Ultrasound of Superficial Endometriosis According to the IDEA 2025 Protocol
What the IDEA 2025 Addendum Changed
The IDEA 2025 addendum expands the previous approach of the International Deep Endometriosis Analysis group: now the standardization subject is not only deep endometriosis but also superficial peritoneal lesions. This is important for practice because superficial lesions are often small, do not form a mass, and are easily missed with the usual pelvic protocol.
The document does not turn ultrasound into an absolute method for excluding superficial endometriosis. Its goal is different: to unify where to look, what signs to consider suspicious, and how to formulate conclusions so that the surgeon, gynecologist, and ultrasound diagnostician speak the same language.
Definition and Place in the Endometriosis Protocol
Superficial endometriosis is considered a peritoneal lesion without signs of deep infiltration. If infiltration under the peritoneum of more than 5 mm is visualized or suspected, this is already the domain of the deep endometriosis protocol and should be described as a separate finding.
In practice, superficial endometriosis should be sought after the standard assessment of the uterus, ovaries, endometriomas, and signs of deep lesions. This order reduces the risk of double counting: endometrioma, deep nodule, and superficial peritoneal lesion are not interchangeable findings.
Technical Logic of the Search
The main method is transvaginal ultrasound in grayscale with dynamic assessment. The key technique is slow scanning of the peritoneal surfaces with changing pressure from the probe. It is necessary not only to see the lesion but also to assess the mobility of adjacent structures: the sliding of the uterus, ovary, peritoneum, bowel, and posterior fornix may be preserved, limited, or absent locally.
Scanning should be targeted. A quick overview of the pelvis, performed only to exclude masses, is not a sufficient study when there is clinical suspicion of superficial endometriosis.
Where to Look: Anatomical Map
IDEA 2025 suggests describing superficial findings anatomically. For the report, not only the presence of a lesion is important but also its localization: anterior compartment, posterior compartment, lateral compartments, ovarian fossae, peritoneal pockets, and areas of adhesion restriction.
| Inspection Area | What to Assess on TVUS | How to Formulate the Finding |
|---|---|---|
| Anterior Compartment | Peritoneal surfaces between the uterus and bladder, local sliding | Suspicious superficial lesion or adhesions in the anterior compartment, specifying the side and relation to the vesicouterine space |
| Posterior Compartment | Posterior surface of the uterus, Douglas pouch, peritoneal folds, bowel mobility | Superficial peritoneal lesion in the posterior compartment; separately indicate if there are signs of deep lesions |
| Lateral Compartments | Parametrial and lateral peritoneal surfaces, area of the ovarian fossae | Right-sided, left-sided, or bilateral suspicious superficial lesion |
| Ovarian Area | Ovary mobility, contact with peritoneum, local adhesions, tenderness upon compression | Superficial lesion near the ovary or adhesive fixation; describe endometrioma separately |
| Areas of Restricted Sliding | Local loss of mobility without an obvious deep nodule | Indirect sign of superficial or adhesive lesion, with anatomical reference |
Sonographic Signs
The report should distinguish between direct and indirect signs. A direct sign is the visualization of a suspicious peritoneal lesion: a small formation, thickening, or irregularity of the peritoneal surface, differing from surrounding tissues. Indirect signs are local adhesions, restricted sliding, ovary fixation, tenderness when pressing with the probe in the area of the suspicious finding.
It is unacceptable to substitute superficial endometriosis with general phrases like "pelvic adhesive process" without localization. If a lesion is visible, it should be described as a lesion: where it is located, how it looks, what it contacts, whether there is dynamic fixation.
Step-by-Step Examination Algorithm
- Start with a standard TVUS assessment of the uterus and adnexa: uterine position, ovarian endometriosis, other masses.
- Assess signs of deep endometriosis according to the current IDEA protocol: posterior compartment, anterior compartment, bowel, bladder, uterosacral ligaments if visualization is accessible.
- Proceed to a slow overview of the peritoneal surfaces: anterior compartment, posterior compartment, lateral zones, ovarian fossae.
- Perform dynamic maneuvers: gentle pressure with the probe, assessment of sliding, local fixation, and reproducible tenderness.
- Record each suspicious finding separately: localization, side, appearance, mobility, relation to the ovary, bowel, uterus, or bladder.
- In the conclusion, indicate diagnostic confidence: finding visualized directly or presumed by indirect signs.
How to Write a Conclusion
The optimal formulation should be anatomical and clinically useful. For example: "In the left ovarian fossa, a suspicious superficial peritoneal lesion is determined; the left ovary is locally limited in mobility; no signs of a deep infiltrative nodule in this area were detected." Such a record is better than "signs of endometriosis" because it helps plan treatment and correlate ultrasound with the laparoscopic map.
If no lesions are detected, it is correct to write: "No sonographic signs of superficial endometriosis were obtained." This does not equal exclusion of the disease, especially with high clinical probability.
Typical Errors
- Examining only the ovaries and uterus without assessing peritoneal surfaces.
- Lack of dynamic sliding test.
- Combining superficial lesions, endometriomas, and deep infiltrate into one nonspecific phrase.
- Describing "adhesions" without specifying the side, pelvic compartment, and relation to organs.
- Categorically excluding superficial endometriosis with negative ultrasound.
Method Limitations
Superficial endometriosis remains the most challenging form of the disease to visualize. Negative transvaginal ultrasound reduces the likelihood of pronounced sonographically noticeable changes but does not exclude microscopic or low-contrast peritoneal lesions.
Therefore, the value of the IDEA 2025 protocol is not in promising 100% visualization but in standardizing the search. The more consistently the inspection map is followed, the less variability between specialists and the more useful the conclusion for clinical decision-making.
Frequently asked questions
Can superficial endometriosis be excluded with normal TVUS?
No. According to IDEA 2025, a negative study should be formulated as the absence of sonographic signs. Superficial peritoneal lesions may be too small or low-contrast for visualization.
How does superficial endometriosis differ from deep endometriosis on ultrasound?
Superficial endometriosis refers to peritoneal lesions without signs of deep infiltration. If invasion under the peritoneum of more than 5 mm is suspected, the finding is described in the logic of deep endometriosis.
What must be indicated in the protocol?
Localization, side, appearance of the suspicious lesion, presence or absence of local sliding restriction, relation to the ovary, uterus, bowel, or bladder, and the degree of confidence: direct lesion or indirect signs.