Figure 14a. Focal myometrial contraction mimicking an intramural leiomyoma in a 38-year-old pregnant woman. (a) Sagittal T2-weighted fast SE MR image shows a well-circumscribed mass of low signal intensity within the anterior uterine wall (*). (b) Axial T2-weighted fast SE MR image obtained 20 minutes later shows almost complete resolution of the mass (*), thus allowing exclusion of a diagnosis of leiomyoma. An embryo is shown in the sagittal plane (arrow).