ULTRASONOGRAPHIC DETECTION AND ASSESSMENT OF THE SEVERITY OF CROHN’S DISEASE RECURRENCE AFTER ILEAL RESECTION Running head: SICUS AND POSTOPERATIVE CROHN’S DISEASE RECURRENCE

BACKGROUND Recurrence and severity of Crohn’s disease mucosal lesions after “curative” ileal resection is assessed at endoscopy. Intramural lesions can be detected as increased wall thickness at Small Intestine Contrast Ultrasonography (SICUS). AIMS To asses after ileal resection whether: 1) SICUS detects recurrence of Crohn’s disease lesions, 2) the intestinal wall thickness measured at the level of ileo-colonic anastomosis predicts the severity of endoscopic lesions, 3) the extension of intramural lesions of the neo-terminal ileum is useful for grading severity of the recurrence, 4) the combined measures of wall thickness of the ileo-colonic anastomosis and the extension of intramural lesions at level of the neo-terminal ileum may predict the endoscopic Rutgeerts score METHODS & PATIENTS Fifty eight Crohn’s disease patients (M 37, age range 19-75 yrs) were prospectively submitted at 6-12 months intervals after surgery to endoscopy and SICUS for a total of 111 observations. RESULTS. Six months or more after surgery wall thickness of ileo-colonic anastomosis >3.5 mm identified 100% of patients with endoscopic lesions (p<0.0001). ROC curve analysis, combining wall thickness of ileo-colonic anastomosis and the extension of intramural lesions of neo-terminal ileum, discriminated ( 0.95) patients with, from those without, endoscopic lesions. Performing two multiple logistic regressions analyses only wall thickness of ileo-colonic anastomosis and extension of neo-terminal ileum intramural lesions were significantly associated with absence or presence of endoscopic lesions. An ordinal polychotomus logistic model, considering all investigated variables, confirmed that only SICUS variables were associated with endoscopic grading of severity. CONCLUSIONS In patients submitted to ileal resection for Crohn’ disease non-invasive Small Intestine Contrast Ultrasonography 1) by assessing thickness of ileo-colonic anastomosis accurately detects initial, minimal Crohn’s disease recurrence, and 2) by assessing both thickness of ileocolonic anastomosis and extension of intramural lesions of neoterminal ileum grades the severity of the post-surgical recurrence.