MRI evaluation of abdominal pain during pregnancy and abnormal placentation

Abdominal pain in pregnancy is a common complaint and can be secondary to a variety of pathologic processes. Normal anatomy may be displaced by the gravid uterus, which often confuses the differential diagnosis. Additional pregnancy-related symptoms and altered laboratory values, including nausea, vomiting, musculoskeletal pain, tachycardia, and physiologic leukocytosis confound the overall clinical picture. Magnetic resonance imaging (MRI) is an essential tool in the diagnosis of abdominal pain in pregnant patients, offering excellent anatomic detail and tissue differentiation without the harmful effects of ionizing radiation. MRI can simultaneously depict multiple organ systems and can efficiently differentiate between gastrointestinal, hepatobiliary, genitourinary, gynecological, and other pathologic processes in the pregnant patient, which leads to early accurate diagnosis and treatment. In addition, when there is concern for patient with abnormal placentation, with either increased risk, positive sonographic screening, or with painless vaginal bleeding, placental MRI can detect abnormal placental adherence and invasion into the uterine myometrium or adjacent structures. The purpose of this review is to familiarize the reader with MRI characteristics of common causes of abdominal pain in pregnancy and to recognize MRI features for abnormal placentation.