Intestinal Ultrasound in Pediatric Ulcerative Colitis: ESPGHAN/ECCO 2025
The Role of Intestinal Ultrasound in the New Consensus
The updated ESPGHAN/ECCO 2025 consensus on outpatient management of children with ulcerative colitis strengthens the role of non-invasive monitoring. In practice, this means shifting from symptom assessment alone to regular checks of inflammatory activity: clinical scale, laboratory markers, fecal markers, and intestinal ultrasound should be used together.
Intestinal ultrasound is particularly convenient for treat-to-target: the method is repeatable, does not require sedation, carries no radiation exposure, and allows for dynamic assessment of the colon wall. Therefore, it is especially useful between endoscopies, in evaluating response to induction therapy, when subclinical inflammation is suspected, and before deciding on escalation or de-escalation of treatment.
Treat-to-Target Goal in Pediatric UC
The treat-to-target strategy in pediatric ulcerative colitis is not limited to the disappearance of blood in the stool or normalization of bowel movement frequency. Symptoms are important, but they may lag behind inflammation or persist for functional reasons when colitis is controlled. Therefore, the goal is formulated as the consistent achievement of clinical remission, normalization of objective inflammatory markers, and, when necessary, confirmation of mucosal healing.
Intestinal ultrasound occupies an intermediate position between symptoms and endoscopy. It does not provide histology and does not assess the mucosa as detailed as colonoscopy, but it shows transmural and pericolonic signs of activity: wall thickening, disruption of stratification, hypervascularization, decreased compressibility, and perifocal changes.
Clinical Reference Point: PUCAI
PUCAI remains the main pediatric scale for clinical activity of UC. The physician should compare the ultrasound findings not with a subjective description of well-being but with the numerical PUCAI category. This allows for standardized control and communication with the gastroenterologist in a common language.
| PUCAI | Activity Category | Practical Significance for Ultrasound Monitoring |
|---|---|---|
| <10 | Clinical Remission | Ultrasound helps exclude persistent objective activity before de-escalation or in case of doubtful fecal markers. |
| 10–34 | Mild Activity | Look for limited inflammation, often in distal sections; compare with previous protocol. |
| 35–64 | Moderate Activity | Assess the extent, intensity of vascular signal, and dynamics during therapy. |
| ≥65 | Severe Activity | Outpatient ultrasound assessment should not delay routing for severe exacerbation. |
When to Schedule Intestinal Ultrasound
A rational scheme is to perform the study at clinically significant points, not just during pronounced exacerbation. The first ultrasound is useful as a baseline map of lesions after diagnosis or before changing therapy. A repeat study is conducted to assess response if treatment changes, symptoms persist, fecal or systemic inflammatory markers increase, or therapy reduction is planned.
In clinical remission, ultrasound is especially valuable as a method for detecting asymptomatic activity. In relapse, it serves as a quick way to confirm that symptoms are related to colon inflammation rather than infection, irritable bowel syndrome, constipation, or another cause. When PUCAI, fecal markers, and ultrasound findings diverge, decisions are made based on the aggregate data rather than a single test.
What Must Be Described in the Protocol
The protocol should be segmental. At a minimum, describe the rectum if accessible, sigmoid, descending, transverse, ascending colon, cecum, and terminal ileum. For each segment, record wall thickness in millimeters, preservation of layered structure, Doppler vascular signal, compressibility, haustration, tenderness on compression, and changes in surrounding tissue.
For monitoring, isolated phrases like "signs of colitis" are less important than the comparability of studies. The protocol should specify where the maximum wall thickness was measured, what Doppler settings were used, which segments were visualized with limitations, and what the dynamics are relative to the previous study. This reduces the risk of misinterpreting the response to therapy.
Ultrasound Signs of Activity
Active ulcerative colitis on ultrasound typically manifests as thickening of the affected segment wall, increased color Doppler signal, decreased compressibility, loss of normal haustration, and changes in wall stratification. The more extensive and pronounced these signs, the higher the likelihood of objective inflammatory activity.
In distal colitis, it is technically more challenging to assess the rectum, so a normal ultrasound picture of proximal sections does not exclude isolated proctitis. In such cases, clinical scale, fecal markers, and endoscopic assessment by indications are particularly important.
How to Use Ultrasound to Assess Response
The response to treatment on ultrasound is assessed by comparison with the baseline study. Favorable dynamics include a decrease in wall thickness in previously affected segments, reduction in vascular signal, restoration of compressibility, and reduction of perifocal inflammatory changes. The absence of such dynamics despite PUCAI improvement should be considered as possible incomplete anti-inflammatory efficacy of therapy.
If PUCAI has decreased to remission but ultrasound still shows signs of activity, this argues against premature de-escalation. If symptoms persist while ultrasound and inflammatory markers are calm, non-inflammatory causes of complaints should be sought. This branching makes ultrasound a treat-to-target tool rather than just a method for confirming exacerbation.
Method Limitations
Intestinal ultrasound is operator-dependent. Quality depends on the physician's experience, the probe, Doppler settings, the child's body habitus, gas filling, and accessibility of distal sections. Therefore, for monitoring, it is desirable that studies be conducted according to a unified local protocol and, if possible, within one expert group.
The method does not replace ileocolonoscopy in primary diagnosis, uncertainty in the phenotype of inflammatory bowel disease, suspicion of complications requiring endoscopic verification, or the need for morphological assessment. Ultrasound is also not intended for independent decisions on biological therapy without a clinical-laboratory context.
Practical Algorithm
- At the Visit: calculate PUCAI, collect data on therapy, infection, adherence, and side effects.
- Objectification: compare PUCAI with laboratory and fecal inflammatory markers.
- Intestinal Ultrasound: perform a segmental assessment of the colon and terminal ileum, record measurements and Doppler activity.
- Decision: if clinical and ultrasound activity coincide, discuss therapy intensification; if remission is achieved in all domains, maintain the strategy; if discordant, clarify the reason, including endoscopy by indications.
- Dynamics: use subsequent ultrasounds for comparison with the baseline map, not as isolated descriptive conclusions.
Conclusion for Ultrasound Diagnostician
In pediatric UC, intestinal ultrasound becomes part of active monitoring rather than an optional study "for pain." Its task is to show whether there is objective inflammatory activity, where it is located, and whether it decreases with therapy. The maximum value of the method is achieved with a standardized segmental protocol and interpretation together with PUCAI, fecal markers, and treat-to-target goals formulated in the ESPGHAN/ECCO 2025 consensus.
Frequently asked questions
Can intestinal ultrasound replace a follow-up colonoscopy in a child with UC?
No. Ultrasound is suitable for frequent non-invasive monitoring of activity and response to therapy, but it does not provide histology and does not replace endoscopy in diagnostic uncertainty or the need for mucosal assessment.
What is more important for treat-to-target: PUCAI or ultrasound?
These are different domains. PUCAI reflects clinical activity, while ultrasound shows objective signs of inflammation in the intestinal wall. Decisions are better made by combining them with laboratory and fecal markers.
How to interpret remission by PUCAI with persistent activity on ultrasound?
Such a discrepancy should be regarded as possible subclinical inflammation. It is a reason to review the entire picture: fecal markers, laboratory indicators, quality of therapy, and indications for endoscopic clarification.