Contemporary clinical applications of spatio-temporal image correlation in prenatal diagnosis

Application of Semiautomatic Fetal Intelligent Navigation Echocardiography (FINE) in Twin Pregnancies: Half the Work or Twice the Effort?

OBJECTIVE

To assess the performance of fetal intelligent navigation echocardiography (FINE, 5D Heart™) for automated volumetric investigation of the fetal heart in twin pregnancies.

METHODS

Three hundred twenty-eight twin fetuses underwent fetal echocardiography in the second and third trimesters. Spatiotemporal image correlation (STIC) volumes were obtained for a volumetric investigation. The volumes were analyzed using the FINE software, and the data were investigated regarding image quality and many properly reconstructed planes.

RESULTS

Three hundred and eight volumes underwent final analysis. 55.8% of the included pregnancies were dichorionic twin pregnancies, and 44.2% were monochorionic twin pregnancies. The mean gestational age (GA) was 22.1 weeks, and the mean maternal BMI was 27.3 kg/m². The STIC-volume acquisition was successful in 100.0% and 95.5% of cases. The overall depiction rates of FINE were 96.5% (twin 1) and 94.7% (twin 2), respectively (p = 0.0849, not significant). In 95.9% (twin 1) and 93.9% (twin 2), at least 7 planes were reconstructed properly (p = 0.6056, not significant).

CONCLUSION

Our results indicate that the FINE technique used in twin pregnancies is reliable. No significant difference between the depiction rates of twin 1 and twin 2 could be detected. In addition, the depiction rates are as high as those derived from singleton pregnancies. Due to the challenges of fetal echocardiography in twin pregnancies (i.e., greater rates of cardiac anomaly and more difficult scans), the FINE technique might be a valuable tool to improve the quality of medical care in those pregnancies.

Maximal Reduction of STIC Acquisition Time for Volumetric Assessment of the Fetal Heart—Benefits and Limitations of Semiautomatic Fetal Intelligent Navigation Echocardiography (FINE) Static Mode

(1) Objective: To scrutinize the reliability and the clinical value of routinely used fetal intelligent navigation echocardiography (FINE) static mode (5DHeartStatic™) for accelerated semiautomatic volumetric assessment of the normal fetal heart. (2) Methods: In this study, a total of 296 second and third trimester fetuses were examined by targeted ultrasound. Spatiotemporal image correlation (STIC) volumes of the fetal heart were acquired for further volumetric assessment. In addition, all fetal hearts were scanned by a fast acquisition time volume (1 s). The volumes were analyzed using the FINE software. The data were investigated regarding the number of properly reconstructed planes and cardiac axis. (3) Results: A total of 257 volumes were included for final analysis. The mean gestational age (GA) was 23.9 weeks (14.3 to 37.7 weeks). In 96.9 (standard acquisition time, FINE standard mode) and 94.2% (fast acquisition time, FINE static mode) at least seven planes were reconstructed properly (p = 0.0961, not significant). Regarding the overall depiction rate, the standard mode was able to reconstruct 96.9% of the planes properly, whereas the static mode showed 95.2% of the planes (p = 0.0098). Moreover, there was no significant difference between the automatic measurement of the cardiac axis (37.95 + 9.14 vs. 38.00 + 8.92 degrees, p = 0.8827, not significant). (4) Conclusions: Based on our results, the FINE static mode technique is a reliable method. It provides similar information of the cardiac anatomy compared to conventional STIC volumes assessed by the FINE method. The FINE static mode has the potential to minimize the influence of motion artifacts during volume acquisition and might therefore be helpful concerning volumetric cardiac assessment in daily routine.

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.

A "holistic" sonographic view on congenital heart disease: How automatic reconstruction using fetal intelligent navigation echocardiography eases unveiling of abnormal cardiac anatomy part II-Left heart anomalies

Volume ultrasound has been shown to provide valid complementary information on fetal anatomy. Four-dimensional assessment (4D) of the fetal cardiovascular system using spatial-temporal image correlation (STIC) allows for detailed examination of a highly complex organ from the early second trimester onward. There is compelling evidence that this technique harbors quite a number of diagnostic opportunities, but manual navigation through STIC volume datasets is highly operator dependent. In fact, STIC is not incorporated yet into daily practice. Application of the novel fetal intelligent navigation echocardiography (FINE) considerably simplifies fetal cardiac volumetric examinations. This automatic technique applied on cardiac volume datasets reportedly has both high sensitivity and specificity for the detection of congenital heart defects (CHDs). Part I reviewed current data regarding detection rates of CHDs and illustrated the additional value of an automatic approach in delineating cardiac anatomy exemplified by congenital lesions of the right heart. In part II of this pictorial essay, we focused on left heart anomalies and aimed to tabulate recent findings on the quantification of normal and abnormal cardiac anatomy.

Fetal Intelligent Navigation Echocardiography (FINE) Detects 98% of Congenital Heart Disease

OBJECTIVE

Fetal intelligent navigation echocardiography (FINE) is a novel method that automatically generates and displays 9 standard fetal echocardiographic views in normal hearts by applying intelligent navigation technology to spatiotemporal image correlation (STIC) volume data sets. The main objective was to determine the sensitivity and specificity of FINE in the prenatal detection of congenital heart disease (CHD).

METHODS

A case-control study was conducted in 50 fetuses with a broad spectrum of CHD (cases) and 100 fetuses with normal hearts (controls) in the second and third trimesters. Using 4-dimensional ultrasound with STIC technology, volume data sets were acquired. After all identifying information was removed, the data sets were randomly distributed to a different investigator for analysis using FINE. The sensitivity and specificity for the prenatal detection of CHD, as well as positive and negative likelihood ratios were determined.

RESULTS

The diagnostic performance of FINE for the prenatal detection of CHD was: sensitivity of 98% (49 of 50), specificity of 93% (93 of 100), positive likelihood ratio of 14, and negative likelihood ratio of 0.02. Among cases with confirmed CHD, the diagnosis with use of FINE completely matched the final diagnosis in 74% (37 of 50); minor discrepancies were seen in 12% (6 of 50), and major discrepancies were seen in 14% (7 of 50).

CONCLUSIONS

This is the first time the sensitivity and specificity of the FINE method in fetuses with normal hearts and CHD in the second and third trimesters has been reported. Because FINE identifies a broad spectrum of CHD with 98% sensitivity, this method could be used prenatally to screen for and diagnose CHD.

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.

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.

Prenatal Diagnosis of Fetal Interrupted Aortic Arch Type A by Two-Dimensional Echocardiography and Four-Dimensional Echocardiography with B-Flow Imaging and Spatiotemporal Image Correlation

BACKGROUND

Fetal interrupted aortic arch (IAA) is a rare cardiac anomaly and its prenatal diagnosis is challenging. The purpose of our report is to evaluate the use of two-dimensional echocardiography (2DE) and 4D echocardiography with B-flow imaging and spatiotemporal image correlation (4D BF-STIC) in detecting IAA type A (IAA-A).

MATERIALS & METHODS

Twenty-three cases of confirmed IAA-A identified by fetal echocardiography were involved in the study. The fetal echocardiography image data were reviewed to analyze the ratio of right ventricle to left ventricle (RV/LV) diameter, the ratio of main pulmonary artery to ascending aorta (MPA/AAO) diameter, and the correlation of RV/LV diameter ratio and size of ventricular septal defect (VSD). 4D BF-STIC was performed in 21 fetuses using the sagittal view (4D BF-STIC-sagittal) and the four-chamber view (4D BF-STIC-4CV) as initial planes of view. An additional 183 normal fetuses were also included in our study. RV/LV and MPA/AAO ratios were calculated and compared with that of IAA-A fetuses. Fetal 2DE, 4D BF-STIC-sagittal, and 4D BF-STIC-4CV were used to visualize the aortic arch and its associated neck vessels. Six subgroups were evaluated according to gestational age.

RESULTS

Fetal 2DE, 4D BF-STIC-sagittal, and 4D BF-STIC-4CV made the correct prenatal diagnosis of IAA-A in 19/23 (82.6%), 14/21 (66.7%), and 19/21 (90.5%) of patients, respectively. A significantly enlarged MPA combined with symmetric ventricles was found in the IAA-A fetuses, while the size of the VSD was negatively correlated with RV/LV ratio. 4D BF-STIC-sagittal and 4D BF-STIC-4CV were better than traditional 2D ultrasound in detecting the aortic arch and neck vessels between 17 and 28 gestational weeks and 29 to 40 gestational weeks in normal fetuses.

CONCLUSION

It is demonstrated that IAA-A could be diagnosed by traditional fetal echocardiography, while 4D technique could better display the anatomic structure and the spatial relationships of the great arteries. Use of volume reconstruction may promote its clinical usage and help prenatal diagnosis.

The value of 3D and 4D assessments of the fetal heart

The objective of this review was to demonstrate the main tools of three- and four-dimensional ultrasonography, using the spatiotemporal image correlation software and its respective applications for assessing the fetal heart and its vascular connections, along with its potential contribution towards screening for congenital heart diseases. Today, conventional, two-dimensional, echocardiography continues to be the gold standard for diagnosing congenital heart diseases. However, recent studies have demonstrated that spatiotemporal image correlation offers some advantages that boost two-dimensional accuracy in detecting congenital heart diseases, given that the fetal heart assessment can be completed in the absence of the patient (offline) and be discussed by different examiners. Additionally, data volumes can be sent for analysis in reference centers via internet links. Spatiotemporal image correlation also enables direct measurement of heart structures in rendering mode, such as the interventricular septum and the annulus of the atrioventricular valves. Furthermore, it enables assessment of cardiac function when used in association with the virtual organ computer-aided analysis software, thus making it possible to calculate the total systolic function, ejection fraction, and cardiac output.

Differential insertion of the atrioventricular valves: measurement protocol to detect various congenital heart defects

OBJECTIVES

The objectives of this study were to develop reference values for the distance between the atrioventricular valves, called differential insertion of the atrioventricular valves (DIAVV), in normal fetuses using four-dimensional ultrasound with spatio-temporal image correlation and to explore if DIAVV measurement can differentiate between normal hearts and hearts with cardiac defects.

METHODS

The DIAVV was analysed longitudinally following a measurement protocol in 74 fetuses between 15 and 36 weeks gestational age. The DIAVV was measured in an apical four-chamber view of the heart in end-diastole. Furthermore, the DIAVV was measured in 70 fetuses with cardiac defects.

RESULTS

In total, 337 normal and 70 abnormal spatio-temporal image correlation volumes were examined. Longitudinal regression analysis revealed a positive relationship of the DIAVV with gestational age and fetal biometry (p < 0.0001). The DIAVV of fetuses with double outlet right ventricle, truncus arteriosus, atrioventricular septal defects, Ebstein and tetralogy of Fallot all differed from normal fetuses (p < 0.05).

CONCLUSION

Measurement of the DIAVV is a promising tool; however, a well-defined measurement protocol should be followed to accomplish the correct plane and exact moment in the cardiac cycle. This study presents new nomograms following this measurement protocol and reports an abnormal DIAVV in a wide spectrum of congenital heart disease.

[Contribution of volume ultrasound in the evaluation and prenatal care of fetal cardiovascular anomalies]

OBJECTIVES

To highlight the value of 3D ultrasound in the prenatal assessment of fetal cardiovascular abnormalities.

PATIENTS AND METHODS

A retrospective offline analysis of volume datasets of fetuses diagnosed with cardiovascular anomalies by 2D ultrasound was performed.

RESULTS

Thirty-four fetuses with 38 cardiac malformations were evaluated. Mean gestational age at diagnosis was 26 weeks. Isolated cardiovascular malformations were detected in 23 fetuses. Extracardiac abnormalities were identified in eight fetuses. Ten terminations of pregnancy were performed.

CONCLUSION

Offline analysis of cardiovascular anomalies conferred significant diagnostic advantages over 2D ultrasound. 3D ultrasound is a valuable tool for the prenatal diagnosis and the management of congenital heart diseases.

A fetal telecardiology service: patient preference and socio-economic factors

OBJECTIVE

The aims of this study were to evaluate patients' opinions on a fetal cardiology telemedicine service compared with usual outpatient care, the effect of the telemedicine consultation on maternal anxiety and its impact on travel times and time absent from work.

METHODS

Prospective study over 20 months. Eligible patients attended for routine anomaly scan followed by fetal echocardiogram transmitted to the regional centre with live guidance by a fetal cardiologist, followed by parental counselling. All patients were offered a fetal cardiology appointment at the regional centre. Structured questionnaires assessing maternal satisfaction, travel times/days off and anxiety scores completed at time of both fetal echocardiograms.

RESULTS

Sixty-seven patients were recruited and 66 completed the study. Participants expressed very high satisfaction rates with fetal telecardiology, equivalent to face-to-face consultation. The telecardiology appointments were associated with significantly reduced travel times and days off work (p < 0.01). Expectant mothers expressed a clear inclination for a fetal cardiology appointment at the local hospital facilitated by telemedicine (p < 0.01).

CONCLUSIONS

Fetal telecardiology is highly acceptable to patients and is even preferred compared with travelling to a regional centre. There are additional socio-economic benefits that should encourage the development of remote fetal cardiology services.