Evaluation of 24-segment sphericity index of fetal heart using FetalHQ

Feasibility and reproducibility of speckle tracking echocardiography in routine assessment of the fetal heart in a low-risk population

OBJECTIVES

The objective of this study was to evaluate the feasibility and reproducibility of speckle tracking echocardiography (STE) in routine fetal cardiac assessments by non-cardiac experts in an NHS clinical setting.

METHODS

A prospective longitudinal cohort study was performed from April 2022 to June 2023. During all ultrasound scans between 18 and 40 weeks' gestation a 3 s cineloop of the fetal four chamber view was stored. Parameters of global cardiac function were analysed off-line using STE software by two researchers independently.

RESULTS

Of 393 ultrasound scans performed in fetuses fulfilling criteria, 50.9 % were able to be analysed using STE. Intraobserver variability was poor to moderate for both operators (Operator 1 correlation coefficient for FAC 0.28, EF 0.17, SV 0.01, SV/kg 0.00, CO 0.74, CO/kg 0.39; Operator two correlation coefficient for FAC 0.58, EF 0.65, SV 0.67, SV/kg 0.02, CO 0.66, CO/kg 0.31). Interobserver variability was also poor to moderate (Operator 1 vs. Operator two correlation coefficient for FAC 0.01, EF 0.00, SV 0.00, SV/kg 0.00, CO 0.64, CO/kg 0.25; Operator 2 vs. Operator 1 correlation coefficient for FAC 0.16, EF 0.06, SV 0.72, SV/kg 0.008, CO 0.70, CO/kg 0.34).

CONCLUSIONS

Routine speckle tracking echocardiography of global cardiac function by non-cardiac experts in low-risk fetuses has low to moderate feasibility and reproducibility in a real-world NHS setting. A high grade of expertise is likely necessary to use STE in order to achieve high reproducibility. Future research should investigate factors contributing to variability in STE measurements and standardisation of protocols.

Reproducibility Challenges in Fetal Cardiac Function Analysis with 2D Speckle-Tracking Echocardiography: Insights from FetalHQ

Background/Objectives: Functional assessment of the fetal heart remains a significant challenge in contemporary perinatology due to the absence of a universally accepted gold standard for such evaluations. The aim of this study was to evaluate the reproducibility of parameters derived from two-dimensional speckle-tracking echocardiography (2D STE) using the FetalHQ software. Methods: We enrolled 87 pregnant women between 19 and 23 weeks of gestation who were undergoing mid-trimester screening at the Provincial Hospital Complex in Kielce. Two independent operators acquired 5 s cine-loops of four-chamber views (4CVs) according to a standardized protocol. Reproducibility was assessed by examining intra- and interobserver variability using the intraclass correlation coefficient (ICC) for several cardiac parameters, including the global sphericity index (GSI), global longitudinal strain (GLS), stroke volume (SV), and fractional area change (FAC). Results: Reproducibility varied substantially across the assessed parameters. The highest intraobserver reproducibility was observed for the 4CV GSI (ICC > 0.9). Moderate intraobserver reproducibility (ICCs ranging from 0.5 to 0.75) was noted for left ventricular (LV) parameters, such as end-diastolic area, end-systolic area, end-diastolic volume, and end-systolic volume. Interobserver variability demonstrated higher ICC values, with excellent reproducibility (ICC > 0.9) for the 4CV GSI and LV volume measurements. Good reproducibility (ICCs between 0.75 and 0.9) was observed for specific left ventricular segmental strain indices, whereas other parameters showed moderate to poor reproducibility (ICC < 0.5). Conclusions: Two-dimensional speckle-tracking echocardiography (2D STE) using FetalHQ exhibits variable reproducibility, which is influenced by the choice of parameters, operator experience, and technical factors. This method holds potential for fetal cardiac assessment; however, additional research is required to improve its predictive accuracy and streamline the evaluation process for routine clinical application.

Evaluation of Fetal Heart Using Fetal Heart Quantification (fetalHQ) Technique in an Indian Cohort

OBJECTIVE

To evaluate the intra- and interobserver reproducibility of parameters used to determine cardiac morphometry and deformation using FetalHQ in Indian population.

METHODOLOGY

Two operators blinded to each other performed FetalHQ analysis independently on 35 normal fetuses of gestational age between 18 + 0 and 37 + 0 weeks and days. Intra- and interobserver correlation coefficient and limits of agreement were ascertained for parameters obtained from HQ analysis.

RESULTS

Excellent reproducibility (ICC > 0.9) was observed for global morphometric parameters. Ejection fraction, stroke volume, stroke volume/kg demonstrated excellent reliability (ICC > 0.9), cardiac output, fractional area change showed a lower correlation (ICC < 0.8), and right and left ventricular global strain showed no correlation. Twenty-four segment sphericity index of left ventricle (LV) and right ventricle (RV) showed low to moderate correlation (LV-ICC 0.48-0.79; RV-ICC 0.43-0.82). Fractional shortening (FS) showed poor intraobserver reliability in RV.

CONCLUSION

FetalHQ provides reliable estimates of the global cardiac morphometry but not for global cardiac strain. Regional transverse contractility represented by FS has poor correlation in right ventricle, especially in the apical region, possibly due to moderator band. Nevertheless, it is a promising tool which requires technical advancements and validation to improve its accuracy and reliability.

Reproducibility Analysis of Two Speckle Tracking Software for the Antenatal Semiautomated Assessment of the Fetal Cardiac Function

INTRODUCTION

Speckle tracking echocardiography is a non-Doppler modality allowing the semiautomated evaluation of the fetal cardiac function by tracking the speckles of the endocardial borders. Little evidence is available on the evaluation and comparison of different software for the functional assessment of the fetal heart by means of speckle tracking echocardiography. The aim of this study was to evaluate the reproducibility and agreement of two different proprietary speckle tracking software for the prenatal semiautomated assessment of the fetal cardiac function.

METHODS

The prospective study including non-anomalous fetuses was referred for different indications at two tertiary academic units in Italy (University of Parma) and Spain (University of Barcelona). Two-dimensional clips of the four-chamber view of the fetal heart were acquired by two dedicated operators using high-end ultrasound machines with a frame rate higher than 60 Hz. The stored clips were pseudo-anonymized and shared between the collaborating units. Functional echocardiographic analyses were independently performed using the two proprietary software (TomTec GmbH and FetalHQ®) by the same operators. Inter-software reproducibility of the endocardial global longitudinal strain (EndoGLS) and fractional area change (FAC) of the left (LV) and the right ventricles (RV) and ejection fraction (EF) of the LV were evaluated by the intraclass correlation coefficient (ICC).

RESULTS

Forty-eight fetuses were included at a median of 31+2 (21+6-40+3) gestational weeks. Moderate reproducibility was found for the functional parameters of the LV: EndoGLS (Pearson's correlation 0.456, p < 0.01; ICC 0.446, 95% CI: 0.189-0.647, p < 0.01); EF (Pearson's correlation 0.435, p < 0.01; ICC 0.419, 95% CI: 0.156-0.627, p < 0.01); FAC (Person's correlation 0.484, p < 0.01; ICC 0.475, 95% CI: 0.223-0.667, p < 0.01). On the contrary, RV functional parameters showed poor reproducibility between the two software: EndoGLS (Pearson's correlation 0.383, p = 0.01; ICC 0.377, 95% CI: 0.107-0.596, p < 0.01) and FAC (ICC 0.284, 95% CI: 0.003-0.524, p = 0.02).

CONCLUSION

Our results demonstrate a moderate reproducibility of the speckle tracking analysis of the LV using TomTec GmbH and FetalHQ®, with poor reproducibility for RV analysis.

How automated techniques ease functional assessment of the fetal heart: Applicability of two-dimensional speckle-tracking echocardiography for comprehensive analysis of global and segmental cardiac deformation using fetalHQ®

BACKGROUND

Prenatal echocardiographic assessment of fetal cardiac function has become increasingly important. Fetal two-dimensional speckle-tracking echocardiography (2D-STE) allows the determination of global and segmental functional cardiac parameters. Prenatal diagnostics is relying increasingly on artificial intelligence, whose algorithms transform the way clinicians use ultrasound in their daily workflow. The purpose of this study was to demonstrate the feasibility of whether less experienced operators can handle and might benefit from an automated tool of 2D-STE in the clinical routine.

METHODS

A total of 136 unselected, normal, singleton, second- and third-trimester fetuses with normofrequent heart rates were examined by targeted ultrasound. 2D-STE was performed separately by beginner and expert semiautomatically using a GE Voluson E10 (FetalHQ®, GE Healthcare, Chicago, IL). Several fetal cardiac parameters were calculated (end-diastolic diameter [ED], sphericity index [SI], global longitudinal strain [EndoGLS], fractional shortening [FS]) and assigned to gestational age (GA). Bland-Altman plots were used to test agreement between both operators.

RESULTS

The mean maternal age was 33 years, and the mean maternal body mass index prior to pregnancy was 24.78 kg/m2. The GA ranged from 16.4 to 32.0 weeks (average 22.9 weeks). Averaged endoGLS value of the beginner was -18.57% ± 6.59 percentage points (pp) for the right and -19.58% ± 5.63 pp for the left ventricle, that of the expert -14.33% ± 4.88 pp and -16.37% ± 5.42 pp. With increasing GA, right ventricular endoGLS decreased slightly while the left ventricular was almost constant. The statistical analysis for endoGLS showed a Bland-Altman-Bias of -4.24 pp ± 8.06 pp for the right and -3.21 pp ± 7.11 pp for the left ventricle. The Bland-Altman-Bias of the ED in both ventricles in all analyzed segments ranged from -.49 mm ± 1.54 mm to -.10 mm ± 1.28 mm, that for FS from -.33 pp ± 11.82 pp to 3.91 pp ± 15.56 pp and that for SI from -.38 ± .68 to -.15 ± .45.

CONCLUSIONS

Between both operators, our data indicated that 2D-STE analysis showed excellent agreement for cardiac morphometry parameters (ED and SI), and good agreement for cardiac function parameters (EndoGLS and FS). Due to its complexity, the application of fetal 2D-STE remains the domain of scientific-academic perinatal ultrasound and should be placed preferably in the hands of skilled operators. At present, from our perspective, an implementation into clinical practice "on-the-fly" cannot be recommended.

Quantitative Analysis of Morphology and Function in the Fetal Heart with Severe Tricuspid Regurgitation by Speckle Tracking Imaging

Morphology and function in a fetal heart with severe tricuspid regurgitation remains challenging. The aim of this study was to assess cardiac morphology and function in fetuses with severe tricuspid regurgitation by fetal heart quantification (HQ) and to assess the practical value of fetal HQ. Clinical information was analyzed for 63 pregnant women who underwent fetal cardiac ultrasonography. The women were divided into those who had a fetus with severe tricuspid regurgitation (n = 20) and those with a normal fetus (n = 40). The global sphericity index (GSI), fractional area change (FAC), and global longitudinal strain (GLS) of both ventricles and the sphericity index (SI) and fractional shortening (FS) of 24 segments were quantified by fetal HQ using speckle tracking imaging. Fetuses with severe tricuspid regurgitation had a significantly lower GSI (1.14 ± 0.10 vs. 1.26 ± 0.08, p < 0.001) and a higher GSI Z-score (-0.98 ± 1.01 vs. 0.25 ± 0.87, p < 0.001) as well as a significantly lower right ventricular FAC (36.50 ± 7.34% vs. 45.19 ± 3.39%, p < 0.001), FAC Z-score (-1.02 ± 1.41 vs. 0.49 ± 0.74, p < 0.001), and GLS (-21.01 ± 5.66% vs. 45.19 ± 3.49%, p < 0.001). The SI and SI Z-score were significantly lower in segments 1-18 of the right ventricle in fetuses with severe tricuspid regurgitation (p < 0.05); furthermore, FS of segments 1-12 and 19-24 and the FS Z-score of segments 18-24 were significantly lower in fetuses with severe tricuspid regurgitation (p < 0.05). Fetal HQ is useful for evaluation of cardiac morphology and function in fetuses with severe tricuspid regurgitation and can provide important reference information for both clinical diagnosis and treatment.

Prenatal Diagnosis of Right-Sided Congenital Ventricular Diverticulum (CVD) Assisted by Spatiotemporal Image Correlation (STIC) Acquisition and the Speckle-Tracking Technique to Assess Fetal Cardiac Function: A Case Report

Congenital ventricular diverticulum (CVD) is a cardiac malformation defined as an outpouching lesion of a ventricle with normal contractility and thickness, and the advancement of prenatal sonography has led to its prenatal diagnosis. In the prenatal period, CVD is reported in association with pericardial effusion, arrhythmia, and fetal hydrops or as an isolated condition. With the development of prenatal echocardiography, CVD can be diagnosed from the early stage of pregnancy, and prenatal procedures, such as pericardiocentesis, are also possible. Spatiotemporal image correlation (STIC) acquisition, a novel approach for the clinical evaluation of fetal hearts, provides easy-to-use techniques for acquiring data from fetal hearts and helping visualization with two-dimensional and three-dimensional (3D) cine sequences. Furthermore, the speckle-tracking technique enables a more comprehensive evaluation of the shape, continuity, and function of the fetal heart. These recent techniques have never been used for CVD diagnosis and evaluation. Here, we present a case of right-sided CVD, which is the first in which STIC acquisition and cardiac function assessment with the speckle-tracking technique were used to assist in the diagnosis and evaluation.

HDlive Flow Silhouette with spatiotemporal image correlation for assessment of fetal cardiac structures at 12 to 14 + 6 weeks of gestation

OBJECTIVES

To assess fetal cardiac structures using HDlive Flow Silhouette with spatiotemporal image correlation (STIC) at 12 to 14 + 6 weeks of gestation, and verify the feasibility of obtaining five cardiac views in the late first and early second trimesters of pregnancy. The fetal cardiac shape and the aspect of the descending aorta were also evaluated.

METHODS

Eighty normal fetuses at 12 to 14 + 6 weeks of gestation were studied using trans-abdominal HDlive Flow Silhouette with STIC to assess the feasibility of five fetal cardiac views (frontal, spatial three-vessel, panoramic, posterior, and right lateral views). Target structures in each cardiac view were evaluated. 'Good' was assigned when all structures were noted, 'Fair' when only one structure was missed, and 'Poor' when two and more structures could not be detected. Frequencies of an elongated heart and those of a tortuous descending aorta were counted.

RESULTS

Forty-nine fetuses were effectively included in the analysis. Success rates of 'Good' and 'Fair' were significantly higher with spatial three-vessel (p<0.01) and panoramic views (p<0.05). Frequencies of "Elongated heart", "Elongated left ventricle", and "Spherical heart" were 12.2, 6.2, and 81.6%, respectively. Frequencies of "Tortuous descending aorta" and "Straight descending aorta" were 12.2 and 87.8%, respectively.

CONCLUSIONS

The feasibility of obtaining fetal five cardiac views using HDlive Flow Silhouette with STIC is good, and this technique provides useful information for evaluating fetal cardiac structures in the late first and early second trimesters of pregnancy.

Feasibility of 4D-Spatio Temporal Image Correlation (STIC) in the Comprehensive Assessment of the Fetal Heart Using FetalHQ®

Fetal Heart Quantification (FetalHQ®) is a novel speckle tracking software that permits the study of global and regional ventricular shape and function from a 2D four-chamber-view loop. The 4D-Spatio Temporal Image Correlation (STIC) modality enables the offline analysis of optimized and perfectly aligned cardiac planes. We aimed to evaluate the feasibility and reproducibility of 4D-STIC speckle tracking echocardiography (STE) using FetalHQ® and to compare it to 2D STE. We conducted a prospective study including 31 low-risk singleton pregnancies between 20 and 40 weeks of gestation. Four-chamber view volumes and 2D clips were acquired with an apex pointing at 45° and with a frame rate higher than 60 Hz. Morphometric and functional echocardiography was performed by FetalHQ®. Intra- and interobserver reproducibility were evaluated by the intraclass correlation coefficient (ICC). Our results showed excellent reproducibility (ICC > 0.900) for morphometric evaluation (biventricular area, longitudinal and transverse diameters). Reproducibility was also good (ICC > 0.800) for functional evaluation (biventricular strain, Fractional Area Change, left ventricle volumes, ejection fraction and cardiac output). On the contrary, the study of the sphericity index and shortening fraction of the different ventricular segments showed lower reproducibility (ICC < 0.800). To conclude, 4D-STIC is feasible, reproducible and comparable to 2D echocardiography for the assessment of cardiac morphometry and function.

Novel Speckle Tracking Analysis Showed Excellent Reproducibility for Size and Shape of the Fetal Heart and Good Reproducibility for Strain and Fractional Shortening

INTRODUCTION

This study aimed to evaluate reproducibility and agreement of fetal cardiac shape and deformation using FetalHQ.

METHODS

Fifty normal fetuses at 20-38 weeks of gestation were evaluated. Two operators independently selected an optimal cardiac cycle using FetalHQ®™software for speckle tracking analysis. Intra- and interobserver correlation coefficient and limits of agreement for cardiac shape and deformation were estimated.

RESULTS

Global cardiac markers: high correlation (r = 0.98) and agreement (mean difference, standard deviation [MD, SD] 5.07, 75.8) for ventricular area; moderate correlation (r = 0.78) and agreement (MD, SD: 0.016, 0.08) for global sphericity index (SI) and for left ventricle (LV) global strain (r = 0.65; MD, SD: -4.48, 11.9); and low but still significant correlation (r = 0.58) and agreement (MD, SD: -3.77, 12.27) for right ventricle (RV) global strain. For individual ventricular parameters: high correlation for LV ([median r; range] 0.98; 0.93-0.99) and RV (r = 0.98; 0.97-1.0) SI, and for LV (r = 0.92: 0.56-0.99) and RV (r = 0.96; 0.67-0.99) end diastolic diameters; moderate correlation for LV fractional shortening (r = 0.53; 0.87-0.98); and no significant correlation for RV fractional shortening (r = 0.36; 0.32-0.97). Inter- and intraobserver correlation and agreement were similar for all evaluated parameters.

CONCLUSION

Speckle tracking analysis of the fetal heart provides reliable estimations of global and LV shape and deformation. Low correlation in the RV can be related to anatomical structures such as the moderator band.

Evaluation of the sphericity index of the fetal heart during middle and late pregnancy using fetalHQ

OBJECTIVE

To explore the feasibility of the fetal heart quantitative technique (fetalHQ) for evaluating the sphericity index (SI) of the fetal heart during middle and late pregnancy.

METHODS

Ninety-six normal fetuses in middle and late gestation who underwent systemic ultrasound examination in the Department of Ultrasound of the Maternal and Child Health Care Hospital of Hunan Province in November 2020 were enrolled, and dynamic images of the four-chamber view of the fetal heart were collected. The correlation between the global sphericity index (GSI), ventricular 24-segment SI, and gestational age (GA) was analyzed, and the differences between the left and right ventricular 24-segment SI were compared.

RESULTS

The success rate of fetalHQ analysis was 93.75%. There was no significant linear correlation between GSI and ventricular 24-segment SI and GA (all ps > .05). The differences in SI between segments 1 and 9 and 15 and 24 in the left and right ventricles were statistically significant (all ps < .05), while the differences in SI between segments 10 and 14 were not statistically significant (all ps > .05). In segments 1-9, the SI of the right ventricle was smaller than that of the left ventricle, indicating that the right ventricle was significantly more spherical than the left ventricle. In segments 15-24, the opposite was true.

CONCLUSION

FetalHQ is a simple and reliable method for evaluating the GSI and 24-segment SI of the left and right ventricles. It can provide some theoretical basis for the clinical quantitative evaluation of fetal heart geometry and lay a foundation for the quantitative evaluation of fetal heart function in cases of structural and functional abnormalities.