HM-PAO-labeled leukocyte scintigraphy in pediatric patients with inflammatory bowel disease

Pediatric Gastrointestinal Nuclear Medicine

General localization of gastrointestinal bleeding through the use of labeled red blood cells may be performed in children, or (99m)Tc-pertechnetate may be used if a Meckel's diverticulum is suspected. As in adults, cholecystitis and biliary leak may be assessed in children via (99m)Tc-IDA derivatives. Gastroesophageal reflux can be evaluated by oral consumption of the child's usual diet labeled with (99m)Tc sulfur colloid. For the scintigraphic determination of pulmonary aspiration, a relatively high concentration of tracer within a drop of liquid is placed beneath the child's tongue followed by dynamic imaging of the respiratory tract. Colonic transit scintigraphy can aid in the identification and therapeutic decision-making in patients with functional fecal retention, the most common cause of chronic constipation in children. (18)F-DOPA positron emission tomography is useful for classifying pancreatic involvement in infantile hyperinsulinism as focal or diffuse, thereby differentiating between patients who should receive curative focal pancreatic resection versus those who should receive medical management. Assessment of protein-losing enteropathy can be conducted scintigraphically and, compared with fecal alpha-1 antitrypsin collection, the scintigraphic method can detect esophageal and gastric protein loss. Also, scintigraphic quantification of protein loss can be performed without the requirement for fecal collection. Intestinal inflammation in children with inflammatory bowel disease can be evaluated using (99m)Tc white blood cells. The scintigraphic method is safe, accurate, well-tolerated by children and complementary to endoscopy in most patients.

[99mTc-HMPAO-leukocyte-labeled scintigraphy in the detection and follow-up of inflammatory bowel disease]

To assess the clinical value of 99mTc-HMPAO-leukocyte-labeled scintigraphy (LLS) in the detection and follow-up of inflammatory bowel disease (IBD) in the pediatric population, we retrospectively reviewed 33 patients (15 boys; mean age 10.7 +/- 2.2 years) with suspected IBD. A total of 58 examinations were performed: 29 for screening purposes, 23 for follow-up and 6 to detect relapses. LLS was compared with clinical symptoms (PCDAI index), biologic markers of inflammation, barium contrast radiology (BCR; n = 22), sonography (n = 22), colonoscopy (n = 16), and biopsy (n = 13). The final diagnosis was Crohn's disease in 12, ulcerative colitis in 4, and no IBD in 17. In the 17 patients without IBD, LLS was always negative. Among the 16 patients with IBD, LLS showed concordant results with BCR in 7/10 patients, with sonography in 6/11, with colonoscopy in 9/12 and with biopsy in 8/9. The severity of LLS increased with the PCDAI index (p < 0.001), with a positive correlation between the scintigraphic activity index/PCDAI r = 0.76. An increase in the PCDAI index with the severity of LLS (p < 0.001) was also observed in the follow-up, and a weak correlation (r = 0.50) between erythrocyte sedimentation rate/scintigraphic activity index was obtained. In 5 patients with normal biologic markers, LLS detected inflammation. All 6 patients with relapses were symptomatic; 5 had inflammation on LLS and 5 had abnormal biologic markers. In conclusion, LLS can be a useful screening tool in the detection of IBD in children to assess the grade of inflammation and extension of IBD. This technique can detect the presence of inflammation during follow-up and should be performed when relapses are suspected.

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.

Temporal Correlation of the Erythrocyte Sedimentation Rate With Tc-99m WBC Uptake on Children With Inflammatory Bowel Disease

The goal of this study was to evaluate the temporal correlation of Tc-99m WBC studies with the erythrocyte sedimentation rate, a commonly used index of intensity of inflammation, in a large population of children with inflammatory bowel diseases. Over a 6-year period, 313 Tc-99m WBC studies were performed and the hospital charts of these consecutive children were reviewed. In each set of scans (0.5-1 hour and 2-3 hours) from the 313 patients, the bowel was divided into 8 segments resulting in 5008 bowel segments for scoring. The intensity of uptake on the planar images was graded on a scale of 0 to 6 and compared with the erythrocyte sedimentation rate obtained within 3 days, 1 week, 2 weeks, 1 month, 3 months, 6 months, or 1 year of the Tc-99m WBC scan, when available. A dataset of 508 erythrocyte sedimentation rates was available for computation. In children with Crohn's disease, when erythrocyte sedimentation rate is obtained within 3 days of the Tc-99m WBC scan, the correlation coefficient is R=0.314 (P<0.005), within 1 week R=0.358 (P<0.05), within 2 weeks R=0.254 (P=0.129), within 1 month R=-0.029 (P=0.84), within 3 months R=-0.002 (P=0.989), within 6 months R=0.241 (P=0.145), and within 1 year R=0.068 (P=0.759). In children with Crohn's disease, the uptake of Tc-99m WBC correlates well with the erythrocyte sedimentation rate during the flare of inflammation, and the correlation progressively subsides after a few weeks. No such correlation was noted in children with ulcerative colitis.

Evaluation of 99mTc-HMPAO leukocyte scintigraphy in the investigation of pediatric inflammatory bowel disease

OBJECTIVE

To evaluate (99m)Tc-HMPAO leukocyte scintigraphy as an investigation for inflammatory bowel disease (IBD).

STUDY DESIGN

Scintigraphy was performed in 95 children undergoing investigation for IBD in a tertiary Gastroenterology Department. Diagnosis was based on conventional investigations including small bowel barium contrast radiology (BCR), upper gastrointestinal endoscopy (UGIE), colonoscopy, and endoscopic biopsy (the "gold standards"). IBD was confirmed in 73 (57 Crohn's disease; 10 ulcerative colitis; 6 indeterminate colitis) and excluded in 22 (controls). Scintigraphy was (1) evaluated as a screening test, (2) compared with individual conventional tests, (3) assessed for each gut segment.

RESULTS

Screening test: sensitivity 0.75 (95% CI, 0.63-0.85), specificity 0.82 (95% CI, 0.59-0.94), PPV 0.93, NPV 0.5. Comparison with BCR: sensitivity 0.87 (95% CI, 0.72-0.96), specificity 0.57 (95% CI, 0.39-0.73), PPV 0.69, NPV 0.2. Comparison with UGIE: specificity 0.9 (95% CI, 0.79-0.96), NPV 0.13 (sensitivity and PPV unavailable). Comparison with colonoscopy: sensitivity 0.57 (95% CI, 0.41-0.73), specificity 0.71 (95% CI, 0.54-0.85), PPV 0.71, NPV 0.42. Comparison with biopsies paralleled that with endoscopy. False negatives were especially common (NPV< or =0.2) in the proximal gut.

CONCLUSIONS

(99m)Tc-HMPAO leukocyte scintigraphy should not be relied on as a screening test for IBD because false negative results are common. This method is especially unreliable at detecting disease in the proximal gut.

99mTc-HMPAO leucocyte scintigraphy fails to detect Crohn's disease in the proximal gastrointestinal tract

OBJECTIVE

To investigate the use of (99m)Tc-HMPAO (hexamethyl propylene amine oxime) leucocyte scintigraphy as a non-invasive screening test for inflammatory bowel disease.

PATIENTS

10 children with suspected Crohn's disease, in whom routine investigation using barium contrast radiology, upper gastrointestinal endoscopy, colonoscopy, and mucosal biopsies had identified severe gastroduodenal and/or jejunal involvement.

DESIGN

(99m)Tc-HMPAO leucocyte scintigraphic studies performed in each of these cases were assessed by a radiologist who was blinded to the disease distribution.

RESULTS

In nine cases there was no scintigraphic evidence of inflammation in the proximal gastrointestinal tract. The 10th child had both gastroduodenal and jejunal involvement, but scintigraphy only revealed faint jejunal positivity.

CONCLUSIONS

(99m)Tc-HMPAO leucocyte scintigraphy should not be depended upon as a screening test for Crohn's disease. False negative results are likely in cases with Crohn's disease confined to the proximal gastrointestinal tract.

Technetium-99m HMPAO-labeled leukocyte imaging compared with endoscopy, ultrasonography, and contrast radiology in children with inflammatory bowel disease

BACKGROUND

The purpose of this study was to evaluate retrospectively the value of leukocyte-labeled scintigraphy, ultrasonography, and contrast radiography compared with endoscopy in children suspected of having inflammatory bowel disease (IBD).

METHODS

Twenty-eight children (17 boys; mean age, 10.2 years) with IBD based on standard colonoscopic, histologic, and radiologic criteria (16 with Crohn's disease, 5 with ulcerative colitis, 5 with nonspecific colitis, I with granulomatous disease, and I with Beh,cet's disease) were included. Endoscopic, ultrasonographic, and contrast radiologic examinations were realized for 28, 23, and 19 children respectively.

RESULTS

Sensitivity and specificity were 75% and 92% for leukocyte-labeled scintigraphy, 39% and 90% for ultrasonography, and 58% and 83% for contrast radiography. The authors noted discontinuous uptake for 14 of 15 true-positive results for patients with Crohn's disease and continuous uptake for 4 of 4 true-positive results for patients with ulcerative colitis. A negative correlation between scan activity index and Lloyd-Still clinical score was found for 11 patients with Crohn's disease (r = -0.77).

CONCLUSIONS

Leukocyte-labeled scintigraphy, a noninvasive and reproducible technique, is a useful tool in the diagnosis and therapeutic strategy of IBD, and provides information on the presence, the intensity, and the extent of the disease, particularly in the terminal ileum. Leukocyte-labeled scintigraphy may not replace colonoscopy with biopsies for diagnosis confirmation. Its reliability seems higher than that of ultrasonography.

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.

Pediatric inflammatory bowel disease imaged with Tc-99m white blood cells

Studies have suggested that Tc-99m white blood cell (WBC) imaging is superior to contrast radiology for assessing the extent and activity of inflammatory bowel disease (IBD). The Tc-99m WBC scan seems ideally suited to obtain, in only one examination, a precise temporal snapshot of the distribution and intensity of inflammation, whereas radiographic methods of investigation tend to represent changes that are more chronic. The test is useful in children with inconspicuous signs suggesting IBD in whom laboratory test results are either normal or slightly abnormal. In those cases, a negative Tc-99m WBC study will obviate endoscopic investigations. The author's current experience, in more than 500 patients, indicates that the Tc-99m WBC scan is a virtual gold standard to establish, or exclude, the diagnosis of IBD. The minimal invasiveness of the Tc-99m WBC scan makes it an especially attractive method for evaluating children with IBD. It is economical compared with endoscopy, and its diagnostic sensitivity is excellent. The ability to evaluate the small and large bowel simultaneously is an important advantage for the patient. In conclusion, the Tc-99m WBC scan is a useful tool to evaluate IBD and should be added to the clinician's investigative armamentarium.

Are 99mTc leukocyte scintigraphy and SBFT studies useful in children suspected of having inflammatory bowel disease?

OBJECTIVE

The goal of this retrospective study was to assess whether 99mTc-white blood cell (WBC) scintigraphy and upper gastrointestinal small bowel follow-through (UGI-SBFT) could exclude inflammation in children suspected of having inflammatory bowel disease (IBD).

METHODS

Of a population of 313 children who had a 99mTc-WBC scan, 130 children were studied exclusively to rule out IBD. Sixty-nine colonoscopies with biopsies were done within a short time interval of the 99mTc-WBC scans. There were also 51 controls studied with 99mTc-WBC scintigraphy.

RESULTS

Of the 130 children studied to exclude IBD, the final diagnosis was Crohn's disease in 27, ulcerative colitis in nine, miscellaneous colitis in 13, probably normal in 42, and normal in 39. The 99mTc-WBC scans were positive in all but three newly diagnosed Crohn's disease, ulcerative colitis, or miscellaneous colitis children. The false-negative 99mTc-WBC studies were seen in children with mild inflammation on biopsies and normal UGI-SBFT studies. In the 46 children with a true-positive 99mTc-WBC scan, 81% (17/21) of UGI-SBFT studies were normal. In five children with equivocal UGI-SBFT studies, the 99mTc-WBC scan correctly predicted if inflammation was present in the terminal ileum.

CONCLUSIONS

Our results suggest that 99mTc-WBC is useful as an initial screening modality to exclude IBD, and is more sensitive than UGI-SBFT studies.

Pediatric inflammatory bowel disease: assessment with scintigraphy with 99mTc white blood cells

PURPOSE

To evaluate the sensitivity and specificity of scintigraphy with technetium 99m white blood cells (WBC) for detection of colonic inflammation in children with and children without inflammatory bowel disease (IBD).

MATERIALS AND METHODS

In 215 patients, uptake of 99mTc WBC in 3,440 bowel segments was graded. In 137 of the 215 patients, the 99mTc WBC scans were interpreted blindly and findings compared with results at colonoscopy and endoscopic biopsy. Planar, single photon emission computed tomographic, and maximum-activity-projection images were reviewed together. In 78 children without recent endoscopic biopsy results, 99mTc WBC scan findings were compared with laboratory values, the gastroenterologist's initial clinical assessment, and findings at long-term clinical follow-up.

RESULTS

In 128 of 137 children with recent biopsies, findings at histologic examination and on 99mTc WBC scans were correlated. There were seven false-negative and two false-positive studies. Sensitivity was 90%, specificity 97%, positive predictive value 97%, negative predictive value 93%, prevalence of disease 53%, and overall accuracy 93%. In 75 of 78 (96%) children without recent biopsies, 99mTc WBC scan findings were consistent with the laboratory values, gastroenterologist's clinical assessment, and long-term clinical follow-up findings.

CONCLUSION

Scintigraphy with 99mTc WBC is a useful noninvasive diagnostic test to determine the extent and distribution of inflammation in children with IBD.

Technetium leukocyte imaging in inflammatory bowel disease

Technetium-99m white blood cell ((99m)Tc-WBC) imaging has been part of the initial evaluation and follow-up of more than 400 children presenting with inflammatory bowel disease (IBD) at Children's Hospital of Pittsburgh. Studies have suggested that (99m)Tc-WBC imaging is superior to contrast radiology in assessing the extent and activity of IBD. With only one examination, (99m)Tc-WBC imaging is ideally suited to obtain a precise temporal snapshot of the distribution and intensity of inflammation, whereas radiography tends to detect more chronic changes. There is a high correlation between (99m)Tc-WBC imaging findings and those of endoscopy. When total colonoscopy cannot be completed satisfactorily or when contrast radiography findings are negative or equivocal, scintigraphy can confirm the presence of ileitis or right-sided colitis. Occasionally, (99m)Tc-WBC imaging is useful in differentiating Crohn's disease from ulcerative colitis. Some studies have suggested that (99m)Tc-WBC imaging is useful as an initial screening modality to exclude IBD. Technetium-99m WBC imaging is noninvasive, practical, safe, requires no bowel preparation, and entails less radiation exposure than contrast radiology or computed tomography.