Fetal left-atrial posterior-space-to-diagonal ratio at 17-37 weeks' gestation for prediction of total anomalous pulmonary venous connection

OBJECTIVES

To develop normative data for the left-atrial posterior-space-to-diagonal (LAPSD) ratio and post-left atrium space (PLAS) index in fetuses from 17 to 37 weeks' gestation, and determine the optimal cut-offs of the LAPSD ratio and PLAS index to discriminate between normal fetuses and those with total anomalous pulmonary venous connection (TAPVC).

METHODS

This was a prospective cross-sectional assessment of 428 structurally normal fetuses between 17 and 37 weeks' gestation and a retrospective study of 27 TAPVC fetuses. The fetal LAPSD ratio was calculated by dividing the left atrium-descending aorta distance (LDD) by the left atrial diagonal diameter (LA). The PLAS index was calculated as the ratio of the LDD to the descending aorta diameter (DA). Pearson's correlation analysis was used to examine the correlation of cardiac parameters with gestational age (GA) and fetal somatic growth. The PLAS index and LAPSD ratio were compared between the normal and TAPVC groups to assess their usefulness in the prenatal diagnosis of TAPVC.

RESULTS

LDD, LA and DA measures showed moderate to strong positive correlation, whereas both the LAPSD ratio and PLAS index showed a slight decrease with increasing GA and biometric variables. The fetal LAPSD ratio and PLAS index in TAPVC cases were significantly greater compared with those of fetuses with a normal heart (both P < 0.001). There were no significant differences in the PLAS index and LAPSD ratio between the isolated and complex TAPVC groups (both P = 1). No significant associations of the PLAS index and LAPSD ratio with fetal gender, four-chamber view type (apical, basal or lateral) or TAPVC type were found. Using values of ≥ 0.35 for the LAPSD ratio and of ≥ 1 for the PLAS index exhibited similar excellent diagnostic performance, with a sensitivity of 100% and specificity of 97.0% or 95.1% for detecting TAPVC.

CONCLUSIONS

Our study demonstrates that the LAPSD ratio is a practical and effective screening tool for diagnosing fetal TAPVC, similar to the PLAS index. Incorporating these parameters into routine cardiac scanning may enhance the prenatal detection of TAPVC. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Nomograms of fetal cardiothoracic ratio from 17 to 37 weeks' gestation as assessed by three different measurement techniques and their correlation with gestational age

OBJECTIVE

To create nomograms for fetal cardiothoracic (CT) ratio as assessed by three different 2-dimensional sonographic measurements, including CT diameter, circumference, and area ratios, in Thai fetuses with a gestational age (GA) of 17-37 weeks, and to evaluate both their correlation with GA or biparietal diameter (BPD) and variability among the three measurement methods.

METHODS

Two-dimensional sonographic measurements of fetal CT ratio in 4-chamber view were assessed by three different measurement techniques. The 95% reference intervals and Z-scores of all measurement methods based on GA or BPD were constructed. Intraclass correlation coefficients (ICC) for the reproducibility of each technique were compared.

RESULTS

A total of 511 uncomplicated singleton pregnancies were included. The fetal CT ratio values by all measurement techniques gradually and smoothly increased with increasing GA and BPD. The fetal CT circumference ratio showed the least correlation with both GA and BPD. The intraobserver and interobserver reliability coefficients of all techniques demonstrated almost excellent agreement (all ICCs at least 0.87).

CONCLUSION

Reference intervals and Z-score reference ranges were developed using three different techniques for fetal CT ratio with a GA of 17-37 weeks. These nomograms are a simple and reliable screening tool for identifying abnormal fetal heart size.

Morphology, intrafetal vascular pattern, and umbilical artery Doppler indices of acardiac twins

BACKGROUND

Twin reversed arterial perfusion (TRAP) sequence consists of acardiac twin (A) paradoxically perfused by pump twin (P) through an umbilical artery (UA). We proposed characterization of acardiac twins with intrafetal vascular pattern (IVP), and assessed its correlation with morphology and UA Doppler indices.

METHODS

We prospectively evaluated 21 cases of TRAP sequence. Morphology (acardia vs hemicardia) and IVP (simple vs complex) of acardiac twins were characterized with ultrasound and color Doppler. Twins weight ratio (A/P Wt) and UA Doppler indices of acardiac and pump twins including (1) difference of systolic/diastolic ratio (UA ∆S/D), (2) difference of resistance index (UA ∆RI), and (3) ratio of pulsatility index (UA PI A/P) were calculated.

RESULTS

The median (min, max) gestational age at diagnosis was 18 (11, 27) weeks. Acardia (n = 14) were associated with simple IVP (n = 16) (P < .05). After exclusion of acardia with complex IVP (n = 1), the A/P Wt, UA ∆S/D, UA ∆RI, and UA PI A/P of acardia with simple IVP (n = 13), hemicardia with simple IVP (n = 3), and hemicardia with complex IVP (n = 4) were not significantly different (P > .05).

CONCLUSIONS

Most of acardiac twins were acardia with simple IVP. Morphology and IVP of acardiac twins were not associated with UA Doppler indices.