FIGURE 19-5 Various transvaginal sonographic findings with ectopic tubal pregnancies. For sonographic diagnosis, an ectopic mass should be seen in the adnexa separate from the ovary and may be seen as: (A) a yolk sac (shown here) and/or fetal pole with or without cardiac activity within an extrauterine sac, (B) an empty extrauterine sac with a hyperechoic ring, or (C) an inhomogeneous of fire," which reflects increased vascularity typical of ectopic pregnancies. LT OV = left ovary; SAG LT AD = sagittal left adnexa; UT = uterus.
Placental blood low within the periphery of the complex adnexal mass-the ring ofire-can be seen with transvaginal color Doppler imaging. Although this can aid diagnosis, this finding can also be seen with a corpus luteum cyst, and differentiation can be challenging.
Hemoperitoneum. In afected women, blood in the peritoneal cavity is most often identified using sonography, but assessment can also be made by culdocentesis (Fig. 19-6). Sonographically, anechoic or hypoechoic luid initially collects in the dependent retrouterine cul-de-sac, and then additionally surrounds the uterus as it fills the pelvis. As much as 50 mL of blood can be seen in the cul-de-sac using TVS, and transabdominal imaging then is used to assess the hemoperitoneum extent. Importantly, however, a small amount of peritoneal luid is physiologically normal. With signiicant intraabdominal hemorrhage, blood will track up the pericolic gutters to fill Morison pouch near the liver. Free luid in this pouch typically is not seen until accumulated volumes reach 400 to 700 mL (Branney, 1995; Rodgerson, 2001; Rose, 2004). Diagnostically, peritoneal fluid in conjunction with an adnexal mass is highly predictive of ectopic pregnancy (Nyberg, 1991). Ascites from ovarian or other cancer is a notable mimic.
Culdocentesis is a simple technique used commonly in the past. The cervix is pulled ourward and upward toward the symphysis with a tenaculum, and a long 18-gauge needle is inserted through the posterior vaginal fornix into the retrouterine culde-sac. If present, fluid can be aspirated. However, a failure to do so is interpreted only as unsatisfactory entry into the culde-sac. Fluid containing fragments of old clots or bloody fluid that does not clot suggests hemoperitoneum. In contrast, if the blood sample clots, it may have been obtained from an adjacent blood vessel or from a briskly bleeding ectopic pregnancy. Several studies have challenged its usefulness, and culdocentesis has been largely replaced by TVS (Glezerman, 1992; Vermesh, 1990).
Several endometrial changes accompany ectopic pregnancy, and all lack coexistent trophoblast. Decidual reaction is found in 42 percent of samples, secretory endometrium in 22 percent, and proliferative endometrium in 12 percent (Lopez, 1994). Some recommend that the absence of trophoblastic tissue be confirmed by D&C before methotrexate treatment is given (Chung, 201i1; Shaunik, 201l). Investigators found that the presumptive diagnosis of ectopic pregnancy is inaccurate in nearly 40 percent of cases without histological exclusion of a spontaneous pregnancy loss. Nevertheless, the risks of D&C are weighed against the limited maternal risks of methotrexate.