快速平衡稳态采集和单次激发快速自旋回波序列产前诊断胎盘植入的价值比较

目的 比较磁共振成像(MRI)快速平衡稳态采集(FIESTA)和单次激发快速自旋回波(SSFSE)序列在产前诊断胎盘植入中的价值,为产前诊断的序列选择提供参考。方法 回顾性分析疑诊胎盘植入的121例孕妇的MRI资料,评价FIESTA序列和SSFSE序列的图像质量及两序列对胎盘植入征象的显示能力,与手术及病理结果对照,分别计算这两个序列中各征象诊断胎盘植入的敏感度、特异度、阳性预测值和阴性预测值。结果 FIESTA序列的图像优良率为74.38%,明显高于SSFSE序列的39.67%(χ ²=29.74,P=0.000)。FIESTA序列对子宫肌层不连续的显示能力明显高于SSFSE序列(χ ²=6.750,P=0.006),对胎盘内异常血管影(χ ²=8.471,P=0.020)、胎盘信号不均匀(χ ²=13.885,P=0.000)、T2W低信号带(χ ²=4.267,P=0.035)的显示能力明显低于SSFSE序列;两者在子宫局部膨隆(χ ²=0.250,P=0.625)、胎盘局部凹陷征(χ ²=0.167,P=0.687)、胎盘穿透及宫旁植入(χ ²=0.800,P=0.375)、胎盘组织突入宫颈管内(χ ²=0.081,P=0.776)的显示能力差异无统计学意义。在两序列中,胎盘局部凹陷、胎盘穿透及宫旁植入、胎盘组织突入宫颈管诊断胎盘植入的特异度均为100%。 结论 FIESTA序列对胎盘子宫的轮廓和分界显示效能较高,SSFSE序列对胎盘内信号改变显示较好,在FIESTA中观察胎盘与周围结构的关系及是否有植入周围组织,在SSFSE中观察胎盘内信号改变的征象,结合两个序列观察血管,有望提高产前诊断胎盘植入的能力。

Comparison of Prenatal Diagnostic Value between Fast Imaging Employing Steady State Acquisition and Single Shot Fast Spin Echo Sequence in Diagnosis of Placental Invasion

Objective To compare the prenatal diagnostic value and image quality of magnetic resonance imaging(MRI)with fast imaging employing steady state acquisition(FIESTA)or single shot fast spin echo(SSFSE)sequence,in order to provide references for sequence selection of prenatal diagnosis.Methods The MRI data of 121 patients with suspected placental invasion were retrospectively analyzed. The ability of FIESTA in displaying MRI signs associated with placental invasion and its image quality were assessed and compared with SSFSE. Based on the records of cesarean section and pathological finding,the sensitivity,specificity,positive predictive values,and negative predictive values of these two sequences were calculated.Results The image quality was significantly higher in FIESTA than in SSFSE(χ ²=29.74,P=0.000). FIESTA had significantly higher ability to display focal interruptions in the myometrial wall than SSFSE(χ ²=6.750,P=0.006);in addition,the ability to display abnormal vessel in the placenta(χ ²=8.471,P=0.020),placental heterogeneity(χ ²=13.885,P=0.000),hypointense intraplacental bands(χ ²=4.267,P=0.035)were also significantly higher in SSFSE than in FIESTA,while the efficiency for displaying uterine bulging(χ ²=0.250,P=0.625),uterine recess(χ ²=0.167,P=0.687),uterine penetration and parametrium implantation(χ ²=0.800,P=0.375),and protrusion of the placenta into the cervix(χ ²=0.081,P=0.776)were not significantly different between these two sequences. Both sequences had a specificity of 100% in displaying uterine penetration and parametrium implantation,uterine recess,and protrusion of the placenta into the cervix. Conclusions FIESTA has better ability in displaying the contour and demarcation of placenta and uterine,whereas SSFSE is more efficient in displaying the changes of intraplacental signals. FIESTA can be used to observe the relationship between the placenta and the surrounding structures and whether the surrounding tissue is implanted,and the changes of placental signals can be observed in SSFSE. The combination of these two sequences can improve the prenatal diagnosis of placenta invasion.