Technetium-99m HMPAO granulocyte scintigraphy as a tool to measure inflammatory load in Ulcerative Colitis: a cross-sectional study

Anti-TNF antibodies have become a generally accepted therapy for Inflammatory
Bowel Disease (IBD), such as Ulcerative Colitis (UC). Nevertheless dose
regimens remain arbitrary: a substantial part of patients lose their response
to anti-TNF treatment. It is hypothesized that this loss of response is partly
due to a fluctuation in inflammatory load, in which the optimal dose-response
plateau is not yet reached.
A problem with dose-response studies is that the golden standard with regard to
response, colonoscopy with biopsies, isn*t very suitable for frequent
monitoring. Since patients experience colonoscopy as an uncomfortable and
invasive examination and because it has some risks, especially in severe
colitis (perforation), there*s a need for a different tool in assessing disease
activity and response to therapy.
One, minimal invasive, instrument of determining inflammatory load is
Technetium-99m Hexamethylpropyleneamine Oxime granulocyte scintigraphy (WBC
scintigraphy), which has been described for IBD in several studies before.
But WBC scintigraphy hasn't been correlated with both colonscopy and
inflammation markers such as CRP and fecal calprotectin for different
severities of Ulcerative Colitis.
Moreover last decade imaging technique has been remarkably improved. Nowadays
better gamma cameras and more precise labeling and cell isolation have been
developed. Moreover the combination of scintigraphy with computed tomography
(CT) scanning has enlarged its possibilities even more.
Therefore an updated study is necessary to determine the value of WBC
scintigraphy in measuring inflammatory load in Ulcerative Colitis.

The main objective is to validate WBC scintigraphy as a sensitive tool to
measure and quantify inflammatory load in different severities of UC.
The secondary objectives are to explore whether other disease activity markers,
like serum C-reactive protein (CRP) and fecal calprotectin are a representative
reflection of inflammatory load.

The design of the study is a single center, prospective, cross-sectional study.

All patients will undergo blood and feces testing one time, 1 colonoscopy with
biopsies (biopsies in the 2 endoscopically most affected areas of each of the 5
segments) and 1 WBC scintigraphy. Within 48 hours all of the examinations will
be done, also a symptom scoring and physical examination will be performed.
Prior to scintigraphy, an 18G iv-line will be placed in an antecubital vein and
100 ml of blood will be drawn. From this, granulocytes will be isolated and
labeled with technetium-99m. After labelling, the white blood cells will be
reinjected intravenously through the same iv line. This procedure is identical
to the validated clinical procedure of WBC scintigraphy.
200 MBq (0.011mSv/MBq) Tc-99m-labeled granulocytes will be reinjected in to the
patient. The total amount of radiation will be approximately 4.0mSv.