Scintigraphic head-to-head comparison between 99mTc-WBCs and 99mTc-LeukoScan in the evaluation of inflammatory bowel disease: a pilot study.

Scintigraphy with technetium-99m labelled white blood cells (WBCs) is routinely used in our hospital for the assessment of inflammatory bowel disease (IBD). The main disadvantages of this diagnostic tool are its time-consuming nature and the handling of blood itself. 99mTc-LeukoScan is a relatively new, easily prepared agent that is used for the detection of osteomyelitis. To assess its value in IBD, a scintigraphic head-to-head comparison was performed between 99mTc-LeukoScan and 99mTc-WBCs. 99mTc-LeukoScan scintigraphy was performed in six patients with clinically active IBD and increased uptake on 99mTc-WBC images. The interval between the scintigraphic studies ranged from 2 to 7 days, and endoscopy was subsequently performed to confirm active IBD. In three out of six patients with increased uptake on the 99mTc-WBC scans, 99mTc-LeukoScan images showed very discreet activity in the bowel, but the sites did not correspond with the inflammation sites seen on 99mTc-WBC scintigraphy and found at endoscopy. In the other three patients, 99mTc-LeukoScan scintigraphy revealed a physiological distribution but no abnormalities. In conclusion, 99mTc-LeukoScan is not an alternative agent for the assessment of IBD. A prospective study is not justified owing to the false-negative results.