Quantitative Assessment of Radiologically Indeterminate Local Colonic Wall Thickening on Iodine Density Images Using Dual-Layer Spectral Detector CT

Abstract

To assess local colonic wall thickening (LCWT, thicknesses: >3 mm, lengths: <5 cm) quantitatively on iodine density images using dual-layer spectral detector computed tomography (DLSCT). This retrospective study included 80 patients who underwent both conventional contrast-enhanced CT and colonoscopy within one month. The region of interest was delineated on the chosen images with the iodine density image model. The iodine concentration (IC), normalized IC (NIC), and thickness of the colonic wall in the lesion area were compared between the pathological and nonpathological groups. There were 50 patients whose area of LCWT discovered at CT scans displayed colon neoplasia at colonoscopy. The other 30 patients with LCWT on CT images showed normal appearances during colonoscopy. There was no significant difference in colonic wall thickness between the pathological and nonpathological (p> 0.05) LCWT groups. The IC and NIC of patients with colon neoplasms were significantly higher than those with nonpathologic LCWT (both p< 0.001). The ROC curve showed that when IC and NIC was 1.49 mg/mL and 0.33, the sensitivity and specificity for diagnosing colon neoplasm were 91.5% and 75.8%, 85.1% and 84.8%, respectively. IC and NIC values from DLSCT could provide a satisfied diagnostic value to identify LCWT caused by colon neoplasia.