Sonography of Adenomyosis

Sonography of Adenomyosis

Sonographic Findings

The sonographic findings of adenomyosis, best obtained by transvaginal sonography, include the following4–17:

1. Uterine enlargement—Globular uterine enlargement that is generally up to 12 cm in uterine length and that is not explained by the presence of leiomyomata is a characteristic finding (Figure 3).
2. Cystic anechoic spaces or lakes in the myometrium—The cystic anechoic spaces within the myometrium are variable in size and can occur throughout the myometrium (Figure 4). The cystic changes in the outer myometrium may on occasion represent small arcuate veins rather than adenomyomas. The application of color Doppler imaging at low velocity scales may help in this differentiation.
3. Uterine wall thickening—The uterine wall thickening can show anteroposterior asymmetry, especially when the disease is focal (Figure 5).
4. Subendometrial echogenic linear striations—Invasion of the endometrial glands into the subendometrial tissue induces a hyperplastic reaction, which appears as echogenic linear striations fanning out from the endometrial layer (Figure 6).
5. Heterogeneous echo texture—There is a lack of homogeneity within the myometrium with evidence of architectural disturbance (Figures 1 and 4). This finding has been shown to be the most predictive of adenomyosis.
6. Obscure endometrial/myometrial border—Invasion of the myometrium by the glands also obscures the normally distinct endometrial/myometrial border (Figures 2–6).
7. Thickening of the transition zone—This zone is a layer that appears as a hypoechoic halo surrounding the endometrial layer. A thickness of 12 mm or greater has been shown to be associated with adenomyosis.

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Figure 2.

Focal adenomyoma (arrows).

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Figure 3.

Globular uterine enlargement with an obscure endometrial/myometrial border (arrow).

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Figure 4.

Anechoic cystic lacunae in the posterior uterine wall (arrow) with a heterogeneous echo texture.

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Figure 5.

Measurement of the length of a posterior uterine wall that is greater than that of the anterior wall (calipers) and has a heterogeneous myometrial echo texture.

There is literature to support the observations that a globular uterus, cystic spaces, and linear striations are the most specific findings in the diagnosis of adenomyosis.17 Chiang et al16 used color Doppler sonography to differentiate adenomyosis from leiomyomas. In their study, 87% of the cases of adenomyosis had randomly scattered vessels or intramural signals. In 88% of leiomyoma cases, however, peripheral scattered vessels or outer feeding vessels were noted. In addition, in 82% of the adenomyomas, arteries within or around the uterine tumors had a pulsatility index of greater than 1.17, and 84% of leiomyomas had a pulsatility index of 1.17 or less.

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Figure 6.

Linear striations (arrows) in the presence of a heterogeneous echo texture.

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Conclusions

Adenomyosis is a common finding in women of reproductive age. Most women with adenomyosis are asymptomatic. When symptomatic, adenomyosis can cause pelvic pain and abnormal uterine bleeding. The diagnosis of adenomyosis by sonography has been well defined and has diagnostic capabilities comparable to MRI. When a diagnostic imaging modality is required for suspected adenomyosis, sonography should be given first consideration given its efficacy, safety, and lower cost.