FDG-PET-CT Enterography Helps Determine Clinical Significance of Suspected Ileocecal Thickening: A Prospective Study

Ileocecal thickening (ICT) on imaging could result from diverse etiologies but may also be clinically insignificant. Evaluation of role of combined 2-deoxy-2-fluorine-18-fluoro-d-glucose(18F-FDG)-positron emission tomography and computed tomographic enterography (PET–CTE) for determination of clinical significance of suspected ICT. This prospective study enrolled consecutive patients with suspected ICT on ultrasound. Patients were evaluated with PET–CTE and colonoscopy. The patients were divided into: Group A (clinically significant diagnosis) or Group B (clinically insignificant diagnosis) and compared for various clinical and radiological findings. The two groups were compared for maximum standardized uptake values of terminal ileum, ileo-cecal valve, cecum and overall. Of 34 patients included (23 males, mean age: 40.44 ± 15.40 years), 12 (35.3%) had intestinal tuberculosis, 11 (32.4%) Crohn’s disease, 3 (8.8%) other infections, 1 (2.9%) malignancy, 4 (11.8%) non-specific terminal ileitis while 3 (8.8%) had normal colonoscopy and histology. The maximum standardized uptake value of the ileocecal area overall (SUVmax-ICT-overall) was significantly higher in Group A (7.16 ± 4.38) when compared to Group B (3.62 ± 9.50, P = 0.003). A cut-off of 4.50 for SUVmax-ICT-overall had a sensitivity of 70.37% and a specificity of 100% for prediction of clinically significant diagnosis. Using decision tree model, the SUVmax-ICT with a cut-off of 4.75 was considered appropriate for initial decision followed by the presence of mural thickening in the next node. PET–CTE can help in discrimination of clinically significant and insignificant diagnosis. It may help guide the need for colonoscopy in patients suspected to have ICT on CT.