[The diagnosis and differential diagnosis of Crohn's disease and ulcerative colitis by hydrocolonic sonography].

As part of a prospective study the value of hydrocolonic sonography in the diagnosis and differential diagnosis of Crohn's disease (CD) and ulcerative colitis (UC) was assessed and compared with that of coloscopy as standard reference. Of 440 patients who were examined, 41 (23 men, 18 women; mean age 25 +/- 6 years) had CD and 36 (20 men, 16 women; mean age 32 +/- 8 years) had UC. CD and UC were correctly diagnosed by hydrocolonic sonography in 39 and 33 cases, respectively (sensitivity 95 and 91%, specificity 100 and 99%, respectively). Among healthy subjects five layers of variable echo density were demonstrated in the intestinal wall, while in all those with CD the wall was clearly thickened and in 36 of them the wall structure was also abnormal. In 16 patients the wall structure was homogeneous without evidence of layers and in 20, layers 1-3 were not demonstrable and layers 4 and 5 only rudimentary. In contrast, the 33 patients with UC diagnosed by hydrocolonic sonography had only slight thickening of the intestinal wall and all layers were present in 30 of them. CD and UC were correctly distinguished in 91%. Hydrocolonic sonography makes it possible to demonstrate in detail the structural changes in the intestinal wall in CD and UC so that the two conditions can be distinguished.