The Diagnostic Value Of CT And MRI In Uterine Rupture

ObjectiveUterine rupture is a life-threating complication during gestation period.The purpose of this study is to evaluate the diagnostic value of CT and MRI in uterine rupture and to explore its image features.Materials and methodsA total of 35 patients proved to be uterine rupture or uterine dehiscence(incomplete uterine rupture)was retrospectively evaluated.All of them had underwent CT or MRI examination at the Third Affiliated Hospital of Guangzhou Medical University between Jan.2013 and Feb.2020.Thirty-five patients were divided into the uterine rupture group(n=12)and the uterine dehiscence group(n=23).Uterine rupture is a complete interruption of all three layers of the uterus including the endometrium,myometrium,and perimetrium.Therefore the uterine cavity can be directly communicated to the abdominal cavity,accompanied by displacement of the fetus into abdominal cavity.Incomplete uterine rupture is defined as very thin uterine wall with only serosa and lost muscular layer.We collected data from medical records as follows: including patient’s basic information,etiology,clinical manifestations,childbearing history,surgical history,treatment,and outcome,etc.We mainly analyzed the differences of etiology,high-risk factors,clinical manifestations,rupture site,maternal and fetal outcomes between two groups.All the patients underwent CT or MRI examination.CT scanning of the pelvis was performed using TOSHIBA Aquilion 64-slice spiral CT,and non-ionic iodine contrast agent was used for enhanced CT examination.After the scanning,three-dimensional reconstruction of coronal and sagittal was performed,and the reconstructed image was transferred to the PACS system workstation for image post-processing.MRI scanning of the pelvis was performed using 3.0T magnetic resonance imaging machine with an 8-channel body coil.Scanning sequences included: coronal,sagittal,and axial T2WI-TSE,sagittal T2WI-TSE--SPAIR and axial T1WI.The images were transferred to the PACS system and were analyzed combined with clinical data.By observing the CT or MRI images of the two groups,we found different image features in the uterine rupture and uterine dehiscence.Results1.Clinical data:uterine rupture group(n=12):The patients in this group were 20-40 years old,with an median age of 31.5years old.Five of them were primigravids(41.7%),and the rest were multiparous(58.3%).Only 4 patients had a history of previous cesarean section which was significantly less than that of the uterine dehiscence group,and 8 patients with other gynecological surgery history.The etiology or risk factor for each group was different.In uterine rupture,the major etiology or risk factor for this group were scar uterus(n=9),followed by placental implantation(n=3)and using of oxytocin(n=3),other rare cause of disease include uterine malformation(n=1),multiple pregnancies(n=1).In the uterine dehiscence group,the most common etiology was scar uterus(n=23).Uterine rupture is more common seen in primigravid patient and has more serious consequences.Patients with a uterine rupture may describe acute onset abdominal pain that begins with a “ripping” sensation,and it was the most frequent sign and symptoms in this group(75%),with the remaining three patients presenting as vaginal bleeding(8.3%),dysuria(8.3%),and asymptomatic(8.3%).The cause of dysuria was due to the bladder had been injuried.After timely treatment,all the maternals survived,but 4 of the 12 fetuses were stillborn.Uterine dehiscence group(n=23):The patients in this group were 25-39 years old,with an median age of 34,all of them were multiparous and had a history of previous cesarean delivery.We found that uterine dehiscence most often occurred in the third trimester or postpartum,except for two cases in the first trimester.Scar uterus is the most common cause and risk factors for this group(100%),eight of them had other gynecological surgical history.The signs and symptoms of uterine dehiscence were very different in this group.Generally speaking,uterine dehiscence is an occult finding as asymptomatic in patients and could be seen in 9 patients in this group(39.1%),other symptoms include abdominal pain(30.4%)and vaginal bleeding(26.0%),the other with increased vaginal bleeding(4.3%)during delivery.All the maternal survived,21 fetuses survived except for 2 were stillborn after abortion.2.CT and MRI finding:uterine rupture:The direct imaging finding is a complete rupture of all three layers of the uterus,which was found in 8 patients(66.7%).It failed to show the direct imaging finding in other 4 patients because the rupture hole was so small(all of them were less than 1 cm~2)and blocked by a clot that it could not been detected by MRI.The fetus remained in the uterine cavity in those 4 patients.However,three patients missed diagnosis because placental penetration confirmed by MRI covered the small fractured hole and the rupture sites were found in the operation.Indirect findings mainly included amniotic sac or pregnancy sac enter the abdominal cavity which was found in 5 patients(41.7%),hematocele in uterine cavity(83.3%),hemoperitoneum(50%),and air around the rupture site(16.7%).Uterine dehiscence :The direct finding of uterine dehiscence is an incomplete tear of the uterus that does not penetrate all layers.There were 8 patients(34.7%)with uterine dehiscence and it could be seen in patients only in the first trimester and postpartum.Hematoma in uterine cavity presented in 8 patients(34.8%).Air bubbles around the rupture site was a rare finding(n=1,4.3%),and diverticulum(8.6%)was found in 2 patients.Fifteen patients(65.3%)had no positive finding except a thin lower uterine wall in which the thickness of thinned wall was less than 2mm on sagittal MRI T2 WI and display as a line-like low signal shadow.In laparoscopy,operator could seen the fetus through the thinning uterine wall in this group.Just as we expected,all the fetuses were in the uterine cavity and most of them survived.Conclusion1.Uterine rupture and uterine dehiscence were differences in risk factors,clinical manifestations,rupture site,rupture period,maternal and fetal outcomes,and showed various imaging features.2.CT and MRI showed characteristic finding in most cases of complete uterine rupture.However,it is difficult to diagnose the cases of the complete uterine rupture caused by penetrating placenta implantation.Only hemoperitoneum or nothing appeared around the rupture hole,which were usually be misdiagnosed.3.CT and MRI also have characteristic finding in uterine dehiscence.As for incomplete rupture occured in the first trimester,second trimester and postpartum,direct signs included myometrial interruption with serosal continuity.But incomplete rupture in the third trimester can only display thinning anterior wall of the lower segment of the uterus,part of them showed the uterine hematoma.4.CT and MRI examination could be used as an important supplementary means to diagnose uterine rupture.