Equine Echocardiography.

This article provides an overview on the principles of transthoracic echocardiography in horses. Indications for echocardiography, equipment, and technical considerations are discussed and a systematic approach for a complete echocardiographic examination in horses is described. Methods for assessment of chamber dimensions, allometric scaling of measurements, assessment of systolic and diastolic ventricular function, assessment of atrial function, hemodynamic assessment, and evaluation of valvular regurgitation are explained, focusing on traditional 2-dimensional (2D), motion-mode, and Doppler echocardiographic methods. Selected applications of newer echocardiographic methods, such as tissue Doppler imaging and 2D speckle tracking are also described.

Understanding the scope of intracardiac echocardiography in catheter ablation of ventricular arrhythmia.

Over the last few decades, catheter ablation has emerged as the first-line treatment for ventricular arrhythmias. However, detailed knowledge of cardiac anatomy during the surgery remains the prerequisite for successful ablation. Intracardiac echocardiography (ICE) is a unique imaging technique, which provides real-time visualization of cardiac structures, and is superior to other imaging modalities in terms of precise display of cardiac tissue characteristics as well as the orientation of anatomical landmarks. This article aimed to introduce the various advantages and limitations of ICE in the ablation of ventricular arrhythmias.

Radiomics classifier to quantify automatic segmentation quality of cardiac sub-structures for radiotherapy treatment planning.

PURPOSE: A radiomics features classifier was implemented to evaluate segmentation quality of heart structures. A robust feature set sensitive to incorrect contouring would provide an ideal quantitative index to drive autocontouring optimization. METHODS: Twenty-five cardiac sub-structures were contoured as regions of interest in 36 CTs. Radiomic features were extracted from manually-contoured (MC) and Hierarchical-Clustering automatic-contouring (AC) structures. A robust feature-set was identified from correctly contoured CT datasets. Features variation was analyzed over a MC/AC dataset. A supervised-learning approach was used to train an Artificial-Intelligence (AI) classifier; incorrect contouring cases were generated from the gold-standard MC datasets with translations, expansions and contractions. ROC curves and confusion matrices were used to evaluate the AI-classifier performance. RESULTS: Twenty radiomics features, were found to be robust across structures, showing a good/excellent intra-class correlation coefficient (ICC) index comparing MC/AC. A significant correlation was obtained with quantitative indexes (Dice-Index, Hausdorff-distance). The trained AI-classifier detected correct contours (CC) and not correct contours (NCC) with an accuracy of 82.6% and AUC of 0.91. True positive rate (TPR) was 85.1% and 81.3% for CC and NCC. Detection of NCC at this point of the development still depended strongly on degree of contouring imperfection. CONCLUSIONS: A set of radiomics features, robust on "gold-standard" contour and sensitive to incorrect contouring was identified and implemented in an AI-workflow to quantify segmentation accuracy. This workflow permits an automatic assessment of segmentation quality and may accelerate expansion of an existing autocontouring atlas database as well as improve dosimetric analyses of large treatment plan databases.

Left ventricular function and cardiac valvar annular dimensions among children with sickle cell anemia compared to those with hemoglobin AA type in Enugu, Nigeria.

Background: Enumerating the relationship between cardiac structures, function and chamber sizes in children with sickle cell anemia would help in delineating some cardiovascular abnormalities which will aid the Pediatric cardiologist and the cardiac surgeons in a number of decision-making situations. Objectives: The objectives of this study are to assess the dimension of cardiac structures and left ventricular function in children with sickle cell anemia in steady state and controls using echocardiography. Methods: A cross-sectional prospective study that assessed cardiac structures and left ventricular function among fifty-one children with sickle cell anemia (HBSS) and compared with fifty children with HB AA type serving as controls. Results: A significant high proportion of children with sickle cell anemia had abnormal Valvar dimension and left ventricular function above two standard deviations (2-SD) from the mean of the standard population compared to the control group, showing a statistically significant difference (χ2 = 10.42, p= 0.001).All the mean annular valves diameter, left ventricular internal dimension in systole and diastole, inter-sinus distance diameter and sinu-tubular junction diameter are higher in children with sickle cell anemia than controls and this is statistically significant. (p<0.005). Conclusion: This result shows that children with sickle cell anemia have increased valvar size diameter compared with those with normal hemoglobin type. A significantly higher proportion of respondents in type SS group had abnormal left ventricular systolic and diastolic dysfunction when compared with those in type AA group.

Application of an automatic segmentation method for evaluating cardiac structure doses received by breast radiotherapy patients.

BACKGROUND AND PURPOSE: Quantifying radiation dose to cardiac substructures is important for research on the etiology and prevention of complications following radiotherapy; however, segmentation of substructures is challenging. In this study we demonstrate the application of our atlas-based automatic segmentation method to breast cancer radiotherapy plans for generating radiation doses in support of late effects research. MATERIAL AND METHODS: We applied our segmentation method to contour heart substructures on the computed tomography (CT) images of 70 breast cancer patients who received external photon radiotherapy. Two cardiologists provided manual segmentation of the whole heart (WH), left/right atria, left/right ventricles, and left anterior descending artery (LAD). The automatically contours were compared with manual delineations to evaluate similarity in terms of geometry and dose. RESULTS: The mean Dice similarity coefficient between manual and automatic segmentations was 0.96 for the WH, 0.65 to 0.82 for the atria and ventricles, and 0.06 for the LAD. The mean average surface distance was 1.2 mm for the WH, 3.4 to 4.1 mm for the atria and ventricles, and 6.4 mm for the LAD. We found the dose to the cardiac substructures based on our automatic segmentation agrees with manual segmentation within expected observer variability. For left breast patients, the mean absolute difference in mean dose was 0.1 Gy for the WH, 0.2 to 0.7 Gy for the atria and ventricles, and 1.8 Gy for the LAD. For right breast patients, these values were 0.0 Gy, 0.1 to 0.4 Gy, and 0.4 Gy, respectively. CONCLUSION: Our automatic segmentation method will facilitate the development of radiotherapy prescriptive criteria for mitigating cardiovascular complications.

Prognostic impacts of dynamic cardiac structural changes in heart failure patients with preserved left ventricular ejection fraction.

AIMS: We aimed to examine temporal changes in left ventricular (LV) structures and their prognostic impacts in patients with heart failure (HF) and preserved ejection fraction (HFpEF). METHODS AND RESULTS: In the Chronic Heart Failure Analysis and Registry in the Tohoku District-2 (CHART-2) study (n = 10 219), we divided 2698 consecutive HFpEF patients (68.9 ± 12.2 years, 32.1% female) into three groups by LV hypertrophy (LVH) and enlargement (LVE) at baseline: (-)LVH/(-)LVE (n = 989), (+)LVH/(-)LVE (n = 1448), and (+)LVH/(+)LVE (n = 261). We examined temporal changes in LV structures and their prognostic impacts during a median 8.7-year follow-up. From (-)LVH/(-)LVE, (+)LVH/(-)LVE to (+)LVH/(+)LVE at baseline, the incidence of the primary outcome, a composite of cardiovascular death or HF admission, significantly increased. Among 1808 patients who underwent echocardiography at both baseline and 1 year, we noted substantial group transitions from baseline to 1 year; the transition rates from (-)LVH/(-)LVE to (+)LVH/(-)LVE, from (+)LVH/(-)LVE to (-)LVH/(-)LVE, from (+)LVH/(-)LVE to (+)LVH/(+)LVE, and from (+)LVH/(+)LVE to (+)LVH/(-)LVE were 27% (182/671), 22% (213/967), 6% (59/967), and 26% (44/170), respectively. In the univariable Cox proportional hazard model, patients who transitioned from (+)LVH/(-)LVE to (+)LVH/(+)LVE or remained in (+)LVH/(+)LVE had the worst subsequent prognosis [hazard ratio (HR) 4.65, 95% confidence interval (CI) 3.09-6.99, P < 0.001; HR 4.01, 95% CI 2.85-5.65, P < 0.001, respectively], as compared with those who remained in (-)LVH/(-)LVE. These results were unchanged after adjustment for the covariates including baseline LV ejection fraction (LVEF) and 1-year LVEF change. CONCLUSION: In HFpEF patients, LV structures dynamically change over time with significant prognostic impacts, where patients who develop LVE with LVH have the worst prognosis.

Automatic segmentation of cardiac structures for breast cancer radiotherapy.

BACKGROUND AND PURPOSE: We developed an automatic method to segment cardiac substructures given a radiotherapy planning CT images to support epidemiological studies or clinical trials looking at cardiac disease endpoints after radiotherapy. MATERIAL AND METHODS: We used a most-similar atlas selection algorithm and 3D deformation combined with 30 detailed cardiac atlases. We cross-validated our method within the atlas library by evaluating geometric comparison metrics and by comparing cardiac doses for simulated breast radiotherapy between manual and automatic contours. We analyzed the impact of the number of cardiac atlas in the library and the use of manual guide points on the performance of our method. RESULTS: The Dice Similarity Coefficients from the cross-validation reached up to 97% (whole heart) and 80% (chambers). The Average Surface Distance for the coronary arteries was less than 10.3 mm on average, with the best agreement (7.3 mm) in the left anterior descending artery (LAD). The dose comparison for simulated breast radiotherapy showed differences less than 0.06 Gy for the whole heart and atria, and 0.3 Gy for the ventricles. For the coronary arteries, the dose differences were 2.3 Gy (LAD) and 0.3 Gy (other arteries). The sensitivity analysis showed no notable improvement beyond ten atlases and the manual guide points does not significantly improve performance. CONCLUSION: We developed an automated method to contour cardiac substructures for radiotherapy CTs. When combined with accurate dose calculation techniques, our method should be useful for cardiac dose reconstruction of a large number of patients in epidemiological studies or clinical trials.

Quantification of heart, pericardium, and left ventricular myocardium movements during the cardiac cycle for thoracic tumor radiotherapy.

PURPOSE: The purpose of this study was to quantify variations in the heart, pericardium, and left ventricular myocardium (LVM) caused by cardiac movement using the breath-hold technique. PATIENTS AND METHODS: In this study, the electrocardiography-gated four-dimensional computed tomography (CT) images of 22 patients were analyzed, which were sorted into 20 phases (0-95%) according to the cardiac cycle. The heart, pericardium, and LVM were contoured on each phase of the CT images. The positions, volume, dice similarity coefficient (DSC) in reference to 0% phase, and morphological parameters (max 3D diameter, roundness, spherical disproportion, sphericity, and surface area) in different phases of the heart, pericardium, and LVM were analyzed, which were presented as mean ± standard deviation. RESULTS: The mean values of displacements along the X, Y, and Z axes respectively were as follows: 1.2 mm, 0.6 mm, and 0.6 mm for the heart; 0.5 mm, 0.4 mm, and 0.8 mm for the pericardium; and 1.0 mm, 4.1 mm, and 1.9 mm for the LVM. The maximum variations in volume and DSC respectively were 16.49%±3.85% and 10.08%±2.14% for the heart, 12.62%±3.94% and 5.20%±1.54% for the pericardium, and 24.23%±11.35% and 184.33%±128.61% for the LVM. The differences in the morphological parameters between the maximum and minimum DSC phases for the heart and pericardium were not significantly different (p>0.05) but were significantly different for the LVM (p<0.05). CONCLUSION: The volumetric and morphological variations of the heart were similar to those of pericardium, and all were significantly smaller than those of the LVM. This inconsistency in the volumetric and morphological variations between the LVM and the heart and pericardium indicates that special protection of the LVM should be considered.

Association between echocardiographic structural parameters and body weight in Wistar rats.

BACKGROUND: The association between echocardiographic structural parameters and body weight (BW) during rat development has been poorly addressed. We evaluated echocardiographic variables: left ventricular (LV) end-diastolic (LVDD) and end-systolic (LVSD) diameters, LV diastolic posterior wall thickness (PWT), left atrial diameter (LA), and aortic diameter (AO) in function of BW during development.Results/Materials and Methods: Male Wistar rats (n = 328, BW: 302-702 g) were retrospectively used to construct regression models and 95% confidence intervals relating to cardiac structural parameters and BW. Adjusted indexes were significant to all relationships; the regression model for predicting LVDD (R2 = 0.678; p < 0.001) and AO (R2 = 0.567; p < 0.001) had the highest prediction coefficients and LA function the lowest prediction coefficient (R2 = 0.274; p < 0.01). These relationships underwent validation by performing echocardiograms on additional rats (n = 43, BW: 300-600 g) and testing whether results were within confidence intervals of our regressions. Prediction models for AO and LA correctly allocated 38 (88.4%) and 39 rats (90.7%), respectively, within the 95% confidence intervals. Regression models for LVDD, LVSD, and PWT included 27 (62.7%), 30 (69.8%), and 19 (44.2%) animals, respectively, within the 95% confidence intervals. CONCLUSIONS: Increase in cardiac structures is associated with BW gain during rat growth. LA and AO can be correctly predicted using regression models; prediction of PWT and LV diameters is not accurate.

A cardiac contouring atlas for radiotherapy.

BACKGROUND AND PURPOSE: The heart is a complex anatomical organ and contouring the cardiac substructures is challenging. This study presents a reproducible method for contouring left ventricular and coronary arterial segments on radiotherapy CT-planning scans. MATERIAL AND METHODS: Segments were defined from cardiology models and agreed by two cardiologists. Reference atlas contours were delineated and written guidelines prepared. Six radiation oncologists tested the atlas. Spatial variation was assessed using the DICE similarity coefficient (DSC) and the directed Hausdorff average distance (d→H,avg). The effect of spatial variation on doses was assessed using six different breast cancer regimens. RESULTS: The atlas enabled contouring of 15 cardiac segments. Inter-observer contour overlap (mean DSC) was 0.60-0.73 for five left ventricular segments and 0.10-0.53 for ten coronary arterial segments. Inter-observer contour separation (mean d→H,avg) was 1.5-2.2mm for left ventricular segments and 1.3-5.1mm for coronary artery segments. This spatial variation resulted in <1Gy dose variation for most regimens and segments, but 1.2-21.8Gy variation for segments close to a field edge. CONCLUSIONS: This cardiac atlas enables reproducible contouring of segments of the left ventricle and main coronary arteries to facilitate future studies relating cardiac radiation doses to clinical outcomes.

Appropriateness criteria for the use of cardiovascular imaging in heart valve disease in adults: a European Association of Cardiovascular Imaging report of literature review and current practice.

Heart valve disease is common and a major indication for imaging. Echocardiography is the first-line imaging technique for diagnosis, assessment, and serial surveillance. However, other modalities, notably cardiac magnetic resonance imaging and computerized tomography, are used if echocardiographic imaging is suboptimal or to obtain complementary information, particularly to aid risk assessment in individual patients. This review is a summary of current evidence for state-of-the-art clinical practice to inform appropriateness criteria for heart valve disease. It is divided according to common clinical scenarios: detection of valve disease, assessment of the valve and other cardiac structures, risk assessment, screening, and intervention.

Maternal educational level and blood pressure, aortic stiffness, cardiovascular structure and functioning in childhood: the generation R study.

BACKGROUND: In adults, low level of education was shown to be associated with higher blood pressure levels and alterations in cardiac structures and function. It is currently unknown whether socioeconomic inequalities in arterial and cardiac alterations originate in childhood. Therefore, we investigated the association of maternal education with blood pressure levels, arterial stiffness, and cardiac structures and function at the age of 6 years and potential underlying factors. METHODS: The study included 5,843 children participating in a prospective cohort study in the Netherlands. Maternal education was assessed at enrollment. Blood pressure, carotid-femoral pulse wave velocity, left atrial diameter, aortic root diameter, left ventricular mass, and fractional shortening were measured at the age of 6 years. RESULTS: Children with low educated (category 1) mothers had higher systolic (2.80mm Hg; 95% confidence interval (CI) = 1.62-2.94) and diastolic (1.80mm Hg; 95% CI = 1.25-2.35) blood pressure levels compared with children with high educated (category 4) mothers. The main explanatory factors were the child's body mass index (BMI), maternal BMI, and physical activity. Maternal education was negatively associated with fractional shortening (P trend = 0.008), to which blood pressure and child's BMI contributed the most. No socioeconomic gradient was observed in other arterial and cardiac measurements. CONCLUSIONS: Socioeconomic inequalities in blood pressure are already present in childhood. Higher fractional shortening among children from low socioeconomic families might be a first cardiac adaptation to higher blood pressure and higher BMI. Interventions should be aimed at lowering child BMI and increasing physical activity among children from low socioeconomic families.

Parental smoking during pregnancy and cardiovascular structures and function in childhood: the Generation R Study.

BACKGROUND: Foetal smoke exposure might lead to foetal developmental adaptations that permanently affect the cardiovascular system. We assessed the associations of both maternal and paternal smoking during pregnancy with childhood cardiovascular structures and function. METHOD: In a prospective cohort study among 5565 children, we examined whether maternal and paternal smoking during pregnancy are associated with blood pressure, carotid-femoral pulse wave velocity and left cardiac structures and function in 6-year-old children. RESULTS: As compared with children from non-smoking mothers, children from mothers who smoked more than 10 cigarettes per day had a higher diastolic blood pressure [difference 1.43 mmHg (95% confidence interval: 0.22, 2.63)]. Maternal smoking during pregnancy was not associated with systolic blood pressure, childhood carotid-femoral pulse wave velocity or left cardiac structures. Maternal smoking of 10 or more cigarettes per day was associated with a higher fractional shortening in childhood [difference 1.01% (95% confidence interval: 0.18, 1.84)]. Among mothers who did not smoke during pregnancy, paternal smoking was associated with aortic root diameter but not with other cardiovascular outcomes. CONCLUSIONS: Maternal smoking during pregnancy is associated with higher diastolic blood pressure and fractional shortening, although the effect estimates are small. The stronger effect estimates for maternal smoking compared with paternal smoking might suggest that direct intrauterine adaptive responses are involved as underlying mechanisms.

Non-coronary cardiac findings and pitfalls in coronary computed tomography angiography.

Non-coronary incidental findings are not rare. Kirsch et al found 67% non-coronary abnormalities with coronary computed tomography angiography (CCTA). Radiologists are expected to identify the extracoronary, intra- and para-cardiac anatomical structures and distinguish them from pathologic processes in CCTA. We have reviewed 2000 CCTA studies done at our institution with 64-MDCT. This pictorial essay presents case studies of non-atherosclerotic cardiovascular findings to recognize cardiac anatomic structures and how to distinguish them from pathologic processes. Correct interpretation of benign, clinically insignificant findings is crucial to avoid unnecessary additional imaging tests.