Our Statement: The Importance of Preparation for Endometriosis Ultrasound Mapping 

Endometriosis ultrasound mapping is a specialized diagnostic tool that allows for the detailed assessment of deep infiltrative endometriosis (DIE). While some international guidelines and authors suggest that no specific preparation is required for this exam, at Miami Sonogram, based on our experience has shown that proper preparation significantly improves diagnostic accuracy.

Why Do We Recommend Preparation?

Unlike general pelvic ultrasounds, endometriosis mapping requires a comprehensive evaluation of multiple pelvic structures, including the ovaries, rectum, parametrium, uterosacral ligaments, and potential adhesions. A lack of preparation can hinder crucial findings, leading to an incomplete or inconclusive assessment.

1. The Impact of a Carbohydrate-Rich Diet on Ultrasound Imaging

The typical Western diet, particularly in the United States, is predominantly high in carbohydrates, which contributes to excessive intestinal gas production and increased bowel content. This has several negative effects on ultrasound imaging:

-Bowel Gas Interference: Excessive gas causes acoustic enhancement, preventing the clear visualization of the rectosigmoid colon and other pelvic structures. This is crucial because deep infiltrating endometriosis often affects the intestines.

-Poor Definition of Parametrium and Ureters: The parametrium and ureters are key areas for detecting deep endometriosis. However, gas and excessive bowel distension can displace these structures, making it difficult to assess their visualization during maneuvers.

-Ovarian Displacement: Ovaries may be pushed out of their natural position, especially in cases of adhesions, making it harder to assess their mobility and potential fixation—a critical finding in advanced endometriosis.

2. The Unique Position of the Ovaries in the Intra-Peritoneal Space

Unlike most pelvic organs, the ovaries are the only reproductive structures located within the intra-peritoneal space, sharing this space directly with the intestines. This anatomical relationship is significant for several reasons:

-Intestinal distension and gas accumulation can obscure ovarian visualization.

-Ovarian mobility can be altered by bowel displacement.

3. Rectal Residual Content and Its Effect on Imaging

Even when fasting is not required for general gynecological ultrasounds, the presence of rectal content and fecal residues significantly affects the visibility of the rectosigmoid colon. This is problematic because:

-Endometriosis commonly affects the rectosigmoid, and failure to adequately visualize it can result in missed lesions.

-Poor contrast between the rectal wall and surrounding structures makes it difficult to assess deep infiltrative lesions.

-Bowel peristalsis and movement of fecal matter create additional artifacts that reduce image clarity.

4. Effects of Hormonal Treatment on Gas Distension and Bloating

Endometriosis is one of the leading causes of infertility, affecting a large percentage of patients undergoing fertility treatments. Many of these patients are placed on hormonal therapy, such as oral contraceptives, progestins, GnRH analogs, or hormonal IUDs. However, these treatments can also lead to significant gastrointestinal effects, including increased bloating and intestinal distension, which may negatively impact ultrasound imaging.

How Does Hormonal Treatment Cause Bloating?

-Progesterone slows gastrointestinal motility – High levels of progesterone, commonly found in hormonal treatments, relax the smooth muscles of the intestines, leading to delayed bowel transit, increased gas retention, and constipation.

-Fluid retention – Hormonal fluctuations, particularly with estrogen and progestins, can lead to fluid retention, which exacerbates bloating.

-Changes in gut microbiota – Some hormonal treatments alter gut microbiome composition, increasing fermentation and gas production, which contributes to abdominal distension and discomfort.

These side effects make proper preparation even more crucial for patients undergoing hormonal treatment, as they are already at a higher risk of bloating and gas interference.

5. Improved Evaluation of Intestinal Layers

A crucial advantage of preparation is that it allows for the detailed assessment of the different layers of the intestinal wall. This is essential because:

-Clear visualization of the submucosa, muscularis, and serosa helps distinguish true endometriotic invasion from extrinsic compression or adhesions.

6. Improved Evaluation of the Sliding Sign and Adhesions

One of the most valuable assessments in endometriosis ultrasound is the sliding sign, which helps determine the presence of adhesions between the uterus, ovaries, and bowel. Without proper preparation, excessive bowel distension alters normal movement patterns, reducing the accuracy of this test.

Our Recommended Preparation Protocol

To minimize these issues and optimize image quality, Miami Sonogram strongly recommends preparation for endometriosis ultrasound mapping. Our protocol includes:

-Low-residue diet for 24-48 hours before the exam (reducing fiber and carbohydrates to decrease gas and stool volume).

-Mild bowel preparation (such as a small-volume enema the night before or the morning of the exam, depending on individual tolerance).

-Avoidance of carbonated drinks and gas-producing foods (e.g., legumes, dairy, and artificial sweeteners).

-Hydration with clear liquids to help maintain optimal imaging conditions.

-Consideration of the patient’s hormonal treatment status, as those under hormonal therapy may require additional dietary modifications or adjustments in bowel preparation.

Final Thoughts

While some international guidelines suggest that endometriosis ultrasound mapping can be performed without preparation, our experience at Miami Sonogram has proven that a prepared bowel significantly enhances diagnostic accuracy. Given the high incidence of deep infiltrative endometriosis affecting the rectosigmoid colon and parametrium, this preparation is essential for detecting lesions that might otherwise be missed.

Additionally, patients undergoing hormonal therapy—many of whom are seeking treatment for infertility—are at a higher risk of bloating and gas retention, which further compromises imaging quality. Understanding the physiological effects of hormones on the gastrointestinal system reinforces the importance of proper preparation to ensure optimal visualization of the intestines, and ovaries.

Most importantly, because the ovaries are the only reproductive structures located in the intra-peritoneal space and share this space with the intestines, bowel preparation is critical to ensure optimal visualization, prevent ovarian displacement, and enhance the detection of endometriosis.

By adopting a patient-centered approach that emphasizes meticulous preparation, we ensure a more precise and reliable assessment, ultimately leading to better management and treatment outcomes for individuals suffering from endometriosis.

If you are scheduled for an endometriosis ultrasound mapping, we encourage you to follow our preparation guidelines for the most accurate and comprehensive evaluation possible.