QUANTIFICATION OF INFLAMMATORY BOWEL-DISEASE ACTIVITY USING TC-99M HMPAO LABELED LEUKOCYTE SINGLE-PHOTON EMISSION COMPUTERIZED-TOMOGRAPHY (SPECT)

Technetium-99m HMPAO labelled white cell bowel uptake was quantified in 23 patients with suspected colitis by means of the novel technique of single photon emission computerised tomography (SPECT) using a standard gamma-camera. Uptake in colon segments was quantified on transaxial images and expressed as a fraction of marrow uptake (SPECT score). Segmental histological disease activity was assessed at (20) or at surgery (3). histology score with SPECT score r=0.79 Overall SPECT score for all affected segments correlated with Crohn's disease activity index (CDAI) r=0.66, p=0.001 and with laboratory activity indices; erythrocyte sedimentation rate p=0.03, C reactive protein r=0.38, p=0.05, and albumin r=-0.46, p=0.03. Small bowel SPECT score in 13 patients correlated with CDAI r=0.65, p<0.01 but not with erythrocyte sedimentation rate or C reactive protein. Five patients with positive small bowel white cell uptake had normal C reactive protein and erythrocyte sedimentation rate. Overall SPECT score for disease at all sites correlated with both CDAI and with laboratory indices of inflammation. Tc-99m HMPAO SPECT provides non-invasive and accurate quantification of inflammatory bowel disease activity in both large and small bowel and may be useful in the objective evaluation of treatment for inflammatory bowel disease.