The role of the sagittal view of the ductal arch in identification of fetuses with conotruncal anomalies using 4-dimensional ultrasonography

2D versus 3D real time ultrasound with live xPlane imaging to visualize aortic and ductal arches: comparison between methods

Background

The diagnosis of congenital heart defects is challenging, especially for what concerns conotruncal anomalies. Indeed, although the screening techniques of fetal cardiac anomalies have greatly improved, the detection rate of conotruncal anomalies still remains low due to the fact that they are associated with a normal four-chamber view. Therefore, the study aimed to compare real-time three-dimensional echocardiography with live xPlane imaging with two-dimensional (2D) traditional imaging in visualizing ductal and aortic arches during routine echocardiography of the second trimester of gestation.

Methods

This was an observational prospective study including 114 women with uncomplicated, singleton pregnancies. All sonographic studies were performed by two different operators, of them 60 by a first level operator, while 54 by a second level operator. A subanalysis was run in order to evaluate the feasibility and the time needed for the two procedures according to fetal spine position and operator’s experience.

Results

The measurements with 2D ultrasound were performed in all 114 echocardiographies, while live xPlane imaging was feasible in the 78% of the cases, and this was mainly due to fetal position. The time lapse needed to visualize aortic and ductal arches was significantly lower when using 2D ultrasound compared to live xPlane imaging (29.56 ± 28.5 s vs. 42.5 ± 38.1 s, P = 0.006 for aortic arch; 22.14 ± 17.8 s vs. 37.1 ± 33.8 s, P = 0.001 for ductal arch), also when performing a subanalysis according to operators’ experience (P < 0.05 for all comparisons). Feasibility of live xPlane proved to be correlated with the position of the fetal spine and the operator’s experience.

Discussion

To find a reproducible and standardized method to detect fetal heart defects may bring a great benefit for both patients and operators. In this scenario live xPlane imaging is a novel method to visualize ductal and aortic arches. We found that the position of the fetal spine may affect the feasibility of the method since, when the fetal back is anterior or transverse, the visualization of the correct view of three-vessels and trachea in order to set the reference line properly becomes more challenging. In addition, the fetal spine position influences the duration of the ultrasound examination. Regarding operator’s skills and experience, in our study a first level operator was able to perform the complete 2D and xPlane examination in a lower number of cases compared to second level operators. In addition, the time required for the complete examination was higher for first level operators. This means that this technique is based on an adequate operators’ expertise.

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.

Is the "I-Sign" in the 3-Vessel and Trachea View a Valid Tool for Prenatal Diagnosis of D-Transposition of the Great Arteries?

Prenatal diagnosis of D-transposition of the great arteries remains less frequent compared to other major congenital heart defects. In this study, we examined how often the 3-vessel and trachea view was abnormal in a large series of prenatally diagnosed cases of D-transposition of the great arteries. We found that an abnormal 3-vessel and trachea view in the shape of an "I" ("I-sign"), which represents an anteriorly displaced aorta, was present in all fetuses with D-transposition of the great arteries when a 3-vessel and trachea view was successfully obtained. Therefore we believe that the 3-vessel and trachea view can be used to reliably detect D-transposition of the great arteries during prenatal sonography.

Comparison of fetal cardiac spatiotemporal image correlation segmental analysis between cardiac- and body-based scrolling

OBJECTIVES

The purpose of this study was to compare success rates for depiction of the 5 typical transverse planes in the fetal upper thorax between cardiac- and body-based scrolling techniques.

METHODS

Spatiotemporal image correlation volume data sets acquired at the 4-chamber view level were obtained from low-risk singleton pregnancies with healthy fetuses. Each data set was analyzed by the authors using both cardiac- and body-based techniques. With the cardiac-based technique, the exact 4-chamber view was first identified as an initial plane before scrolling, whereas with the body-based technique, a volume data set was first manipulated to get the fetal orientation in the exact dorsal supine position as an initial plane. In both techniques, the volumes were then scrolled through the upper thorax to identify the standard planes, including the 4-chamber, 5-chamber, 3-vessel, 3-vessel and trachea, and aortic arch views.

RESULTS

An analysis of 50 volume data sets to evaluate intraobserver and interobserver variability in the success rates for the 4-chamber, 5-chamber, 3-vessel, 3-vessel and trachea, and aortic arch views showed good agreement. In an analysis of 296 separate data sets, cardiac-based scrolling was associated with significantly higher success rates than body-based scrolling in all standard planes (P < .05).

CONCLUSIONS

Cardiac-based scrolling resulted in higher success rates for obtaining the standard spatiotemporal image correlation planes than body-based scrolling. Therefore, examiners in the early part of the learning curve should be encouraged to first identify a perfect 4-chamber view at the start of an examination.

Detection of the fetal conotruncal anomalies using real-time three-dimensional echocardiography with live xPlane imaging of the fetal ductal arch view

OBJECTIVE

To evaluate the role of live xPlane imaging of ductal arch view in detection of fetal conotruncal anomalies.

METHODS

Two hundred selected singleton pregnancies, including 152 normal cases, 27 conotruncal anomalies and 21 other types of fetal heart abnormalities were enrolled in this observational study. All the cases were scanned to visualize the ductal arch view with live xPlane imaging by a single observer. The detection rate of conotruncal and non-conotruncal anomalies with live xPlane imaging was compared.

RESULTS

In using this new method of live xPlane imaging, an abnormal ductal arch view was visualized in 92.6% of fetal conotruncal anomalies, compared with that of non-conotruncal anomalies (23.8%, p < 0.001).

CONCLUSION

The ductal arch view can be obtained by live xPlane imaging. This method is relatively simple and feasible, hence may be a useful tool to detect fetal conotruncal anomalies.

A novel way of visualizing the ductal and aortic arches by real-time three-dimensional ultrasound with live xPlane imaging

OBJECTIVE

To describe a novel method of visualizing the ductal and aortic arches by real-time three-dimensional echocardiography with live xPlane imaging.

METHODS

Live xPlane imaging was used to display the ductal- and aortic-arch views in 107 women with singleton pregnancies, including seven cases with suspected congenital heart defects (CHDs). The three vessels and trachea (3VT) view was obtained in such an orientation that either the pulmonary artery or the aorta was parallel to the direction of the ultrasound beam. The xPlane reference line was then placed across the targeted vessel, which in a normal case would provide an image of the corresponding arch view as a dual-image display.

RESULTS

Once the 3VT view had been obtained, live xPlane imaging showed the aortic and ductal arches in all 100 normal cases. In seven cases with suspected CHD, the 3VT view was abnormal in five cases and normal in the other two. However, the ductal-arch view demonstrated by live xPlane imaging was abnormal in five cases of conotruncal anomalies and normal in two cases in which conotruncal anomalies were excluded. CHDs were confirmed at autopsy following termination of pregnancy in five cases and on postnatal echocardiography in one case. The heart was found postnatally to be normal in one case of suspected CHD; in this case live xPlane imaging showed that the observed abnormal 3VT view was caused by a tortuous course of the thoracic aorta associated with an abnormal diaphragm.

CONCLUSION

Live xPlane imaging is a novel and relatively simple method of visualizing the ductal- and aortic-arch views, and may potentially be a useful tool in the screening of fetal conotruncal and aortic-arch anomalies.

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

PURPOSE OF REVIEW

Four-dimensional fetal echocardiography has the potential to reduce the operator dependency of two-dimensional ultrasonography and increase the detection rate of congenital heart defects (CHDs). This review is intended to summarize recent evidence of the important role that four-dimensional ultrasonography with spatio-temporal image correlation (STIC) may play in the prenatal diagnosis of CHDs.

RECENT FINDINGS

Four-dimensional ultrasonography with STIC may provide the opportunity for telemedicine in the prenatal diagnosis of CHDs because four-dimensional volume datasets can be remotely acquired and accurately interpreted by different centers. Four-dimensional ultrasonography with STIC is an accurate and reproducible technique for the prenatal diagnosis of CHDs. Different four-dimensional rendering techniques can provide important insight into the spatial relationships of normal and abnormal fetal vascular structures.

SUMMARY

Four-dimensional fetal echocardiography with STIC may facilitate the examination of the fetal heart and could potentially increase the detection rate of CHDs.

Collaborative study on 4-dimensional echocardiography for the diagnosis of fetal heart defects: the COFEHD study

OBJECTIVE

Congenital anomalies are the leading cause of infant mortality in the United States, and congenital heart defects (CHDs) are the most common type of birth defects. Recently, 4-dimensional ultrasonography (4DUS) with spatiotemporal image correlation (STIC) has been introduced for fetal echocardiography. Accumulating evidence indicates that 4DUS with STIC may facilitate the examination of the fetal heart. Our objectives were to determine the accuracy of 4DUS for the diagnosis of CHDs and the agreement among centers.

METHODS

This study included 7 centers with expertise in 4D fetal echocardiography. Fetuses with and without confirmed heart defects were scanned between 18 and 26 weeks, and their volume data sets were uploaded onto a centralized file transfer protocol server. Intercenter agreement was determined using a κ statistic for multiple raters.

RESULTS

Ninety volume data sets were randomly selected for blinded analysis. Overall, the median (range) sensitivity, specificity, positive and negative predictive values, and false-positive and -negative rates for the identification of fetuses with CHDs were 93% (77%-100%), 96% (84%-100%), 96% (83%-100%), 93% (79%-100%), 4.8% (2.7%-25%), and 6.8% (5%-22%), respectively. The most frequent CHDs were conotruncal anomalies (36%). There was excellent intercenter agreement (κ = 0.97).

CONCLUSIONS

(1) Four-dimensional volume data sets can be remotely acquired and accurately interpreted by different centers. (2) Among centers with technical expertise, 4DUS is an accurate and reliable method for fetal echocardiography.

Eleven fetal echocardiographic planes using 4-dimensional ultrasound with spatio-temporal image correlation (STIC): a logical approach to fetal heart volume analysis

BACKGROUND

Theoretically, a cross-sectional image of any cardiac planes can be obtained from a STIC fetal heart volume dataset. We described a method to display 11 fetal echocardiographic planes from STIC volumes.

METHODS

Fetal heart volume datasets were acquired by transverse acquisition from 200 normal fetuses at 15 to 40 weeks of gestation. Analysis of the volume datasets using the described technique to display 11 echocardiographic planes in the multiplanar display mode were performed offline.

RESULTS

Volume datasets from 18 fetuses were excluded due to poor image resolution. The mean visualization rates for all echocardiographic planes at 15-17, 18-22, 23-27, 28-32 and 33-40 weeks of gestation fetuses were 85.6% (range 45.2-96.8%, N = 31), 92.9% (range 64.0-100%, N = 64), 93.4% (range 51.4-100%, N = 37), 88.7%(range 54.5-100%, N = 33) and 81.8% (range 23.5-100%, N = 17) respectively.

CONCLUSIONS

Overall, the applied technique can favorably display the pertinent echocardiographic planes. Description of the presented method provides a logical approach to explore the fetal heart volumes.

Satisfactory visualization rates of standard cardiac views at 18 to 22 weeks' gestation using spatiotemporal image correlation

OBJECTIVE

The purpose of this study was to determine the frequency with which 3 standard screening views of the fetal heart (4-chamber, left ventricular outflow tract [LVOT], and right ventricular outflow tract [RVOT]) can be obtained satisfactorily with the spatiotemporal image correlation (STIC) technique.

METHODS

A prospective study of 111 patients undergoing anatomic surveys at 18 to 22 weeks was performed. Two ultrasound machines with fetal cardiac settings were used. The best volume set that could be obtained from each patient during a 45-minute examination was graded by 2 sonologists with regard to whether the 4-chamber, LVOT, and RVOT images were satisfactory for screening.

RESULTS

All 3 views were judged satisfactory for screening in most patients: 1 sonologist graded the views as satisfactory in 70% of the patients, whereas the other found the views to be satisfactory in 83%. The position of the placenta did not alter the probability of achieving a satisfactory view, but a fetus in the spine anterior position was associated with a significantly lower probability that the views were regarded as satisfactory for screening (odds ratio, 0.28; 95% confidence interval, 0.09-0.70; P < .05).

CONCLUSIONS

This study suggests that STIC may assist with screening for cardiac anomalies at 18 to 22 weeks' gestation.

Screening for fetal abnormalities with ultrasound

PURPOSE OF REVIEW

This review serves to explore literature published during the past year that has focussed on sonographic screening for fetal abnormalities.

RECENT FINDINGS

The evolving nature of screening for fetal aneuploidy has continued to feature strongly in recent literature. There is growing interest in early detailed ultrasound of fetal anatomy at the time of nuchal translucency thickness assessment. Demonstration of tricuspid regurgitation and ductus venosus assessment have been shown to be beneficial additional second-line tests for aneuploidy screening in high-risk patients. Frontomaxillary facial angle assessment has been explored as a new marker for aneuploidy. The limitations of first-trimester nasal bone measurement were reiterated while its measurement has been shown to be beneficial in the second trimester, especially when calculated with multiples of the median. As regards second-trimester screening, studies have explored the effectiveness of congenital heart-defect screening and the efficiency of the genetic sonogram for trisomy 21. The role of nuchal translucency discordance in monochorionic twins has also been readdressed.

SUMMARY

Screening for fetal abnormalities continues to evolve with the introduction of novel techniques and the further refinement of previously proposed screening tools. How these modalities are implemented into routine clinical practice remains to be seen.

A review of findings in fetal cardiac section drawings: part 4: sagittal and parasagittal views

OBJECTIVE

The goal of this presentation is to review some of the common and rare fetal heart abnormalities and to provide an easy approach to these findings with schematic drawings. In this presentation, we limit the scope to the sagittal and parasagittal sections.

METHODS

Over the past 10 years, we collected cases in which the common views of the heart were abnormal and the differential diagnoses that existed for each. This presentation shows the normal sonographic sections and then variations of these sections and the associated anomalies. We used illustrative drawings to present these findings, enabling us to point out the main sonographic features of abnormalities of the heart.

RESULTS

The work reviews 7 fetal heart abnormalities in schematic drawings.

CONCLUSIONS

This short review highlights several of the anomalies that can be recognized on the common sonographic views. The drawings tend to simplify the findings but should serve as a basis for those doing fetal echocardiography when they encounter an unusual finding.

Application of automated sonography on 4-dimensional volumes of fetuses with transposition of the great arteries

OBJECTIVE

The purpose of this study was to assess, in second-trimester fetuses with transposition of the great arteries (TGA), the performance of software (sonographically based volume computer-aided analysis) that automatically retrieves diagnostic cardiac planes from a 4-dimensional volume of the fetal chest obtained with spatiotemporal image correlation.

METHODS

We retrospectively evaluated the 4-dimensional spatiotemporal image correlation volumes of 12 fetuses with TGA (complete TGA, 10 cases; correct TGA, 2 cases). The data were analyzed to determine whether the target diagnostic planes, that is, cardiac plane 1 (left ventricle outflow tract) and cardiac plane 2 (right ventricle outflow tract), were correctly identified in at least 1 of the 7 automatically generated tomographic sonographic image displays and whether they allowed diagnosis of TGA.

RESULTS

In 9 of 10 fetuses with complete TGA, target diagnostic cardiac plane 1 showed a branching arterial vessel (pulmonary artery) arising from the left ventricle, whereas in 7 of 10 fetuses, the aorta arising from the right ventricle was shown. In both cases with correct TGA, the pulmonary artery starting from the morphologic left ventricle was shown, whereas in 1 of 2, the connection of the aorta with the morphologic right ventricle was found. In all of the fetuses with TGA, a ventricular arterial connection anomaly was shown in either cardiac plane 1 or 2.

CONCLUSIONS

This automatic approach shows good retrieval of diagnostic cardiac planes in fetuses with TGA, which may improve diagnostic efficacy for this disease.