Utility of Intestinal Ultrasound in Clinical Decision-Making for Inflammatory Bowel Disease

Abstract

Background: There is a clinical need to improve the monitoring of inflammatory bowel disease (IBD) activity. Despite being used regularly in European countries, intestinal ultrasound (IUS) has been implemented less in the United States for unclear reasons.

Aims: The aim of this study is to illustrate how IUS can be used as a clinical decision-making tool in an American IBD cohort.

Methods: This retrospective cohort analysis evaluated patients with IBD seen at our institution who underwent IUS as part of routine evaluation of their IBD from July 2020 to March 2022. To evaluate the clinical utility of IUS for different patient populations and against more frequently used measures of inflammation, we compared patient demographics, inflammatory markers, clinical scores, and medications between patients in remission and those with active inflammation. Treatment plans between the 2 groups were compared and we analyzed patients with follow-up IUS visits to validate treatment plan decisions at initial evaluation.

Results: Out of 148 total patients with IUS, we found that 62.1% (N = 92) of our patients had active disease and 37.9% (N = 56) were in remission. Ulcerative colitis activity index and Mayo scores were both significantly correlated with IUS findings. The treatment plan was significantly correlated with IUS findings (P = .004). At follow-up, we observed an overall decrease in intestinal thickening, improvements in vascular flow, and mural stratification.

Conclusions: Clinical decisions incorporating IUS findings effectively reduced inflammation in our IBD patients. IUS should be strongly considered by IBD clinicians in the United States for monitoring disease activity in IBD.

Keywords: inflammatory bowel disease; intestinal ultrasound; point-of-care.

Figure 1.

Intestinal ultrasound images demonstrating mural stratification obtained from patients with inflammatory bowel disease using the Canon i700 machine. The image is from the sigmoid colon of Crohn’s disease patient in remission. The arrows point to the beginning of each layer moving in an external to internal direction.

Figure 2.

Intestinal ultrasound images comparing patients with inflammatory bowel disease using the Canon i700 machine. (A) Normal sigmoid colon from Crohn’s disease patient in remission with mucosal measurements denoted at points along the sigmoid colon with line A measuring 0.2 cm and B measuring 0.3 cm. (B) Inflamed sigmoid in a Crohn’s patient with mucosal measurements A, B, and C measuring 0.25 cm, 0.3 cm, and 0.34 cm, respectively. Mural stratification is intact.

Figure 3.

Intestinal ultrasound images demonstrating the use of Doppler ultrasound and other adjunct measures of inflammation using the Canon i700 machine. (A) Normal terminal ileum, cecum, and ileocecal valve from Crohn’s disease patient in remission. Points A, B, and C measure the bowel wall thickness at 0.23 cm, 0.13 cm, and 0.16 cm, respectively. (B) Inflamed terminal ileum in a Crohn’s disease patient in an active flare. Points A and B measure at 0.53 cm and 0.43 cm, respectively. There is mural stratification is minimally disrupted and a Limberg score of 1 can be seen by the active blood flow in the area.

Figure 4.

IUS results for patients with both biomarker and clinical score data (N = 125) found to be in a combined remission defined as both a clinical remission (UCAI ≤ 5 and partial Mayo ≤ 2 or HBI ≤ 5) and biomarker remission (ESR ≤ 40 mm/h and CRP ≤ 10 mg/L and fecal calprotectin ≤ 50 μg/mg and fecal lactoferrin ≤ 30 μg/mL). CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; HBI, Harvey–Bradshaw index; IUS, intestinal ultrasound; UCAI, ulcerative colitis activity index.

Figure 5.

Clinical decisions made based on intestinal ultrasound findings. Bar graphs compare percentage of patients who maintained, changed, or de-escalated therapy. (A) Patients were stratified according to bowel wall thickness (BWT) with the 3 categories of BWT ≥ 5 mm (green), 3 mm < BWT < 5 mm (orange), and BWT ≤ 3 mm (blue). The treatment plans were compared between the 3 groups using χ² analysis with P = .002. (B) Patients stratified according to Limberg scoring with Limberg score of 0 being 1 group, Limberg score = 1 being another, and Limberg score ≥ 2 being another. The treatment plans were compared between the 3 groups using χ² analysis with P = .001. Separate χ² analysis between Limberg = 1 and Limberg ≥ 2 was not significant.