Technetium leukocyte imaging in inflammatory bowel disease.

Technetium-99m white blood cell ((99m)Tc-WBC) imaging has been part of the initial evaluation and follow-up of more than 400 children presenting with inflammatory bowel disease (IBD) at Children's Hospital of Pittsburgh. Studies have suggested that (99m)Tc-WBC imaging is superior to contrast radiology in assessing the extent and activity of IBD. With only one examination, (99m)Tc-WBC imaging is ideally suited to obtain a precise temporal snapshot of the distribution and intensity of inflammation, whereas radiography tends to detect more chronic changes. There is a high correlation between (99m)Tc-WBC imaging findings and those of endoscopy. When total colonoscopy cannot be completed satisfactorily or when contrast radiography findings are negative or equivocal, scintigraphy can confirm the presence of ileitis or right-sided colitis. Occasionally, (99m)Tc-WBC imaging is useful in differentiating Crohn's disease from ulcerative colitis. Some studies have suggested that (99m)Tc-WBC imaging is useful as an initial screening modality to exclude IBD. Technetium-99m WBC imaging is noninvasive, practical, safe, requires no bowel preparation, and entails less radiation exposure than contrast radiology or computed tomography.