MRI与超声在产前胎盘植入诊断中的对比研究

Comparison of MRI and ultrasound in the diagnosis of prenatal placental accretion

目的:探讨磁共振成像(MRI)和超声显像技术在产前胎盘植入诊断中的价值。方法:回顾性分析医院收治的49例疑似产前胎盘植入的患者资料,所有患者均分别行MRI和超声检查,经手术和(或)病理检查确诊,分析并比较两种检查方法对产前胎盘植入的诊断价值。结果:MRI与超声均可以清晰显示胎盘的形态、位置、边界、内部信号及血管分布等情况。胎盘植入的MRI影像学特征包括迂回流空血管、子宫下段肿胀、基层局限性变薄或中断、宫颈肿胀;超声影像学特征包括胎盘内部及周边血管不畅、胎盘后间隙消失、基层局限性变薄或中断、胎盘位置异常。所有患者中经手术和(或)病理检查确诊为胎盘植入患者18例,MRI检查提示胎盘植入阳性17例,阴性32例,误诊1例,漏诊2例;超声检查提示胎盘植入阳性16例,阴性33例,误诊1例,漏诊3例。统计分析发现MRI和超声的Kappa值分别为0.87和0.82(均>0.75)。MRI和超声对胎盘植入诊断的灵敏度、特异度和准确率比较差异均无统计学意义(x^2=1.786,x^2=0.346,x^2=0.189;P>0.05)。结论:MRI与超声在产前胎盘植入诊断中与手术和(或)病理检查具有较高一致性,且互为补充,因此应根据各自的影像学特征分别对胎盘植入患者进行产前诊断,降低误诊率和漏诊率,提高检出率。

Objective:To discuss the diagnostic value of magnetic resonance imaging(MRI)and ultrasound on prenatal placental accretion.Methods:49patients who were suspected to be prenatal placental accretion were selected.MRI and ultrasound were performed on them,respectively,at the same time,they were confirmed by operation and/or pathology.And then,the diagnostic value of two methods for prenatal placenta accretion were analyzed and compared dependent above results.Results:Both of MRI and ultrasound could clearly reveal the placental morphology,location,boundaries,internal signals,vascular distribution and so on.The imaging features of MRI for placental accretion included circuitously empty vessel,the swelling of lower segment of uterine,localized thinning or interruption of the basal layer and cervical swelling.The imaging features of ultrasound included impeded vessel in interior and peripheral of placental,disappearing of posterior placental,localized thinning or interruption of the basal layer and abnormal placental position.In all of these patients,18patients were confirmed as placental accretion by operation and/or pathology.The examination of MRI revealed that there were17positive cases,32negative cases,1misdiagnosed cases and2missed diagnosis cases.While examination of ultrasound revealed that there were16positive cases,33negative cases,1misdiagnosed cases and3missed diagnosis cases.The relevantly statistical analysis revealed that the Kappa values of MRI and ultrasound were0.87and0.82(each value was more than0.75),respectively.Besides,the differences of sensitivity,specificity and accuracy for the diagnosis of placental accretion between MRI and ultrasound were no significant(x2=1.786,x2=0.346,x2=0.189,P>0.05).Conclusion:MRI and ultrasound have a great consistency with operation and/or pathology,respectively,in the diagnosis of prenatal placenta accretion,and the two methods can complement each other.Therefore,the patient should be implemented prenatal diagnosis according to the different imaging futures of the two methods to grasp whether patient has placental accretion so as to reduce misdiagnosed rate and missed diagnosis rate and increase detection ratio.