Which test is performed to assess active bowel inflammation in IBD?

Updated: Jul 26, 2019
  • Author: Leyla J Ghazi, MD; Chief Editor: Praveen K Roy, MD, AGAF  more...
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Leukocytes labeled with either technetium-99m (99m Tc )-HMPAO (hexamethyl propylene amine oxime) or indium-111 (111 In) can be used to assess for active bowel inflammation in IBD. The99m Tc-labeled leukocytes may be able to obtain an exact image of the inflammatory disease distribution and intensity at a moment in time—in a single examination. [65]

Compared with the111 In label, the99m Tc-HMPAO label has better imaging characteristics and can be imaged much sooner after injection. However, imaging must typically be performed within 1 hour after the injection of99m Tc- HMPAO–labeled leukocytes because there is normal excretion into the bowel after this time; in contrast,111 In-labeled leukocytes have no normal bowel excretion.

Fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG) combined with positron emission tomography (PET) or CT helps improve localization of the tracer in areas of active inflammation, but false-positive results can occur with inadequate distention of the bowel. [65] Studies are being conducted to evaluate combining PET/CT with CT enterography/enteroclysis techniques with the aim of further improving localization while reducing the rate of false-positive findings. [65]

For more information, see Imaging in Crohn’s Disease.

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