Active inflammatory bowel disease: head-to-head comparison between 99mTc-hexamethylpropylene amine oxime white blood cells and 99mTc(V)-dimercaptosuccinic acid scintigraphy.

Objective: Evaluation and comparison between pentavalent 99mTc dimercaptosuccinic acid (99mTc(V)-DMSA) and 99mTc-hexamethylpropylene amine oxime white blood cell (99mTc-HMPAO WBC) scintigraphy in the detection and assessment of disease activity in patients with active inflammatory bowel disease (IBD).

Methods: 99mTc(V)-DMSA scintigraphy was performed in 23 patients with active IBD and true positive 99mTc-HMPAO WBC scintigraphy. Images were considered positive when an area of increased uptake was observed. To assess severity of IBD, semi-quantitative analysis was included with reference to the uptake in the iliac crest. Comparison with endoscopic, radiological and clinical data was performed.

Results: The diagnostic accuracy of 99mTc-HMPAO WBC and 99mTc(V)-DMSA was 91% and 84%, respectively. A significant correlation between the findings of both radioisotopic methods and scintigraphy score was demonstrated. Endoscopic findings were significantly correlated with scintigraphic results. Kappa statistics showed a moderate to good agreement between the two scintigraphic methods. Two patients (8.8%) had negative findings with 99mTc(V)-DMSA scintigraphy (false negative results).

Conclusions: 99mTc(V)-DMSA compared to 99mTc-HMPAO WBC could provide a simple, non-invasive alternative method for the assessment of disease activity, although it is slightly inferior to 99mTc-HMPAO WBC scintigraphy especially in the evaluation of disease localization in IBD patients.