In this study, we propose an extension of the BEAS framework, introducing B-splines with uncoupled scaling. This formulation improves the shape support for less regular and more variable structures, by giving independent control over smoothness and number of control points. Semiautomatic segmentation of the LA endocardium using this framework was tested in a setup requiring little user input, on 20 volumetric sequences of echocardiographic data from healthy subjects. The segmentation results were evaluated against manual reference delineations of the LA. Relevant LA morphological and functional parameters were derived from the segmented surfaces, in order to assess the performance of the proposed method on its clinical usage. The results showed that the modified BEAS framework is capable of accurate semiautomatic LA segmentation in 3-D transthoracic US, providing reliable quantification of the LA morphology and function.This work was supported by the European Union under a Marie Curie Initial Training Network (USART project, Grant PITN-GA-2012-317132)

Blood volume expansion does not explain the increase in peak oxygen uptake induced by 10~weeks of endurance training

Purpose The endurance training (ET)-induced increases in peak oxygen uptake (V\u2d9 O2peak) and cardiac output (Q\u2d9peak) during upright cycling are reversed to pre-ET levels after removing the training-induced increase in blood volume (BV). We hypothesised that ET-induced improvements in V\u2d9O2peak and Q\u2d9peak are preserved following phlebotomy of the BV gained with ET during supine but not during upright cycling. Arteriovenous O2 difference (a-v\uafO2diff; V\u2d9O2/Q\u2d9), cardiac dimensions and muscle morphology were studied to assess their role for the V\u2d9 O2peak improvement. Methods Twelve untrained subjects (V\u2d9 O2peak: 44\u2009\ub1\u20096 ml kg 121 min 121) completed 10 weeks of supervised ET (3 sessions/week). Echocardiography, muscle biopsies, haemoglobin mass (Hbmass) and BV were assessed pre- and post-ET. V\u2d9O2peak and Q\u2d9 peak during upright and supine cycling were measured pre-ET, post-ET and immediately after Hbmass was reversed to the individual pre-ET level by phlebotomy. Results ET increased the Hbmass (3.3\u2009\ub1\u20092.9%; P\u2009=\u20090.005), BV (3.7\u2009\ub1\u20095.6%; P\u2009=\u20090.044) and V\u2d9 O2peak during upright and supine cycling (11\u2009\ub1\u20096% and 10\u2009\ub1\u20098%, respectively; P\u2009 64\u20090.003). After phlebotomy, improvements in V\u2d9O2peak compared with pre-ET were preserved in both postures (11\u2009\ub1\u20094% and 11\u2009\ub1\u20099%; P\u2009 64\u20090.005), as was Q\u2d9peak (9\u2009\ub1\u200914% and 9\u2009\ub1\u200910%; P\u2009 64\u20090.081). The increased Q\u2d9peak and a-v\uafO2diff accounted for 70% and 30% of the V\u2d9 O2peak improvements, respectively. Markers of mitochondrial density (CS and COX-IV; P\u2009 64\u20090.007) and left ventricular mass (P\u2009=\u20090.027) increased. Conclusion The ET-induced increase in V\u2d9 O2peak was preserved despite removing the increases in Hbmass and BV by phlebotomy, independent of posture. V\u2d9O2peak increased primarily through elevated Q\u2d9peak but also through a widened a-v\uafO2diff, potentially mediated by cardiac remodelling and mitochondrial biogenesis

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

status: publishe

Heart morphology differences induced by intrauterine growth restriction and preterm birth measured on the ECG at preadolescent age

Intrauterine Growth Restriction (IUGR) and premature birth are associated with higher risk of cardiovascular diseases throughout adulthood. The aim of this study was to evaluate the influence of these factors in ventricular electrical remodeling in preadolescents. Electrocardiography was performed in a cohort of 33-IUGR, 32-preterm with appropriate weight and 60 controls. Depolarization and repolarization processes were studied by means of the surface ECG, including loops and angles corresponding to QRS and T-waves. The angles between the dominant vector of QRS and the frontal plane XY were different among the study groups: controls [20.03°(10.11°-28.64°)], preterm [25.48°(19.79°-33.56°)], and IUGR [27.77°(16.59°-33.23°)]. When compared to controls, IUGR subjects also presented wider angles between the difference of QRS and T-wave dominant vectors and the XY-plane [5.28° ± 12.15° vs 0.49° ± 14.15°, p < 0.05] while preterm ones showed smaller frontal QRS-T angle [4.68°(2.20°-12.89°) vs 6.57°(2.72°-11.31°), p < 0.05]. Thus, electrical remodeling is present in IUGR and preterm preadolescents, and might predispose them to cardiovascular diseases in adulthood. Follow-up studies are warranted.N. Ortigosa acknowledges the support from Generalitat Valenciana under grants PrometeoII/2013/013, ACOMP/2015/186, and MINECO under grant MTM2013-43540-P. This project has also been partially funded by TEC2013-42140-R and TIN2014-53567-R from CICYT, by Grupo Consolidado BSICoS from DGA (Aragón) and European Social Fund, the Erasmus + Program of the European Union (Framework Agreement number: 2013-0040), the South-Eastern Norway Regional Health Authority, the Bergesen foundation and grants from Instituto de Salud Carlos III (grant numbers PI12/00801 and PI14/00226), Ministerio de Economía y Competitividad (grant number SAF2012-37196), cofinanced by the Fondo Europeo de Desarrollo Regional de la Unión Europea “Una manera de hacer Europa”, Fundación Mutua Madrileña, Obra Social La Caixa (Spain), Cerebra Foundation for the Brain Injured Child (Carmarthen, Wales, UK), and the European Commission (VP2HF no.611823). This publication reflects the views only of the authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein. The computation was performed by the ICTS 0707NANBIOSIS, by the High Performance Computing Unit of the CIBER in Bioengineering, Biomaterials & Nanomedicine (CIBER-BBN) at the University of Zaragoza

Left Ventricular Regional Wall Motion Abnormality is a Strong Predictor of Cardiotoxicity in Breast Cancer Patients Undergoing Chemotherapy

Abstract Background: Chemotherapeutic agents of anthracyclines class and humanized monoclonal antibodies are effective treatments for breast cancer, however, they present a potential risk of cardiotoxicity. Several predictors have been recognized as predictors in the development of cardiac toxicity, and the evaluation of left ventricular segmental wall motion abnormalities (LVSWMA) has not been studied. Objective: To analyze prospectively the role of LVSWMA among echocardiographic parameters in the prediction of development of cardiotoxicity in breast cancer patients undergoing treatment with chemotherapy. Methods: Prospective cohort of patients diagnosed with breast cancer and in chemotherapy treatment with potential cardiotoxicity medications including doxorubicin and trastuzumab. Transthoracic echocardiograms including speckle tracking strain echocardiography were performed at standard times before, during and after the treatment to assess the presence (or lack thereof) of cardiotoxicity. Cardiotoxicity was defined by a 10% decrease in the left ventricular ejection fraction, on at least one echocardiogram. Multivariate logistic regression models were used to verify the predictors related to the occurrence of cardiotoxicity over time. Results: Of the 112 patients selected (mean age 51,3 ± 12,9 years), 18 participants (16.1%) had cardiotoxicity. In the multivariate analysis using the logistic regression model, those with LVWMA (OR = 6.25 [CI 95%: 1.03; 37.95], p < 0,05), LV systolic dimension (1.34 [CI 95%: 1.01; 1.79], p < 0,05) and global longitudinal strain by speckle tracking (1.48 [CI 95%: 1.02; 2.12], p < 0,05) were strongly associated with cardiotoxicity. Conclusion: In the present study, we showed that LVWMA, in addition to global longitudinal strains, were strong predictors of cardiotoxicity and could be useful in the risk stratification of these patients

Vigorous physical activity impairs myocardial function in patients with arrhythmogenic right ventricular cardiomyopathy and in mutation positive family members

Aims: Exercise increases risk of ventricular arrhythmia in subjects with arrhythmogenic right ventricular cardiomyopathy (ARVC). We aimed to investigate the impact of exercise on myocardial function in ARVC subjects. Methods and Results: We included 110 subjects (age 42±17 years), 65 ARVC patients and 45 mutation-positive family members. Athletes were defined as subjects with ≥4 h vigorous exercise/week [≥1440 metabolic equivalents (METs × minutes/week)] during a minimum of 6 years. Athlete definition was fulfilled in 37/110 (34%) subjects. We assessed right ventricular (RV) and left ventricular (LV) myocardial function by echocardiography, and by magnetic resonance imaging (MRI). The RV function by RV fractional area change (FAC), RV global longitudinal strain (GLS) by echocardiography, and RV ejection fraction (EF) by MRI was reduced in athletes compared with non-athletes (FAC 34±9% vs. 40±11%, RVGLS –18.3±6.1% vs. –22.0±4.8%, RVEF 32±8% vs. 43±10%, all P<0.01). LV function by LVEF and LVGLS was reduced in athletes compared with non-athletes (LVEF by echocardiography 50±10% vs. 57±5%, LVEF by MRI 46±6% vs. 53±8%, and LVGLS –16.7±4.2% vs. –19.4±2.9%, all P <0.01). The METs × minutes/week correlated with reduced RV and LV function by echocardiography and MRI (all P <0.01). The LVEF by MRI was also reduced in subgroups of athlete index patients (46±7% vs. 54±10%, P=0.02) and in athlete family members (47±3% vs. 52±6%, P <0.05). Conclusion: Athletes showed reduced biventricular function compared with non-athletes in ARVC patients and in mutation-positive family members. The amount and intensity of exercise activity was associated with impaired LV and RV function. Exercise may aggravate and accelerate myocardial dysfunction in ARVC

Persistence of cardiac remodeling in preadolescents with fetal growth restriction

Fetal growth restriction (FGR) affects 5% to 10% of newborns and is associated with increased cardiovascular mortality in adulthood. We evaluated whether prenatal cardiovascular changes previously demonstrated in FGR persist into preadolescence. A cohort study of 58 FGR (defined as birth weight below 10th centile) and 94 normally grown fetuses identified in utero and followed-up into preadolescence (8–12 years of age) by echocardiography and 3-dimensional shape computational analysis. Compared with controls, FGR preadolescents had a different cardiac shape, with more spherical and smaller hearts. Left ventricular ejection fraction was similar among groups, whereas FGR had decreased longitudinal motion (decreased mitral annular systolic peak velocities: control median, 0.11 m/s [interquartile range, 0.09–0.12] versus FGR median 0.09 m/s [interquartile range, 0.09–0.10]; P<0.01) and impaired relaxation (isovolumic relaxation time: control, 0.21 ms [interquartile range, 0.12–0.35] versus FGR, 0.35 ms [interquartile range, 0.20–0.46]; P=0.04). Global longitudinal strain was decreased (control mean, −22.4% [SD, 1.37] versus FGR mean, −21.5% [SD, 1.16]; P<0.001) compensated by an increased circumferential strain and with a higher prevalence of postsystolic shortening in FGR as compared with controls. These differences persisted after adjustment for parental ethnicity and smoking, prenatal glucocorticoid administration, preeclampsia, gestational age at delivery, days in intensive care unit, sex, age, and body surface area at evaluation.This work was partially supported by the Erasmus + Programme of the European Union (framework agreement number: 2013-0040), the South-Eastern Norway Regional Health Authority, the Bergesen foundation, and grants from Instituto de Salud Carlos III (grant numbers PI12/00801 and PI14/00226) and Ministerio de Economía y Competitividad (grant numbers SAF2012-37196 and TIN2014-52923-R); cofinanced by the Fondo Europeo de Desarrollo Regional de la Unión Europea “Una manera de hacer Europa” (FEDER), Fundación Mutua Madrileña, Obra Social La Caixa (Spain), Cerebra Foundation for the Brain Injured Child (Carmarthen, Wales, UK), and the EU FP7 for research, technological development and demonstration under grant agreement VP2HF (no 611823)

Estimating 3D ventricular shape from 2D echocardiography: feasibility and effect of noise

Comunicació presentada a la 9th international conference on Functional Imaging and Modeling of the Heart (FIMH 2017), celebrada els dies 11 a 13 de juny de 2017 a Toronto, Canadà.Many cardiac diseases are associated with changes in ventricular shape. However, in daily practice, the heart is mostly assessed by 2D echocardiography only. While 3D techniques are available, they are rarely used. In this paper we analyze to which extent it is possible to obtain the 3D shape of a left ventricle (LV) using measurements from 2D echocardiography. First, we investigate this using synthetic datasets, and afterwards, we illustrate it in clinical 2D echocardiography measurements with corresponding 3D meshes obtained using 3D echocardiography. We demonstrate that standard measurements taken in 2D allow quantifying only the ellipsoidal shape of the ventricle, and that capturing other shape features require either additional geometrical measurements or clinical information related to shape remodelling. We show that noise in the measurements is the primary cause for poor association between the measurements and the LV shape features and that an estimated 10% level of noise on the 2D measurements limits the recoverability of shape. Finally we show that clinical variables relating to the clinical history can substitute the lack of geometric measurements, thus providing alternatives for shape assessment in daily practice.This study was partially supported by the Spanish Ministry of Economy and Competitiveness (grant TIN2014-52923-R; Maria de Maeztu Units of Excellence Programme - MDM-2015-0502), FEDER and the European Union Horizon 2020 Programme for Research and Innovation, under grant agreement No. 642676 (CardioFunXion)