[Tc-99m labeled leukocyte scintigraphy and CT for the evaluation of patients with inflammatory bowel disease]
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1Department of Medical Imaging, Sapporo City General Hospital.
Seventeen cases (11 patients) of inflammatory bowel disease (IBD) were studied to define the intensity and extent of disease by 99mTc-HMPAO-labeled leukocytes scintigraphy (TLLS), and 10 cases underwent CT examination to evaluate the bowel wall, lymph-nodes, and mesenteric surroundings. Serial TLLS were obtained up to 4 hours and CT was carried out within one week before or after TLLS. The sensitivities of early (1 hour) and delayed (4 hours) TLLS were 91% and 100%, respectively. The respective specificities were 100% and 33%. However, it appeared that mild IBD may yield false negative results in early TLLS while non-specific bowel activity and migration of white cells may cause false positive results in delayed imaging. By setting the diagnostic criteria for labeled leukocyte accumulation on visualization of the small bowel regardless of uptake or activity of the large bowel similar to or greater than lumbar bone marrow, the sensitivity and specificity of delayed TLLS changed to 91% and 83%, respectively. On CT examination, mesenteric lymph-node swelling, periintestinal blurring and dilatation of mesenteric vasa recta were observed in all five patients with active Crohn's disease, while wall thickening and enhancement were seen in four of them. None of the other three cases of inflammatory disease showed positive findings of dilatation of the mesenteric vasa recta, and they revealed relatively low uptake of labeled leukocytes in TLLS. A "scintigram score" was calculated by comparing uptake of tracer in five bowel segments with lumbar bone marrow activity, and a "CT score" was calculated by adding abnormalities of the intestine and mesenteric surroundings. The scintigram score correlated closely with CT score and clinical disease activity. Combined use of CT and TLLS for the evaluation of patients with IBD was an excellent means to obtain the findings of intensity and extent of disease of the bowel wall and mesenteric surroundings and provided useful information in determining the patient management.
Seventeen cases (11 patients) of inflammatory bowel disease (IBD) were studied to define the intensity and extent of disease by 99mTc-HMPAO-labeled leukocytes scintigraphy (TLLS), and 10 cases underwent CT examination to evaluate the bowel wall, lymph-nodes, and mesenteric surroundings. Serial TLLS were obtained up to 4 hours and CT was carried out within one week before or after TLLS. The sensitivities of early (1 hour) and delayed (4 hours) TLLS were 91% and 100%, respectively. The respective specificities were 100% and 33%. However, it appeared that mild IBD may yield false negative results in early TLLS while non-specific bowel activity and migration of white cells may cause false positive results in delayed imaging. By setting the diagnostic criteria for labeled leukocyte accumulation on visualization of the small bowel regardless of uptake or activity of the large bowel similar to or greater than lumbar bone marrow, the sensitivity and specificity of delayed TLLS changed to 91% and 83%, respectively. On CT examination, mesenteric lymph-node swelling, periintestinal blurring and dilatation of mesenteric vasa recta were observed in all five patients with active Crohn's disease, while wall thickening and enhancement were seen in four of them. None of the other three cases of inflammatory disease showed positive findings of dilatation of the mesenteric vasa recta, and they revealed relatively low uptake of labeled leukocytes in TLLS. A "scintigram score" was calculated by comparing uptake of tracer in five bowel segments with lumbar bone marrow activity, and a "CT score" was calculated by adding abnormalities of the intestine and mesenteric surroundings. The scintigram score correlated closely with CT score and clinical disease activity. Combined use of CT and TLLS for the evaluation of patients with IBD was an excellent means to obtain the findings of intensity and extent of disease of the bowel wall and mesenteric surroundings and provided useful information in determining the patient management.