Double-contrast micro-CT colonoscopy in live mice

Abstract

Models of colon cancer in small rodents are of particular interest as they most closely simulate the development and growth of colonic cancer in humans. Micro-computed tomography has been used for detection of polyps in murine models of colon cancer. The study was performed to evaluate whether a novel high-speed continuous-rotation, single-breath-hold scanning protocol in combination with double-contrasting of the colon can be successfully applied for colonoscopy of live mice at acquisition times of 40 s. C57BL/6JApcMin/+ mice were intubated and ventilated. After double-contrasting the colon with barium and air, mice underwent continuous rotation micro-CT (mean resolution 41 × 41 × 53 μm) during a single-breath-hold period of 40 s. Sensitivity to detect colon polyps by four blinded radiologists was analysed. Number and location of polyps were verified in the excised colon. Radiation dose was measured using a thermoluminescence dosimeter placed within the distal colon. In six of seven mice, a total of 12 polyps were detected in the explanted colon (one mouse without polyps). One tumor (8.3%) was located in the proximal third, seven tumors (58.1%) and four tumors (33.2%) were located in the middle and in the distal third of the colon, respectively. Mean tumor volume was 6.5 ± 3.6 mm(3). Sensitivity to detect colon polyps was 0.85 ± 0.1. Mean radiation dose was 0.241 ± 0.002 Gy. Using a high-speed continuous rotation micro-CT protocol, double-contrast single-breath-hold colonoscopy in mice is feasible and yields sufficient contrast to visualize the proximal colonic folds and to detect colonic polyps in vivo.