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

Abstract

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 ± 15.40years), 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.