Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah Health, Salt Lake City, Utah.
Department of Obstetrics and Gynecology, Intermountain Healthcare, Salt Lake City, Utah.
Am J Perinatol. 2021 Jul;38(9):960-967. doi: 10.1055/s-0040-1701196. Epub 2020 Jan 27.
This study aims to define the accuracy, predictive value, and interobserver reliability of magnetic resonance imaging (MRI) in the diagnosis of placenta accreta spectrum (PAS) disorders.
Two experienced radiologists independently interpreted the MRI studies of patients with possible PAS from two referral centers. Radiologists were blinded to sonographic and clinical information. We calculated diagnostic testing characteristics and kappa statistics of interobserver reliability for MRI findings of PAS.
Sixty-eight MRI cases were evaluated. Confirmed PAS and severe PAS were present in 44 (65%) and 20 (29%) cases. For the diagnosis of any PAS, MRI had a sensitivity 66%, specificity 71%, positive predictive value (PPV) 81%, negative predictive value (NPV) 53%, and accuracy 68%. For the diagnosis of severe PAS (percreta), MRI had a sensitivity 85%, specificity 79%, PPV 63%, NPV 93%, and accuracy 81%. The accuracy of individual signs of PAS was lower (44-65%). Interobserver agreement was almost perfect for previa; substantial for myometrial interruptions, PAS, severe PAS, and placental bulging/balling; and moderate to slight for other signs of PAS.
Although the interobserver reliability of MRI for a diagnosis of PAS is substantial, the accuracy and predictive value are modest and lower than previously reported.
本研究旨在定义磁共振成像（MRI）在胎盘植入谱系（PAS）疾病诊断中的准确性、预测值和观察者间可靠性。
两位经验丰富的放射科医生分别独立解读两个转诊中心疑似 PAS 患者的 MRI 研究。放射科医生对超声和临床信息均不知情。我们计算了 PAS 的 MRI 表现的诊断测试特征和观察者间可靠性的 Kappa 统计数据。
评估了 68 例 MRI 病例。44 例（65%）和 20 例（29%）病例证实存在 PAS 和重度 PAS。对于任何 PAS 的诊断，MRI 的灵敏度为 66%，特异性为 71%，阳性预测值（PPV）为 81%，阴性预测值（NPV）为 53%，准确性为 68%。对于重度 PAS（穿透性）的诊断，MRI 的灵敏度为 85%，特异性为 79%，PPV 为 63%，NPV 为 93%，准确性为 81%。PAS 的各个征象的准确性较低（44-65%）。观察者间对前置胎盘的一致性近乎完美；对子宫中断、PAS、重度 PAS 和胎盘隆起/球状的一致性为实质性；对 PAS 其他征象的一致性为中度至轻度。
尽管 MRI 对 PAS 诊断的观察者间可靠性较高，但准确性和预测值适中，且低于之前的报道。
