Use of spatiotemporal image correlation at 11-14 weeks' gestation

Prenatal evaluation of fetal atrioventricular valves by real-time 4D volume imaging with electronic matrix probe

Background

The purpose of this study is to evaluate the feasibility using real-time four-dimensional (RT 4D) volume imaging with electronic matrix probe to observe the morphology of atrioventricular valves in normal and abnormal fetuses, measure the area and circumference of atrioventricular valves in normal fetuses and analyze the correlation with gestational age.

Methods

RT 4D volume imaging with electronic matrix probe was used to collect cardiac volume data of 162 normal fetuses with the gestational age from 22 to 32 weeks and 19 fetuses with atrioventricular valves abnormalities were also enrolled. All the volume data were analyzed and processed in real-time. The morphology of mitral and tricuspid valves was observed in surface mode. The area and circumference of valves were measured in a 4D render view at the end of diastole and analyzed the correlation with gestational age.

Results

In 148 of 162 fetuses (91%), the 4D rendered image could be successfully obtained, which clearly showed the morphology of the atrioventricular valves. The area and circumference of mitral and tricuspid valves were positively correlated with gestational age (P < 0.01). Furthermore, 4D rendered images were successfully obtained in 17 of 19 fetuses (89%) with atrioventricular valves abnormalities.

Conclusions

The reference range of the area and circumference of atrioventricular valves in normal fetuses at different gestational weeks could be determined by using the RT 4D volume imaging with electronic matrix probe, which can provide certain diagnostic information for the clinic. The RT 4D images could display the valves morphology vividly in both normal and abnormal fetuses, including some subtle lesions which are not identified by traditional two-dimensional (2D) echocardiography. It is feasible to use the RT 4D volume imaging with electronic matrix probe to perform the prenatal evaluation in the fetal atrioventricular valves.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12947-021-00240-7.

Tetralogy of Fallot and Outlet Ventricular Septal Defect with Anterior Malalignment Detected at Early Fetal Echocardiography

OBJECTIVES

To examine the evolution of tetralogy of Fallot (TOF) and outlet ventricular septal defect (VSD) with anterior malalignment (am) from the initial diagnosis at early fetal echocardiography through the gestation and to evaluate the impact of the first-trimester scan on the outcome.

METHODS

We identified cases of TOF or outlet VSD with am diagnosed before 16 weeks' gestation. For all cases, prenatal data and pregnancy outcomes were evaluated. In continuing pregnancies, the evolution in severity of the disease was assessed.

RESULTS

Fifty-one fetuses with TOF or outlet VSD with am were diagnosed at early fetal echocardiography. Parents opted for termination of pregnancy in all 23 cases associated with additional anomalies. In 2 of 28 continuing pregnancies, there was an intrauterine death. In the remaining 26, there was progression in severity in 7 (by 20-22 weeks in 3 cases and during the third trimester in the remaining 4).

CONCLUSIONS

TOF and outlet VSD with am diagnosed before 16 weeks' gestation can progress in severity throughout pregnancy in over one-quarter of cases. In addition, a high proportion of cases diagnosed in the first trimester may have associated extracardiac anomalies, with a significant impact on clinical management and on the rate of early termination of pregnancy.

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.

Assessment of Fetal Congenital Heart Diseases by 4-Dimensional Ultrasound Using Spatiotemporal Image Correlation: Pictorial Review

The aim of this pictorial review is to describe the technical advances achieved through the application of 4-dimensional (4D) ultrasound using spatiotemporal image correlation (STIC) over conventional 2-dimensional ultrasound in the prenatal detection of congenital heart disease (CHD). Spatiotemporal image correlation is a volume imaging technique that simplifies fetal heart studies while providing more diagnostic information than is typically available from traditional 2-dimensional studies. Four-dimensional software allows the study of cardiac anatomy and function during a single cardiac cycle and has greatly contributed to diagnostic enhancement of CHD. Color flow and power Doppler can be added to STIC in the study of vessel anatomy and to increase the detection of ventricular septal defects. Anatomical details of the fetus can be displayed in multiple images such as using computed tomography or magnetic resonance imaging. In addition, cardiac anatomy can be sectioned freely and reconstructed using different reformatting applications. Realistic views of the fetal heart, with particular emphasis on myocardium and endocardium cushion, can be reached using novel lightening techniques. Moreover, using 4D ultrasound, echolucent structures can be converted into solid voxels generating "digital casts" of the fetal heart that enhances the understanding of the great vessel relationships in the ventricular inflow and outflow tracts. Recently, sillhouette mode has shown to improve depth perception and resolution compared with conventional 3D power Doppler in the study of inflow and outflow tracts. Here, a gallery of prenatally detected CHD using 4D ultrasound with STIC and different applications is described.

Early fetal echocardiography

OBJECTIVES

To explore the technical aspects and clinical utility of early fetal echocardiography and screening of the fetal heart in early pregnancy. Also, to document differences in cardiac structure and function which can be demonstrated in the late first/early second trimesters.

METHODS

In addition to summarizing our own experiences of late first/early second trimester fetal echocardiography, we reviewed the literature to explore clinical indications for, technical aspects, safety, accuracy, strengths and weaknesses of early fetal echocardiography.

RESULTS

In the current era, an increasing number of fetuses are identified as being at risk of congenital heart disease from as early as the late first trimester. In experienced hands, early fetal echocardiography can pick up a high proportion of congenital heart disease with good reliability for the majority of lesions. Early fetal echocardiography is relatively poor at assessing pulmonary veins, the atrioventricular valves and lesions that typically occur later or progress during the course of pregnancy. There is increasing interest in widespread implementation of an early obstetric anomaly screen which includes an assessment of the fetal heart for all pregnancies. There are a variety of hemodynamic differences in the late first/early second trimester compared with later in pregnancy.

CONCLUSION

Early fetal echocardiography is has become an established tool for detection of congenital heart disease. It affords opportunities to learn about the true spectrum and progression of congenital heart disease in-utero. Operators should be mindful of safety issues, technical aspects and hemodynamic findings which differ when performing echocardiograms at this stage of pregnancy.

4D fetal echocardiography-An update

With the introduction of the electronic 4-dimensional and spatial-temporal image Correlation (e-STIC), it is now possible to obtain large volume datasets of the fetal heart that are virtually free of artifact. This allows the examiner to use a number of imaging modalities when recording the volumes that include two-dimensional real time, power and color Doppler, and B-flow images. Once the volumes are obtained, manipulation of the volume dataset allows the examiner to recreate views of the fetal heart that enable examination of cardiac anatomy. The value of this technology is that a volume of the fetal heart can be obtained, irrespective of the position of the fetus in utero, and manipulated to render images for interpretation and diagnosis. This article presents a summary of the various imaging techniques and provides clinical examples of its application used for prenatal diagnosis of congenital heart defects and abnormal cardiac function.

Color and power Doppler combined with Fetal Intelligent Navigation Echocardiography (FINE) to evaluate the fetal heart

OBJECTIVE

To evaluate the performance of color and bidirectional power Doppler ultrasound combined with Fetal Intelligent Navigation Echocardiography (FINE) in examining the fetal heart.

METHODS

A prospective cohort study was conducted of fetuses in the second and third trimesters with a normal heart or with congenital heart disease (CHD). One or more spatiotemporal image correlation (STIC) volume datasets, combined with color or bidirectional power Doppler (S-flow) imaging, were acquired in the apical four-chamber view. Each successfully obtained STIC volume was evaluated by STICLoop™ to determine its appropriateness before applying the FINE method. Visualization rates for standard fetal echocardiography views using diagnostic planes and/or Virtual Intelligent Sonographer Assistance (VIS-Assistance®) were calculated for grayscale (removal of Doppler signal), color Doppler and S-flow Doppler. In four cases with CHD (one case each of tetralogy of Fallot, hypoplastic left heart and coarctation of the aorta, interrupted inferior vena cava with azygos vein continuation and asplenia, and coarctation of the aorta with tricuspid regurgitation and hydrops), the diagnostic potential of this new technology was presented.

RESULTS

A total of 169 STIC volume datasets of the normal fetal heart (color Doppler, n = 78; S-flow Doppler, n = 91) were obtained from 37 patients. Only a single STIC volume of color Doppler and/or a single volume of S-flow Doppler per patient were analyzed using FINE. Therefore, 60 STIC volumes (color Doppler, n = 27; S-flow Doppler, n = 33) comprised the final study group. Median gestational age at sonographic examination was 23 (interquartile range, 21-27.5) weeks. Color Doppler FINE generated nine fetal echocardiography views (grayscale) using (1) diagnostic planes in 73-100% of cases, (2) VIS-Assistance in 100% of cases, and (3) a combination of diagnostic planes and/or VIS-Assistance in 100% of cases. The rate of generating successfully eight fetal echocardiography views with appropriate color and S-flow Doppler information was 89-100% and 91-100% of cases, respectively, using a combination of diagnostic planes and/or VIS-Assistance. However, the success rate for the ninth echocardiography view (i.e. superior and inferior venae cavae) was 33% and 30% for color and S-flow Doppler, respectively. In all four cases of CHD, color Doppler FINE demonstrated evidence of abnormal fetal cardiac anatomy and/or hemodynamic flow.

CONCLUSIONS

The FINE method applied to STIC volumes of normal fetal hearts acquired with color or bidirectional power Doppler information can generate successfully eight to nine standard fetal echocardiography views (via grayscale, color Doppler or power Doppler) in the second and third trimesters. In cases of CHD, color Doppler FINE demonstrates successfully abnormal anatomy and/or Doppler flow characteristics. Published 2017. This article is a U.S. Government work and is in the public domain in the USA. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Prenatal screening of fetal ventriculoarterial connections: benefits of 4D technique in fetal heart imaging

Background

Identification of prenatal ventriculoarterial connections in fetuses with conotruncal anomalies (CTA) remains one of the greatest challenges for sonographers performing screening examinations. Herein, we propose a novel protocol of 4D volume analysis that identifies ventriculoarterial connections and evaluate its clinical utility in routine screenings.

Methods

Twenty-nine cases of transposition of the great arteries (TGA), 22 cases of double-outlet right ventricle (DORV), 36 cases of tetralogy of Fallot (TOF), 14 cases of truncus arteriosus (TCA), and randomly selected 70 normal fetuses were reviewed in this study. All cases were evaluated using 2D data alone (2D method), post-processing volumes with no exact algorithm (4D-1 method), or with the proposed algorithm (4D-2 method), or using the 2D and 4D data together (combined method). Comparisons were made to evaluate the detection rate of ventriculoarterial connections for these different methods.

Results

During 18–28 gestational weeks, the detection rate of 4D-2 modality was satisfactory. The detection rate of the combined method was significantly higher than 2D method in the identification of TGA, TOF, and TCA. The detection rate of 4D-1 method was significantly lower than 4D −2 modality for CTA fetuses. During late pregnancy, the detection rate for both 4D modalities was very low due to the poor quality of the 4D volumes.

Conclusions

We proposed a detailed protocol, which allowed the examiner to identify fetal ventriculoarterial connections by 4D volumes. Inclusion of blood information into the volumes improved diagnosis. Our findings suggest that the incorporation of 4D STIC into routine screenings could improve the detection for TGA, TOF, and TCA.

Electronic supplementary material

The online version of this article (doi:10.1186/s12947-017-0108-5) contains supplementary material, which is available to authorized users.

How to Acquire Cardiac Volumes for Sonographic Examination of the Fetal Heart: Part 2

The effective performance of fetal cardiac examination using spatiotemporal image correlation (STIC) technology requires 2 essential steps: volume acquisition and postprocessing. An important prerequisite is training sonologists to acquire high-quality volume data sets so that when analyzed, such volumes are informative. This article is part 2 of a series on 4-dimensional sonography with STIC. Part 1 focused on STIC technology and its features, the importance of operator training/experience and acquisition of high-quality STIC volumes, factors that affect STIC volume acquisition rates, and general recommendations on performing 4D sonography with STIC. In part 2, we discuss a detailed and practical stepwise approach for STIC volume acquisition, along with methods to determine whether such volumes are appropriate for analysis.

How to Acquire Cardiac Volumes for Sonographic Examination of the Fetal Heart: Part 1

Four-dimensional sonography with spatiotemporal image correlation (STIC) technology allows acquisition of a fetal cardiac volume data set and displays a cine loop of a complete single cardiac cycle in motion. Part 1 of this 2-part article reviews STIC technology and its features, the importance of operator training/experience, and acquisition of high-quality STIC volumes, as well as factors that affect STIC volume acquisition rates. We also propose a detailed and practical stepwise approach to performing 4-dimensional sonography with STIC and begin herein by providing general recommendations. Part 2 will discuss specifics of the approach, along with how to determine whether such volumes are appropriate for analysis.

Intelligent navigation to improve obstetrical sonography

'Manual navigation' by the operator is the standard method used to obtain information from two-dimensional and volumetric sonography. Two-dimensional sonography is highly operator dependent and requires extensive training and expertise to assess fetal anatomy properly. Most of the sonographic examination time is devoted to acquisition of images, while 'retrieval' and display of diagnostic planes occurs rapidly (essentially instantaneously). In contrast, volumetric sonography has a rapid acquisition phase, but the retrieval and display of relevant diagnostic planes is often time-consuming, tedious and challenging. We propose the term 'intelligent navigation' to refer to a new method of interrogation of a volume dataset whereby identification and selection of key anatomical landmarks allow the system to: 1) generate a geometrical reconstruction of the organ of interest; and 2) automatically navigate, find, extract and display specific diagnostic planes. This is accomplished using operator-independent algorithms that are both predictable and adaptive. Virtual Intelligent Sonographer Assistance (VIS-Assistance®) is a tool that allows operator-independent sonographic navigation and exploration of the surrounding structures in previously identified diagnostic planes. The advantage of intelligent (over manual) navigation in volumetric sonography is the short time required for both acquisition and retrieval and display of diagnostic planes. Intelligent navigation technology automatically realigns the volume, and reorients and standardizes the anatomical position, so that the fetus and the diagnostic planes are consistently displayed in the same manner each time, regardless of the fetal position or the initial orientation. Automatic labeling of anatomical structures, subject orientation and each of the diagnostic planes is also possible. Intelligent navigation technology can operate on conventional computers, and is not dependent on specific ultrasound platforms or on the use of software to perform manual navigation of volume datasets. Diagnostic planes and VIS-Assistance videoclips can be transmitted by telemedicine so that expert consultants can evaluate the images to provide an opinion. The end result is a user-friendly, simple, fast and consistent method of obtaining sonographic images with decreased operator dependency. Intelligent navigation is one approach to improve obstetrical sonography. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Are There Head Volume Alterations at 11 to 14 Weeks in Fetuses with Congenital Heart Defects? A First Trimester Case Series

Objective This study aims to assess head volume (HV) alterations at 11 to 14 weeks in fetuses with congenital heart defects (CHD). Methods A retrospective case-control study on 100 normal and 26 CHD fetuses was conducted. The fetuses had a first trimester scan with volume data sets stored from which HV was calculated. The mean HV and HV as a function of crown-rump length (CRL) in normal fetuses were compared with established normograms. Mean HV, HV as a function of CRL, and HV/CRL were compared between normal and CHD fetuses. Nonparametric Kruskal-Wallis H test was used with p < 0.05 considered significant. Results Overall, 83 normal and 19 CHD fetuses were included. The mean HV and HV as a function of CRL in the normal fetuses were comparable to what has been established (p = 0.451 and 0.801, respectively). The mean HV was statistically smaller in fetuses with CHD, particularly those with hypoplastic left heart (HLH): 10.7 mL in HLH versus 13.0 mL in normal fetuses (p = 0.043). The HV/CRL was statistically smaller in fetuses with CHD (p = 0.01). Conclusion Despite the small sample size, our case series suggests that alterations in HV may potentially be apparent as early as 11 to 14 weeks in CHD fetuses, particularly those with HLH. Larger prospective studies are needed to validate our findings.

First-trimester fetal cardiac examination using spatiotemporal image correlation, tomographic ultrasound and color Doppler imaging for the diagnosis of complex congenital heart disease in high-risk patients

OBJECTIVE

A four-dimensional (4D) fetal echocardiographic technique utilizing spatiotemporal image correlation, tomographic ultrasound imaging display (STIC-TUI echo) and color Doppler has previously been shown to be effective in displaying the examination planes constituting the extended cardiac examination. The aim of this study was to evaluate the performance of this first-trimester STIC-TUI echo technique in identifying complex congenital heart disease (CHD) in high-risk pregnancies.

METHODS

This was a prospective study of patients presenting at first-trimester screening who were at high risk for CHD owing to pregestational diabetes, in-vitro fertilization (IVF), increased nuchal translucency (NT) thickness, first-trimester tricuspid regurgitation or reversed ductus venosus (DV) a-wave, a previous child with CHD or who were on anticonvulsant medication. First-trimester STIC-TUI echo was performed, and the findings were correlated with second-trimester echocardiography and post-delivery echo findings in survivors.

RESULTS

One hundred and sixty-four fetuses from 152 patients were enrolled (77 diabetics, 38 IVF, 14 with increased NT, 23 cases of tricuspid regurgitation or reversed a-wave in the DV, 22 with prior CHD and two on anticonvulsants). STIC-TUI echo was abnormal in 20 (12%), showing atrioventricular canal defect (n = 9), hypoplastic left heart (n = 2), pulmonary stenosis (n = 2), right aortic arch (n = 1), interrupted aortic arch (n = 1), tricuspid atresia (n = 1), heterotaxy (n = 1), persistent truncus arteriosus (n = 1), double outlet right ventricle and ventricular septal defect (n = 1) and double inlet ventricle with transposition of the great arteries (n = 1). 85% of these anomalies were evident in the four-chamber view plane of the TUI display, and the remainder were diagnosed in the outflow tract planes with color Doppler imaging. In 13, CHD was isolated while seven had extracardiac anomalies. Thirteen fetuses had aneuploidy and all 13 underwent first-trimester termination of pregnancy. In the remaining seven, second-trimester echocardiography and neonatal echo/postmortem examination confirmed anomalies (two stillborn neonates, one neonatal death, four live births). Two cases of CHD missed by first-trimester STIC-TUI echo were diagnosed on second-trimester echo. Accordingly, first-trimester STIC-TUI echo had 91% sensitivity and 100% specificity for the detection of CHD.

CONCLUSIONS

First-trimester 4D echocardiography using a standardized application of STIC, TUI and color Doppler imaging is effective in displaying the imaging planes that are necessary for achieving the diagnosis of complex cardiac anomalies in high-risk patients. Optimal imaging of the four-chamber view with two-dimensional ultrasound is the major determinant of successful volume acquisition.