MR Imaging for Ectopic Pregnancy.

Ectopic pregnancy (EP) is diagnosed based on laboratory values and ultrasonography (US) findings. Evaluation for suspected EP should begin with a quantitative measurement of the serum β-human chorionic gonadotropin levels and transvaginal US. MR imaging is not preferentially performed in the evaluation of EP; however, if the findings of transvaginal US are uncertain, MR imaging can be used, as it has the advantages of superior soft-tissue contrast resolution and a wide scanning range. Identifying the exact location of implantation transfer using MR imaging can help in the diagnosis and establishment of treatment strategies for ectopic pregnancies, including laparoscopy. In particular, as the incidence of heterotopic pregnancy has increased with the recent increase in use of assisted reproductive technology, the scope of application of MR imaging is expected to expand further. This pictorial essay describes the various manifestations of EP and related conditions on MR imaging and US. Familiarity with the clinical setting and the US and MR imaging features of EP and associated conditions can lead to a more accurate diagnosis and treatment.