Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA.
Radiographics. 2012 Sep-Oct;32(5):1445-60; discussion 1460-2. doi: 10.1148/rg.325115153.
Because of its lack of ionizing radiation and excellent soft-tissue contrast, magnetic resonance (MR) imaging is being increasingly used in the evaluation of acute abdominal pain in the pregnant patient. Roughly 2% of all pregnancies are ectopic. Although ectopic pregnancy is usually diagnosed on the basis of a combination of clinical, laboratory, and ultrasonographic findings, it occasionally is initially identified at MR imaging. Thus, it is imperative that the radiologist should be familiar with the variable appearance of ectopic pregnancy at MR imaging and should evaluate for ectopic pregnancy at any time when (a) a patient has positive results of a pregnancy test and (b) an intrauterine pregnancy is not definitively seen. Because of potential issues of fetal safety, a conservative approach should be used for MR imaging in pregnancy. An MR imaging protocol for the evaluation of possible appendicitis in pregnant women is detailed. Specific findings that can aid in the diagnosis of ectopic pregnancy are the lack of an intrauterine pregnancy, isolated hemoperitoneum, tubal masses, hematosalpinx, and interstitial masses. In the differential diagnosis of acute abdominal pain in pregnancy, consideration should be given to the more unusual forms of ectopic pregnancy, such as angular pregnancy, cornual pregnancy, and abdominal pregnancy. Potential mimics of ectopic pregnancy include placental abnormalities, ovarian neoplasms, and corpus luteum cysts.
由于磁共振成像（MR）没有电离辐射且软组织对比度极佳，因此它在评估孕妇急性腹痛方面的应用越来越多。大约有 2%的妊娠属于异位妊娠。虽然异位妊娠通常基于临床、实验室和超声检查结果的综合表现来诊断，但偶尔也会在 MR 成像中初步识别。因此，放射科医生必须熟悉 MR 成像中异位妊娠的各种表现，并在以下两种情况时评估是否存在异位妊娠：（a）妊娠试验阳性，（b）未见宫内妊娠。由于存在胎儿安全的潜在问题，在妊娠期间应谨慎使用 MR 成像。本文详细介绍了一种用于评估疑似阑尾炎的孕妇 MR 成像方案。有助于诊断异位妊娠的特定表现包括：宫内妊娠缺失、孤立性腹腔积血、输卵管肿块、血肿输卵管和间质肿块。在妊娠急性腹痛的鉴别诊断中，应考虑到一些不太常见的异位妊娠形式，如角状妊娠、宫角妊娠和腹腔妊娠。异位妊娠的潜在类似疾病包括胎盘异常、卵巢肿瘤和黄体囊肿。
