technetium-tc-99m-exametazime and Colonic-Diseases--Functional

This study was designed to evaluate the role of technetium-99m (99mTc) hexamethyl propylene amine oxime (HMPAO)-labelled leucocyte imaging as an initial screening test in patients suspected of having inflammatory bowel disease (IBD).. Thirty-one patients in whom a final diagnosis of irritable bowel syndrome (IBS) was made (group 1) and another 33 patients with established Crohn's disease (group 2) were studied. All patients had 99mTc HMPAO-labelled leucocyte scan with imaging at 40 and 120 min. Scans with abnormal bowel uptake were considered positive and this uptake was quantified by visual grading and computer-based methods (scan score). Group 1 patients with positive 99mTc HMPAO scan underwent an indium-111 (111In)-labelled leucocyte scan (imaging at 180 min) followed by endoscopy and barium radiology as deemed necessary in order to verify the 99m Tc HMPAO result.. Three scan patterns were seen: well localized and unequivocally positive scans at both 40 min and 2 h were obtained from 28 patients. All but one had established Crohn's disease. Diffuse bowel uptake was seen in 14 scans. Ten of these (false positive) were obtained from symptomatic patients with IBS and four (false negative) from patients with asymptomatic Crohn's disease. No bowel uptake at 40 min and 2 h was seen in 22 scans. All but two of these (who had quiescent Crohn's disease) were obtained from patients with IBS. Active Crohn's disease is associated with significantly higher scan score (mean +/- SEM, 82.1 +/- 13.6) than the false positive scans (12.5 +/- 3.1, P > or = 0.001). Patients with false positive 99mTc HMPAO scans had negative 111In scans, endoscopy and barium radiology.. Bowel scanning using either 111In or 99mTc HMPAO is useful in excluding active IBD. Because of radiation dose, image quality and availability 99mTc may be preferred to 111In.

Topics: Adult; Case-Control Studies; Colonic Diseases, Functional; Crohn Disease; False Positive Reactions; Female; Humans; Indium Radioisotopes; Inflammatory Bowel Diseases; Intestines; Leukocytes; Male; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Technetium Tc 99m Exametazime; Time Factors

Forty-seven patients, 29 with chronic inflammatory bowel disease (IBD) and 18 with presumed irritable bowel syndrome, including one with uncomplicated diverticular disease, were studied with simultaneous technetium-99m hexamethylpropylene amine oxime and indium-111 oxine labelled leucocyte scans performed at 1, 3 and 24 h. Twenty-seven patients with IBD had active disease as judged by clinical and laboratory criteria and all of these had positive scans with both agents. No false positive studies were obtained. The 1-h 99mTc-HMPAO WBC scans showed the same distribution to disease as the 3-h 111-In WBC scans, with no difference in intensity (P < 0.92); they showed more extensive disease (P < 0.02) and more intense uptake (P < 0.001) than did the 1-h 111-In scans. The 3-h 99mTc-HMPAO WBC scans showed more extensive disease (P < 0.002), with greater intensity (P < 0.0005), than did the 3-h 111In WBC scans. Physiological bowel activity on 3-h 99mTc-HMPAO WBC scans was present in 12 patients but was faint and did not interfere with assessment of disease extent and activity. It is concluded that in terms of isotope availability, radiation dosimetry and image quality, 99mTc-HMPAO is the agent of choice in detecting active IBD, with localization of disease possible at 1-h after re-injection and optimal resolution and definition of disease extent at 3 h. A negative scan reliably excludes active disease.

Topics: Adult; Colonic Diseases, Functional; Female; Humans; Indium Radioisotopes; Inflammatory Bowel Diseases; Intestines; Leukocytes; Male; Organometallic Compounds; Organotechnetium Compounds; Oximes; Oxyquinoline; Radionuclide Imaging; Technetium Tc 99m Exametazime; Time Factors