Release date: 2015-12-10 With the development of the current social science and technology have increased environmental pollution, according to the authority of the "Chinese Birth Defects Prevention Report (2012)" Our data show that the overall incidence of birth defects is about 5.6% per year up to 90 new cases of birth defects Ten thousand cases. Therefore, prenatal screening and diagnosis of fetal malformation and smooth production are the most effective preventive measures to reduce birth defects in children. As the national two-child policy has just been implemented, some pregnant women will become pregnant again after cesarean section. In this case, the incidence of placenta previa, placenta implantation and uterine rupture will be much higher than that of vaginal delivery. Prenatal ultrasound has long been considered the preferred imaging method for understanding placental status and screening for fetal malformations. However, due to the shape of the pregnant woman, intestinal gas accumulation and bone effects, the penetration of the ultrasonic waves is reduced or the reflected waves are increased, and the lesions are unclear, especially for the observation of the posterior wall of the uterus. Magnetic resonance imaging has a wide range of MRI examinations, is less affected by intestinal gas and bones, has high tissue resolution, and can be imaged at multiple angles at any angle, so it can be used as an important supplement to ultrasound examination. MRI examination has no ionizing radiation, and it is safe. There is no report that a magnetic field has caused harm to the fetus. In order to further ensure the safety of the fetus, MRI is not performed for the fetus within 3 months of pregnancy, and the fetus within 3 to 5 months is not recommended or carefully performed MRI. In order to avoid the potential danger of the thermal effect of the RF pulse, it is advisable to choose a low field strength 1.5T model. Studies to date have not shown that MRI-enhanced contrast agents may cause harm to the fetus, and may be injected when the condition is needed, but it is not recommended to be performed in the third to sixth months of the pregnancy. Sedatives are forbidden due to their effects on the fetus. Fetal MRI technology has been applied to the clinic since 1983. With the development of fast scan sequences, artifacts caused by fetal movements are overcome, and anatomical structures can be clearly displayed. It is of great value especially in the prenatal diagnosis of the central nervous system and chest and abdomen diseases of the fetus. Fetal MRI is non-invasive and is not affected by factors such as gestational age, oligohydramnios, fetal position and maternal body shape. The soft tissue contrast resolution is high, and the organs of the mother and fetus can be clearly displayed, and images of any level can be obtained, which can effectively evaluate almost All organ systems. The rapid scanning sequences applied to fetal MRI examination include plane echo imaging, gradient echo imaging, and fast spin echo imaging. Currently, the main techniques used are as follows: (1) Half-Fourier acquisition single-shot RARE Sequence (Siemens called HASTE), rarely produces fetal movement artifacts, with high temporal resolution and good image contrast, mostly used to evaluate the nervous system; (2) balanced steady-state free precession sequence (Siemen called True FISP ), its imaging speed is fast, single-layer image acquisition time is often within 1s, no obvious motion artifacts, especially suitable for fetal examination; (3) T1WI fast small angle excitation sequence (2D FLASH), compared to the above two sequences The signal to noise ratio and contrast of the sequence image are not ideal. Rapid imaging greatly reduces the effects of fetal movement and maternal respiration on the image, but the involuntary movement of the fetus still affects the position of the image. Therefore, the scan line positioning of each sequence must be based on the previous scan sequence. With the development and wide application of magnetic resonance rapid scanning imaging technology, MRI will play an important and decisive role in the examination of pregnancy complications and fetal screening. Source: People's Liberation Army No. 306 Hospital Eas Detector,Eas Anti Theft System,Electronic Article Surveillance,Sensormatic Anti Theft System WENZHOU BOSHINE ELECTRONIC SECURITY CO.,LTD , https://www.boshine.com