Study of Ultrasound Diagnosis of Acrania-Exencephaly-Anencephaly Sequence in Middle First Trimester: A Multicenter Center, Retrospective Analysis.

OBJECTIVES

To explore the ultrasound diagnosis of fetal acrania-exencephaly-anencephaly sequence before 11 weeks of gestation.

METHODS

A retrospective multicenter study was carried out in 5 medical institutions in Guangxi Zhuang Autonomous Region. The crown-rump length (CRL), occipitofrontal diameter (OFD), and anteroposterior abdominal diameter (AAD) were measured in the median sagittal view. The ratios of AAD/OFD and CRL/OFD were computed. The correlations among various growth parameters of the normal group of fetus were analyzed. The receiver operating characteristic (ROC) curve was plotted, and the area under the curve (AUC) value was calculated to predict the acrania-exencephaly-anencephaly sequence. Additionally, the cranial ultrasound image characteristics of fetus with the acrania-exencephaly-anencephaly sequence at 11 weeks of gestation were analyzed.

RESULTS

As the CRL of normal fetuses increased, both OFD and AAD also increased. Spearman correlation analysis revealed positive correlations for both parameters, with r values of 0.99 and 0.97 (P < .01), respectively. The ROC curves of AAD/OFD and CRL/OFD in predicting the acrania-exencephaly-anencephaly sequence indicated areas under the curves of 0.998 (95% CI 0.993-1.000, P < .01) and 1.00 (95% CI 1.000-1.000, P  < .01), respectively. The optimal threshold of AAD/OFD was 0.874, with a sensitivity of 97.1% and a specificity of 100%. The optimal threshold of CRL/OFD was 2.261, with a sensitivity of 100% and a specificity of 99.7%. Morphological alterations in the cephalon were observed in all 34 cases.

CONCLUSION

The CRL/OFD is a reliable indicator for predicting the acrania-exencephaly-anencephaly sequence. When combined with cranial ultrasound morphological changes, it can accurately diagnose the acrania-exencephaly-anencephaly sequence before 11 weeks of gestation. However, diagnosis at this stage still requires reconfirmation after 11 weeks to enable doctors and parents to make the ultimate decision.