Comparative Study Of Ultrasound And Magnetic Resonance In Prenatal Diagnosis Of Fetal Malformations

Background and objective:Fetal malformations are the most common manifestation of fetal developmental abnormalities,occurring in 1% of all live births[1].The main means of prenatal diagnosis of fetal malformations is ultrasound,however,due to the influence of amniotic fluid volume,fetal bones,maternal obesity,and uneven operator ability,it is easy to cause misdiagnosis or missed diagnosis [9].Since Smith et al.first applied MRI to fetal examination in 1983[4],MRI has gradually been used in the examination of fetal structural abnormalities.MRI is increasingly being used to examine fetal structural abnormalities.Fetal MRI is an important imaging test in conjunction with ultrasound,which not only confirms the ultrasound results,but also supplements the ultrasound results[8].In this article,a retrospective cohort study was used to compare fetal MRI with prenatal ultrasound results to provide more adequate fetal prognosis information for prenatal consultation,diagnosis and timely intervention,so as to better guide clinical practice.Methods:This study is a retrospective cohort study with several potential biases.We collected a total of 777 pregnant women who were diagnosed with abnormal development of the fetal central nervous system,chest,abdomen and other by ultrasound results between September 2018 and February 2022,and underwent further MRI examinations.The MRI diagnosis results were grouped and compared with the US diagnosis results.We explored the clinical value of US and MRI in the diagnosis of fetal central nervous system,abnormal chest development,abnormal abdominal development and other abnormalities.We also explored the influence of MRI examination on prenatal consultation and pregnancy outcome and the influence of gestational age on the consistency of prenatal ultrasound and fetal MRI examination results.Results:566 cases in the fetal central nervous system dysplasia group: In 341 cases(60.25%),the diagnostic results of MRI were consistent with those of ultrasonography.MRI corrected the ultrasound diagnosis in 52 cases(9.19%).MRI revealed an additional 139(24.56%)fetal abnormalities that could not be detected by ultrasound,of which 35(6.18%)had abnormal findings that influenced fetal prognosis and perinatal clinical decision-making.The ultrasound diagnostic information in 34 cases(6.01%)was more than in the MRI group,and all were intracranial cystic echoes.Among different types of central nervous system dysplasia,there were statistically significant differences in the complementary and corrective effects of MRI on ultrasonography(P<0.001).The older gestational age,the more MRI corrected and supplemented the antenatal ultrasound results,and the difference was statistically significant(P<0.001).14 cases in the fetal chest dysplasia group: The MRI diagnosis results of 7 cases(50.00%)were consistent with the results of ultrasonography.MRI corrected ultrasound measurements in 3 cases(21.43%).MRI revealed an additional 4(28.57%)fetal abnormalities that could not be detected by ultrasound,of which 2(14.29%)had abnormal findings that influenced fetal prognosis and perinatal clinical decisionmaking.127 cases in the fetal abdominal dysplasia group: The MRI diagnosis results of 54 cases(42.52%)were consistent with the results of ultrasonography.MRI corrected ultrasound measurements in 17(13.39%)cases.MRI revealed an additional 56(44.09%)fetal abnormalities that could not be detected by ultrasound,of which 14(11.02%)had abnormal findings that affected fetal prognosis and perinatal clinical decision-making.There were statistically significant differences in the complementary and corrective role of MRI in the different types of abdominal dysplasia(P<0.001).MRI findings were not statistically significant for correcting and supplementing antenatal ultrasound findings in different gestational age groups(P = 0.686).70 cases fetal in the other phylogenetic abnormalities group(including abnormal development of the spine,abnormal position of the conus medullaris,cleft lip and palate,and other malformations): In 36 cases(51.43%),the MRI diagnosis results were consistent with the ultrasound results.MRI corrected ultrasound measurements in 23(32.86%)cases.MRI revealed an additional 11(15.71%)fetal abnormalities that could not be detected by ultrasound,of which 9(12.86%)had abnormal findings that affected fetal prognosis and perinatal clinical decision-making.Among the three types of developmental abnormalities of spinal dysplasia,spinal cone position abnormality and cleft lip and palate,MRI had a statistically significant difference in the supplementary and corrective effect of ultrasound(P=0.02),among which fetal MRI had the greatest effect on supplementing and correcting prenatal ultrasound among spinal cone position abnormalities.Conclusion:In fetal central nervous system dysplasia,MRI has obvious advantages over prenatal ultrasound in the diagnosis of fetal lateral ventricle dilation,transparent septum abnormality and posterior fossa abnormality.Prenatal ultrasound has obvious advantages over fetal MRI in the diagnosis of intracranial cystic echoes such as choroidal plexus cyst,arachnoid cyst,and central sail cavity,and fetal ultrasound is still a follow-up method during pregnancy for fetal intracranial abnormalities.When prenatal ultrasound suggests abnormal development of the fetal central nervous system,it should be recommended that patients undergo MRI after 24 weeks of gestation under the premise of assessing urgency,so as to facilitate clinicians to provide more accurate and comprehensive clinical counseling for patients.In the diagnosis of fetal urinary system dysplasia,intestinal obstruction,intrahepatic mass lesions,and abdominal masses,MRI has important clinical value,which can clarify the lesion site and the nature of the mass,which is conducive to the perinatal management of the fetus.Among fetal spinal cord dysplasia,MRI is more accurate than prenatal ultrasound for the diagnosis of tethered cord syndrome,suggesting that when prenatal ultrasound finds spinal dysplasia and spinal cone position is low,further MRI examination is conducive to fetal perinatal management and improves fetal prognosis.