Crohn's disease. Pilot study comparing MRI of the abdomen with clinical evaluation.

Fourteen patients underwent magnetic resonance imaging (MRI) examination (16 studies) and clinical evaluation concurrently. MRI studies included gadolinium enhancement and TI-weighted fat-suppressed spin echo. Separate investigators determined the severity of disease on MR images and on clinical evaluation in a blinded fashion. MRI studies were evaluated for percentage of mural contrast enhancement, wall thickness, and length of diseased bowel. An MR product was generated using these parameters. Clinical evaluation used the Crohn's Disease Activity Index (CDAI) and modified Index of the International Organization for the Study of Inflammatory Bowel Disease (IOIBD). Linear correlation was found between the MR product and clinical indexes of disease activity. The correlation between MR product and the modified IOIBD index was statistically significant (R(2) = 0.633, p = 0.0012). The correlation of MR product and CDAI was less close (R(2) = 0.274, p = 0.0373). Among individual MR parameters, length of diseased bowel showed the greatest correlation with CDAI (R(2) = 0.537, p = 0.012). Percentage contrast enhancement and bowel wall thickness showed significant correlation to the modified IOIBD index (R(2) = 0.739, p = 0.021) but not to the CDAI (R(2) = 0.004, p = 0.825). The results of this study show that the product of mural contrast enhancement, wall thickness, and length of diseased bowel correlated with clinical indexes of disease activity in Crohn's disease. Our findings suggest that MRI may be useful in evaluating the severity of Crohn's disease and may provide information complementary to clinical evaluation.