ABSTRACT
Objective: To observe the manifestations of terminal ileitis on gemstone energy spectrum CT imaging (GSI) and its diagnostic efficacy compared conventional CT enterography (CTE), so as to evaluate the diagnosis value of GSI for terminal ileitis. Methods: Data of 120 patients with suspected terminal ileum diseases were retrospectively analyzed, including 115 cases of pathologically proved diseases (72 cases of terminal ileum enteritis, 6 cases of ileum polyps or tumorlike lesions, 30 cases of ileum Crohn's disease and 7 cases of ileum tuberculosis) and 5 cases without obvious abnormality. Among them 70 patients received conventional CTE (CTE group) and 50 received GSI (GSI group). Imaging characteristics of terminal ileitis were observed and compared between 2 groups. The consistency of the results of 2 methods for detecting terminal ileitis with pathological results were analyzed, and their sensitivities and specificities were compared. ROC curves of 2 methods for detecting terminal ileitis were drawn, and their relative diagnostic efficacy were analyzed. Results: Compared with conventional CTE, the lesions were clearer on low keV single energy imaging. The energy spectrum curve and iodide maps clearly identified the lesion's wall, normal wall, the fluid in intestinal cavity and the adjacent fat tissue. The iodine concentration of terminal ileitis at the arterial and venous phase was (10.90±0.55)μg/cm3 and (14.33±0.75)μg/cm3, respectively. Conventional CTE showed poor, while GSI showed high consistency with the pathological results for detecting terminal ileitis (Kappa=0.35, 0.72, P=0.16, <0.01). The sensitivity and specificity of GSI (86.21%, 85.71%) were bith higher than those of conventional CTE (65.12%, 51.85%, χ2=3.97, 6.10, both P<0.05). The AUC of GSI (0.86) was higher than that of conventional CTE (0.57, Z=2.42, P=0.02). Conclusion: GSI could clearly show lesions of terminal ileitis, therefore having high diagnostic efficacy for detecting terminal ileitis.