Summary of basic knowledge of ultrasound(part three)

Section 7 Measurement methods and normal values of gynecological ultrasonography
one. Uterus
Three diameters need to be measured, the longitudinal diameter, transverse diameter and anteroposterior diameter of the uterus.
1. Uterine longitudinal diameter (upper and lower diameter) measurement;
(1) Measurement section: Sagittal section of the uterus. It is necessary to clearly show the symmetrical sections from the fundus of the uterus to the internal os of the cervix, the muscle layer, and the front and back layers of the endometrium.
(2) Measurement location: Uterine body: the distance between the outer edge of the uterine fundus and the internal os of the cervix. Cervix: the distance between the internal os of the cervix and the external os of the cervix.
(3) Normal value: palace body 5.0 ± 1.0cm. Cervix 2.5-3.0cm.

2. Measurement of the transverse diameter (left and right diameter) of the uterus:
(1) Measurement section: coronal section of the uterus. The uterus needs to be transected, and the measurement is performed at the middle of the uterine body and when the image shows the largest elliptical section (not at the place where the image is triangular).
(2) Measurement position: the maximum left and right diameter passing through the uterine body.
(3) Normal value: 4.3 soil 0.73cm
3. Measuring the anteroposterior diameter of the uterus (also measuring the distance between the outer edges of the anterior and posterior layers of the endometrium):
(1) Measurement cut plane: the same as the measurement plane of the longitudinal diameter of the uterus.
(2) Measurement position: perpendicular to the longitudinal meridian of the uterus, measuring the maximum anteroposterior distance.
(3) Normal value: 4.3 ± 0.9Cm
two. ovary
Also need to measure three diameter lines, longitudinal diameter, transverse diameter and front and rear diameter.
1. Measurement section: same as the uterine measurement section, the measurement of longitudinal diameter, transverse diameter and anteroposterior diameter is carried out. When the ovary is not easy to identify, the patient can be placed in an oblique position, and the contralateral ovary can be scanned and measured through the full bladder as an acoustic window.
2. Measurement location: the largest diameter line through the ovary.
3. Normal value: Since the size of the ovary is related to factors such as age, the commonly used volume formula is: length × width × thickness / 2, and the normal value should be less than 6ml. The size of the ovary of an adult woman is about 4cm×3cm×1cm.
4. Observe and judge whether there is follicular development and whether it is mature and ovulated.
Section 8 Obstetric Ultrasound Measurement Methods and Normal Values
one. Gestational sac (GS)
The fetal sac is usually visible at 5-6 weeks.
1. Measuring section: under moderate filling of bladder gel, take the longitudinal section of the uterus to measure the maximum longitudinal diameter and anteroposterior diameter of the gestational sac, and measure the maximum transverse diameter on the transverse section of the uterus.
2. Measuring position: each diameter line should measure its inner diameter
two. Biparietal diameter (BPD) measurement
1. Measurement section: In the cross-sectional view of the fetal head, when the thickness of the skull plates on both sides is consistent, the measurement should be performed when the midline of the brain, thalamus, and third ventricle are clearly displayed.
2. Measurement location: through and perpendicular to the midline of the brain, measure the maximum distance between the outer edge of the proximal skull plate and the inner edge of the outer edge of the distal skull plate, that is, the maximum transverse diameter of the fetal head.
3. Normal value: This diameter line is suitable for mid-term pregnancy to full-term pregnancy, that is, from 12 weeks to full-term. The biparietal diameter increased by an average of 3mm per week before the 31st week of pregnancy, by an average of 1.5mm during the 31st to 36th week of pregnancy, and by an average of 1mm per week after the 36th week of pregnancy.
three. fetal spine
1. Observation section: longitudinally observe the cervical, thoracic, lumbar and sacral vertebrae from the cervical vertebrae along the fetal head.
2. Observation content: In the longitudinal section, the fetal spine is two bright spots in the shape of beads arranged in parallel and neatly arranged until the caudal vertebra closes. When the probe is moved sideways, three light bands can be seen, and the middle is the echo of the vertebral body. The whole picture and physiological curvature of the spine can be displayed in the second trimester, and segmented observation is required in the third trimester. In the transverse section, three strong points of light in an inverted triangle shape formed by the ossification center of two vertebral arches and one vertebral body can be seen.
Four. fetal heart rate
1. Observation planes: At present, four-chamber, left ventricular long-axis and aortic short-axis planes are mostly used.
Fives. Measurement of amniotic fluid volume
The amount of amniotic fluid can reflect the growth status of the fetus in the uterus. In the early and middle stages, the fetus floats in the amniotic fluid, and in the third trimester, the amniotic fluid is around the fetus.
1. Measuring section: The probe moves parallel to the abdominal wall to measure the maximum depth of amniotic fluid.
2. Measurement position: In general measurement, the maximum depth of amniotic fluid is usually measured vertically; when the amount of amniotic fluid is small, the abdomen of the pregnant woman should be divided into four quadrants of upper right, lower right, upper left, and lower left centered on the navel, and the maximum depth of amniotic fluid in each area should be measured (Carcass and limbs cannot be included in the measurement area), and the average value is taken.
3. Normal value: It is not necessary to accurately calculate the amount of amniotic fluid. It is only estimated by the amount of excess, medium, and less during the inspection. ≥8cm is polyhydramnios, 3-8cm is normal, and ≤3cm is oligohydramnios.
six. placenta
1. Observation section: Move the probe perpendicular to the abdominal wall. In the early pregnancy, a half-moon-shaped diffuse fine spot attached to the inner wall of a certain side of the uterus can be detected. Until the full-term pregnancy, the echo gradually increases, and scattered spots can be detected in the middle. Or dense linear, flake, ring hyperechoic or anechoic areas.
2. Observation content and normal range:
(1) Thickness of the placenta: the normal thickness is 2 to 4 cm, generally not more than 5 cm.
(2) Placental location: The placenta can be located on any side of the uterine wall.
(3) Maturity of the placenta: Ultrasonic examination judges the maturity of the placenta by the echo changes of the chorion, placental parenchyma and basal layer, and the maturity of the placenta is often divided into four grades.
Table 8-1-7 Placenta Maturity Grading Standards
Grade Chorionic plate Placental parenchyma Basal layer
0 Flat and smooth linear echoes Evenly distributed point echoes No enhanced echoes
Ⅰ Slightly wave-like linear echoes Scattered point-like echoes No enhanced echoes
Ⅱ Obviously wavy, the notch extends into the placental parenchyma, but does not reach the basal layer Scattered inhomogeneous point-like hyperechoes Linear hyperechoes
Ⅲ Prominent notch extending into the placental parenchyma, reaching the basal layer Ring-shaped hyperechoic, scattered in the anechoic area Large and fused hyperechoic