Diagnostic ultrasound ( PDFDrive )

1142 PART IV Obstetric and Fetal Sonography
TABLE 33.1 Normal Orbital Diameters in the Fetus
Gestational
Age (wk)
INNER DIAMETERS (mm)
OUTER DIAMETERS (mm)
5th Percentile 50th Percentile 95th Percentile 5th Percentile 50th Percentile 95th Percentile
13 4 7 10 12 16 20
14 5 8 11 14 18 22
15 5 8 11 17 21 25
16 6 9 12 19 23 27
17 7 10 13 21 25 29
18 8 11 14 24 27 31
19 8 11 14 26 30 34
20 9 12 15 28 32 36
21 10 13 16 30 34 38
22 10 13 16 32 36 40
23 11 14 17 33 37 41
24 12 14 17 35 39 43
25 12 15 18 37 41 45
26 13 16 19 39 43 47
27 13 16 19 40 44 48
28 14 17 20 42 46 50
29 14 17 20 43 47 51
30 15 18 21 45 49 52
31 15 18 21 46 50 54
32 16 19 22 47 51 55
33 17 20 23 48 52 56
34 17 20 23 49 53 57
35 18 21 24 50 54 58
Table generated from raw data using two separate quadratic regression models:
Outer diameter = −2.17 + 3.36(Age) − 0.03 (Age 2 )
R 2 = 0.96, p < .001
Inner diameter = −4.14 + 0.94(Age) − 0.007 (Age 2 )
R 2 = 0.84; p < .001
With permission from Trout T, Budorick NE, Pretorius DH, McGahan JP. Signiicance of orbital measurements in the fetus. J Ultrasound Med.
1994;13(12):937-943. 32
A
B
FIG. 33.9 Hypotelorism. (A) Microtia and hypotelorism. Axial sonogram shows small orbits (arrowheads), close together in the face, and
the protuberant maxilla (arrow). The fetus also had agnathia and low-set ears (see Fig. 33.29). (B) Hypotelorism and abnormal nose (arrow) at 35
weeks’ gestation. Axial magnetic resonance image of a 35-week fetus shows the relatively small intraorbital distance and an abnormal nose. The
fetus was in deep vertex prone position, and the face could not be seen on fetal sonography before magnetic resonance imaging. This fetus was
diagnosed postnatally with a complex Tessier cleft.