Characterization of normal ileocecal valve density on CT colonography

The objective of this study was to evaluate normal ileocecal valve (ICV) attenuation and composition on CT colonography (CTC). Two hundred twelve patients who underwent CTC at the authors' institution were retrospectively identified. Two independent readers recorded three region-of-interest (ROI) measurements, which were used to determine mean ICV density. ICV attenuation measurements were compared with age and abdominal body fat using Pearson correlation. A subjective classification system was applied to characterize the relative fat and soft tissue density of the ICV. Mean ICV density was -26.3+/-14 HU (range -60.1 to 18.3 HU). There was no correlation between the fat content of the ICV and age (r=0.06) or body fat (r=-0.47). The majority of valves (83.5%) were classified as heterogeneously low density or heterogeneously high density, whereas a small fraction of valves (6.1%) were categorized as homogeneously low density. The results of this study suggest that ICVs have a varying range of densities, and this feature alone cannot be used to distinguish the ICV from a polyp or neoplastic lesion on CTC.