AIR ENEMA RADIOLOGY COMPARED WITH LEUKOCYTE SCINTIGRAPHY FOR IMAGING INFLAMMATION IN ACTIVE ULCERATIVE-COLITIS

Objective: To compare air enema radiology with a leukocyte scintigraph y technique using technetium-99m-hexamethyl propylene amine oxime-labe lled leukocytes for imaging colonic inflammation in ulcerative colitis . Design: Prospective study in a University hospital. One radiologist and one nuclear physician independently graded the degree of inflammat ion in six colon segments per patient using radiographs and leukocyte scans. Patients: Twenty consecutive patients with symptoms of active u lcerative colitis requiring corticosteroids, inflammation on rigid sig moidoscopy and a positive leukocyte scan above the rectum. Results: Us ing air enema radiology, inflammation above the rectum was observed in 17 of the 20 patients. Eleven patients had the same extent of disease with both imaging techniques (total n = 5; extensive n = 3; distal n = 3). Seven patients had more widespread colitis using leukocyte scint igraphy. In the remaining two patients with extensive inflammation at scintigraphy, air enema films showed total colitis. When the colon was subdivided into six different segments, prediction of the presence of inflammation in individual segments was 0.88 for air enema radiology compared with leukocyte scintigraphy and 0.60 for the prediction of ab sence of inflammation. All segments with an irregular mucosal contour or ulceration on air enema films had intense inflammation at scintigra phy. Conclusions: In patients with active ulcerative colitis, air enem a radiology underestimates the extent of inflammation because this inv estigation shows secondary patho-anatomical changes, while leukocyte s cintigraphy visualizes the acute cellular infiltrate. In patients with more severe inflammation, there is excellent agreement between the tw o methods.