Background: The role of combined localized positron emission tomography (lPET) and computed tomography enterography (CTe) in Crohn's disease is unclear. We examined if this imaging modality using fluorine-18 labeled-fluoro-2-deoxy-D-glucose (FDG) could more effectively identify disease activity.
Methods: 52 lPET-CTe scans were analyzed in this retrospective study. CTe scores and FDG uptake were quantified. Correlations of CTe scores and standard uptake value (SUV) with C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), short Inflammatory Bowel Disease Questionnaire (sIBDq), and Harvey-Bradshaw index (HBI) were estimated using Pearson analysis. Imaging scores were compared to medical outcome by logistics regression model.
Results: CTe scores correlated with SUV, but additional abnormal segments of small bowel were not identified. In all, 38 (79%) abnormal CTe segments demonstrated increased FDG uptake with mean SUVmax 4.77; 10 (21%) abnormal CTe segments lacked FDG accumulation, with mean SUVmax 1.27. There was no correlation between SUVmax and CRP, ESR, sIBDq, or HBI. There were no significant differences in clinical indices, biochemical parameters, and presence of multiple abnormal segments between medical responders and uptake were associated with failed medical therapy (P = 0.001).
Conclusions: PET scanning added to CTe did not identify additional abnormal segments when compared to CTe alone. Abnormal segments with mucosal enhancement on CTe that did not accumulate FDG were significantly associated with failure of medical therapy. A larger trial is warranted to confirm if combined lPET-CTe has an important role in the clinical management of stricturing Crohn's disease.