Value of positive technetium-99m leucocyte scans in predicting intestinal inflammation.

Abstract

The value of positive scans of autologous 'Tc-labelled leucocytes in the detection of intestinal inflammation was assessed in 29 patients with known inflammatory bowel disease and a high probability of intestinal inflammation and 58 with a low probability of intestinal inflammation comprising 37 with intestinal symptoms and 21 with suspected abscess. Autologous leucocytes were labelled with 9mTc using either of the established methods. In patients with inflammatory bowel disease, 3/13 with ileocaecal and 1/11 with colonic accumulation of 99Tc were incorrectly diagnosed in that there was no histological evidence of inflammation in those regions. In the low probability patients, all 26 positive images were false positives: there were 19 in the ileocaecal and 7 in colonic regions and no differences between the two subgroups. False positives were more common in low probabilitythanhigh probabilitypatients (p=0.011). The results were independent of the 'Tc cell labelling technique used. Three false positive patients also had normal scans for "'lInlabelled granulocytes. The time of first detection of 'Tc in the bowel was earlier in true than in false positive patients (92% v 33% within 1 h, p=0.008), the false positive rates in the first hour of imaging being 5% in high and 15% in low probability patients. In -Tc scinti-

Leukocyte scintigraphy compared to intraoperative small bowel enteroscopy and laparotomy findings in Crohnʼs disease

“…32 Nonspecific bowel activity, unrelated to inflammatory bowel disease, has in other studies been observed in the small bowel and proximal colon as early as 30 minutes after injection of technetium-99m exametazime-labeled cells 33 and been found in about 15% of subjects within the first hour. 29,34 In other series, such activity has first been seen on 2-hour images in 7% or on 3-4-hour images in 5%-28% of examinations 31,[35][36][37] or to occur only later than 3 hours. 38 We applied neither fasting conditions before scanning 39 nor injection of pethidine before the reinjection of labeled cells, 40 which has been shown to increase the frequency of gall bladder visualization from 10% to 44% and from 29% to 72%, respectively.…”

“…28,29 The controls also had a full small bowel enteroscopy with biopsy in order to definitively evaluate the performance of the scan technique in noninflammed bowel, in parallel with a previous study where we included noninflammed controls who underwent colonoscopy. 22 The early 45-minute scan was negative for the small bowel in all control patients, that is, there were no falsepositives in this group.…”

Technetium-99m hexamethylpropylene amine oxime labelled leucocyte scintigraphy in ulcerative colitis and Crohn's disease

“…An advantage of 1 ~ 1in oxine is the high resolution of the late images available with this technique. Because of the high frequency of false-positive findings, late images with 99mTc-HMPAO-labelled leucocytes are not feasible [15]. On the other hand a disadvantage of ~lln LS in Crohn's disease patients is the use of purified granulocytes in contrast to the use of mixed leucocytes.…”

Paediatric Crohn's disease: a radiological review

“…Involved bowel shows tracer uptake at 1 h, whereas normal bowel does not show any activity for 3±4 h; however, some normal patients may show bowel activity at 1 h [26,27]. A study by Malcolm et al [28] in which patients with suspected Crohn's disease underwent technetium scanning as the initial investigation with subsequent diagnosis confirmed by radiology and endoscopy found overall sensitivity 100 %, specificity of 91 % and accuracy of 93 % for white cell scanning.…”