Value of using angled insonation technique in three dimensional ultrasonic imaging of the fetal palate

Objective To evaluate the value of angled insonation technique in obtaining the volumes of the fetal palate and in three-dimensional post-processing.Methods Five hundred and sixty-six cases of 20~28 weeks fetuses with normal face were confirmed by systemic ultrasound examinations and post-natal examination.The volumes in the standard midsagittal plane and angled midsagittal plane were obtained,then post-processed these data by 4D-View software.The same technology was used for volume data acquisition and processing to 1 case of cleft lip and palate fetal.Results In 566 fetuses,two groups of volume data were successfully acquired in 458 cases (standard midsagittal plane group) and 411 cases (angled midsagittal plane group).Fetal primary palate in the standard group and the angled group can be both well visualized(100%).Axial plane of hard palate can not be reconstructed in the standard group.Only 36% of the fetal hard palate's coronal plane and transoral oblique coronal plane can be reconstructed.The visualization rate of soft palate was 87% in the standard group,which was slightly higher than the angled group (82%).The visualization rate of hard palate's axial plane,coronal plane and transoral oblique coronal plane was 100% respectively in the angled group.Cleft alveolar process involving the secondary palate can be clearly visualized in 1 case of cleft lip and palate fetus.Conclusions By using the angled insonation technique,which is based on clearly visualizing secondary palate to obtain volumes,using three-dimensional post-processing technique can obtain the conventional three orthogonal planes and any other section of the whole palate.By using it we can assess the integrity of fetal palate,diagnose cleft lip with or without cleft palate and classify the cleft palate,even make prenatal diagnosis of the isolated cleft palate possible. Key words: Ultrasonography,prenatal; Ultrasonography,three-dimensional; Palate