The value of abdominal ultrasonography compared to colonoscopy and faecal calprotectin in following up paediatric patients with ulcerative colitis.

Aim: To evaluate the value of abdominal ultrasonography (US) in the follow-up of paediatric patients with ulcerative colitis (UC) compared to faecal calprotectin (FC) and colonoscopy.

Material And Method: In this retrospective study we enrolled 30 paediatric patients previously diagnosed with UC, examined by abdominal US and colonoscopy within the same week. FC was also determined during the same week. Disease activity was established using the paediatric ulcerative colitis activity index (PUCAI). The global endoscopic activity was evaluated using the Mayo endoscopic subscore.

Results: Endos-copy revealed pathological findings of active disease in 27 out of 30 patients; 3 patients were in endoscopic remission. Only 18 of them had clinical active disease (PUCAI >10), [sensitivity (Se) 66.7% and specificity (Sp) 33% of PUCAI in detecting endoscopic active disease). Twenty-three (76.7%) patients had FC >250 mcg/g, but in 2 of these cases the colonoscopy was normal (Se 77.8% and Sp 33.3% in detecting active disease). At US examination, pathological findings (increased bowel wall thickness, hypervascularity, lymphadenopathies, and/or mesenteric inflammatory fat) were found in 27 patients (90%), all with endoscopic active disease (agreement US - colonoscopy, at patient level, k=1.0, p<0.001, Se 100% and Sp 100%). At seg-ment level (totally 180 bowel segments examined by US), the overall agreement between US and colonoscopy was k=0.767, p<0.001, Se 86.5%, Sp 90.1%. Of the 27 patients with US pathological findings in any of colonic segments, 23 had FC >250 mcg/g (85.1%). The inter-observer agreement for the US measurements had an overall ICC of 0.926 with p<0.001.

Conclusion: Abdominal US findings demonstrate a good to excellent concordance with endoscopic examination and are correlated with elevated FC levels. Therefore, US appears as an accurate technique in assessing activity in patients with UC and might replace colonoscopic evaluation for the follow-up.