The Diagnostic Value Of The Three-dimensional Color Doppler Ultrasound And Magnetic Resonance Imaging In Placenta Accrete

BackgroundPlacenta accreta is an abnormal adherence of the placenta to the uterine wall. It can lead to a severe pregnancy complication and is currently the most common indication for peripartum hysterectomy. In recent years, it is becoming an increasingly common complication mainly due to the increasing of intrauterine operation. Since the differences of inter-ethnic and regional diagnosis of disease, the incidence of placenta accreta ranged from1/1205to1/533. There are several complications such as injury, intrauterine infection and serious bleeding due to uncomplete separation of adjacent placenta organs during childbirth, etc. Spontaneous rupture of uterine, hemorrhagic shock and abdominal hemorrhage are the important causes of maternal mortality. Consequently, the diagnosis of placenta accreta on time can make fully preparation to reduce the complications caused by placenta accreta and then reduce maternal and perinatal mortality.The most important risk factors of placenta accreta are followed:①Endometrial injury. A retrospective study from Washecka analyzed54pregnant women diagnosed with placenta accrete, it found that abortion, excessive curettage, repeated abortion, intrauterine infection, multiple pregnancy,the placenta stripped bare history endometritis, etc closely related to the incidence of placenta accreta. The possible mechanism may be a result of the basal layer of the endometrium is damaged, at the same time, the endometrial functional layer cannot be effectively repaired because of a variety of reasons. At the end of the decidua implantation dysplasia occurs even absent when pregnant again, villus may implant in the placenta to become placenta accreta.②Abnormal placental attachment site. It has been reported that, incidence of placenta accreta is higher in patients with placenta previa than incidence of normal placental implantation, the reason may be, under the circumstance of central placenta previa, if the placenta attached to the lower section of the cervix, uterus or uterine corner, because the endometrium here relatively thin, the villus is more likely to invade in the muscular wall of the uterus.③Uterine scar. It will inevitably leave scars after cesarean section and myomectomy,defects often appear on decidua basalis, when zygote implanted here, trophoblast cells can invade directly into the uterine myometrium and continue to grow, Thus caused placenta accreta, even penetrate the muscle.Studies have confirmed that the incidence of placenta accreta in normal uterine is very low, about0.5/10000, however, the rate of placenta accreta in scar uterine occurred high. Other studies also suggest that the risk of placenta accreta with previous history of cesarean section in pregnant women is35times more likely than the one without previous cesarean section. The occurrence of placenta accreta increased to over50%in pregnant woman with more than2previous cesarean sections.④In addition to above factors, age over35are also a risk factors for placenta accreta.Placenta accreta can be divided into several kinds by the degrees placenta invade in uterine myometrium:①Adhesive placenta (shallow implanted), the placenta only attached to the uterine myometrium.②Placenta accreta (deeply implanted) Placenta for invade deeply into the uterine myometrium.③Penetrating placenta (deeper implanted), placental villi invaded into uterine serosa deeply, even the serosa, bladder or rectum. In accordance with the area and degree of placenta attached or penetrated to the uterine myometrium, it can be divided into partial and complete placenta accreta. Its clinical manifestations are quite different:It can be no special performance during pregnancy when implant shallow and range small, When childbirth or after delivery of the fetus, it may occur that the placenta does not even peel or peel difficultly. When placenta implanted deeper and broader, it often showed placenta not peeling and active bleeding, even uterine rupture and abdominal bleeding, thereby endangering the lives of mother and child. Thus it can be seen; it is important and of clinical significance to have corrected and timely diagnosis of placenta accretes.Prenatal diagnosis of placenta accreta currently mainly rely on two-dimensional black and white ultrasound, three-dimensional color Doppler ultrasound, three-dimensional power Doppler ultrasound, MRI(magnetic resonance imaging) and other methods. Two-dimensional ultrasound is more economical, but cannot show blood flow in the area after placenta; three-dimensional color doppler ultrasound can show the blood flow in the area after placenta more clearly, however, observation will be affected when the placenta is located in the posterior wall of the uterus; the most prominent advantage of three-dimensional power doppler ultrasound is the ability to detect even low blood flow without affected by the angle of the ultrasonic, but it is expensive and requires a high level operator.MRI and ultrasound has the same advantage of non-ionizing radiation, no trauma, reproducible and can be multi-planar imaging. Comparatively speaking, ultrasound is the first choice of imaging methods in obstetrics because the advantage is cheap, simple and real-time imaging. Advantage of MRI is not affected by the position of the placenta, placenta accreta than in the posterior wall of the uterus showed ultrasound, ultrasound large field of view are more. MRI is not affected by the position of the placenta, has better display than ultrasound in the posterior wall of the uterus, and the field of view is broader. Most scholars believe that the information MRI can provide is richer than ultrasound, so it is an important supplement of ultrasound in placenta accreta diagnosis, can provide more diagnostic evidences. A retrospective analysis from Dwyer showed that the sensitivity and specificity of ultrasound and MRI have no difference. Even a retrospective analysis from Masselli, etc found that in classification of placenta accreta, MRI is more meaningful than ultrasound. Thus,it remains controversial on the diagnostic value of two diagnostic methods in the placenta accrete. Therefore, in order to explore the value of three-dimensional color Doppler ultrasound and MRI in the diagnosis of placenta accrete, this study retrospectively analyzed104cases of patients with suspicious clinical features of placenta accreta and its three-dimensional color Doppler ultrasound, MRI and pathology diagnosis.Objectives1. Retrospectively analyze the clinical features and treatment of104cases of suspicious placenta accreta patients.2. Assessing the diagnostic value of the three-dimensional color doppler ultrasound, MRI and combination of them in diagnosis of placenta accreta.3. Discussion the value of three-dimensional reconstruction of ultrasound technology (three-dimensional color power Doppler ultrasound) in application of placenta accreta.Methods1. Object of study104placenta accreta suspicious outpatients (uterine scar or placenta previa) from the nanfang hospital between January2011and June2013were collected.60of them had the three-dimensional color Doppler ultrasound diagnosis data,69had MRI diagnosis data and25cases of them had the two diagnosis data.2. Clinical data collectionCollect104cases of placenta accreta suspicious patients’ data including age, pregnancy history (the number of pregnancy, delivery times and history of cesarean section) gestational age, pregnancy complications, risk factors (whether has endometrial injury, abnormal placental site, uterine scar, age over35), mode of delivery, amount of bleeding during perinatal period, clinical treatment (hysterectomy, uterine artery embolization, intrauterine bladders oppression, transfusion of blood, manual removal of the placenta, curettage and ICU treatment, etc), postpartum complications, etc.3. Diagnosis and groupingDiagnosis of placenta accreta is based on clinical diagnosis and/or pathological diagnosis.①The clinical diagnosis:including medical history, symptoms, laboratory tests, auxiliary examinations, treatment and postoperative follow-up, etc. If the placenta is difficult to peel off on their own when cesarean or natural birth, it found that part or all of the placenta adhere to the uterine wall when manual removal of the placenta, stripping difficult, peeled surface is roughness, bleeding, the placenta is not complete, or even found to have residual placenta when postpartum curettage.②Pathological diagnosis:placenta histopathological examination after partial or total removal of the uterus found that partial loss of decidua basalis, chorionic villi invade the myometrium, serosa or even adjacent organs, or histopathological examination after postpartum curettage showed residual placental tissue. According to above criteria,104patients should be divided into no placenta accreta group and placenta accreta group.4. Three-dimensional color Doppler ultrasound and MRIThree-dimensional color doppler ultrasound examination using Volusion E8U.S. production, owes virtual organ computer aided analysis (VOCAL) software. Three-dimensional reconstruction was conducted by using4Dview software (Kretztechnik). MRI adopt Siemens Symphony1.5T superconducting MRI scanner, after-treatment image processing workstation use LEONARDO workstation instrument. Collected104suspicious placenta accreta patients’ images and diagnosis from three-dimensional color doppler ultrasound and MRI, and compare with clinical and/or pathological diagnosis.5. Statistical treatmentData processing and analyzing applied SPSS13.0statistical software. Measurement data are described by X±S deviation, enumeration data described by absolute and relative percentage, normal distribution data between the two groups used x2test, when the theoretical frequency was less than5, we applied Fisher’s exact test; not normally distributed data applying corresponding non-parametric test (like Kruskal-WallisTest); appling McNemar test compare the differences among three-dimensional color doppler ultrasound, MRI, a combination of both and the "gold standard"(diagnostic criteria combined clinical with pathology)in the diagnosis of placenta accrete, and appling Kappa coefficient test to evaluate the consistency of results from the two standards separately, using2×2tables calculate sensitivity, specificity, false-positive, false-negative rate, positive and negative predictive values, positive and negative likelihood ratio separately; All P values are two-sided test, the statistical differences were considered as statistically significant when P value was <0.05.Results1. Clinical characteristic of patients with placenta accreta1.1In104cases of suspicious placenta accreta patients, their age distribution is19-46years, and mean age is30.6±5.22years old. According to clinical diagnosis and/or final pathological diagnosis, no placenta accreta group has51cases (49.0%), Placenta accreta group has53cases (51.0%);33cases in no placenta accreta group (64.7%) combined with placenta previa,21cases in placenta accreta group (41.2%) combined with placenta previa.1.2Placenta accreta is age-related, age of no placenta accreta group range from26to46(30.3±5.4) years old, age of placenta accreta group range from26to43(33.9±5.0) years old, the probability of placenta accreta increased by the increasing maternal age(x2=7.746, p=0.021).1.3In the distribution of The number of pregnancy, there is no statistically significant difference between placenta accreta group and the group without placenta accreta(x2=0.067, p=0.796); In the distribution of delivery times, there are more pantients deliveried more than2times in the placenta accreta group(Fisher exact test, P<0.001);In the distribution of the number of abortions, the more the number of abortions,the more the possibility of placenta accreta (χ2=5.268,p=0.022)1.4The results showed that diagnosis of placenta accreta related with previous cesarean section and whether is placenta previa. There are more proportion of patients had previous cesarean section in the placenta accreta group (χ2=5.548,p=0.019), but there was no difference in the distribution of types of placenta previa in two groups (χ2=3.118, p=0.077) 1.5The average of the total amount of bleeding perinatal in no placenta accreta group is285.71±153.09ml, the average of the total amount of bleeding perinatal in placenta adherence group is638.02±267.38ml, and the average of the total amount of bleeding perinatal in no placenta adherence placenta accreta group is713.67±461.33ml. There was significant difference in these groups (χ2=6.938,p=0.008)1.6Clinical treatment and outcome of the patients, among the104cases of suspicious placenta accreta patients, average gestational age of no placenta accreta group is36.2±3.3weeks, which placenta accreta group is36.4±3.5weeks, when bleeding occurs intrapartum or postpartum, usually underwent conservative treatment (mifepristone, misoprostol, methotrexate, etc), hysterectomy, uterine artery embolization, intrauterine bladders oppression, transfusion therapy,manual removal of placenta, curettage, etc. Main postpartum and postpartum complications of2groups are bleeding, anemia and infection, others included disseminated intravascular coagulation and bladder involvement, etc. all the suspicious placenta accreta patients with stillbirth had miscarriage or abortion during early and mid-term pregnancy, the number of stillbirth in no placenta accreta and placenta accreta group were9cases and21cases separately, the number of premature baby in them were13cases and2cases separately.2. Diagnostic value of the three-dimensional color Doppler ultrasound, MRI and combined diagnosis of placenta accreta.2.160cases of patients had three-dimensional color doppler ultrasound, according to the clinical and/or pathological diagnosis of "gold standard", the sensitivity and specificity were84%and82.9%, there is no significant difference between the two diagnostic methods (McNemar, p=0.754), goodness of fit of the two methods is general(κ=0.661, P<0.001).2.269cases of patients had MRI, according to the clinical and/or pathological diagnosis of "gold standard", the sensitivity and specificity were81.8%and66.7%, there is no significant difference between the two diagnostic methods (McNemar, p=0.078), goodness of fit of the two methods is weak(κ=0.397, p=0.001). 2.325patients had three-dimensional color doppler ultrasound and MRI as a Joint diagnosis method, according to the clinical and/or pathological diagnosis of "gold standard", the sensitivity and specificity were91.7%and61.5%, there is no significant difference between the two diagnostic methods (McNemar:p=0.219); goodness of fit of the two methods is general (κ=0.525,p=0.006)Conclusion1. Along with the increase of maternal age, delivery times, the number of childbirth and the number of cesarean section, risk of placenta accreta increased. While it cannot be concluded yet that pregnant times was associated with placenta accrete. Because the suspect placenta accreta patients included in were all have placenta previa and/or uterine scar. So there is a certain bias in patients included. Therefore, the conclusion cannot be reached that placenta previa increases the risk of placenta accrete.2. Placenta accreta in pregnant women may lead abortion, labor induction, premature birth, and the complications of postpartum hemorrhage including hemorrhagic anemia, hemorrhagic shock, intrauterine infection, DIC, bladder involvement, etc. All of those harmed on maternal-fetal safety.3. The sensitivity and specificity of three-dimensional color doppler ultrasound are superior than of MRI on placenta accreta diagnosis. The combination of them can improve the sensitivity, but the specificity declined. MRI examination is not affected by placental location advantage. And it is sensitive to blood flow and havs the higher the resolution to the organization. In addition, MRI has the advantage on the judgment of placenta accreta depth. Therefore, MRI may be a important complement method in the diagnosis of placenta accrete.4. Three-dimensional color power Doppler ultrasound can make three-dimensional imaging of villi vascular by three-dimensional reconstruction techniques. It can also observe from different perspectives and scanning planes to detect the low and tiny blood flow, but not affected by the Ultrasonic incident angle. The sensitivity in detection of the blood flow with three-dimensional color power Doppler ultrasound was higher than with three-dimensional color Doppler ultrasound. The "alcove display mode" can assess the location, extent and depth of vascular invasion of the myometrium and bladder accurately. It may improve the diagnostic rate of placenta accrete and help to the detection of the placenta accreta area and depth.