前置胎盘并胎盘植入的MRI诊断价值

The value of magnetic resonance imaging on the placenta previa with placenta implantation

目的:探讨MRI对前置胎盘并胎盘植入的诊断价值。方法:将临床疑诊前置胎盘的63例患者分别行经腹超声及MRI检查,MRI采用半傅里叶采集单次激发快速自旋回波(HASTE)序列和真实稳态进动快速成像(true FISP)序列,以手术或病理为金标准,比较MRI与超声对胎盘植入的诊断效能。比较MRI两种序列对前置胎盘并胎盘植入各征象的显示率。结果:63例临床疑诊前置胎盘患者中,合并胎盘植入者46例,发生率为73%。HASTE联合true FISP序列能较超声更清晰的显示胎盘结构及胎盘植入灶。超声的诊断敏感度为52.2%,特异度为64.7%;MRI产前诊断的敏感度为97.8%,特异度为76.5%。HASTE序列对子宫下段肌层、联合带、胎盘内低信号及植入灶的显示率均高于true FISP序列(P均<0.05)。结论:与超声相比,MRI HASTE序列对前置胎盘合并胎盘植入的诊断具有更大优势。

Objective:To investigate the value of magnetic resonance imaging(MRI)on placenta previa with placenta implantation.Methods:MRI and transabdominal color Doppler ultrasound were performed in 63 suspicious placenta previa patients.MRI examination was performed with half-Fourier acquisition single-shot turbo spin-echo(HASTE)sequence and true fast imaging with steady-state precession(true FISP)sequence.The diagnostic performance of MRI and ultrasound was determined with operation or pathology as the reference standard.Visuability of imaging features of placenta previa with placenta implantation were compared between HASTE and true FISP.Results:Among 63 suspected cases of placenta previa,46(73%)had placenta implantation.Compared with ultrasound,the combination of HASTE and true FISP sequences showed better diagnostic performance with the sensitivity of 97.8%and specificity of 76.5%,in comparison of ultrasound with the sensitivity of 52.2%and specificity of 64.7%.The detection rate of HASTE sequence showed higher detection rate for lower uterine segment,combined bands,placental hypointensity and implantation lesion compared with true FISP sequence(P<0.05).Conclusion:Compared with the transabdominal color ultrasound,HASTE sequence of MR demonstrates higher diagnostic performance for the diagnosis of the placenta previa with placenta implantation.