Recent research

OBJECTIVE: To report our experience with magnetic resonance imaging (MRI) in fetal heart evaluation.

METHOD: Two radiologists examined 31 MRI of fetuses with no ultrasound (US) evidence of cardio-thoracic anomalies. T2-weighted half-Fourier single-shot turbo spin-echo sequences were acquired for anatomic evaluation; fast imaging with steady-state free precession (TrueFISP) and cine-MR sequences with real-time steady-state free precession oriented like standard fetal echocardiographic projections were acquired for the characterization of cardiovascular morphology and function.

RESULTS: In every case, MRI assessed the viscero-atrial situs. The four-chamber view and the short-axis view of the left ventricle were obtained in all fetuses, the long-axis view of the aortic arch in 28, the long-axis view of the ductus arteriosus in 17, the five-chamber view in 12, the long-axis of the left ventricle in 9, the three-vessel view in 7, the tricuspid-aortic view in 3, and the transverse view of the aortic arch and the angulated view of the arch and the ductus arteriosus simultaneously in 2 fetuses.

CONCLUSION: Our preliminary experience demonstrates the feasibility to visualize the fetal heart with routine fetal MRI protocols in particular, by means of acquisition of TrueFISP imaging (morphological study) and real-time cine-MRI (dynamic study), potentially making MRI a second-level tool to add to fetal echocardiography in the prenatal study of congenital cardiac malformations.

OBJECTIVE: The purpose of the study was to evaluate coping and psychological functioning of parents of children prenatally or postnatally diagnosed with congenital heart disease.

STUDY DESIGN: Parents of 10 infants prenatally diagnosed by fetal echocardiogram and 7 infants postnatally diagnosed with severe congenital heart disease completed the Brief Symptom Inventory (BSI) at the time of diagnosis, at the time of birth and 6 months after birth. Prenatal and postnatal groups were compared to each other and to BSI norms.

RESULT: Although both groups scored higher than test norms at the time of diagnosis, they did not differ significantly from each other. Six months after birth, the postnatal group scores did not differ from test norms, but the prenatal group scores were still significantly higher than test norms. The severity of the child's heart lesion at diagnosis was related to parental distress levels; parents with children with more severe lesions had higher BSI scores.

CONCLUSION: Results suggest the need to provide parents with psychological support, regardless of the timing of diagnosis. Parents of children with more severe lesions may be at risk for higher levels of psychological distress, particularly over time.

OBJECTIVE: To investigate the congenital heart disease (CHD) found in association with an increased nuchal translucency (NT) at 11-14 weeks of gestation in chromosomally normal and abnormal fetuses.

METHODS: Patients referred from January 1998 until May 2007 with an increased NT (> or = 95th percentile) where CHD was diagnosed were included. Chromosome analysis, fetal and postnatal echocardiography were performed. A postmortem examination followed pregnancy termination when possible.

RESULTS: Major CHD was identified in 68 of 967 fetuses with an increased NT (median NT 4.8 mm, range 2.5-22 mm).Major CHD was found in 34 of 693 fetuses (4.9%) with a normal karyotype and increased NT (median 5.2 mm, range 2.5-9.6 mm). CHD frequency increased from 1.9%, with NT between 2.5 and 3.5 mm, to 27.7% when NT was > or = 6.5 mm. Septal defects predominated (20%) when NT was < or = 3.5 mm. With NT > 3.5 mm an equal distribution of CHD types was seen.Major CHD was identified in 34 of the 274 fetuses with an abnormal karyotype and increased NT (median 4.2 mm, range 2.5-22 mm).

CONCLUSIONS: A variety of CHD is associated with an increased NT in the first trimester of pregnancy. Conotruncal defects, branchial arch derivative defects, left and right obstructive lesions (inflow and outflow) and shunts were seen.

OBJECTIVE: To assess the performance of nuchal translucency (NT) measurement in the first trimester of pregnancy as a marker for congenital heart defects (CHD) in the fetus in a low-risk obstetric population.

METHODS: Nuchal translucency screening was offered over a 3-year period to consecutive pregnant women without known a priori risk factors and attending midwife practices in three different areas in the Netherlands. In chromosomally normal fetuses and infants from the study population the NT measurements were matched with CHD detected either prenatally or postnatally.

RESULTS: NT screening was offered to 6132 women with an uptake of 83%. A total of 4876 NT measurements was performed. Pregnancy outcome data were available in 4181 cases (86%). Defects of the heart and great arteries (CHD) were diagnosed in 24 cases (prevalence 5.8/1000). Thirteen of these were classified as major (prevalence 3.1/1000). Two major CHD occurred in fetuses showing an increased NT at the first-trimester scan. The sensitivity of NT measurement > 95th and > 99th percentile for all CHD and for major CHD, was 8% and 15%, respectively. The positive likelihood ratios of NT > 95(th) and > 99th percentile for major CHD were 6, 5 and 33, respectively.

CONCLUSION: In pregnancies without known risk factors also, an increased NT is associated with major cardiac defects in the fetus and therefore represents an indication for specialized fetal echocardiography. However, this association is too weak to envisage a role for NT measurement as single screening strategy for the prenatal detection of cardiac defects.

The aim was to compare the right ventricular (RV) Tei index obtained by the tissue Doppler imaging (TDI) method with that obtained by the pulsed Doppler method in 29 fetuses aged 24-39 weeks (29.9 +/- 4.0 weeks). From pulsed Doppler recordings, the tricuspid closing-to-opening time (a) and RV ejection time (b) were measured. The Tei index determined by the pulsed Doppler method was calculated as (a - b)/b. From TDI recordings, the time interval during diastole (a') and the duration of the systole S-wave (b') were measured. The modified Tei index obtained by TDI was calculated as (a' - b')/b'. The time a' correlated strongly with a (r = 0.90, p < 0.0001). The mean difference between a' and a was 0.3 +/- 5.0 ms. There was also a strong correlation between b' and b (r = 0.94, p < 0.0001). The mean difference between b' and b was 0.5 +/- 3.3 ms. The TDI-Tei index correlated with the pulsed Doppler-Tei index (r = 0.83, p < 0.0001). The mean difference between the TDI-Tei index and the pulsed Doppler-Tei index was -0.003 +/- 0.04. This study demonstrated that the TDI-Tei index correlates well with the Tei index determined by pulsed Doppler in fetuses, suggesting that the TDI-Tei index is a feasible approach to assess global RV function in fetuses.

OBJECTIVE: We sought to determine the incremental diagnostic utility of pediatric cardiac assessment in the offspring of women with congenital heart disease who have had previous fetal echocardiography.

PATIENTS AND METHODS: We prospectively followed pregnant women with congenital heart disease who were receiving care at 2 obstetric and cardiac centers and identified 276 infants who underwent both fetal echocardiography and pediatric cardiac assessment. All of the infants with abnormal fetal echocardiography findings or abnormal pediatric cardiac assessments underwent subsequent confirmatory pediatric echocardiography.

RESULTS: In this cohort, congenital heart disease was detected in 22 (8%) of 276 offspring born to women with congenital heart disease. There was concordance between the results of fetal echocardiography and pediatric cardiac assessment in 235 (85%) of 276 offspring (231, both normal; 4, both abnormal) and discordance between the results of fetal echocardiography and pediatric cardiac assessment in 41 (15%) of 276 infants. In the 41 subjects with discordant results, there were normal fetal echocardiography findings but abnormal pediatric cardiac assessments in 35 of 41 (pediatric echocardiography revealed congenital heart disease in 18 of 35 and normal anatomy in 17 of 35) and abnormal fetal echocardiography findings but normal pediatric cardiac assessments in 6 of 41 (pediatric echocardiography findings normal in all 6 of the infants). Fetal echocardiography detected all of the major forms of congenital heart disease. Lesions missed by fetal echocardiography but detected on pediatric cardiac assessment included shunt lesions and minor valvular abnormalities.

CONCLUSIONS: Although fetal echocardiography can reliably exclude major forms of congenital heart disease, minor congenital heart disease lesions can be missed on fetal echocardiography; however, these can be diagnosed with careful pediatric cardiac assessment. Postnatal pediatric cardiac assessment has incremental diagnostic utility for the detection of congenital heart disease in the offspring of women with congenital heart disease and previous fetal echocardiography.

PURPOSE: To use B-flow imaging with 4-dimensional (4D) sonography and spatiotemporal image correlation (STIC) in the evaluation of normal fetal heart and congenital heart disease during pregnancy.

METHOD: Volume data sets of the fetal heart were acquired with automated transverse and longitudinal sweeps of the anterior chest wall. We studied 13 normal fetuses and 2 fetuses with congenital heart disease (1 double-outlet right ventricle and 1 hypoplastic left heart syndrome) at gestation ages ranging from 13 to 39 weeks using transabdominal 4D B-flow sonography with STIC (4D BF-STIC).

RESULTS: 4D BF-STIC demonstrated dynamic angiographic features in both normal and abnormal fetal hearts. 4D BF-STIC images could not be obtained in 2 normal fetuses at 18.1 and 33.1 weeks because of the high fetal heart rate and inappropriate fetal position. In normal fetal heart, characteristic hemodynamic changes in both atria and ventricles were clearly demonstrated in systole and diastole. 4D BF-STIC also allowed visualization of the relationship, size, and course of the outflow tracts, thus helping the examiner to better understand the relationships between the vessels. In a case of hypoplastic left heart syndrome, dramatic hemodynamic changes including the right atrium, right ventricle, and pulmonary artery were evident. In a case of double-outlet right ventricle with ventricular septal defect, left-to-right shunt flow through a ventricular septal defect was clearly shown, as were great arteries originating in parallel from the right ventricle.

CONCLUSION: 4D BF-STIC provides a means of real-time 3-dimensional evaluation of fetal intracardiac and extracardiac hemodynamics in the second and third trimesters. This novel technique assists in the evaluation of fetal cardiac hemodynamics and may play an important role in future fetal cardiac research and in the evaluation of congenital heart disease in the fetus.

OBJECTIVE: Correct prenatal determination of the fetal right/left axis is essential for the diagnosis of fetal malformations, in particular congenital heart anomalies. A reliable method of transabdominal echocardiographic assessment of the fetal situs in the late second trimester was established. We aimed to determine the validity of the transvaginal approach to assess fetal axis.

METHOD: The study group consisted of 108 consecutive women in the second trimester of a singleton pregnancy, undergoing elective transvaginal anatomy scans. All had undergone previous transabdominal echocardiography to establish fetal axis. The same technique was used to assess the fetal axis during the transvaginal study, and the findings were compared.

RESULTS: There was total agreement in fetal axis determination between transabdominal and transvaginal scans in all cases. The accuracy of the transvaginal study was not affected by maternal obesity, fetal position or the presence of cardiac malformation (in one case).

CONCLUSION: Transvaginal ultrasonography is the reliable and accurate means of determining the fetal axis.

Fetal echocardiography remains the mainstay for diagnosis in those pregnancies identified to be at risk for congenital heart disease (CHD). Prenatal diagnosis of CHD remains essential to provide families with thorough pregnancy options as well as allow for transfer to facilities experienced in the management of pediatric cardiac disease in cases of ongoing pregnancy. First-trimester and early second-trimester fetal echocardiography is now feasible and will be increasingly in demand as enlarged nuchal translucency and first-trimester cystic hygroma are becoming common indications for early fetal echocardiography. Although the reported performance characteristics of early fetal echocardiography are good, the technique should be viewed as an adjunct to mid-trimester echocardiography, with its biggest benefit likely to be the ability to provide earlier reassurance to couples at risk for CHD. Early fetal echocardiograms should be reserved for patients at risk for CHD and be performed in centers experienced in this technique.

OBJECTIVE: Quantification of fetal heart ventricle volume can aid in the evaluation of functional and anatomical aspects of congenital heart disease. The aim of this study was to establish nomograms for ventricular volume using three-dimensional (3D) inversion mode ultrasonography with the spatio-temporal image correlation (STIC) modality and to calculate ejection fraction and stroke volume.

METHODS: The fetal heart was scanned using the STIC modality, during fetal quiescence with abdomen uppermost, at an angle of 30-50 degrees , without color Doppler flow mapping. In post-processing, starting with the classic four-chamber view plane in the A-frame, the reference point was moved to the center of the ventricle. The operator used the edit volume followed by Virtual Organ Computer-aided AnaLysis (VOCAL) mode options; in manual trace the VOCAL settings were set to 15 degrees . The trace was drawn and included the myocardium; inversion mode thresholding provided the volume of the intraventricular (anechoic) voxels within the region of interest. The total volume and the intraventricular volume were displayed. The process was repeated for right (R) and left (L) ventricles at end diastole (EDV) and end systole (ESV). The stroke volume (SV = EDV - ESV) and ejection fraction (EF = SV/EDV) were calculated from these measurements. Intraclass correlation was used to evaluate intra- and interobserver agreement.

RESULTS: One hundred fetuses ranging from 20 + 5 to 40 + 0 gestational weeks were included in the study. In addition, six fetuses diagnosed during the study period with a cardiac anomaly were examined and their ventricular volumes compared with those of the main study group. LEDV ranged from a mean of 0.53 cm(3) at midgestation to a mean of 3.96 cm(3) at term. LESV ranged from a mean of 0.17 cm(3) at midgestation to 1.56 cm(3) at term. REDV ranged from a mean of 0.68 cm(3) at midgestation to a mean of 5.44 cm(3) at term. RESV ranged from a mean of 0.26 cm(3) at midgestation to 2.29 cm(3) at term. Total stroke volume ranged from a mean of 0.78 cm(3) at midgestation to a mean of 5.5 cm(3) at term. The mean right : left ventricle ratio was 1.4, and left ejection fraction ranged from 42.5 to 86% in these fetuses. Nomograms were created for RESV, LESV, REDV, LEDV and total stroke volumes vs. estimated fetal weight and gestational age. Intra- and interobserver agreement reached 96%.

CONCLUSIONS: 3D inversion mode sonography combined with STIC represents a simple and reproducible method for estimating fetal cardiac ventricle volume. This innovative methodology may add to overall evaluation of cardiac volume and function, and improve our understanding of normal and abnormal cardiac structure, as well as the severity and prognosis of cardiac lesions.

PURPOSE OF REVIEW: This review describes the recent advances in timing and effectiveness of first and early second trimester fetal echocardiography screening.

RECENT FINDINGS: Fetal echocardiography can now be reliably performed from 11 weeks' gestation owing to improvements in ultrasound transducers and processors. Three-dimensional and four-dimensional ultrasound modalities in image acquisition and postprocessing analysis, including spatio-temporal image correlation, rendering three-dimensional power Doppler and high definition power flow Doppler, and B-flow have further improved our capabilities in this area. Fetal nuchal translucency measurement screening programs create a new population of at-risk pregnancies that will be referred for early fetal echocardiography. The majority of congenital heart defects, however, still occur in low-risk patients. Improved technology has lowered the gestational age at which fetal cardiac anatomy scanning can be reliably performed by properly trained and experienced examiners.

SUMMARY: Early fetal echocardiography can be offered as a screening examination to at-risk and low-risk patients, with the proviso that it be repeated following screen-negative scans at mid-gestation to exclude later developing lesions.