Emerging research suggests that intestinal ultrasound may be a viable option for evaluating creeping fat (CF), a recognized hallmark of Crohn’s disease.
For a retrospective study, recently published in Insights into Imaging, researchers compared intestinal ultrasound and computed tomography enterography (CTE) for CF assessment in 93 patients (median age of 34) with Crohn’s disease. The study authors noted a history of smoking in 34 patients and perianal involvement in 31 patients.
Overall, the researchers found an 88.2 percent agreement between intestinal ultrasound and CTE for assessing CF.
“ … (Intestinal ultrasound) provided an accurate and feasible method for the semiquantitative analysis method for CF evaluation. The characteristics of no radiation and no need to use contrast agents significantly increase patient tolerance and safety. It is expected to play an important role in prognosis evaluation and predictive value for treatment,” wrote lead study author Mengyuan Zhou, M.D., who is affiliated with the Department of Ultrasound at Peking Union Medical College Hospital in Beijing, China, and colleagues.
For patients with a CF wrapping angle < 180o, the researchers noted a 78.1 percent agreement between intestinal ultrasound and CTE. However, for those with a CF wrapping angle > 180o, there was 93.4 percent agreement between the two imaging modalities, according to the study authors.
Three Key Takeaways
1. High diagnostic agreement. The study found an 88.2 percent overall agreement between intestinal ultrasound and computed tomography enterography (CTE) for evaluating creeping fat (CF) in Crohn's disease, especially for patients with more severe disease (CF wrapping angle >180° had 93.4 percent agreement).
2. A safer alternative. Intestinal ultrasound offers a safe and feasible alternative for CF assessment as it avoids radiation and does not require contrast agents, potential increasing patient tolerance and safety.
3. Lesion site accuracy. The study showed high interobserver agreement for ileocecal (94.6 percent) and colonic segments (95.2 percent), areas typically more affected by Crohn’s disease. Moderate agreement was seen for small intestinal segments (76.2 percent), indicating ultrasound's potential variability based on lesion location.
The study authors also pointed out that inter-rater assessments with intestinal ultrasound varied per lesion site. There was moderate inter-rater agreement for small intestinal segments at 76.2 percent, an 88.2 percent agreement for evaluation of anastomosis, and robust agreement on ileocecal segments (94.6 percent) and colonic segments (95.2 percent), according to the study findings.
“The ileocecal and colonic regions are common sites of (Crohn’s disease) with a relatively fixed anatomical position, and usually, the lesions are more severe than in other regions, which may lead to higher interobserver consistency,” added Zhou and colleagues.
(Editor’s note: For related content, see “Image IQ Quiz: What Do You See on This Small Bowel GI Series?,” “Image IQ Quiz: Middle-Aged Male Presents with Fever and Abdominal Pain” and “Ultrasound Detects As Much Pediatric IBD as MR Enterography.”)
Beyond the inherent limitations of a single-center, retrospective study, the authors acknowledged the small sample size and the possibility of selection bias due to patients with moderate and severe Crohn’s disease comprising a significant proportion of the study cohort.
