Basal Indentation Due to a Function of Geometry on CT Air-Contrast Enema for Sessile Colorectal Polyps: Quantitative Evaluation using Cross-Sectional Multiplanar Reconstruction

Objective: Basal Indentation (BI) on CT air-contrast enema (CT enema) for colorectal cancer consists essentially of the both factors of a function of geometry and a tumor invasion. This study was conducted to investigate the feasibility of quantitative evaluation of the basal indentation due to a function of geometry (BI-G) on CT enema for colorectal polyps using Cross-Sectional Multiplanar Reconstruction (CS-MPR) images. Materials and Methods: The study group consisted of 21patients with 37 sessile colorectal polyps that were pathologically confirmed as restricted to the mucosa. We calculated the maximal depth of BI-G (max BI-G) on CT enema for colorectal polyps, and compared the max BI-G with the estimated max BI-G (e-max BI-G), which was calculated using the CS-MPR images. Results: A strong positive correlation was found between e-max BI-G and max BI-G (R2= 0.91, P <0.0001), although there was a significant difference in the mean values between e-max BI-G and max BI-G (0.64 ± 0.52 mm and 0.51 ± 0.73 mm, respectively; P < 0.05). Conclusion: CS-MPR is effective for quantitative evaluation of BI-G on CT enema for sessile colorectal polyps. Such evaluation may lead to improvement of the diagnostic accuracy of the invasion depth of colorectal cancers. Research Article Basal Indentation Due to a Function of Geometry on CT Air-Contrast Enema for Sessile Colorectal Polyps: Quantitative Evaluation using Cross-Sectional Multiplanar Reconstruction Mitsutoshi Miyasaka1*, Masanobu Ueda2, Toshio Muraki2, Michio Yoshida2, Daisuke Tsurumaru1, Yusuke Nishimuta1, Masahiro Komori1, Yoshiki Asayama1 and Hiroshi Honda1 1Department of Clinical Radiology, Kyushu University, Japan 2Department of Radiology, Munakata Medical Association Hospital, Japan