99mTc-HMPAO planar white cell scanning

Repeat planar white cell scanning to monitor short-term therapy of active inflammatory bowel disease: a methodological study and comparison with clinical scores and novel inflammatory markers

OBJECTIVES

Radiolabelled white cell scans provide non-invasive quantification of inflammatory activity. Clinical activity scores measure severity of disease but are partly subjective. White cell scans may provide a suitable method of monitoring the treatment response of active inflammatory bowel disease.

METHODS

Ten subjects with active ulcerative colitis and 13 subjects with active Crohn's disease were recruited. White cell scans were carried out before and 2 weeks after treatment. Prior to each scan, activity scores for ulcerative colitis or Crohn's disease were calculated and serum and faecal tumour necrosis factor-alpha and calprotectin measured. White cell scan activity at 1 h was calculated by using a validated visual grading system.

RESULTS

Following anti-inflammatory treatment, 70% of white cell scans improved, 17% remained unchanged and 13% deteriorated. In the ulcerative colitis subgroup subjects there was modest agreement for change in scan score and activity scores. In the Crohn's disease subjects there was better agreement between change of white cell scan score and clinical scores. Planar white cell scans correlated with the van Hees activity index (r=0.68, P=0.002) and faecal calprotectin (r=0.58, P=0.0003). Changes in planar white cell scans correlated with changes in serum calprotectin (r=0.45, P=0.05).

CONCLUSION

Non-invasive white cell scanning is a feasible and objective method to monitor the anti-inflammatory efficacy of treatments for active inflammatory bowel disease.

A review of leukofiltration therapy for decreasing the morbidity associated with cardiopulmonary bypass and acute inflammatory bowel disease

Complications of cardiopulmonary bypass (CPB) and acute inflammatory bowel disease (IBD) are associated with increased morbidity and cost. During reperfusion post-CPB, activated neutrophils adhere to microvascular endothelial cells mediated by cell adhesion molecules (CAMs) and cytokines/chemokines with subsequent myocardial damage caused by activated neutrophil-derived oxidants and enzymes. Leukofiltration was shown to reduce myocardial reperfusion injury and improve gas exchange as suggested by improvements in surrogate markers of inflammation and clinical end points. In acute IBD, characterized by rectal bleeding and protracted hospital stays, circulating neutrophils emigrate to the inflamed colon and adhere to microvascular endothelial cells by CAMs. Multiple treatments with leukofiltration in IBD were shown to induce long-term remission of acute IBD. Hence, leukofiltration may reduce reperfusion injury and rectal bleeding in CPB and IBD, respectively, and therefore decrease the morbidity and cost associated with these diseases.

Tc-99m HMPAO white blood cell scintigraphy in the assessment of the extent and severity of an acute exacerbation of ulcerative colitis

PURPOSE

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with frequent exacerbations, including the risk for toxic megacolon and severe complications. In very active disease, colonoscopy should not be performed to assess the severity and the extent of the disease. The aim of the current study was to determine whether Tc-99m HMPAO-labeled white blood cell (WBC) scintigraphy can be used as an alternative to colonoscopy to determine the extent and the severity of the disease in critically ill patients.

METHODS

Twenty consecutive patients (7 women, 13 men; age 38.1 +/- 13.1 years) who had a severe attack of UC underwent scintigraphy on the day of admission. Leukocytes were labeled with 200 MBq (5.35 mCi) Tc-99m HMPAO. Planar anterior and posterior imaging of the abdomen was performed 45 and 120 minutes after WBC reinjection. The tracer uptake in the different colon segments was scored visually compared with bone marrow uptake. A symptom score was made and C-reactive protein was measured as a serologic marker of inflammation. Rectosigmoidoscopy with biopsy was performed within 24 hours of scintigraphy. Scintigraphic, endoscopic, and histologic results were compared for disease activity.

RESULTS

The mean symptom score was 12.7 (+/-0.7) on a scale of 21, and mean the C-reactive protein level was 6.8 (+/-1.2) mg/l. No significant difference was found between the scintigraphic score of the rectum and the endoscopic or the histologic score. The best correlation was found with the latter (r = 0.66, P < 0.01). Based on the results of scintigraphy, disease involved the left side of the colon up to the splenic flexure in 10 patients. The other patients had pancolitis.

CONCLUSIONS

Disease severity can be determined adequately by planar WBC scintigraphy in patients with severe attacks of UC. Because the presence and severity of disease correlates well with endoscopic and histologic findings, WBC scintigraphy can assess disease extent without the need for colonoscopy. This decreases the number and severity of complications that can occur in already critically ill patients.

Inflammatory bowel disease

Although ulcerative colitis and Crohn's disease are relatively uncommon disorders, most primary care practices include a number of individuals with these diagnoses. Much of the initial evaluation and long-term care of these patients is managed or coordinated by their primary care physicians. A familiarity with current principles of diagnosis and treatment is essential. Ulcerative colitis and Crohn's disease are related, immunologically mediated disorders of unknown cause. Both are characterized by chronic relapsing courses, frequent need for surgical intervention, and increased colorectal cancer risk. Significant differences are seen between these two inflammatory bowel disease syndromes, in their histopathologic features, clinical manifestations, and response to treatment. This review focuses on the colorectal manifestations of inflammatory bowel disease, emphasizing clinical presentation, approach to diagnosis, medical and surgical management, and long-term prognosis.

The technetium white cell scan as an initial imaging investigation for evaluating suspected childhood inflammatory bowel disease

BACKGROUND

The technetium white cell scan (WCS) may be a useful investigation for patients with inflammatory bowel disease (IBD). In a retrospective study we assessed the use of the WCS as an initial imaging investigation in evaluating children with suspected IBD.

METHODS

Over a 3-year period, 60 WCS were performed on 55 patients (25 boys, median age 12.1 years, age range 1.5-18 years) with known or suspected IBD. There were two clinical groups: those with previously diagnosed IBD (histologically and radiologically) and in clinical relapse (13 patients), and newly presenting patients with suspected IBD (42 patients).

RESULTS

Eighteen scans were performed on the 13 patients presenting with relapse. Seventeen were positive and one patient, subsequently shown to have an inactive stricture, had a negative scan. Seven of the 42 newly presenting patients had abnormal scans, confirmed to be due to IBD by a combination of histology and barium examinations. Of the remaining 35 scans, three were abnormal and 32 were normal. None of these patients were subsequently proven to have IBD. These results show that in detecting active IBD, a positive WCS has a 100% sensitivity (24/24) and a 91% specificity (32/35) in the diagnosis of IBD.

CONCLUSIONS

Our results show that the WCS is very useful as an initial imaging investigation in evaluating patients with suspected IBD to select patients for further investigation.

Labelling of leucocytes with technetium-99m exametazime causes in vitro upregulation of granulocyte CD11b without correlation to tissue uptake in vivo

The aims of this study were to investigate whether labelling with technetium-99m exametazime alters the expression of adhesion molecule CD11b on granulocytes and monocytes, and to study whether the expression of CD11b on unlabelled or labelled cells correlates with uptake of the labelled cells in the inflamed bowel, in the lungs or in the reticuloendothelial system. Leucocytes were obtained from 25 patients with inflammatory bowel disease who underwent leucocyte scan. The cellular expression of CD11b was analysed using flow cytometry. Labelling with 99mTc-exametazime induced an increased surface expression of CD11b on granulocytes (P<0.01), but not on monocytes. The increase in CD11b expression on granulocytes was lower than the spontaneous mobilization that occurred at 37 degrees C and correlated neither with this, nor with N-formyl-methionyl-phenylalanine induced expression of the same receptor. Basal expression of CD11b on unlabelled granulocytes, but not on monocytes, correlated with bowel and lung uptake 45 min after reinjection of labelled cells, but not with uptake on later images. No correlation was found between the CD11b expression on labelled granulocytes or monocytes and scintigraphic uptake. Our findings show that labelling with 99mTc-exametazime increases the expression of adhesion protein CD11b on granulocytes. The increase in surface expression of CD11b does not correlate with the scintigraphic uptake of labelled cells in the bowel, in the lungs or in the reticuloendothelial system.