Evaluation of Crohn's Disease Activity: Validation of a Segmental Simple Ultrasound Score in a Multicenter Study

Objective: Our objective was to validate a previously published simple ultrasound (US) score for Crohn's disease (CD).

Methods: A total of 107 CD patients from 2 hospitals prospectively underwent both ileocolonoscopy (reference standard) and US as part of their clinical care. Endoscopic activity was assessed using the Simple Endoscopic Score for Crohn's Disease (SES-CD) and was also categorized as absent, mild (inflammation without ulcers), or severe (presence of ulceration). The US data of 27 patients were reexamined for interobserver assessment using weighted kappa.

Results: The analysis encompassed 126 intestinal segments. Consistent with the prior derivation study, independent predictors of disease severity, using SES-CD as a reference, were determined to be bowel wall thickness and color Doppler grade. Interobserver agreement for both wall thickness and color Doppler assessment was excellent. The simple US score, derived from the sum of mural thickness and color Doppler grade, demonstrated a significant correlation with SES-CD (r = .757, P < .001). In the validation cohort, the score exhibited high accuracy in diagnosing active disease, with a receiver operating characteristic (ROC) area of 0.979, sensitivity of 92.5%, and specificity of 100%, using a cutoff point of 3.1. However, using the same cutoff point of 5.5 in the simple intestinal US (IUS) activity index obtained in the development phase, the results obtained were almost identical to those previously published, with a sensitivity of 90%, a specificity of 86.4%, and an ROC area of 0.923. For detecting the presence of ulceration, the ROC area was 0.853, sensitivity was 0.73, and specificity was 0.81, using a cutoff point of 7.

Conclusions: The validation of a simple IUS scoring system for CD, based on the sum of bowel wall thickness and color Doppler grade, has been established. This scoring system can effectively diagnose endoscopically active CD and identify cases of severe disease.