Diagnosis Of Fetal Intestinal Dilatation And Evaluation Of Intestinal Wall Function By Multimodal Ultrasound

Background:Fetal intestinal dilation is usually only detected on ultrasound examination in the middle or late stages of pregnancy,and its incidence in live births is about 1.3-2.8/10000^[1].It can persist without significant clinical symptoms after birth,and may also lead to adverse pregnancy outcomes,especially when combined with intestinal necrosis and other system abnormalities.Prenatal misdiagnosis and untimely intervention can lead to a significant increase in neonatal mortality,which also makes prenatal management and consultation difficult.Currently,there were very limited data on fetal outcomes f in late pregnancy with complex intestinal dilatation.In addition,prenatal ultrasound findings that may help predict the outcome and prognosis of fetal intestinal dilation pregnancy remain unclear.The evaluation of intestinal wall blood circulation and function is particularly important for the prognosis of these diseases,but there is a lack of good prenatal evaluation methods.Objective:1.Different modes of two-dimensional and three-dimensional crystal imaging were used to diagnose the pathological intestinal dilatation of the fetus and identify the obstruction sites,evaluating the diagnostic efficacy of different ultrasonic signs and their value in predicting adverse pregnancy outcomes,providing more diagnostic basis and methods for the diagnosis of fetal pathological intestinal dilation,following up and analyzing the pregnancy outcomes and postoperative results of fetuses with intestinal dilation in different sites,to explore the risk factors for adverse pregnancy outcomes and establish a predictive model for the predictive mode of neonatal surgery.2.MV-Flow technology was used to conduct quantitative analysis of fetal mesenteric blood perfusion,explore the characteristics of fetal mesenteric blood perfusion in different gestational weeks.analyze the changes of mesenteric blood perfusion in fetuses with intestinal dilation and MP,and conduct hierarchical evaluation of microperfusion in the dilated intestinal wall.To explore the feasibility of MV-Flow technology in evaluating intestinal wall blood flow and function.Method:1.A total of 125068 fetuses underwent prenatal ultrasonography in Anhui Maternal and Child Health Hospital and the First Affiliated Hospital of Anhui Medical University from June 2018 to April 2023 were retrospectively analyzed..Among with 141 fetuses with dilated intestinal met the inclusion and exclusion criteria.The dilated intestines were imaged using grayscale and inversion methods in the Crystal Vue mode of three-dimensional volume imaging.The results of prenatal diagnosis were compared with the results of postnatal surgery,imaging examination or induction of labor,and the birth weight and gestational age of the newborns were followed up.The postoperative complications of gastrointestinal tract were followed up for the children undergoing surgery.According to the location of intestinal obstruction,the cases were divided into:duodenal dilation group,small intestinal dilation group,and colon dilation group.The patients were divided into isolated intestinal dilatation group and complex intestinal dilatation group according to whether there were other ultrasonic abnormalities outside the digestive system.The general data and ultrasonic features of intestinal dilatation in different parts were compared and analyzed,and the prediction model for neonatal surgery was established..2.Among 141 fetuses with intestinal dilation,35 fetuses with intestinal dilatation and accompanying symptoms of digestive system were diagnosed by fetal MRI,confirmed by postnatal or post-induced labor follow-up,met the inclusion and exclusion criteria of MP group,and had complete data.160 fetuses with normal test results during the same period were included as the normal control group.The vascular index（VI）of the superior mesenteric artery region obtained by different methods（automatic ellipse method,manual method）was compared.The correlation between the region of interest VI and gestational age was analyzed,and the normal range and 95%confidence interval of the vascularization index VI in the mesenteric blood flow perfusion area were calcalated.According to the outcome of pregnancy,the cases of meconium peritonitis were divided into MP surgical group and MP non-surgical group.The dilated intestinal diameter,abdominal fluid accumulation,and self-healing time of the non-surgical group were analyzed between the two groups.MV-flow technology was used to evaluate the fetal dilated intestinal wall blood flow:the continuous strip blood flow signal of the intestinal wall was set to level I,the short rod blood flow display was set to level II,the star-dot blood flow signal was set to level III,and no blood flow signal was set to level IV.Result:1.Among 141 cases of fetal intestinal dilation,44 cases of duodenal dilation,65 cases of small intestinal dilation,and 32 cases of colon dilation were found.The gestational age of duodenal dilation was the earliest,and the gestational age of duodenal dilation was significantly different among the three groups（P<0.05）.Compared with colonic dilation,the gestational weeks of fetal duodenal dilation and small intestinal dilation were significantly earlier（P<0.05）,and the birth weight in duodenal dilation group was significantly reduced（P<0.05）.There were significant differences in the incidence of other system abnormalities among different of intestinal dilation（P<0.001）.There were significant difference in the incidence of the three ultrasonic signs of fetal volvulus:"vortex sign","coffee bean sign",and"coiling sign"（P<0.05）,with"coiling sign"was the most common.Based on the diameter of the dilated small intestine,an ROC curve was constructed to predict pathological small intestinal dilation.The area under the ROC curve was 0.868（95%confidence interval:0.773-0.963,P<0.05）,and the truncation value of the small intestinal diameter was 13.5mm,the sensitivity was 86%and the specificity was 73%.The ROC curve was used to predict pathological colonic dilation based on colonic diameter,the ROC curve was 0.916（95%confidence interval:0.810-1.00,P<0.05）,with the truncation value of the colonic diameter was 23.5mm,with a sensitivity of 81.8%,and a specificity of 85.7%.In the differential diagnosis of small intestinal obstruction and colonic obstruction,the diagnostic efficiency of three-dimensional ultrasound was higher than that of two-dimensional ultrasound（P<0.05）."Double bubble sign"is an effective sign for predicting neonatal duodenal obstruction surgery.The regression model most suitable for predicting the occurrence of intestinal and colonic dilatation surgery in neonatal is Logit（P）=-1.58+2.32X₁+2.0X₂+1.14X₃（hydramnios is X₁,ascites is X₂,strong intestinal echoes is X₃）.The area under the ROC curve（AUC）of the predictive model with these three factors is 0.874（95%confidence interval,0.766-0.982）,with a sensitivity of 76%and specificity of 94.1%.2.There was no statistically significant difference in the VI values of mesenteric blood flow perfusion area obtained by different methods to trace the area of interest（P<0.05）.There was no significant correlation between the VI value of the mesenteric region and gestational age in the normal group.Compared with the MP surgical group and the non-surgical group:There were no statistically significant difference in maternal age,gestational complications,gestational age at first discovery,and fetal gender at birth（P>0.05）;There were statistical significant differences in delivery method,gestational age,and birth weight（P<0.05）.Compared with the MP non-surgical group,persistent abdominal fluid and reduced intestinal wall echo were more common in the surgical group.There was a significant difference in the VI value of the mesenteric blood flow perfusion area between the MP surgical group and the non-surgical group（P<0.001）,and the VI value of the mesenteric area in the surgical group was significantly lower than the normal reference range.MV-Flow was used to grade the intestinal wall blood flow and determine the pregnancy outcome of MP fetuses.The results showed that grade I to II blood flow had a good prognosis and could heal itself through prenatal observation or postpartum conservative treatment,while Grade III-IV blood flow had a poor prognosis and required surgical intervention,the sensitivity was 94.4%,the specificity was 88.2%,and positive predictive value was 89.5%,the negative predictive value was 93.8%.Conclusion1.Duodenal dilation occursed earlier in pregnancy and had the highest incidence of chromosomal abnormalities and other systemic abnormalities;The echo changes of intestinal contents cannot effectively identify the location of intestinal obstruction.3D volume imaging can effectively identify the location of intestinal obstruction.After the combination of crystal and simulation rendering technology,the inverted mode can better display the adjacent relationships and external changes of tissues and organs.The grayscale mode is helpful for the observation of intestinal contents and the inner wall of the intestine.Fetal intestinal dilatation has the possibility of self-healing.For fetuses with intestinal dilation,ultrasound follow-up should be performed once every 2 weeks.The risk of neonatal surgery increases when the volume of abdominal fluid increases,the amount of amniotic fluid increases,and the presence of strong intestinal echo increases.For the fetal intestinal dilataion,the management that may be required after delivery and the eventual pregnancy outcome cannot be discussed solely on the basis of the results of the examination at one stage.2.The dilation of the small intestine often accompanied by blood flow disorders in the intestinal wall,leading to the occurrence of intestinal necrosis.MV-Flow can provide a semi-quantitative grading evaluation of blood flow in fetal dilated intestinal,and can also well display and quantify the blood flow perfusion between intestinal loops in the mesenteric region.Different measurement methods have good repeatability.There was no significant correlation between the VI value of the mesenteric region blood perfusion and the gestational age,by quantitative evaluation of MP fetal mesenteric blood flow perfusion,it was found that the VI value of fetal mesenteric regional blood flow in the surgical group was significantly reduced.Prenatal evaluation of fetal mesenteric blood flow perfusion and dilated intestinal wall blood flow can provide more effective basis for perinatal management and pregnancy timing selection.