Clinical Review

Skilled US imaging of the adnexae: The fallopian tubes

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The tubes shed some of their mystery during interrogation by ultrasonography, which can highlight abnormalities such as inflammation, infection, torsion, and cancer




Part 1 A Starting Point (September 2010)

Part 2 The non-neoplastic ovarian mass (October 2010)

Part 3 Ovarian neoplasms (November 2010)

An imaging study of the adnexae would not be complete without thorough assessment of the fallopian tubes. Among the pathologies that may be identified or confirmed by ultrasonography are:

  • ectopic pregnancy
  • tubal inflammatory disease, or salpingitis
  • chronic tubal disease, or hydrosalpinx
  • tubo-ovarian complex
  • tubo-ovarian abscess
  • tubal and ovarian torsion
  • cancer.

In this final installment of our four-part series on ultrasonographic (US) imaging of the adnexae, we take these entities as our focus.

Suspect ectopic pregnancy even if the hCG level is not yet available

A detailed discussion of ectopic pregnancy far exceeds the framework of this article. Suffice it to say that ectopic pregnancy should always be considered in a woman of reproductive age, especially one who complains of abdominal or pelvic pain, vaginal bleeding, or both. However, these signs and symptoms are present in only about 25% of women who have this condition. When these signs and symptoms are present, it is wise to be suspicious even if the results of human chorionic gonadotropin (hCG) measurement are not yet available.

A complete history is important in the diagnosis of ectopic pregnancy. Risk factors include a history of ectopic pregnancy, pelvic inflammatory disease (PID), or tubal surgery, or use of an intrauterine device.

Unequivocal US diagnosis of ectopic pregnancy is possible in only about 20% of cases, and depends on identification of an extrauterine pregnancy, which may not be visible in the early days of gestation. However, some grayscale ultrasonographic findings that may suggest ectopic pregnancy include:

  • an empty uterus in a woman who has an hCG level above 1,000 to 1,500 mIu/mL (the discriminatory level)
  • a thick, hyperechoic endometrial echo (decidualization)
  • an adnexal mass other than a simple cyst
  • echogenic fluid in the cul-de-sac (FIGURE 1A1D).

Power Doppler can help the sonographer localize the ectopic pregnancy in the tubes by demonstrating the circular vascularization of the more or less typical “tubal ring” (FIGURE 1E1G).

FIGURE 1 Ectopic pregnancy

A–D. Various cases of tubal ectopic gestation (arrows point to each gestation). E–G. Power Doppler localizes the ectopic pregnancy (arrows), side by side with the corpus luteum (CL).

A patient’s history may yield clues to tubal inflammatory disease

The diagnosis of acute salpingitis begins with a thorough patient history. Look for any report of PID, unexplained fever, foul vaginal discharge, sexually transmitted infection, or recent intrauterine procedures such as hysteroscopy, IUD insertion, endometrial biopsy, or saline infusion sonohysterography.

US diagnosis is based on the findings of a slightly dilated fallopian tube with low-level echogenic fluid content, thick tubal walls, and tenderness to the touch of the transvaginal probe.1

In cross section, the tube forms the “cogwheel sign” (FIGURE 2C). Power Doppler shows the subserosal blood vessels characteristic of this entity (FIGURE 2D).

FIGURE 2 Tubal disease

A–C. Grayscale images showing thick walls, low-level echoic fluid (pus?) and the “cogwheel sign” (CW). D. Subserosal vascularization typical of an inflammatory response in hollow abdominal viscera. E,F. Edematous fimbrial end (arrow) of the inflamed tubes, floating in a small amount of free pelvic fluid. G. Low-level echoic, fluid-filled, thick-walled tubes with incomplete septae (arrow) are the hallmarks of hydrosalpinx. H–J. Bilateral hydrosalpinx. Note the thin walls and anechoic fluid-filled forms (sausage-shaped) (CL = corpus luteum; OV = ovary; UT = uterus).

Look for fluid dilating the tube in chronic tubal disease

Hydrosalpinx is characterized on US by thin tubal walls with a relatively anechoic but large amount of fluid dilating the tube (FIGURE 2G2J). The interior wall is studded with shallow, echogenic, mural nodules (without blood vessels) that assume the appearance of a tube or sausage. The small, shallow internal papillae give the cross section of the tube the appearance of beads on a string.

FIGURE 3 Tubo-ovarian complex

A. The tube (T) and ovary (OV) form an infectious conglomerate. B. Power Doppler appearance. C. Laparoscopic view.

Tubo-ovarian complex

When this complex arises, the anatomy and shape of the tube and the involved ovary are somewhat distorted but still largely discernible (FIGURE 3A AND 3B).

Tubo-ovarian abscess is a more advanced stage of a fast-progressing or neglected pelvic inflammatory process. In it, the tube and the ovary can barely be distinguished, and US signs of abscess appear, among them low-level echoic fluid and linear echogenicity (FIGURE 4).

FIGURE 4 Tubo-ovarian abscess

The tube and ovary are indistinguishable. The fluid is of low-level echogenicity (pus), and the walls are thick.

In ovarian torsion, the follicles press outward

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