In the minds of many pregnant women, four-dimensional color Doppler ultrasound seems to be used to take pictures of the fetus, but in fact, the purpose of four-dimensional examination is much more than that. Li Qiuming, former deputy chief physician of the Imaging Department of Guangzhou Women and Infants Hospital, said that four-dimensional color Doppler ultrasound is mainly used to detect fetal congenital malformations and congenital heart disease. She also reminded that two points should be paid special attention to when conducting four-dimensional color ultrasound examination:
1. Different screening purposes and different inspection times
Li Qiuming introduced that the first trimester (before 12 weeks of pregnancy) is the period when fetal organs are forming. Before 18 weeks of pregnancy, the B-ultrasound examination was not clear enough due to insufficient amniotic fluid. It is recommended to have a four-dimensional color ultrasound examination after 18 weeks of pregnancy. In the second trimester (after 18 weeks of pregnancy), the fetus\’s limbs and major organs are fully developed. Among them, fetal organ development is more complete between 18 and 30 weeks of pregnancy, and the amount of amniotic fluid is larger, which is more suitable for fetal malformation screening; the best time for fetal heart abnormality screening examination is between 20 and 28 weeks of pregnancy. Therefore, the four-dimensional examination can be performed at 28 weeks of pregnancy. Judging from long-term clinical experience, examination at 24-28 weeks of pregnancy has the best effect.
It is recommended that expectant mothers choose at least one type of four-dimensional color Doppler ultrasound during the second trimester ultrasound examination, which can more accurately remove abnormalities. Wei Xiaoming, director of the ultrasound imaging center of a Guangzhou obstetrics and gynecology hospital, said that ordinary color Doppler ultrasound has certain accuracy in excluding abnormalities of fetal large organs. However, for parts such as the face or the back of the head, ordinary color Doppler ultrasound images are blurred, which can easily lead to missed diagnosis. . There was once a pregnant woman who found no abnormality in the fetus through ordinary color ultrasound, but found that the fetus had a cleft lip during 4D color ultrasound.
2. Cannot replace other inspection items
Li Qiuming said: Under normal circumstances, it takes 15 to 30 minutes to do a 4D color ultrasound, but because each pregnant woman\’s situation is different, the time required will also vary. Because the output power of ultrasound is small and it is not pointed at a certain place for a long time, it will not cause harm to the fetus and mother.
She reminded that the four-dimensional examination will be affected by some factors, such as oligohydramnios, maternal obesity, abnormal fetal position, placenta and uterine wall close to the limbs and face, too frequent fetal movements, etc., which will affect the examination results. Four-dimensional fetal examination. Although fetal heart malformation screening technology has perfectly filled the gap in routine fetal heart malformation screening, its main targets are still severe fatal fetal heart malformations, while for some small cardiac malformations and some malformations that can be surgically treated after birth Less sensitive, such as atrial defects and small ventricular defects. Therefore, at this stage, even in European and American countries where this technology is the most developed, the diagnosis rate is only 60%. Therefore, do not think that everything will be fine after this inspection, but ignore its limitations and the inspection effects of other inspection items. Li Qiuming said.