Mark Early Baker MD, Presenter: Medical Advisory Board, E-Z-EM, Inc Speakers Bureau, E-Z-EM, Inc

James Walter, Abstract Co-Author: Nothing to Disclose

Nancy A. Obuchowski PhD, Abstract Co-Author: Consultant, Siemens AG

Jean-Paul Achkar MD, Abstract Co-Author: Nothing to Disclose

David Einstein MD, Abstract Co-Author: Nothing to Disclose

Jon Vogel MD, Abstract Co-Author: Nothing to Disclose

Luca Stocchi MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To measure absolute (AE) and relative wall enhancement (RE), and wall thickness of small bowel in normal and Crohn’s patients on CT enterography (CTE), to assess the association and differences of AE, RE and wall thickness in normal segments and to compare AE, RE and wall thickness in the terminal ileum (TI) in distinguishing normal from Crohn’s.

Out of 630 CTE’s performed in 12 months, 36 had confirmed TI Crohn’s disease and 191 were confirmed normal. We measured: 1) wall thickness and attenuation for duodenum (D), RUQ, LUQ, RLQ, LLQ (collapsed and dilated), and TI in the normal and TI only in Crohn’s; and, 2) arterial attenuation at the same slice level of each segment measured. Normal segments were compared with a linear model. TI data was fit to a multi-variable logistic regression model. For both RE & AE, the best parsimonious model was then compared using area under the ROC curves to determine which better distinguished normal from Crohn's.

In distended loops for RE, D > LUQ, RUQ, LLQ & RLQ; LUQ > RUQ and RLQ (all p LUQ > RUQ, LLQ, RLQ (pRUQ, LLQ, RLQ (p RUQ, LLQ, RLQ; LUQ>LLQ, RLQ (p 0.3 cm). An AE cutoff of 85 H.U. yields a sensitivity and specificity of 89%/67%(89%/79% if wall > 0.3 cm)(Bodily et al cutoff of 109 H.U. AE sensitivity and specificity=50%/96%).

In normal segments, accounting for wall thickness, RE & AE of duodenum and jejunum > distal ileum. Taking into account wall thickness, RE is equivalent to AE in distinguishing normal from Crohn’s.

Small bowel wall thickness is important in assessing enhancement; normal proximal small bowel enhances greater than distal; and RE distinguishes normal from Crohn’s and thus used for follow-up

Baker, M, Walter, J, Obuchowski, N, Achkar, J, Einstein, D, Vogel, J, Stocchi, L, et al, , et al, , Contrast-enhanced CT Enterography in Normal Small Bowel and Crohn’s Disease: Differences in Wall Enhancement and Wall Thickness.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5007626.html