Prenatal diagnosis of coarctation of the aorta with the multiplanar display and B-flow imaging using 4-dimensional sonography

Prenatal Sonographic Predictors of Neonatal Coarctation of the Aorta

OBJECTIVES

To identify practical prenatal sonographic markers for the postnatal diagnosis of coarctation of the aorta.

METHODS

We reviewed the fetal echocardiograms and postnatal outcomes of fetal cases of suspected coarctation of the aorta seen at a single institution between 2010 and 2014. True- and false-positive cases were compared. Logistic regression analysis was used to determine echocardiographic predictors of coarctation of the aorta. Optimal cutoffs for these markers and a multivariable threshold scoring system were derived to discriminate fetuses with coarctation of the aorta from those without coarctation of the aorta.

RESULTS

Among 35 patients with prenatal suspicion of coarctation of the aorta, the diagnosis was confirmed postnatally in 9 neonates (25.7% true-positive rate). Significant predictors identified from multivariate analysis were as follows: Z score for the ascending aorta diameter of -2 or less (P = < .001), Z score for the mitral valve annulus of -2 or less (P= .033), Zscore for the transverse aortic arch diameter of -2 or less (P= .028), and abnormal aortic valve morphologic features (P= .026). Among all variables studied, the ascending aortic Z score had the highest sensitivity (78%) and specificity (92%) for detection of coarctation of the aorta. A multivariable threshold scoring system identified fetuses with coarctation of the aorta with still greater sensitivity (89%) and only mildly decreased specificity (88%).

CONCLUSIONS

The finding of a diminutive ascending aorta represents a powerful and practical prenatal predictor of neonatal coarctation of the aorta. A multivariable scoring system, including dimensions of the ascending and transverse aortas, mitral valve annulus, and morphologic features of the aortic valve, provides excellent sensitivity and specificity. The use of these practical sonographic markers may improve prenatal detection of coarctation of the aorta.

Importance of Relationship between Ductus and Isthmus in Fetal Diagnosis of Coarctation of Aorta

BACKGROUND

The prenatal diagnosis of coarctation of aorta (CoA) can prove problematic, with relatively high false-positive and false-negative rates. This significantly impacts both prenatal counseling and postnatal management. We sought to evaluate a variety of prenatal echo indices to determine which would best predict neonatal CoA.

METHODS

Fetal echocardiograms of those with prenatal diagnosis of COA were analyzed for the following: diameter of cardiac valves, ascending aorta, distal transverse arch, aortic isthmus, and ductus; right (RV) and left ventricular (LV) length and end-diastolic area and isthmus-ductal angle (IDA). Ratios of RV: LV area, aortic: pulmonary valve diameter, mitral: tricuspid valve ratio (MV:TV ratio), and isthmus: ductal diameter (IDD) were calculated. These measures were compared between those with CoA after birth (CoA group) and those without (no CoA group).

RESULTS

Of the 62 subjects, 27 were in CoA and 35 in no CoA group. CoA group had a significantly smaller mitral valve, MV:TV ratio, IDD, and IDA compared to no CoA group. The ROC curves for each of these significant measures showed that mitral valve, IDD, and IDA had an AUC of 0.72, 0.80, and 0.83, respectively. Multiple variable model using at least two of these measures had 85% sensitivity and 60% specificity.

CONCLUSIONS

A smaller mitral valve, MV:TV ratio, IDD, and IDA are associated with development of neonatal coarctation. In cases with suspected prenatal diagnosis of CoA, careful evaluation of the relation between the isthmus and the ductus arteriosus using IDD and IDA may enhance the diagnostic accuracy of fetal echocardiograms.

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.

Difficult prenatal diagnosis: fetal coarctation

The prenatal diagnosis of fetal coarctation is still challenging. It is mainly suspected by ventricular disproportion (smaller left ventricle than right ventricle). The sensitivity of ventricular discrepancy is however moderate for the diagnosis of coarctation and there is a high false positive rate. Prenatal diagnosis of coarctation is important because the delivery can be arranged in a centre with a pediatric cardiac intensive careand this reduces postnatal complications and longterm morbidity. For many years the prenatal diagnosis of coarctation has been investigated to improve specificity and sensitivity by several of measurements. This article reviews all relevant articles from 2000 until 2011 searching pubmed and the reference list of interesting articles. An overview of specific measurements and techniques that can improve the diagnosis of coarctation has been made, such as the isthmus diameter, ductal diameter, isthmus/ductal ratio, z-scores derived from measurements of the distal aortic isthmus and arterial duct, the presence of a shelf andisthmal flow disturbance. Also 3-dimensional (3D) and 4-dimensional (4D) imaging with or without STIC has been -suggested to be used as newer techniques to improve diagnosis of coarctation in fetal life. Although more methods regarding prenatal diagnosis of coarctationare being investigated, the ultrasound specialist remains challenged to correctly diagnose this cardiac anomaly in prenatal life.

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.