Cesarean scar pregnancy: Method to determine location of gestational sac

On a panoramic, longitudinal, sagittal scan, divide the uterus in half by an imaginary line perpendicular to its longitudinal axis and determine the location of the cervix (Cx) and fundus (F). Mark the center of the gestational sac (x). If the center of the sac is above the aforementioned line (closer to the uterine fundus), it is most likely an intrauterine pregnancy (image A). If the center of the sac is below the line (closer to the cervix), it is a CSP* (or, in rare cases, a cervical pregnancy) (image B).