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Atlas of Human Body Ultrasound Scanning_ Methods and Diagnostic Applications ( PDFDrive ).pdf
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480

YQ. Zhou et al.

 

 

1.3.1\ Scanning Method

The patient is maintained in the supine position, with full bladder and exposure of the lower abdomen. The probe should be placed longitudinally on the medioventral line above the pubic symphysis.

1.3.2\ Section Structures

Sagittal section of the uterus and sagittal section of the gestational sac, with yolk sac (YS) and embryo bud (EMB) being shown.

1.3.3\ Measuring Method

The longitudinal diameter and the anteroposterior diameter of uterus are measured in this section, as well as the diameters of gestational sac

and the inner diameter of the yolk sac. Whether there is the embryo bud or not is observed. The mean diameter of the gestational sac is approximately 15–20 mm at 6 weeks of gestation.

1.3.4\ Clinical Significance

The yolk sac shown as a round-shaped echo could be observed at 5 weeks of gestation, which is a marker of intrauterine pregnancy and is helpful in distinguishing a real intrauterine gestational sac from the fake one. The YS shrinks at 9 weeks of gestation and will be incorporated into the umbilical cord finally. The length of the embryo bud, as well as the beats and the rhythm of the original heart tube, should be noticed.

13  Normal Pregnancy

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1.4\ Scanning at 6–7 Weeks

of Gestation

Fig. 13.4  Early pregnancy at 6–7 weeks of gestation. The uterus, the gestational sac, and the fetal body bud are shown. GS gestational sac, EMB embryo bud

GS

EMB

BL

BL

482

YQ. Zhou et al.

 

 

1.4.1\ Scanning Method

The patient is maintained in the supine position, with properly filled bladder and exposure of the lower abdomen. The probe should be placed longitudinally on the medioventral line above the pubic symphysis.

1.4.2\ Section Structures

Sagittal section of the uterus and sagittal section of the gestational sac are shown, with yolk sac (YS) and embryo bud (EMB) being shown.

1.4.3\ Measuring Method

Sizes of the gestational sac and embryo bud are measured in this section. M-mode ultrasound could be applied to detect fetal heart beats.

1.4.4\ Clinical Significance

According to the parameters detected above, the viability of the embryo, the development of the embryo, and the ratio between the GS and the EMB are estimated. In normal pregnancies, equivalence should be there between these parameters and the gestational weeks. The amniotic cavity occupies the extraembryonic coelom gradually after 6 weeks of gestation and becomes the main component of gestational sac.

13  Normal Pregnancy

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1.5\ Scanning of the Gestation at

8–9 Weeks’ Pregnancy

Fig. 13.5  Early pregnancy at 8–9 weeks of gestation. The uterus, the gestational sac, and the fetal body bud are shown. PL placenta, the calipers refer to the fetus

F

F

PL