Biomedical Engineering Reference
In-Depth Information
TABLE 8.7
Mean Gestational Sac Size (GS), Yolk Sac
Diameter (YS), Greatest Length (GL), and Embryonic
Heart Rates (EHR) for Both Rhesus and Long-tailed
Macaque
a
Mean GS
(mm)
YS (mm;
range)
GL
(mm)
EHR
(bpm)
GD
14
1.9
0.2
e
e
e
15
2.6
0.5
e
e
e
16
2.3
0.4
e
e
e
17
3.7
1.0
e
e
e
FIGURE 8.3
Sonogram (sagittal section) of macaque uterus on
gestational day (GD) 16. Note endometrial (uterine) cavity echo (small
arrows) and developing gestational sac (large arrow).
18
5.5
1.4
1e2
e
e
19
5.9
2.4
1e2
e
e
20
7.0
2.6
2e3
e
e
ECE shows a slight irregularity, thickening, or split in the
upper third of the uterine body (
Figure 8.3
). This represents
the developing gestational sac (GS), which by GD 18
appears as an ovoid fluid-filled structure approximately 5.5
21
8.9
2.8
2e3
2.0
0.0
60e80
22
9.3
2.9
2e3
2.9
0.6
72e104
23
10.7
2.3
3
3.4
0.8
80e120
1.4 mm in mean diameter. Early pregnancy (GD 14 or
16
e
30) can be accurately detected and assessed using the
sonographic developmental guidelines previously estab-
lished (
Table 8.6
). These guidelines are useful for assessing
early pregnancies at risk provided that normal develop-
mental variation and methods for mating are kept in mind.
In addition, no false positives or negatives result when
incorporating these techniques (
Tarantal and Hendrickx,
1988d
). Once pregnancy is identified, a variety of
measurements [mean GS size, yolk sac diameter, greatest
length (GL) of the embryo, and heart rate] are important for
monitoring normal development (
Tarantal and Hendrickx,
1988a,b,c
)(
Table 8.7
).
Of interest is the sonographic appearance of “implan-
tation bleeding.” Hypoechoic areas may appear to surround
the developing GS or appear within discrete regions such as
cranial and caudal to the GS. This can be distinguished
24
12.4
3.3
2e3
4.7
0.9
80e144
25
13.0
3.4
2e4
4.9
0.9
92e144
26
13.5
3.3
2e5
5.4
1.9
100e140
27
14.9
3.4
3e4
6.5
1.5
100e144
28
16.0
3.2
3e4
6.5
1.8
108e148
29
18.1
3.9
2e4
7.9
1.5
120e152
30
18.3
3.6
2e4
8.9
1.7
120e156
31
20.7
3.9
3e4
8.8
1.9
128e160
32
19.9
4.0
3e4
10.5
2.3
132e160
33
23.0
3.6
3e5
12.0
2.1
128e160
34
24.2
4.7
3e5
12.9
2.6
128e160
35
24.2
3.5
3e5
14.0
2.7
124e168
36
28.1
3.9
4e5
15.6
2.0
124e156
37
27.0
3.5
4e5
16.3
1.9
144e176
38
29.2
3.6
4e5
17.2
1.9
140e184
Sonographic Developmental Guidelines
a
TABLE 8.6
39
28.1
5.1
4e5
18.1
2.1
132e184
Feature
GD
31.9
3.8
4e5
18.7
2.0
132e168
40
Thickening and/or split in
ECE
14e15
41
32.2
3.4
4e6
20.4
1.9
140e180
42
32.6
3.3
4e5
21.4
2.1
140e172
Gestational sac
16e18
43
33.2
3.7
4e7
24.2
2.9
144e172
Yolk sac
18e20
44
34.4
3.4
4e9
24.4
2.2
144e176
Embryo
21e25
45
33.4
3.8
4e9
26.6
3.7
144e180
Cardiac motion
21e25
46
37.2
3.4
6e9
27.3
3.1
148e184
a
Gestational days (GD) 14e25. ECE, endometrial cavity echo.
From
Hendrickx and Dukelow (1995)
.
47
38.4
2.6
5e9
28.7
4.7
144e180
a
Macaca mulatta, Macaca fascicularis. Gestational days (GD) 14e47. Both
species similar in size during organogenesis (see
Tarantal and Hendrickx,
1988a,b
).
