Adenomyosis Imaging 

Updated: Oct 31, 2018
  • Author: Karen L Reuter, MD, FACR; Chief Editor: Eugene C Lin, MD  more...
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Practice Essentials

Adenomyosis is a benign condition of the uterus caused by a proliferation of endometrial glands and stroma leading to ill‐defined lesions within the myometrium. On the basis of myometrial invasion extension, it can be classifed as either diffuse or focal. In the diffuse type, endometrial glands and/or stroma are extensively intermingled with myometrial muscle fibers with an increase in uterine volume (proportionally correlated with the extent of lesions); focal adenomyosis is generally a single nodular aggregate located in the myometrium. [1]  Patients with adenomyosis can have a range of clinical presentations. The most common symptoms of adenomyosis are menorrhagia, dysmenorrhea, pelvic pain, and uterine enlargement; however, adenomyosis is asymptomatic in one third of cases. [2]  Women with adenomyosis often have other associated gynecologic conditions, such as endometriosis or leiomyomas, therefore making the diagnosis and evaluating response to treatment challenging. [3]

(See the images below.)

Transvaginal sonogram of an enlarged uterus with a Transvaginal sonogram of an enlarged uterus with a thickened posterior myometrium (arrows).
Sagittal magnetic resonance image of an enlarged u Sagittal magnetic resonance image of an enlarged uterus with a thickened posterior myometrium. T2-weighted image without gadolinium enhancement shows a widened junctional zone of 23 mm (arrows) and focal high signal intensity (arrowheads).

Preferred examination

Currently, there are no standard diagnostic imaging criteria. Traditionally, adenomyosis was only diagnosed after hysterectomy; however, studies have shown that a diagnosis can be made with biopsies at hysteroscopy and laparoscopy. [4]  Noninvasive imaging can be used to help guide the differential diagnosis.

The imaging diagnosis of adenomyosis is usually made by means of 2-dimensional  transvaginal ultrasonography (TVUS) or magnetic resonance imaging (MRI). [5]  However, some studies have indicated that 3-dimensional TVUS is superior to 2-dimensional TVUS for the diagnosis of adenomyosis and may allow for the diagnosis of early-stage disease. [6]

MRI is a useful technique in the detection of adenomyosis and especially in the differentiation between adenomyosis and uterine myomatosis. [7] The MRI appearance of adenomyosis can change as a result of hormonal stimulation and treatment. [8] Rarely, endometrial carcinoma arises from adenomyosis. When adenomyosis coexists with endometrial carcinoma at the same site on T2-weighted images, contrast-enhanced T1-weighted images can improve the accuracy of staging. [9]

Hysterosalpingography (HSG) and transabdominal ultrasonography (TAUS) often lack specificity for this diagnosis. The inability to resolve subtle differences in soft-tissue attenuation limits the usefulness of computed tomography (CT) scanning in diagnosing adenomyosis. [10]

 

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Magnetic Resonance Imaging

Although it is more expensive than ultrasonography, MRI can be employed in cases with indeterminate sonographic results for adenomyosis or in patients who are undergoing uterine-sparing surgery for leiomyomas. [8, 9]

Thin-section, high-resolution MRI scans obtained with a pelvic multicoil array are optimal for diagnosing adenomyosis. The uterine zonal anatomy is best seen on T2-weighted images.

Variations in the normal thickness of the inner myometrium, or junctional zone, have been reported, with a mean thickness of 2-8 mm. Widening of this junctional zone has been associated with adenomyosis (see the image below). Furthermore, the thickness of a normal junctional zone changes with the menstrual cycle, while the thickness of diffuse adenomyosis does not.

Sagittal magnetic resonance image of an enlarged u Sagittal magnetic resonance image of an enlarged uterus with a thickened posterior myometrium. T2-weighted image without gadolinium enhancement shows a widened junctional zone of 23 mm (arrows) and focal high signal intensity (arrowheads).

The most established MRI finding is thickening of the junctional zone exceeding 12 mm. A maximum thickness of 8 mm or less excludes the disease. When the maximum junctional zone diameter is 8-12 mm, secondary findings, such as high–signal-intensity foci on T1- or T2-weighted images, are necessary to make the diagnosis. [2]

The bright foci seen in the myometrium on T2-weighted images in 50% of patients are islands of heterotopic endometrial tissue, cystic dilation of heterotopic glands, or hemorrhage. Whether the hemorrhage is from hormonal changes or from spontaneous causes is not known.

Sometimes, linear striations of decreased signal intensity can be seen radiating out from the endometrium into the myometrium on T2-weighted images. These striations are the direct invasion of the basal endometrium into the myometrium. When the striations blend or become indistinct, pseudo-widening of the endometrium is seen.

Focal adenomyosis, as opposed to diffuse adenomyosis, is seen as a localized, low–signal-intensity mass within the myometrium on both T2-weighted and contrast-enhanced T1-weighted MRIs. In one series of T1-weighted images, most of these masses were isointense relative to the surrounding myometrium. These focal adenomyomas were 2-7 cm in diameter, round or oval, and located in the posterior wall. They also had a poorly defined margin.

The main differential diagnosis of adenomyoma is leiomyoma. Adenomyoma appears as a hypointense mass on T2- weighted images with ill-defined borders, minimal mass effect, and, in some cases, multiple bright foci. Leiomyomas have well-defined borders, despite also being hypointense on T2-weighted images. The presence of large vessels at the periphery may also favor this diagnosis. [2]

The most common lesion of adenomyosis seen on MRI is a low–signal-intensity area on T2-weighted images that often gives the appearance of diffuse or focal widening of the junctional zone. This hypointense area is smooth-muscle hyperplasia accompanying the heterotopic endometrial glands.

Rarely, endometrial carcinoma may arise from adenomyosis. It has been shown that when adenomyosis coexists with endometrial carcinoma at the same site on T2-weighted images, contrast-enhanced T1-weighted images improve the accuracy of staging.

Gadolinium contrast enhancement does not aid in the diagnosis of diffuse adenomyosis.

Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see Nephrogenic Systemic Fibrosis. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or magnetic resonance angiography (MRA) scans. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see Medscape.

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Ultrasonography

On sonograms, the most common appearance of adenomyosis is areas of decreased echogenicity or heterogeneity in the myometrium (see the images below). Di Donato et al described the following parameters as main criteria in the diagnosis of adenomyosis by TVS [11] :

  • Heterogeneous myometrium
  • Hyperechoic or hypoechoic linear striation in the myometrium
  • Myometrial anechoic lacunae or cysts
  • Subendometrial microcysts
  • Asymmetric myometrial thickening of the uterine wall
  • Global uterine enlargement
  • The question mark sign
  • Thickening of the junctional zone
  • Hyperechoic myometrial areas
Transvaginal sonogram of an enlarged uterus with a Transvaginal sonogram of an enlarged uterus with a thickened posterior myometrium (arrows).
Sagittal transabdominal sonogram of an enlarged ut Sagittal transabdominal sonogram of an enlarged uterus with a thickened posterior myometrium (arrows).

Endovaginal ultrasonography, especially with a Doppler technique, can be used as the initial imaging modality to determine the presence of adenomyosis. It must be performed meticulously and with real-time imaging.

Chiang and colleagues used color Doppler ultrasonography with the morphologic criteria to improve the diagnostic accuracy of ultrasonography in differentiating adenomyosis from leiomyomas. [12] They found that 87% of the cases of adenomyosis had randomly scattered vessels or intratumoral signals. In 88% of leiomyoma cases, they observed peripheral scattered vessels or outer feeding vessels. In addition, in 82% of the adenomyomas, arteries within or around the uterine tumors had a pulsatility index (PI) greater than 1.17, and 84% of leiomyomas had a PI of 1.17 or less.

Some studies have indicated that 3D-TVUS might be superior to 2D-TVUS in the diagnosis of adenomyosis. Especially in the evaluation of the junctional zone, which is altered by adenomyosis, the 3D technique has been shown to allow a more detailed assessment. Sharma et al reported a rate of 86% of ill-defined junctional zone in 3D transvaginal sonography in patients with adenomyosis. In addition, the feature of central vascularity was found in 93% of adenomyosis lesions in additional Doppler sonography, while leiomyomas showed peripheral vascularity in 89% of cases. [6]

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