EXCELLENT NEGATIVE PREDICTIVE VALUE AND TIMEIMPROVED DIAGNOSTIC YIELD OF CAPSULE ENDOSCOPY IN SUSPECTED ISOLATED SMALL BOWEL CROHN'S DISEASE.

Background. There is no unique diagnostic test for Crohn's disease, and the diagnosis of isolated small bowel Crohn's disease (SBCD) is even more challenging, due to non-patognomonic clinical picture and low availability of accurate exploration methods. Small bowel capsule endoscopy (SBCE) revolutionized the approach of middle gastrointestinal tract, becoming the first investigation tool when small bowel pathology is suspected. Objective of the study. The aim of our study was to assess the value of SBCE in diagnosing isolated SBCD. Materials and Methods. We retrospectively studied the patients undergoing SBCE for suspected isolated SBCD, in a six-year period, including in our analysis only the patients with a minimum one-year follow-up period. We calculated the diagnostic yield of SBCE, defined as number of capsule endoscopy exams whith positive findings, and we also assessed its yearly variation in time over the six-year period. Subsequently, analyzing follow-up data, positive and negative predictive values were assessed. Results. 78 patients were investigated by SBCE for suspected isolated SBCD. SBCE showed lesions compatible with the diagnosis of SBCD in 49 patients, corresponding to a specific diagnostic yield of 62.8%, while for the remaining 29 patients (37.2%), no CD lesions were found. Following additional investigations, three of the 49 patients initially thought as having isolated SBCD were reclassified as SB lymphoma, eosinophilic gastroenteritis and intestinal tuberculosis, respectively, corresponding to a positive predictive value of 93.8%. During followup, none of the 29 patients with negative SBCE was diagnosed with CD, corresponding to a negative predictive value of 100%. We found a progressively increase of the diagnostic yield over time (from 42.6% in the first year to 70.2% in the last year of the analyzed period), corresponding the most probably to the refinement of the indication. Conclusions. Despite a relatively low diagnostic yield, SBCE has a good positive predictive value for isolated SBCD. However, as CE is a purely visual technique with no capability of taking biopsies, final diagnosis needs confirmation by additional investigations. Nevertheless, SBCE has a 100% negative predictive value, being an excellent tool for rulling out isolated SBCD. Refinement of the indication could ensure a better diagostic yield. [ABSTRACT FROM AUTHOR]