Indium-111 leukocyte scanning of the abdomen. Analysis of its value for diagnosis and management of inflammatory bowel disease

Nuclear medicine imaging of inflammatory/infective disorders of the abdomen

Different nuclear medicine modalities are currently used to study inflammatory and infective disorders of the abdomen. They are usually complementary to radiology and endoscopy, but they play a pivotal role in particular clinical situations. Several radiopharmaceuticals (e.g., 111In or 99mTc labelled white blood cells, monoclonal antibodies, human polyclonal immunoglobulins, 75Ga citrate) are commercially available, but they can not be used indifferently to study abdominal inflammatory disorders. The lack of comparative studies showing the accuracy of each radiopharmaceutical for the study of inflammatory/infective abdominal diseases does not allow the best nuclear medicine technique(s) to be chosen in an evidence-based manner. To this end we performed a meta-analysis of peer reviewed articles published between 1984 and 2004 describing the use of nuclear medicine imaging for the study of inflammatory bowel disorders, appendicitis and vascular graft infections. A guideline for the optimal radiopharmaceutical(s) to be used in each clinical condition and for different aims is provided.

The role of nuclear medicine in inflammatory bowel disease. A review with experiences of aspecific bowel activity using immunoscintigraphy with 99mTc anti-granulocyte antibodies

The diagnosis of inflammatory bowel disease (IBD) needs a complex diagnostic work-up. Beside verifying the disease itself, it is fundamental to assess disease extent and activity and to detect associated complications, to find the most effective treatment and for follow up. Scintigraphy with radiolabelled leukocytes is able to provide a complete survey of the whole intestinal tract, both the small and large bowel, and detects septic complications successfully with negligible risk. Radionuclide procedures are useful in establishing or ruling out IBD in patients with intestinal complaints, in assessing disease severity, and in the evaluation of extraintestinal septic complications. Widely available radionuclide procedures are discussed, i.e. scintigraphy by 111Indium oxime or 99mTechnetium HMPAO labelled white blood cells and immunoscintigraphy with 99mTc anti-granulocyte antibodies. Advantages and disadvantages of all three methods are stressed out.

PATIENTS AND METHODS

The immunoscintigraphies with 99mTc anti-granulocyte antibodies (ANTI-GRANULOCYTE(R) BW 250/183) of 27 patients with suspicion of IBD were retrospectively analysed. Planar anterior and posterior images were obtained 4 and 24 h postinjection, respectively. The bowel was divided into six segments and the activity was visually graded with reference to bone marrow in each segments. The scans were compared with the results of radiological and endoscopical investigations. The diagnosis of IBD was proved or ruled out by means of enteroclysis, large bowel enema or endoscopy.

RESULTS

In the 27 patients, 74 bowel segments with increased activity were detected. In the case of 30 segments in 16 patients, bowel inflammation was revealed by the other methods (true positives). In the case of 44 bowel segments, no underlying bowel inflammation could be verified, and these activities were regarded as aspecific activity. We could not differentiate between true positive and aspecific activity based on scan pattern or intensity.

DISCUSSION

These findings of aspecific bowel activity using imuunoscintigraphy are in contrast with the results of former studies, while the existence of non-specific activity decreases the reliability of the method. Based on the literature and our experiences, we conclude that 99mTc HMPAO labelling should be the method of choice for the investigation of IBD patients.

Determination of inflammatory bowel disease activity by breath pentane analysis

PURPOSE

Quantitative determination of breath pentane, an alkane generated by peroxidation of cellular fatty acids, has been used as a noninvasive determinant of inflammation. Herein we report the first examination of the relationship between breath pentane and intestinal inflammation in humans.

METHODS

Patients (N = 33), either with a known history of inflammatory bowel disease (IBD) with symptoms of relapse or with no known history of but having symptoms consistent with IBD, were evaluated with indium-111-labeled leukocyte imaging to assess the presence of active inflammation. At the time of the indium scan, the exhaled breath of the patients was obtained via a collecting tube. Gas chromatography was used to quantify the pentane content, and these values were compared with graded indium scans.

RESULTS

The range of breath pentane found in our population (36 determinations in 33 patients) was from 0 to 38.4 nmol/l of exhaled air. For patients with negative scans, the mean pentane was 2.1 nmol/l, for intermediate scans 3.1, for positive scans 4.3, and for nonintestinal nuclide imaging 5.5 [P = 0.005 by analysis of variance (ANOVA)].

CONCLUSIONS

We have previously demonstrated the correlation of breath pentane with gross and histologic evidence of intestinal inflammation in a rodent colitis model. This current study also demonstrates that pentane analysis can be correlated with inflammatory bowel disease activity in humans.

Do technetium-99m hexamethylpropylene amine oxime-labeled leukocytes truly reflect the mucosal inflammation in patients with ulcerative colitis?

Twenty-five patients with ulcerative colitis and nine controls with macroscopically non-inflamed colon were investigated with technetium-99m hexamethylpropylene amine oxime-labeled leukocyte scintigraphy and colonoscopy with biopsies. The interval between leukocyte scintigraphy and colonoscopy was < or = 14 days in all patients with ulcerative colitis and < or = 30 days in eight of nine controls. Scintigrams were obtained at approximately 45 min and 4 h after injection of labeled leukocytes. One nuclear physician, one internist, and one pathologist graded blindly and independently of each other the degree of active inflammation in seven different colonic segments for each patient, using 4-grade scales for scans and macroscopically and histologically viewed inflammation, respectively. A positive correlation between endoscopic and histologic grading of all colonic segments and scan gradings for all subjects and for ulcerative colitis patients separately was found (all, p < 0.001). By means of kappa statistics, the inter-observer agreement between scintigraphic grading at 45 min and endoscopy was, for all subjects, 0.32 (95% confidence interval (CI), 0.20-0.44; p < 0.001) and, for patients with ulcerative colitis, 0.19 (CI, 0.07-0.31; p < 0.001). When 17 patients who had complete colonoscopies were divided into those with total, extensive, or distal colitis, leukocyte scintigraphy underestimated the extension of active inflammation. A simple scintigraphic scoring system reflects the colonic inflammation viewed endoscopically and histologically in patients with ulcerative colitis but underestimates the presence of active inflammation in individual colonic segments.

The role of indium-111 white blood cells in inflammatory bowel disease

Inflammatory bowel disease in patients may be difficult to diagnose because of the complex problems associated with this disease. Radionuclides are able to provide a rapid and effective method of imaging the bowel in patients with active inflammatory bowel disease. In the past, clinical work-ups have included barium x-ray studies and endoscopy. Scarring and fistula formation have made it difficult to determine between the active disease and abscesses that may occur. Gallium-67 (67Ga) has been very useful in imaging patients with inflammatory bowel disease, but the multiple-day imaging procedure has been a limitation for the clinicians when achieving a diagnosis. Recent results with Indium-111 (111In)--labeled WBCs have provided excellent correlation between clinical symptoms and colonoscopy findings in patients with inflammatory bowel disease. This technique has also allowed the differentiation between reoccurring inflammatory bowel disease and abscesses that accompany the disease within a 24-hour time period. The use of intravenous (IV) glucagon has increased the clarity of the images in the small bowel. Technetium 99m (99mTc) diethylenetriaminepentaacetic acid (DTPA) has been used in patients with inflammatory bowel disease demonstrating promising results. Investigators feel labelling 99mTc with WBCs will be improved, therefore yielding a greater efficiency, which will have a major impact on imaging patients with inflammatory bowel disease. Imaging patients with inflammatory bowel disease using radionuclides has yielded promising results. This is a significant advancement over barium radiography and endoscopy exams.