Cardiovascular Z-scores in fetuses with tetralogy of Fallot

Assessing Fetal Heart Morphology and Function in Fetuses With Right Ventricular Outflow Obstruction by Fetal Heart Quantitative Technique

OBJECTIVES

To investigate the clinical utility of the fetal heart quantification (Fetal HQ) technique in the assessment of morphological and functional changes in fetuses with right ventricular outflow obstruction (RVOTO).

METHODS

This study included 53 fetuses with RVOTO and 30 age-matched normal controls. The RVOTO fetuses were divided into 2 groups based on the occurrence of other cardiovascular malformations: the simple pulmonary stenosis (PS group) and the conotruncal defects (CTD group). Size, shape, and contractility parameters of the fetal heart in 4-chamber view (4CV), left ventricle, and right ventricle (LV and RV) detected by fetal HQ.

RESULTS

Fetuses with RVOTO exhibited an increased 4CV-width, with normal 4CV-Length. The end-diastolic diameter (ED) of the LV segments 1-22 was significantly greater in RVOTO fetuses. The sphericity index (SI) of the LV 24-segment was significantly smaller in the CTD and PS groups. Global longitudinal strain (GLS) and fractional area change (FAC) of the LV and RV were reduced in RVOTO fetuses.

CONCLUSION

Our results suggested that the characteristic changes in the morphology and function of the RVOTO fetal heart could be detected early by the HQ technique, which has clinical utility in analyzing the morphology of the RVOTO fetal heart in a quantitative manner.

A New Method Using the Four-Chamber View to Identify Fetuses With Subsequently Confirmed Postnatal Aortic Coarctation

OBJECTIVE

To determine the sensitivity, specificity, and false-positive rate among fetuses suspected prenatally to have coarctation of the aorta (CoA) using size and shape measurements of the fetal heart from the four-chamber view (4CV).

METHODS

This was a retrospective study of 108 fetuses identified by pediatric cardiologists to be at risk for CoA. 4CV s from the last antenatal ultrasound performed by the cardiologists were analyzed. The end-diastolic area was computed using the point-to-point trace method around the epicardial border of the 4CV, and the largest end-diastolic length and width were measured from the epicardium to the epicardium to compute the global sphericity index (GSI) (length/width). Using speckle tracking analysis, the ventricular end-diastolic area, length, basal and mid-chamber widths were measured. The sphericity index of the base and mid-chamber of the ventricles was computed (length/width). In addition, the end-diastolic area ratios were computed as follows: right ventricular area/4CV area and the left ventricular area/4CV area. The z-scores for the above measurements were computed. Using logistic regression analysis, coefficients for predicting the probability of CoA from a test group of 27 fetuses with CoA and 27 without CoA was done. The logistic regression equation derived from the test group was applied to a validation group of 27 fetuses with CoA and 27 fetuses without CoA.

RESULTS

The regression equation from the test group identified the following end-diastolic measurements: 4CV GSI, RV area/heart area, LV base SI, and the RV Base SI. The test group consisted of 14 of 27 fetuses with an isolated CoA (52%) and 13 of 27 (48%) with additional heart abnormalities. For the validation group, 10 of 27 (37%) had an isolated CoA, and 17 (63%) had additional cardiac abnormalities. Using the logistic regression equation derived from the test group (54 fetuses: 27 with CoA and 27 without CoA), the validation group (54 fetuses: 27 with CoA and 27 without CoA) demonstrated the following: sensitivity for detecting CoA of 98.15%, specificity 98.15%, and a false-positive rate of 1.85%. When the logistic regression was applied to the test group of fetuses with isolated CoA, 100% (14/14) were identified with logistic regression analysis. For the validation group, 9 of 10 (90%) of fetuses with isolated CoA were identified using the logistic regression equation.

CONCLUSIONS

Using length, width, and area measurements of the 4CV and ventricles from which ratios are computed detects 98.15% of high-risk fetuses who will demonstrate CoA following birth, with a specificity of 98.15%, or a false-positive rate of 1.85%.

Automated Assessment of the Pulmonary Artery-to-Ascending Aorta Ratio in Fetal Cardiac Ultrasound Screening Using Artificial Intelligence

The three-vessel view (3VV) is a standardized transverse scanning plane used in fetal cardiac ultrasound screening to measure the absolute and relative diameters of the pulmonary artery (PA), ascending aorta (Ao), and superior vena cava, as required. The PA/Ao ratio is used to support the diagnosis of congenital heart disease (CHD). However, vascular diameters are measured manually by examiners, which causes intra- and interobserver variability in clinical practice. In the present study, we aimed to develop an artificial intelligence-based method for the standardized and quantitative evaluation of 3VV. In total, 315 cases and 20 examiners were included in this study. We used the object-detection software YOLOv7 for the automated extraction of 3VV images and compared three segmentation algorithms: DeepLabv3+, UNet3+, and SegFormer. Using the PA/Ao ratios based on vascular segmentation, YOLOv7 plus UNet3+ yielded the most appropriate classification for normal fetuses and those with CHD. Furthermore, YOLOv7 plus UNet3+ achieved an arithmetic mean value of 0.883 for the area under the receiver operating characteristic curve, which was higher than 0.749 for residents and 0.808 for fellows. Our automated method may support unskilled examiners in performing quantitative and objective assessments of 3VV images during fetal cardiac ultrasound screening.

Automated quantitative evaluation of fetal atrioventricular annular plane systolic excursion before and after intrauterine blood transfusion in pregnancies affected by red blood cell alloimmunization

INTRODUCTION

Maternal red blood cell alloimmunization during pregnancy can lead to hemolysis and various degrees of fetal anemia, which can be treated with intrauterine blood transfusion (IUT) to prevent adverse outcomes. Knowledge about fetal myocardial function and adaptation is limited. The aim of the present study was to measure fetal atrioventricular plane displacement before and after IUT and compare these measurements with previously established reference ranges.

MATERIAL AND METHODS

An observational study was conducted on pregnant women affected by red blood cell alloimmunization. Fetal echocardiography was performed before and after IUT. The atrioventricular plane displacement of the left and right ventricular walls and interventricular septum, described as mitral, septal, and tricuspid annular plane systolic excursion (MAPSE, SAPSE, and TAPSE, respectively), was assessed using color tissue Doppler imaging with automated analysis software. A Mann-Whitney U test was used to compare the z scores to the normal mean before and after IUT.

RESULTS

Twenty-seven fetuses were included. The mean z score for pre-IUT MAPSE was significantly increased compared with the reference ranges, +0.46 (95% confidence interval [CI] +0.17 to +0.75; p = 0.039), while the mean z scores for post-IUT SAPSE and TAPSE were significantly decreased, -0.65 (95% CI -1.11 to -0.19; p < 0.001) and -0.60 (95% CI -1.04 to -0.17; p = 0.003), respectively. The difference in atrioventricular plane displacement z scores before and after IUT was statistically significant in all three locations. The median difference between the pre-IUT and post-IUT z scores was -0.66 (95% CI -1.03 to -0.33, p < 0.001) for MAPSE, -1.05 (95% CI -1.43 to -0.61, p < 0.001) for SAPSE, and -0.60 (95% CI -1.19 to -0.01, p = 0.046) for TAPSE.

CONCLUSIONS

This study suggests that atrioventricular plane displacement, when determined using automated analysis software, may represent a quantitative parameter, describing fetal myocardial function and adaptation before and after IUT.

Aorta Dilatation in Unrepaired Tetralogy of Fallot

Background Aortic root dilation is an increasingly recognized feature in repaired tetralogy of Fallot (TOF) patients. However, the dilation at the aortic root and ascending aorta in unrepaired TOF is rarely studied. This study aims to confirm whether aortic dilation is a common feature in unrepaired TOF and investigate the factors attributed to aortic dilation. Methodology Patients with an echocardiographic diagnosis of TOF undergoing computed tomography angiography were retrospectively studied. Diameters and z scores of aortic annular (Ao1), aortic sinotubular junction (Ao2), ascending aorta (Ao3), and distal transverse aortic arch (Ao4) were measured. Preoperative body surface area (BSA), hemoglobin (Hb), hematocrit (HCT), arterial oxygen saturation (SaO2), and platelet (PLT) count were recorded. Results A total of 101 TOF patients aged 6.8 ± 9.5 years were included in this study, whose mean BSA (m2), Hb (g/L), HCT, SaO2 (%), and PLT (109/L) were 0.7 ± 0.4, 162.1 ± 3.8, 0.5 ± 0.1, 85.1 ± 9.3, and 238.1 ± 101.1, respectively. The mean z score of Ao1, Ao2, Ao3, and Ao4 were 10.3 ± 3.5, 4.7 ± 2.9, 4.0 ± 2.7, and 4.1 ± 2.4, respectively. Age and BSA were positively correlated with the z scores of Ao1 and Ao2. Preoperative Hb and HCT were positively correlated with the z scores of Ao1, Ao2, Ao3, and Ao4. Preoperative SaO2 and PLT were negatively correlated with the z scores of Ao1, Ao2, Ao3, and Ao4. Conclusions Aortic dilation is common in unrepaired TOF patients. The dilation of different levels of the aorta was correlated with age, BSA, preoperative Hb, HCT, SaO2, and PLT.

Realignment of the ventricular septum in tetralogy of Fallot using (partial) direct closure of the ventricular septal defect: Long-term follow-up and comparison to conventional patch repair

Objectives

Aortic dilatation and regurgitation after surgical repair of tetralogy of Fallot (TOF) is known, and beside other factors, mainly addressed to an intrinsic aortopathy. In 2011, we reported the influence of realingement of the left ventricular outflow tract (LVOT) by (partial) direct closure of the ventricular septal defect (VSD) in TOF on aortic structures and function. We now evaluated the further follow-up of this cohort and compared the results to a matched group of TOF patients with classical VSD patch closure.

Patients and Methods

Forty patients with TOF treated between 2003 and 2008 are included in the study, with 20 patients each in the VSD (a) (partial) direct closure and (b) patch closure group. Follow-up time after surgery was 12.3 years (11.3-13.0).

Results

Patient characteristics, echocardiographic measurements, and surgical and intensive care unit parameters were not significantly different between both groups. After surgery and during long-term follow-up, realignement of the LVOT, shown by the angle between the interventricular septum and the anterior aortic annulus in long axis view in echocardiography, was lower in Group A (34 vs. 45°, P < 0.0001). No differences in LVOT or aortic annulus size, aortic regurgitation, or dilation of the ascending aorta and right ventricular outflow tract gradients were found. Transient rhythm disturbances were found in 3 patients in each group, with only one persistent complete atrioventricular block in Group B.

Conclusion

(Partial) direct closure of the VSD in TOF leads to a better realignement of the LVOT and showed comparable short- and long-term results without higher risk for rhythm disturbances during follow-up.

Comparisons of foramen ovale flap in the fetuses with true and false positive diagnosis of coarctation of the aorta

BACKGROUND

Accurate diagnosis of coaractation of aorta (CoA) remains challenging because of its relatively low sensitivity and specificity. It is difficult to distinguish true CoA from a normal physiological right-sided dominance or ventricular discrepancy caused by intracardiac minor anomalies. Redundant foramen ovale flap (RFOF) may cause ventricular disproportion.

METHODS

All fetuses suspected with CoA on routine screening ultrasound were retrospectively reviewed and allotted into two groups: postnatally confirmed CoA (true positive group) and prenatally suspected CoA but without CoA postnatally (false positive group). Sixty-nine normal fetuses were included as a normal group (normal group). The diameters of FOF and left atrium (LA) were measured in the four-chamber view and FOF/LA ratio ≥0.65 was considered as RFOF. Cardiac parameters between groups were compared.

RESULTS

Fifty-seven fetuses undergoing echocardiography for suspicion of CoA were enrolled; 11 (19.2%) had CoA postnatally. A significant linear relationship was identified between ventricular discrepancy degree and FOF prominence (P<0.001, R=0.48). A significant linear relationship was also identified between the RFOF and disproportion of the great arteries (P<0.001, R=0.42). FOF prominence significantly differed between groups true positive and false positive (P<0.001). RFOF occurred significantly differently in the true positive and false positive groups (56.5% vs. 0.91%, P=0.002). Cardiac parameters, including the aortic valve (AO) z-score (P=0.785), aortic isthmus (AOi) z-score (P=0.944), pulmonary artery (PA) z-score (P=0.693), PA/AO ratios (P=0.055), left ventricle (LV) z-score (P=0.192) and right ventricle (RV)/LV ratios (P=0.225), were comparable between fetuses with and without CoA after birth except RV z-score (P=0.035).

CONCLUSIONS

There is no statistical difference of cardiac parameters between fetuses with and without CoA after birth except RV diameter. The proportion of fetuses with RFOF is significantly greater in patients without CoA. Fetal echocardiography including bulging of the FOF in the LA should be investigated for suspected CoA to decrease false positive diagnosis of CoA.

Evaluation of Fetal Cardiac Size and Shape: A New Screening Tool to Identify Fetuses at Risk for Tetralogy of Fallot

OBJECTIVE

Prenatal detection rates for tetralogy of Fallot (TOF) vary between 23 and 85.7%, in part because of the absence of significant structural abnormalities of the 4-chamber view (4CV), as well as the relative difficulty in detection of abnormalities during the screening examination of the outflow tracts. The purpose of this study was to evaluate whether the 4CV and ventricles in fetuses with TOF may be characterized by abnormalities of size and shape of these structures.

METHODS

This study retrospectively evaluated 44 fetuses with the postnatal diagnosis of TOF. Measurements were made from the 4CV (end-diastolic length, width, area, global sphericity index, and cardiac axis) and the right (RV) and left (LV) ventricles (area, length, 24-segment transverse widths, sphericity index, and RV/LV ratios). Logistic regression analysis was performed to identify variables that might separate fetuses with TOF from normal controls.

RESULTS

The mean gestational age at the time of the last examination prior to delivery was 28 weeks 5 days (SD 4 weeks, 4 days). The mean z-scores were significantly lower in fetuses with TOF for the 4CV and RV and LV measurements of size and shape. Logistic regression analysis identified simple linear measurements of the 4CV, RV, and LV that had a sensitivity of 90.9 and specificity of 98.5% that outperformed the 4CV cardiac axis (sensitivity of 22.7%) as a screening tool for TOF.

CONCLUSIONS

Measurements of the 4CV, RV, and LV can be used as an adjunct to the outflow tract screening examination to identify fetuses with TOF.

The diagnostic value of the early extended fetal heart examination at 13 to 14 weeks gestational age in a high-risk population

BACKGROUND

Congenital heart disease (CHD) is the most common congenital malformation that affects high-risk populations. A more definite heart diagnosis in the first trimester should be provided to guide clinical treatment. The study aim was to evaluate the diagnostic precision of the early extended fetal heart examination (EFHE) that includes abdominal situs view, four-chamber view (4CV), left ventricular outflow tract view (LVOT), right ventricular outflow tract view (RVOT), 3-vessel and tracheal view (3VT), ductal arch view, and the aortic arch view in the detection of CHD at the gestational age (GA) 13 to 14 weeks in a population with high risks.

METHODS

This study was a diagnostic test study. EFHE was performed by transabdominal sonography in women at GA 13 to 14 weeks with singleton pregnancies who were at high risk for CHD. The risk of CHD was determined by family history of CHD, rubella infection, metabolic disorders, exposure to teratogens, conception by in-vitro fertilization (IVF), increased nuchal translucency (NT) thickness, abnormal obstetric ultrasound, etc. The operator had more than 5 years of experience in first-trimester scans and fetal echocardiography. Early scans were compared with a fetal echocardiography in the second trimester (16-24 weeks).

RESULTS

EFHE was performed, and the pregnancy outcomes were obtained in 234 single pregnancies with a high risk of CHD. The average crown-rump length (CRL) was (76.17±7.09) mm. CHD was diagnosed in 43 cases by EFHE; 10 of these cases were misdiagnosed, and 2 cases were missed. Four cases were inconsistent in the main diagnosis of CHD. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and kappa coefficient (Ko) value of EFHE in diagnosing CHD by type and severity was 84.6% [95% confidence interval (CI), 69.5-94.1%], 96.9% (95% CI, 93.4-98.9%), 84.6% (95% CI, 69.5-94.1%), 96.9% (95% CI, 93.4-98.9%), and 0.82 (P<0.001), respectively.

CONCLUSIONS

EFHE can work as a diagnose examination for most major CHD cases at GA 13 to 14 weeks by an experienced operator; Therefore, this diagnostic system for fetal CHD may be applied in the first trimester. The study has been registered in the Chinese Clinical Trial Registry (www.chictr.org.cn). The registration number is ChiCTR2000038451.

A 'holistic' sonographic view on congenital heart disease - How automatic reconstruction using fetal intelligent navigation echocardiography (FINE) eases the unveiling of abnormal cardiac anatomy part I: Right heart anomalies

Attempting a comprehensive examination of the fetal heart remains challenging for unexperienced operators as it emphasizes the acquisition and documentation of sequential cross-sectional and sagittal views and inevitably results in diminished detection rates of fetuses affected by congenital heart disease. The introduction of four-dimensional spatio-temporal image correlation (4D STIC) technology facilitated a volumetric approach for thorough cardiac anatomic evaluation by the acquisition of cardiac 4D datasets. By analyzing and re-arranging of numerous frames according to their temporal event within the heart cycle, STIC allows visualization of cardiac structures as an endless cine loop sequence of a complete single cardiac cycle in motion. However, post-analysis with manipulation and repeated slicing of the volume usually requires experience and in-depth anatomic knowledge, which limits the widespread application of this advanced technique in clinical care and unfortunately leads to the underestimation of its diagnostic value to date. Fetal intelligent navigation echocardiography (FINE), a novel method that automatically generates and displays nine standard fetal echocardiographic views in normal hearts, has shown to be able to overcome these limitations. Very recent data on the detection of congenital heart defects (CHDs) using the FINE method revealed a high sensitivity and specificity of 98% and 93%, respectively. In this two-part manuscript, we focused on the performance of FINE in delineating abnormal anatomy of typical right and left heart lesions and thereby emphasized the educational potential of this technology for more than just teaching purposes. We further discussed recent findings in a pathophysiological and/or functional context.

Annular plane systolic excursion Z-scores in evaluation of heart systolic function of fetus with heart failure

OBJECTIVE

To compare fetal tricuspid annular plane systolic excursion(TAPSE）Z-scores and mitral annular plane systolic excursion(MAPSE) Z-scores between fetuses with heart failure (HF) and normal fetuses, and to analysis the correlation between CVPS and annular plane systolic excursion(APSE) Z-score(sum of the TAPSE and MAPSE Z-score) in order to evaluate the ventricle systolic function and severity in fetuses with HF.

METHODS

A total of 1012 normal fetuses and 24 fetuses with heart failure were involved. TAPSE and MAPSE were measured by free angle M-mode(FAM) echocardiography. Normal FAM-TAPSE and FAM-MAPSE Z-score models based on GA were constructed by performing a standard regression analysis followed by weighted regression of absolute residual values . Tei indexes were calculated in all fetuses with heart failure and all of them were divided into left heart failure (LHF)group and right heart failure（RHF)group by Tei index. Subsequently, FAM-MAPSE Z-scores were compared between the normal and LHF groups, FAM-TAPSE Z-scores were compared between the normal and RHF groups．FAM-APSE Z-scores (sum of the FAM-TAPSE and FAM-MAPSE Z-score) and the cardiovascular profile scores (CVPS) in 24 fetuses were calculated, the correlation was analyzed among them.

RESULTS

The models used to calculate Z-score for FAM-TAPSE and FAM-MAPSE were constructed, and GA had significant correlation with them (r = 0.949, p < 0.001for all)．Compared with normal fetuses, the mean Z-scores of FAM-TAPSE and FAM-MAPSE were statistically significantly different in fetuses with HF．In the HF groups, all FAM-TAPSE and FAM-MAPSE Z-scores(22/22) were <-2. CVPS ranged from 3 to 8 (mean 5.25 out of 10) and correlated positively with FAM-APSE Z-score (r = 0.762).

CONCLUSIONS

The FAM-TAPSE and FAM-MAPSE Z-scores declined in fetuses with HF and they can provide quantitative evidence in evaluation of heart systolic function, FAM-APSE Z-score correlated positively with CVPS. FAM-TAPSE, FAM-MAPSE and FAM-APSE Z-scores would be markers for assessing heart systolic function and severity in fetuses with HF.

Enlarged cavum septi pellucidi Z-scores in fetuses with trisomy 18

Objective: We aim to establish a formula calculating the fetal cavum septi pellucidi (CSP) width Z-scores and compare CSP width between the normal fetus and 18-trisomy fetus.Methods: In this retrospective study, 608 normal fetuses and 71 fetuses with the 18-trisomy syndrome were included. Z-scores were calculated after the acquisition of CSP images. Normal CSP width Z-scores formulae were constructed based on gestational age (GA) by performing a standard regression analysis followed by weighted regression of absolute residual values. Subsequently, the Mann-Whitney U test was used to compare the CSP width Z-scores between normal and 18-trisomy groups.Results: Formulae calculating CSP width Z-scores were constructed. Normal fetal CSP width was significantly correlated with GA (R² = 0.50, p < .01). In 18-trisomy group, 69% (34/49) fetuses displayed enlarged fetal CSP width and CSP width Z-scores (p < .01).Conclusions: The CSP width Z-scores formulae established in the current study can provide a quantitative basis for the prenatal diagnosis of 18-trisomy syndrome. Enlarged CSP width Z-score may serve as a novel prenatal diagnostic marker for the 18-trisomy syndrome.

Detailed Echocardiographic Measurements of Individual Chamber in a Chinese Cohort of Hypoplastic Left Heart Syndrome and Comparison with Normal Fetuses via Z-score Modeling

Hypoplastic left heart syndrome (HLHS) is a rare, but exceptionally serious, congenital heart defect. We aimed to explore the best-fitted Z-score models for individual chamber dimension and to draw a comparison between fetuses with HLHS and the normal Chinese cohort. We made measurements of 1674 healthy fetuses and 79 fetuses with HLHS, undertaking echocardiography. Normal fetal cardiovascular Z-score formulae were established by curve-fitting with 5 algorithmic functions and weighted regression of absolute residuals. Classic linear models were fitted for left ventricular diameter against gestational age, and log-transformed linear-power models-were statistically better for left ventricular length, diameter of left atrium and ascending aorta. Fetuses with HLHS manifested significantly lower Z-score means (≤3.5) for these 4 parameters and the vast majority (∼90%) lay beyond -2. Overall, cardiovascular Z-score equations were reliably constructed in a larger Chinese cohort, and their application should benefit evaluation and diagnosis of HLHS.

Z-score reference ranges for pulsed-wave Doppler indices of the cardiac outflow tracts in normal fetuses

To determine Z-score equations and reference ranges for Doppler flow velocity indices of cardiac outflow tracts in normal fetuses. A prospective cross-sectional echocardiographic study was performed in 506 normal singleton fetuses from 18 to 40 weeks. Twelve pulsed-wave Doppler (PWD) measurements were derived from fetal echocardiography. The regression analysis of the mean and the standard deviation (SD) for each parameter were performed against estimated fetal weight (EFW) and gestational age (GA), in order to construct Z-score models. The correlation between these variables and fetal heart rate were also investigated. Strong positive correlations were found between the twelve PWD indices and the independent variables. A linear-quadratic regression model was the best description of the mean and SD of most parameters, with the exception of the velocity time interval (VTI) of ascending aorta against EFW, which was best fitted by a fractional polynomial. Z-score equations and reference values for PWD indices of fetal cardiac outflow tracts were proposed against GA and EFW, which may be useful for quantitative assessment of potential hemodynamic alternations, particularly in cases of intrauterine growth retardation and structural cardiac defects.

"Y Sign" at the Level of the 3-Vessel and Trachea View: An Effective Fetal Marker of Aortic Dextroposition Anomalies in the First Trimester

OBJECTIVES

The "Y sign" at the level of the 3-vessel and trachea view corresponds to thinning of main pulmonary artery and arterial duct and a dilated transverse aortic arch. The purpose of this study was to evaluate the Y sign for the diagnosis of aortic dextroposition anomalies at the time of the first-trimester scan and to assess the screening performance of only the Y sign, only abnormal left axis deviation (axis sign), and their combination for the diagnosis of aortic dextroposition anomalies.

METHODS

A prospective evaluation of 6025 pregnant women undergoing first-trimester ultrasonography was conducted. The cardiac axis was measured in all examined patients and considered abnormal (positive axis sign) at greater than 57 °. The frequency of the Y sign and the axis sign was assessed for this population, and their screening performance for the diagnosis of aortic dextroposition anomalies was calculated.

RESULTS

A total of 5775 patients fulfilled the inclusion criteria. Aortic dextroposition anomalies were diagnosed in 17 cases (tetralogy of Fallot in 8 and Fallot-like double-outlet right ventricle in 9). The Y sign was found in 18 of 5775 (0.3%) fetuses examined, of which 7 of 18 were confirmed with tetralogy of Fallot, 9 of 18 with a Fallot-like double-outlet right ventricle, and 2 of 18 with pulmonary stenosis. A positive axis sign of greater than 57 ° was found in 20 fetuses, including 4 with normal heart anatomy. The sensitivity values of the Y sign, the axis sign, and their combination were 94%, 76%, and 94%, respectively.

CONCLUSIONS

Visualization of the Y sign should increase the suspicion of aortic dextroposition anomalies in the late first trimester. The screening performance of the Y sign alone and in combination with an abnormal cardiac axis was high and may aid in the early diagnosis of aortic dextroposition anomalies in the fetus.

Prenatal Diagnosis of Right Dominant Heart in Fetuses: A Tertiary Center Experience over a 7-year Period

Background:

Right dominant heart (RDH) in fetuses can occur with a number of cardiac as well as noncardiac anomalies. Analysis of the enlargement of the right cardiac chamber in the fetus remains a major challenge for sonographers and echocardiographers. The aim of this study was to report the experience with prenatal diagnosis of RDH in the fetuses over a 7-year period.

Methods:

Fetuses with prenatal diagnosis of RDH from July 2009 to July 2016 were evaluated in two different categories: according to the gestational age, Group I (n = 154, second trimester) and Group II (n = 298, third trimester); and according to the fetal echocardiography diagnosis, Group A (n = 452, abnormal cardiac structure) and Group B (n = 90, normal cardiac structure). Differences in categorical variables were assessed by Chi-square exact test and continuous variables were evaluated by independent Student's t-test or Mann–Whitney U-test depending on parametric or nonparametric nature of the data.

Results:

Over a 7-year period, 452 fetuses were referred for the assessment of suspected RDH. Left-sided obstructive lesions were observed most frequently in the fetuses with RDH. When comparing Group I with Group II and Group A with Group B, the latter groups exhibited significant differences in the right/left ventricle (RV/LV) ratio (1.435 vs. 1.236, P = 0.002; 1.309 vs. 1.168, P = 0.047), RV width Z-score (1.626 vs. 1.104, P < 0.001; 1.553 vs. 0.814, P = 0.014), and above +2 cutoff percentages (14.3% vs. 22.5%; P = 0.038; 21.5% vs. 12.2%, P = 0.046). Multivariable logistic regression revealed no variables associated with perinatal survival.

Conclusions:

The study demonstrates that RDH warrants careful attention to the possible presence of a structural cardiac anomaly, especially left-sided obstructive lesions. A diagnosis of RDH is best supported by a combination of the RV Z-score and RV/LV ratio. Most of the fetuses with RDH and structurally normal hearts had favorable outcomes.

Computing the Z Score and Centiles for Cross-sectional Analysis: A Practical Approach

Although Z scores have been reported in the literature, one of the problems for the nonstatistician is understanding the systematic approach used to compute the predicted mean and standard deviation, components of the Z score equation, which may vary as the independent variable changes over time (eg, gestational age). This review focuses on a step-by-step analysis using linear, quadratic, and fractional polynomials to compute the mean and standard deviation as a function of a continuous independent variable. Once the mean and standard deviation are computed, the Z score and centile can be derived and Z score calculators created that enable investigators to implement the results in the laboratory and/or clinical setting.

Azygos Vein Z Scores in Healthy Fetuses and Fetuses With Venous Malformations Related to the Azygos Vein

OBJECTIVES

To establish fetal azygos vein and descending aorta sonographic Z score formulas based on femur length and gestational age and to determine the value of azygos vein diameter variation for potential use in the diagnosis of fetal venous malformations related to the azygos vein.

METHODS

A total of 452 healthy singleton fetuses and 25 fetuses with venous malformations related to the azygos vein underwent prenatal sonography in this retrospective study. Azygos vein and descending aorta diameters were measured offline after spatiotemporal image correlation volume acquisition. Normal azygos vein and descending aorta Z score formulas were constructed for these measurements based on femur length by performing standard regression analysis followed by weighted regression of absolute residual values. The azygos vein-to-descending aorta ratio was calculated. Three parameters were compared between venous malformations related to the azygos vein and healthy fetuses.

RESULTS

Azygos vein and descending aorta Z score formulas were constructed. Both showed a positive linear correlation with femur length (r = 0.79 and 0.90, respectively; P < .01) and gestational age (r = 0.79 and 0.91; P < .01). The azygos vein Z scores and azygos vein-to-descending aorta ratios of fetuses with malformations were significantly higher than those of healthy fetuses (P < .01). In the abnormal group, 96.0% of azygos vein Z scores (24 of 25) were greater than ±2, and 96.0% of azygos vein-to-descending aorta ratios (24 of 25) were greater than the 95% confidence interval.

CONCLUSIONS

The azygos vein Z score formulas we developed can provide a quantitative basis for prenatal screening of venous malformations related to the azygos vein. Azygos vein dilatation and an abnormal azygos vein-to-descending aorta ratio may contribute to increasing the recognition of venous malformations involving the azygos vein.

Role of the 3-Vessel and Trachea View in Antenatal Detection of Tetralogy of Fallot

Prenatal diagnosis of tetralogy of Fallot 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 tetralogy of Fallot. In addition, we compared its sensitivity to that of the traditional outflow tract views for detection of tetralogy of Fallot. We found that both views were abnormal in all fetuses with tetralogy of Fallot, showing reversed aortic-to-pulmonary valve and aortic arch isthmus-to-ductus arteriosus ratios in the outflow tract and 3-vessel and trachea views, respectively. However, as a single measured marker, the enlarged aortic arch isthmus on the 3-vessel and trachea view appears to be the most sensitive for tetralogy of Fallot.

Quantitative Cardiac Assessment in Fetal Tetralogy of Fallot

OBJECTIVES

The purpose of this study was to quantitatively assess cardiac function and biometric parameters in fetuses with a diagnosis of tetralogy of Fallot and compare them to those in healthy fetuses.

METHODS

Two hundred healthy fetuses and 20 fetuses with a diagnosis of classic tetralogy of Fallot were quantitatively assessed for 16 cardiac parameters, including morphologic characteristics and functions. All recruited fetuses were in the second trimester with correct gestational ages. The measured values that were out of normal reference ranges were considered abnormal. Rates of abnormalities of these parameters were compared between the groups. The significant parameters were further analyzed for their sensitivity, specificity, and likelihood ratio.

RESULTS

Of the 16 parameters, rates of abnormalities in 7 parameters, including right ventricular wall thickness, peak systolic velocities (PSVs) in the pulmonary artery and aorta, time to peak velocity, or acceleration time, in the pulmonary artery, aortic valve diameter, pulmonary valve diameter, and aortic-to-pulmonary valve diameter ratio, were significantly higher in fetuses with tetralogy of Fallot (P < .001). The pulmonary artery PSV, pulmonary artery time to peak velocity, aortic valve diameter, pulmonary valve diameter, and aortic-to-pulmonary valve diameter ratio had high sensitivities (80.0%, 75.0%, 90.0%, 90.0%, and 100.0%, respectively) and specificities (95.5%, 97.0%, 94.5%, 96.0%, and 84.5%).

CONCLUSIONS

In addition to a routine anatomic examination, quantitative assessment of fetal hemodynamics, especially an abnormally high PSV in the pulmonary artery, as well as a shortened acceleration time and abnormal valve size, might be very helpful for confirmation of the diagnosis in cases of suspected tetralogy of Fallot.

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 and Postnatal Survival of Fetal Tetralogy of Fallot: A Meta-analysis of Perinatal Outcomes and Associated Genetic Disorders

OBJECTIVES

The aim of this systematic review was to compare the postnatal outcomes, genetic testing results, and sonographic findings in 3 subtypes of tetralogy of Fallot.

METHODS

Thirty-six articles from the MEDLINE and EMBASE databases were selected for this review. The postnatal outcomes, karyotyping results, and sonographic findings of fetal tetralogy of Fallot with pulmonary stenosis, tetralogy of Fallot with pulmonary atresia, and tetralogy of Fallot with an absent pulmonary valve were collected and compared.

RESULTS

The survival rates (termination of pregnancy was considered fetal death) for prenatally diagnosed tetralogy of Fallot with pulmonary atresia and tetralogy of Fallot with an absent pulmonary valve at the end of neonatal period were significantly lower than the rate for tetralogy of Fallot with pulmonary stenosis (P < .05). The survival rate for tetralogy of Fallot with pulmonary atresia was also lower at birth (P < .001). Major chromosomal anomalies were more frequently detected in tetralogy of Fallot with pulmonary stenosis (P< .05); conversely, 22q11 deletion was present more often in fetuses with tetralogy of Fallot with pulmonary atresia and tetralogy of Fallot with an absent pulmonary valve (P < .001). Compared to tetralogy of Fallot with pulmonary stenosis, a right aortic arch was more associated with tetralogy of Fallot with pulmonary atresia (32.6%; P < .05), and the ductus arteriosus was almost always absent in tetralogy of Fallot with an absent pulmonary valve (87.5%; P < .001).

CONCLUSIONS

The postnatal outcomes, genetic testing results, and sonographic findings are different among subtypes of tetralogy of Fallot. Documenting those details at diagnosis can help specialists better counsel their patients.

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.