MRI of early unruptured ectopic pregnancy: detection of gestational sac.

We report two cases of unruptured tubal pregnancy that were evaluated on MRI at 5 weeks' gestation. In both cases, MRI revealed gestational sac-like structures surrounded by thickened walls outside the ovaries. At the periphery of gestational sac-like structures, small amounts of fresh blood were also identified. These findings highly indicate ectopic pregnancy in a patient with elevated human chorionic gonadotropin level.