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Fetal iliac angle measurements by three‐dimensional sonography
Author(s) -
Lee W.,
Blanckaert K.,
Bronsteen R. A.,
Huang R.,
Romero R.
Publication year - 2001
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 - 10.1046/j.1469-0705.2001.00447.x
Subject(s) - intraclass correlation , medicine , pelvis , trisomy , coronal plane , fetus , gestational age , nuclear medicine , anatomy , pregnancy , clinical psychology , genetics , biology , psychometrics
Objective To determine the technical reliability of fetal iliac angle measurements by three‐dimensional sonography as a prenatal marker for Down syndrome. Methods Three‐dimensional multiplanar views of the fetal pelvis were used to standardize iliac angle measurements from 35 normal second‐trimester pregnancies. Measurement reliability for a single examiner and between two different examiners were analyzed by intraclass correlation. Normal iliac angle measurements were compared to those obtained from 16 fetuses with trisomy 21. Results The mean axial angle for normal fetuses was 79 ± 5.5 °, which was significantly less than that observed in fetuses with trisomy 21 (87.7 ± 4.9 °) (P < 0.001). Iliac angles did not correlate with gestational age. Axial angles were reproducible between two examiners who measured the same multiplanar view of the pelvis. Inter‐ and intraobserver reliability were also acceptable after a standardized multiplanar view was independently obtained by each examiner (intraclass correlation = 0.91 for both). Coronal angles were unreliable because of difficulties with finding a reproducible measurement plane. For a false‐positive rate of 5%, an axial angle threshold of 87 ° correctly identified 56% of fetuses with trisomy 21. Conclusion Axial iliac angle measurements are reliable by standardized three‐dimensional multiplanar views of the pelvis and can be used to identify some fetuses at increased risk for trisomy 21. Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecology