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Frontomaxillary facial angle at 11 + 0 to 13 + 6 weeks: effect of plane of acquisition
Author(s) -
Plasencia W.,
Dagklis T.,
Pachoumi C.,
Kolitsi E.,
Nicolaides K. H.
Publication year - 2007
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.4033
Subject(s) - sagittal plane , medicine , transverse plane , coronal plane , fetal head , anatomy , transducer , plane (geometry) , nuclear medicine , orthodontics , physics , fetus , geometry , acoustics , pregnancy , mathematics , biology , genetics
Objective To determine the range of positions of the fetal head in which a three‐dimensional (3D) volume is acquired for subsequent successful assessment of the frontomaxillary facial (FMF) angle. Method We obtained 3D volumes of the fetal head at 11 + 0 to 13 + 6 weeks. The volumes were acquired with the head in different positions and reconstructed to obtain a mid‐sagittal section and demonstrate the maxilla, palate and frontal bone, which constitute the landmarks for the assessment of the FMF angle. Results In the reconstructed mid‐sagittal sections, it was possible to demonstrate the landmarks that define the FMF angle in most of the cases when the 3D volume acquisition plane was: (a) mid‐sagittal, with the angle between the face of the transducer and the direction of the fetal nose being about 0–99°, 150–199° and 330–359°; (b) transverse at the level of the biparietal diameter when the angle between the transducer and the midline echo of the brain was 0–29°; and (c) oblique around the crown–rump axis when the angle from the mid‐sagittal plane was 0–49°. However, the measurement of the FMF angle was artificially increased when in the mid‐sagittal plane the angle was 40–99° and 150–199°. Conclusion Successful assessment of the FMF angle by 3D ultrasound is dependent on the plane and angle of the volume acquisition. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.