Accuracy of point-of-care intestinal ultrasound for Crohn's disease

Background: Point-of-care ultrasound (POCUS), performed by a gastroenterologist, provides safe and convenient imaging allowing for immediate clinical decision in Crohn's disease. The minimum training required to gain competency, its accuracy and clinical utility requires evaluation. Methods: In this pilot study, Crohn's disease activity and extent were assessed using POCUS (performed by a single gastroenterologist following the completion of 200 supervised scans), magnetic resonance enterography (MRE) and ileo-colonoscopy. The presence of complications was assessed by POCUS and MRE. Accuracy of POCUS was analysed with respect to MRE and ileo-colonoscopy. Agreement between modalities was assessed using kappa coefficient. Results: Forty-two patients had a POCUS paired with MRE. Thirty-eight patients had a POCUS paired with ileo-colonoscopy. When compared to MRE, POCUS was accurate in the assessment of disease activity (sensitivity 87.5%, specificity 61.1%, ROC 0.74), extent (sensitivity 77.8%, specificity 83.3%, ROC 0.81) and complications (sensitivity 85.7%, specificity 94.3%, ROC 0.90). Agreement between POCUS and MRE was moderate (kappa estimates 0.50, P < 0.001, 0.61, P < 0.001 and 0.76, P < 0.001) for disease activity, extent and complications, respectively. When compared to ileo-colonoscopy, POCUS was accurate in the assessment of disease activity (sensitivity 72%, specificity 86%, ROC 0.79) and extent (sensitivity 85.7%, specificity 86%, ROC 0.86). For POCUS and ileo-colonoscopy, kappa estimates were 0.55, P < 0.001 for disease activity and 0.62, P < 0.001 for disease extent. Conclusion: POCUS performed by a gastroenterologist after completion of limited training is accurate for assessing Crohn's disease activity, extent and the presence of complications.