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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5802_Библиотеки_им_академика_М_И_Перельмана.pdf
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Obstetrics
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14
Induni Douglas, Anthony E. Swartz,
and Wui K. Chong
Gestational sac 300
Embryonic/fetal heartbeat
st
(1
trimester) 304
Crown rump length 308
Discriminatory levels
for diagnosis of
pregnancy failure in rst
trimester (transvaginal
ultrasonography) 310
Nuchal translucency
thickness measurement 312
Nuchal fold thickness
measurement 314
Biparietal diameter 316
Head circumference 320
Abdominal circumference 324
Fetal femur length 328
Multiple fetal parameters
in the assessment of
gestational age 332
Multiple fetal parameters
in the assessment of fetal
weight 336
Fetal humerus length 354
Transcerebellar diameter 358
Head to abdominal
circumference ratio 362
Transcerebellar diameter to
abdominal circumference
ratio 364
Systolic/diastolic ratio in
the umbilical artery 366
Cerebral ventricular
measurements and 368
lateral ventricle
transverse atrial
measurement (atrial size) 368
Cisterna magna
measurements 370
Thoracic circumference 372
Renal pelvis diameter 374
Mean renal lengths for
gestational ages 376
Outer orbital diameter 380
Nasal bone length 382
Fetal stomach diameter
measurements 386
Fetal colon
measurements 388
Fetal small bowel
measurements 390
Amniotic uid index 392
Length of cervix and cervical
canal in pregnancy 396
Obstetrics
300
Gestational sac
PREPARATION
Empty bladder.
POSITION
Mother is in the lithotomy position. Sagittal and transverse images of
the endometrial stripe are obtained.
TRANSDUCER
Transvaginal 5.0–8.0 MHz transducer.
METHOD
Average of three perpendicular diameters with the calipers placed at
the inner edge of the gestational sac are obtained.
APPEARANCE
The gestational sac should be visualized by 5 weeks from the last menstrual period, with transvaginal sonography (TVS) and by 6 weeks
with transabdominal sonography (TAS), as a small uid collection
with high-reective rounded edges embedded within the endometrium,
without visible contents.
MEASUREMENTS
β-hCG threshold level above which gestational sac should be seen on
TVS:
• Singleton 1000 milli-international units per milliliter (mIU/ml|) (FIRP)
• Twin 1556 mIU/ml
• IVF/GIFT 3372 mIU/ml
FIRP stands for First International Reference Preparation.
2 5 + 0
3 5 + 1
4 5 + 1
5 5 + 3
6 5 + 3
7 5 + 3
Gestational sac
The gestational sac (GS) is measured at 17 mm in this TAS image (between cursors).
301
8 5 + 4
9 5 + 5
10 5 + 6
11 6 + 0
12 6 + 1
13 6 + 2
14 6 + 3
15 6 + 4
16 6 + 5
17 6 + 5
Obstetrics
302
18 6 + 6
19 7 + 0
20 7 + 1
21 7 + 2
22 7 + 3
23 7 + 4
24 7 + 5
25 7 + 5
26 7 + 6
27 8 + 0
28 8 + 1
29 8 + 2
30 8 + 3
31 8 + 3
32 8 + 4
33 8 + 5
34 8 + 6
35 9 + 0
36 9 + 1
37 9 + 1
38 9 + 2
39 9 + 3
40 9 + 4
41 9 + 4
42 9 + 5
43 9 + 6
Gestational sac
44 10 + 0
45 10 + 1
46 10 + 1
47 10 + 2
48 10 + 3
49 10 + 3
50 10 + 4
FURTHER READING
Daya S, Woods S, Ward S, Lappalainen R, Caco C. Early pregnancy
assessment with transvaginal ultrasound scanning. Can Med
Assoc J. 1991; 15:441–446.
Grisolia G, Milano K, Pilu G, Banzi C, David C, Gabrielli S, Rizzo
N, Morandi R, Bovicelli L. Biometry of early pregnancy with
transvaginal sonography. Ultrasound Obstet Gynecol. 1993;
3:403 – 411.
303
Obstetrics
304
Embryonic/fetal heart rate (1st trimester)
PREPARATION
Empty bladder for transvaginal imaging.
POSITION
Mother is in the lithotomy position. Sagittal and transverse images of
the endometrial stripe are obtained.
TRANSDUCER
Transvaginal 5.0–8.0 MHz transducer.
METHOD
Recorded by M mode or 2D video clip.
APPEARANCE
Heartbeat is initially imaged as a shutterlike pulsation at the point
where the yolk sac joins the wall of the gestational sac. Usually the fetal
heartbeat is observed with the embryo > 2 mm. If an embryo is > 7mm
without cardiac motion, this is suspicious for pregnancy failure.
MEASUREMENTS
6–6.6 126
7–7.6 160
8–8.6 179
9–9.6 178
10–10.6 175
11–11.6 169
12–12.6 164
13–13.6 162
14–14.6 160
Embryonic/fetal heart rate (1st trimester)
305
The heartbeat is measured where the yolk sac (long arrow) joins the wall of the gestational
sac (short arrow). An M-mode trace demonstrates the heartbeat.
1 99
2 104
3 109
4 114
5 119
6 124