4D ultrasound-based strain assessment of cardiac dysfunction in male rats with reperfused and nonreperfused myocardial infarction.

Two-dimensional ultrasound (2DUS) echocardiography is the main noninvasive method used to evaluate cardiac function in animal models of myocardial infarction (MI). However, 2DUS echocardiography does not capture regional differences in cardiac contractility since it relies on planar images to estimate left ventricular (LV) geometry and global function. Thus, the current study was designed to evaluate the efficacy of a newly developed 4-dimensional ultrasound (4DUS) method in detecting cardiac functional differences between two models of MI, permanent ligation (PL), and ischemia/reperfusion (I/R) in rats. We found that only 4DUS was able to detect LV global functional differences between the two models and that 4DUS-derived surface area strain accurately detected infarcted regions within the myocardium that correlated well with histological infarct size analysis. We also found that 4DUS-derived strain, which includes circumferential, longitudinal, and surface area strain, correlated with the peak positive of the first derivative of left ventricular pressure (+dP/dtmax). In conclusion, 4DUS strain echocardiography effectively assesses myocardial mechanics following experimentally induced ischemia in rats and accurately estimates infarct size as early as 1 day after injury. 4DUS also correlates well with +dP/dtmax, a widely used marker of cardiac contractility.

Four-Dimensional Ultrasound Imaging of Spatial Relationship of Great Arteries in Fetuses With Transposition of Great Arteries.

The great artery relationship in transposition of great arteries (TGA) is based on the degree of resorption and growth of subsemilunar conus. In transposition of great arteries, the spatial relationship of the great arteries can be variable. Commonly, the aorta will be related right and anterior to pulmonary artery (D-TGA). Less commonly, the aorta can be related left and anterior (SDL-TGA), side-by-side, and antero-posterior to pulmonary artery. Four fetuses with concordant atrioventricular and discordant ventriculoarterial connection with various great arteries relationship were presented in this imaging essay.

Improvement of diagnostic efficiency in fetal congenital heart disease using fetal intelligent navigation echocardiography by less-experienced operators.

OBJECTIVE: This study investigated the feasibility and accuracy of fetal intelligent navigation echocardiography (FINE) for the prenatal diagnosis of congenital heart disease (CHD) by inexperienced and experienced operators. METHOD: In this prospective study, all volume data sets from 120 fetuses with a broad spectrum of CHD were acquired using spatiotemporal image correlation technology. The prenatal diagnostic procedures were performed by two operators with different experience (beginner: 1 year and expert: 15 years) using FINE and traditional fetal echocardiography. Data were analyzed on the time of examination and acquisition of results. RESULTS: Diagnoses made by FINE and traditional echocardiography were completely consistent with the final diagnosis of CHD in 98 (81.66%) versus 20 (16.66%) (P < 0.001) beginners and 87.50% (n = 105) versus 101 (84.16%) experts, respectively. On the contrary, there was significant difference using traditional echocardiography (16.66% versus 84.16%, P < 0.001) by two examiners. Furthermore, the examination time decreased when using FINE compared with using traditional echocardiography (beginner operators: 4.54 ± 1.03 min versus 20.58 ± 3.36 min, P < 0.001; expert operators: 3.89 ± 0.96 min versus 12.73 ± 1.62 min, P < 0.001). CONCLUSION: Based on our results, a prenatal diagnosis of CHD can be made with high feasibility and accuracy using FINE compared with traditional fetal echocardiography for beginner operators.

Electronic versus conventional spatiotemporal image correlation (STIC) fetal echocardiography: a direct comparison.

OBJECTIVES: Recent advances in Spatial Temporal Image Correlation (STIC) 4 D fetal echocardiography include the application of eSTIC based on electronic probe image acquisition. We aimed to directly compare the performance of conventional STIC versus eSTIC technique (B-Mode and color Doppler imaging) during off-line reconstruction of STIC/eSTIC fetal heart volume pairs. METHODS: Pairs of B-Mode and Color Doppler STIC volumes were acquired sequentially by firstly conventional (STIC) followed by electronic (eSTIC) probes during 33 consecutive obstetric scans at median 23 (range 13-31) gestational weeks. The resulting 66 fetal heart volume pairs were assessed blindly off-line by a fetal cardiologist who documented feasibility of reconstruction, presence of motion artifacts, subjective image quality on a 4-level scale: 1-best to 4-non-diagnostic and morphological diagnosis, to enable a paired comparison of STIC and eSTIC in the same fetus under similar scanning conditions. RESULTS: eSTIC volumes had higher temporal resolution (37 vs. 24 frames per second, p < .001), less motion during acquisition (12 vs. 20 cases, O.R. 7.0, p = .002) and better average image quality (1.9 vs. 2.2, p = .006) compared to STIC volumes. More diagnostic reconstructions were achieved by eSTIC (n = 55, 86%) than STIC (n = 52, 78.8%), p = .001), in a comparable analysis time (mean 4.96 vs. 4.94 min). During a comparison of image quality of the original acquisition (A) and reconstructed planes (B and C planes) e STIC was superior in 22 (33%), 39 (59%) and 21 (38%) volumes, respectively, with the remaining cases being of similar quality (<10% in each plane in favor of STIC). Imaging mode and gestational age had a similar impact on both eSTIC and STIC performance: diagnostically acceptable studies in 49 (75.8%) vs. 48 (72.2%) by B-Mode, 60 (90.9%) vs. 56 (84.8%) by Color Doppler Mode, 8 (62.5%) vs. 10 (50%) in early scans, 38 (95%) vs. 38 (95%) in mid-gestation scans, and 7 (70%) vs. 6 (60%) in third trimester scans. Eight obstetric scans identified a fetus with a cardiac variant or structural abnormality. Diagnostic concordance of the two STIC approaches was comparable (40/48 concordant interpretations, kappa 0.657) all confirmed by fetal and/or postnatal echocardiography. CONCLUSIONS: eSTIC was associated with more effective 4 D fetal heart reconstruction due to reduced motion artifacts and superior image quality in all planes, when compared to STIC. Early gestation reconstructions were not generally successful using either technology. Further study is needed to define the cost-effectiveness and diagnostic impact of eSTIC over conventional STIC and their role over, or in addition to, screening 2 D fetal echocardiography by appropriately trained sonographers.

New and advanced features of fetal intelligent navigation echocardiography (FINE) or 5D heart.

Congenital heart disease (CHD) is the leading organ-specific birth defect, as well as the leading cause of infant morbidity and mortality from congenital malformations. Therefore, a comprehensive screening examination of the fetal heart should be performed in all women to maximize the detection of CHD. Four-dimensional sonography with spatiotemporal image correlation (STIC) technology displays a cine loop of a complete single cardiac cycle in motion. A novel method known as Fetal Intelligent Navigation Echocardiography (or FINE) was previously developed to interrogate STIC volume datasets using "intelligent navigation" technology. Such method allows the automatic display of nine standard fetal echocardiography views required to diagnose most cardiac defects. FINE considerably simplifies fetal cardiac examinations and reduces operator dependency. It has both high sensitivity and specificity for the detection of CHD. Indeed, FINE has been integrated into several commercially available ultrasound platforms.Recently, eight novel and advanced features have been developed for the FINE method and they will be described herein. Such features can be categorized based upon their broad goals. The first goal is to simplify FINE further, and consists of the following features: (1) Auto fetal positioning (or FINE align); (2) Skip points; (3) Predictive cursor; (4) Static mode volume; and (5) Breech sweep. The second goal is to allow quantitative measurements to be performed on the cardiac views generated by FINE: (6) Automatic cardiac axis; and (7) Cardiac biometry. Finally, the last goal is to improve the success of obtaining fetal echocardiography view(s); and consists of (8) Maestro planar navigation.

Prenatal diagnosis of ductal origin of distal pulmonary artery: presentation of three cases and literature review.

Ductal origin of distal pulmonary artery (DODPA) is a rare congenital cardiovascular anomaly, with an incidence of approximately 1 in 200 000 people. It involves the proximal interruption of one pulmonary artery branch, with the distal part arising from the base of the brachiocephalic artery, via the ipsilateral ductus arteriosus (DA) and the intrapulmonary branch of the pulmonary artery is usually intact. If timely treatment is not provided after birth, it is very likely that, due to DA closure, severe hypoplasia will occur in the lung supplied by the abnormal pulmonary artery. Hence, prenatal diagnosis of DODPA is important to enable initiation of prostaglandin treatment and early rehabilitation of the affected lung. Herein, we report three cases of fetal DODPA diagnosed via two-dimensional (2D) ultrasonography combined with four-dimensional (4D) spatiotemporal image correlation. We also present a literature review, and explore the ultrasonographic findings and the importance of 2D and 4D ultrasonography in obtaining an accurate prenatal diagnosis of DODPA. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

First Trimester Prenatal Diagnosis of a Conotruncal Anomaly Using Spatiotemporal Image Correlation Imaging Confirmed by Conventional Autopsy.

BackgroundFetal echocardiography continues to be the first line investigation for detecting congenital heart diseases (CHD). As accurate and complete diagnosis of complex heart disease is often difficult in the first trimester due to small size of the fetal heart, confirmation/expanded description by fetopsy provides the best information for accurate counseling for future pregnancies. Although non invasive fetal autopsy alternatives have been investigated with favorable results, conventional autopsy remains the gold standard procedure used to confirm the fetal abnormalities. Case report: We describe a conotruncal anomaly diagnosed at 12 weeks gestation using spatiotemporal image. The fetopsy confirmed the diagnosis of Type I Truncus arteriosus. Conclusion: Four-dimensional STIC imaging provides incremental benefits in evaluation of fetal cardiac anomalies, and confirmation by autopsy findings allows further refinement of the diagnosis.

Improving characterization of hypertrophy-induced murine cardiac dysfunction using four-dimensional ultrasound-derived strain mapping.

Mouse models of cardiac disease have become essential tools in the study of pathological mechanisms, but the small size of rodents makes it challenging to quantify heart function with noninvasive imaging. Building off recent developments in high-frequency four-dimensional ultrasound (4DUS) imaging, we have applied this technology to study cardiac dysfunction progression in a murine model of metabolic cardiomyopathy. Cardiac knockout of carnitine palmitoyltransferase 2 (Cpt2M-/-) in mice hinders cardiomyocyte bioenergetic metabolism of long-chain fatty acids, and leads to progressive cardiac hypertrophy and heart failure. The proposed analysis provides a standardized approach to measure localized wall kinematics and simultaneously extracts metrics of global cardiac function, LV morphometry, regional circumferential strain, and regional longitudinal strain from an interpolated 4-D mesh of the endo- and epicardial boundaries. Comparison of metric changes due to aging suggests that circumferential strain at the base and longitudinal strain along the posterior wall are most sensitive to disease progression. We further introduce a novel hybrid strain index (HSI) that incorporates information from these two regions and may have greater utility to characterize disease progression relative to other extracted metrics. Potential applications to additional disease models are discussed that could further demonstrate the utility of metrics derived from 4DUS imaging and strain mapping.NEW & NOTEWORTHY High-frequency four-dimensional ultrasound can be used in conjunction with standardized analysis procedures to simultaneously extract left-ventricular global function, morphometry, and regional strain metrics. Furthermore, a novel hybrid strain index (HSI) formula demonstrates greater performance compared with all other metrics in characterizing disease progression in a model of metabolic cardiomyopathy.

Right atrial isomerism diagnosed by STIC-HD live flow and autopsy: A case report.

RATIONALE: Right atrial isomerism (RAI) is one of the most severe forms of congenital heart disease. This case of RAI was so complex that it incorporated 7 heart defects. It can be challenging to display the spatial relationship between different anatomical structures using conventional two-dimensional and color ultrasound (2D-Doppler imaging); therefore, we used spatio-temporal image correlation (STIC) and high definition live flow imaging technology to vividly display this case of RAI in a stereoscopic mode. PATIENT CONCERNS: A 24-year-old woman was referred to our tertiary center at 24 weeks of gestation. The woman had difficult conceiving. Once pregnant, she was opposed to abortion, even if there was a possibility of deformity. DIAGNOSIS: The fetus presented with an atrioventricular septal defect, persistent left superior vena cava, supra-cardiac total anomalous pulmonary venous connection (TAPVC), double outlet right ventricle, right ductus arteriosus, right aortic arch (RAA) with mirror image branching, and aortic arch dysplasia. INTERVENTIONS: After consulting a pediatric cardiologist, the woman requested an abortion and consented to an autopsy. OUTCOMES: Autopsy supported the echocardiographic findings. LESSONS: Accurate diagnosis of RAI is essential for clinical and parent decision making. 2D-Doppler imaging combined with STIC-HD live flow can be used to visualize the spatial morphology of blood vessels, including the cardiac chambers and great vessels of the fetal heart, and smaller peripheral vessels.

Four-Dimensional Volume-Strain Expression in Asymptomatic Primary Hypertension Patients Presenting with Subclinical Left Atrium-Ventricle Dysfunction.

OBJECTIVE: The purpose of this study was to evaluate the different components of left atrial (LA) dysfunction predictors in asymptomatic primary systemic hypertension patients with preserved left ventricular (LV) ejection fraction, particularly using LA 4-dimensional (4D) longitudinal and circumferential strain values. METHODS AND RESULTS: Patients with no left ventricular hypertrophy (NLVH) and left ventricular hypertrophy (LVH) are all asymptomatic regarding primary blood hypertension. Thirty NLVH patients and 30 LVH patients according to LV mass index and 40 controls analyzed by 4D echocardiography were prospectively enrolled. LA volumes and longitudinal and circumferential strains were measured using 4D volume-strain echocardiography with a Vivid E95 Version 203 instrument. Correlation analysis indicated a significant relation between LV 4D mass index and LA 4D longitudinal/circumferential strain (r = -0.446 to 0.381, p = 0.000-0.042). LVH patients had a reduced LA emptying fraction compared with NLVH patients and control subjects (p < 0.01). NLVH patients had an impaired LA conduit function and increased contractile function compared with the control group (p < 0.01). LVH patients had increased LA volumes and significantly decreased reservoir, conduit and contractile functions compared with the controls (p < 0.01). LVH patients had increased LA volumes and decreased reservoir and contractile functions compared with NLVH patients (p < 0.01). The clinical utility of LA 4D volume-strain measurement was verified by receiver-operating characteristic curve analysis showing larger net benefits as evaluated with NLVH, LVH and control group comparisons. Interclass correlation coefficients of interobserver and intraobserver assessments in the LV and LA 4D value evaluations were >0.75 and >0.85, respectively. CONCLUSIONS: LVH patients showed increased LA volumes and decreased LA emptying fractions. LA reservoir, conduit and contractile functions were significantly impaired in LVH patients. Decreased LA conduit function and increased contractile function were revealed in NLVH patients. LA volumetric and functional analyses with 4D volume-strain echocardiography may facilitate the recognition of subtle LA and LV dysfunctions in asymptomatic systemic hypertension patients.

The Evaluation of Fetal Cardiac Remote Screening in the Second Trimester of Pregnancy Using the Spatio-Temporal Image Correlation Method.

We prospectively performed remote fetal cardiac screening using the spatio-temporal image correlation (STIC), and examined the usefulness and problems of remote screening. We performed heart screening for all pregnant women at four obstetrics clinics over the three years from 2009 to 2014. The STIC data from 15,404 examinations in normal pregnancies (16-27 weeks, median 25 weeks) were analyzed. Obstetricians and sonographer collected STIC data from four-chamber view images. Eight pediatric cardiologists analyzed the images offline. A normal heart was diagnosed in 14,002 cases (90.9%), an abnormal heart was diagnosed in 457 cases (3.0%), and poor images were obtained in 945 cases (6.1%). 138 cases had congenital heart disease (CHD) after birth, and severe CHD necessitating hospitalization occurred in 36 cases. We were not able to detect CHD by screening in 12 cases. The sensitivity and specificity of STIC in CHD screening was 50% and 99.5%, respectively. The sensitivity and specificity of STIC in screening for severe CHD was 82% and 99.9%, respectively. The STIC method was useful in fetal remote screening for CHD. However, the fact that > 10% of images that could not be analyzed by this method was a problem.

Commercial 4-dimensional echocardiography for murine heart volumetric evaluation after myocardial infarction.

BACKGROUND: Traditional preclinical echocardiography (ECHO) modalities, including 1-dimensional motion-mode (M-Mode) and 2-dimensional long axis (2D-US), rely on geometric and temporal assumptions about the heart for volumetric measurements. Surgical animal models, such as the mouse coronary artery ligation (CAL) model of myocardial infarction, result in morphologic changes that do not fit these geometric assumptions. New ECHO technology, including 4-dimensional ultrasound (4D-US), improves on these traditional models. This paper aims to compare commercially available 4D-US to M-mode and 2D-US in a mouse model of CAL. METHODS: 37 mice underwent CAL surgery, of which 32 survived to a 4 week post-operative time point. ECHO was completed at baseline, 1 week, and 4 weeks after CAL. M-mode, 2D-US, and 4D-US were taken at each time point and evaluated by two separate echocardiographers. At 4 weeks, a subset (n = 12) of mice underwent cardiac magnetic resonance (CMR) imaging to serve as a reference standard. End systolic volume (ESV), end diastolic volume (EDV), and ejection fraction (EF) were compared among imaging modalities. Hearts were also collected for histologic evaluation of scar size (n = 16) and compared to ECHO-derived wall motion severity index (WMSI) and global longitudinal strain as well as gadolinium-enhanced CMR to compare scar assessment modalities. RESULTS: 4D-US provides close agreement of ESV (Bias: -2.55%, LOA: - 61.55 to 66.66) and EF (US Bias: 11.23%, LOA - 43.10 to 102.8) 4 weeks after CAL when compared to CMR, outperforming 2D-US and M-mode estimations. 4D-US has lower inter-user variability as measured by intraclass correlation (ICC) in the evaluation of EDV (0.91) and ESV (0.93) when compared to other modalities. 4D-US also allows for rapid assessment of WMSI, which correlates strongly with infarct size by histology (r = 0.77). CONCLUSION: 4D-US outperforms M-Mode and 2D-US for volumetric analysis 4 weeks after CAL and has higher inter-user reliability. 4D-US allows for rapid calculation of WMSI, which correlates well with histologic scar size.

Semiautomatic Fetal Intelligent Navigation Echocardiography Has the Potential to Aid Cardiac Evaluations Even in Less Experienced Hands.

OBJECTIVES: To investigate the interobserver and intraobserver variability and corresponding learning curve in a semiautomatic approach for a standardized assessment of the fetal heart (fetal intelligent navigation echocardiography [FINE]). METHODS: A total of 30 stored spatiotemporal image correlation volume data sets of second-trimester fetuses were evaluated by 3 physicians with different levels of expertise in fetal echocardiography by using the FINE approach. Data were analyzed regarding the examination time and proper reconstruction of the diagnostic cardiac planes. The completions and numbers of correct depictions of all diagnostic planes were evaluated by a blinded expert (time t0). To determine interobserver and intraobserver variability, the volumes were reassessed after a 4-week training interval (time t1). RESULTS: All operators were able to perform the investigation on all 30 volumes. At t0, the interobserver variability between the beginner and both the advanced (P = .0013) and expert (P < .0001) examiners was high. Focusing on intraobserver variability at t1, the beginner showed a marked improvement (P = .0087), whereas in advanced and expert hands, no further improvement regarding proper achievement of all diagnostic planes could be noticed (P > .999; P = .8383). The beginner also showed improvement in the mean investigation time (t0, 82.8 seconds; t1, 73.4 seconds; P = .0895); nevertheless, the advanced and expert examiners were faster in completing the examination (t1, advanced, 20.9 seconds; expert, 28.3 seconds; each P < .0001). CONCLUSIONS: Based on our results, the FINE technique is a reliable and easily learned method. The use of this semiautomatic work flow-based approach supports evaluation of the fetal heart in a standardized and time-saving manner. A semiautomatic evaluation of the fetal heart might be useful in facilitating the detection of fetal cardiac anomalies.

Recent Development in Three and Four Dimension Fetal Echocardiography.

Since its introduction >15 years ago, the use of spatial and temporal image correlation (STIC) technology has contributed substantially to fetal echocardiography. Moreover, significant advances have occurred in 3- and 4-dimensional (3D/4D) echocardiography over the past several years including the matrix probe along with advances in gray scale and color Doppler post processing, resulting in improved display of ultrasound images. In this article, we provide examples to show these recent developments including the use of color Doppler with STIC in the glass-body mode and the matrix probe thus enabling the demonstration of cardiac anomalies of the 4-chamber-view and great arteries. The use of the matrix probe allows the examination of cardiac structures in 2 orthogonal planes simultaneously, which can help in display of anatomy side by side (Biplane mode). In addition, the rapid image reconstruction of the matrix probe allows for the display of live 4D and the rapid acquisition of a STIC volume. The display of multiplanar images of the heart in 3D/4D has also been used to automate the display of ultrasound images, resulting in standardization of the image display and thus minimizing the operation dependency of the ultrasound examination. Future addition of image recognition software can also provide assistance in image review.

Combining position-based dynamics and gradient vector flow for 4D mitral valve segmentation in TEE sequences.

PURPOSE: For planning and guidance of minimally invasive mitral valve repair procedures, 3D+t transesophageal echocardiography (TEE) sequences are acquired before and after the intervention. The valve is then visually and quantitatively assessed in selected phases. To enable a quantitative assessment of valve geometry and pathological properties in all heart phases, as well as the changes achieved through surgery, we aim to provide a new 4D segmentation method. METHODS: We propose a tracking-based approach combining gradient vector flow (GVF) and position-based dynamics (PBD). An open-state surface model of the valve is propagated through time to the closed state, attracted by the GVF field of the leaflet area. The PBD method ensures topological consistency during deformation. For evaluation, one expert in cardiac surgery annotated the closed-state leaflets in 10 TEE sequences of patients with normal and abnormal mitral valves, and defined the corresponding open-state models. RESULTS: The average point-to-surface distance between the manual annotations and the final tracked model was [Formula: see text]. Qualitatively, four cases were satisfactory, five passable and one unsatisfactory. Each sequence could be segmented in 2-6 min. CONCLUSION: Our approach enables to segment the mitral valve in 4D TEE image data with normal and pathological valve closing behavior. With this method, in addition to the quantification of the remaining orifice area, shape and dimensions of the coaptation zone can be analyzed and considered for planning and surgical result assessment.

Predictive value of left ventricular myocardial strain by four-dimensional speckle tracking echocardiography combined with red cell distribution width in heart failure with preserved ejection fraction.

OBJECTIVES: The diagnostic difficulty of heart failure with preserved ejection fraction (HFpEF) is differentiating it in patients with similar symptoms and signs. This study aimed to assess the potential predictive value of left ventricular global longitudinal strain (GLS), global radial strain (GRS), global circumferential strain (GCS), and global area strain (GAS) measured by four-dimensional speckle tracking echocardiography (4DSTE) combined with red cell distribution width (RDW) in patients with HFpEF. METHODS: One hundred and sixty-nine patients with symptoms or signs indicative of chronic heart failure and a left ventricular ejection fraction (LVEF) ≥ 50% and fifty controls with normal LVEF were recruited in this study. Standard echocardiography and 4DSTE examinations were performed. Laboratory examinations including RDW were performed on the same day as the echocardiographic study. RESULTS: GLS, GCS, GRS, and GAS in the patient cohort were significantly lower, and RDW was significantly higher than those in the control cohort (P < 0.01), and the strain parameters in definite HFpEF patients were also dramatically lower than the rest patients (P < 0.01). The associations of age, gender, NYHA classification, hypertension history, left ventricular end-diastolic volume index, interventricular septal thickness, and diastolic dysfunction with HFpEF were significantly improved by adding 4DSTE parameters (P < 0.01) and further improved by adding RDW (P < 0.01). CONCLUSIONS: In suspected HFpEF patients, who have symptoms or signs of heart failure, even without other conventional evidence of this diagnosis, GLS, GRS, and GCS have potential independent predictive value, while RDW has independent incremental predictive value for HFpEF.

Four-Dimensional Ultrasound for Evaluating Newborn Cardiac Output: A Pilot Study of Healthy Infants.

BACKGROUND: There is currently no reliable non-invasive method of measuring cardiac output in neonatal intensive care. Spatiotemporal image correlation (STIC) is a novel four-dimensional (4D) ultrasound technique that was developed to assess the foetal heart, and it may be a useful way to assess neonatal haemodynamics. OBJECTIVE: This study aimed to evaluate the feasibility and reproducibility of determining neonatal cardiac output using STIC ultrasound in newborn infants. DESIGN: Infants were recruited opportunistically from a neonatal intensive care unit and then examined by 2 independent observers. STIC was used to obtain images of the heart. End-diastolic and end-systolic ventricular volumes were measured using virtual organ computer-aided analysis (VOCAL) and used to calculate cardiac output. Reproducibility was assessed with intraclass correlation coefficients (ICC) and agreement with Bland-Altman analysis. RESULTS: Twenty-four clinically stable infants of 34-43 weeks corrected gestational age were assessed. Both observers successfully acquired 4D STIC volumes in all infants. Left ventricular output showed good reproducibility, with an intra-observer ICC of 0.86 (0.69-0.94) and inter-observer ICC of 0.87 (0.70-0.95). Right ventricular output also showed good reproducibility, with an intra-observer ICC of 0.88 (0.70-95) and inter-observer ICC of 0.84 (0.63-0.93). CONCLUSIONS: Determining cardiac output using 4D STIC ultrasound is feasible and reproducible in well newborn infants. With further evaluation, this technique may provide valuable information about haemodynamic status in newborn infants requiring intensive care.

4D simultaneous tissue and blood flow Doppler imaging: revisiting cardiac Doppler index with single heart beat 4D ultrafast echocardiography.

The goal of this study was to demonstrate the feasibility of semi-automatic evaluation of cardiac Doppler indices in a single heartbeat in human hearts by performing 4D ultrafast echocardiography with a dedicated sequence of 4D simultaneous tissue and blood flow Doppler imaging. 4D echocardiography has the potential to improve the quantification of major cardiac indices by providing more reproducible and less user dependent measurements such as the quantification of left ventricle (LV) volume. The evaluation of Doppler indices, however, did not benefit yet from 4D echocardiography because of limited volume rates achieved in conventional volumetric color Doppler imaging but also because spectral Doppler estimation is still restricted to a single location. High volume rate (5200 volume s-1) transthoracic simultaneous tissue and blood flow Doppler acquisitions of three human LV were performed using a 4D ultrafast echocardiography scanner prototype during a single heartbeat. 4D color flow, 4D tissue Doppler cineloops and spectral Doppler at each voxel were computed. LV outflow tract, mitral inflow and basal inferoseptal locations were automatically detected. Doppler indices were derived at these locations and were compared against clinical 2D echocardiography. Blood flow Doppler indices E (early filling), A (atrial filling), E/A ratio, S (systolic ejection) and cardiac output were assessed on the three volunteers. Simultaneous tissue Doppler indices e' (mitral annular velocity peak), a' (late velocity peak), e'/a' ratio, s' (systolic annular velocity peak), E/e' ratio were also estimated. Standard deviations on three independent acquisitions were averaged over the indices and was found to be inferior to 4% and 8.5% for Doppler flow and tissue Doppler indices, respectively. Comparison against clinical 2D echocardiography gave a p  value larger than 0.05 in average indicating no significant differences. 4D ultrafast echocardiography can quantify the major cardiac Doppler indices in a single heart beat acquisition.

4D cardiac magnetic resonance imaging, 4D and 2D transthoracic echocardiography: a comparison of in-vivo assessment of ventricular function in rats.

Preclinical cardiovascular research is the foundation of our understanding and broad knowledge of heart function and cardiovascular disease. Reliable cardiac imaging modalities are the basis for applicable results. Four-dimensional cardiac magnetic resonance (4D CMR) has been set as the gold standard for in-vivo assessment of ventricular function in rodents. However, technical improvements in echocardiography now allow us to image the whole heart, which makes four-dimensional echocardiography (4DE) a possible alternative to 4D CMR. To date, no study has systematically assessed 4DE in comparison with 4D CMR in rats. In total we studied 26 juvenile Sprague-Dawley rats (Crl: CD (SD) IGS). Twenty rats underwent echocardiographic imaging (2D and 4D) and 4D CMR. Five of those rats underwent a ligation of the superior and inferior vena cava to reduce the cardiac inflow as a disease model. Six additional rats were used to assess reproducibility of echocardiography and underwent three echocardiographic examinations. 4D CMR was performed on a 7T scanner; 2D and 4D echocardiography was conducted using a 40 MHz transducer. Correlation between 4D CMR, 4DE and 2DE for left-ventricular ejection fraction (LVEF) was assessed. An excellent correlation was observed between 4DE and 4D CMR ( r = 0.95, p < 0.001). Correlation of 2DE and 4D CMR was weak ( r = 0.57, p < 0.01). 4DE provides results that are equally precise as 4D CMR and highly reproducible with less technical effort than 4D CMR.

The unique mechanism of functional mitral regurgitation in acute myocardial infarction: a prospective dynamic 4D quantitative echocardiographic study.

AIMS: Mechanisms of chronic ischaemic mitral regurgitation (IMR) are well-characterized by apically tethered leaflet caused by papillary muscles (PMs) displacement and adynamic mitral apparatus. We investigated the unique geometry and dynamics of the mitral apparatus in first acute myocardial infarction (MI) by using quantified 3D echocardiography. METHODS AND RESULTS: We prospectively performed 3D echocardiography 2.3 ± 1.8 days after first MI, in 174 matched patients with (n = 87) and without IMR (n = 87). 3D echocardiography of left ventricular (LV) volumes and of mitral apparatus dynamics throughout cardiac cycle was quantified. Similar mitral quantification was obtained at chronic post-MI stage (n = 44). Mechanistically, acute IMR was associated with larger and flatter annulus (area 9.29 ± 1.74 cm2 vs. 8.57 ± 1.94 cm2, P = 0.002, saddle shape 12.7 ± 4.5% vs. 15.0 ± 4.6%, P = 0.001), and larger tenting (length 6.36 ± 1.78 mm vs. 5.60 ± 1.55 mm, P = 0.003) but vs. chronic MI, mitral apparatus displayed smaller alterations (all P < 0.01) and annular size, PM movement remained dynamic (all P < 0.01). Specific to acute IMR, without PM apical displacement (P > 0.70), greater separation (21.7 ± 4.9 mm vs. 20.0 ± 3.4 mm, P = 0.01), and widest angulation of PM (38.4 ± 6.2° for moderate vs. 33.5 ± 7.3° for mild vs. 31.4 ± 6.3° for no-IMR, P = 0.0009) wider vs. chronic MI (P < 0.01). CONCLUSIONS: 3D echocardiography of patients with first MI provides insights into unique 4D dynamics of the mitral apparatus in acute IMR. Mitral apparatus remained dynamic in acute MI and distinct IMR mechanism in acute MI is not PM displacement seen in chronic IMR but separation and excess angulation of PM deforming the mitral valve, probably because of sudden-onset regional wall motion abnormality without apparent global LV remodelling. This specific mechanism should be considered in novel therapeutic strategies for IMR complicating acute MI.