Colorectal Carcinoma: In Vitro Evaluation with High-Spatial-Resolution 3D Constructive Interference in Steady-State MR Imaging

Abstract

To retrospectively assess the accuracy of high-spatial-resolution three-dimensional (3D) constructive interference in steady-state (CISS) magnetic resonance (MR) imaging in the evaluation of mural invasion of colorectal carcinoma by using prospectively obtained in vitro images, with histopathologic analysis as the reference standard. Institutional review board approval was obtained for the prospective and retrospective components of this study, with informed consent for the former and waiver of informed consent for the latter. Surgical specimens were obtained in 92 patients (61 men, 31 women; mean age, 65 years) and contained 96 colorectal carcinomas. Specimens were examined with a 1.5-T MR system and a 4-cm-diameter loop coil. High-spatial-resolution 3D CISS MR images were obtained with 80 x 80-mm field of view, 512 x 512 matrix, and 0.7-mm section thickness, which resulted in a 0.017-mm(3) voxel size. The 3D data sets were postprocessed with surface-rendering software to generate virtual MR endoscopic images. The 3D CISS MR images were compared with histopathologic findings, and virtual MR endoscopic images were compared with macroscopic findings at surgery. Statistical analysis was performed with Spearman rank correlation. In 92 (96%) colorectal carcinomas, the depth of mural invasion depicted by 3D CISS MR imaging correlated well with the histopathologic stage, although the stage assigned with 3D CISS MR imaging was higher than that assigned with histopathologic analysis in four (4%) carcinomas (r = 0.976, P < .001). Sensitivity, specificity, and accuracy were 100%, 94%-96%, and 98%-100%, respectively. In 91 (95%) carcinomas, virtual MR endoscopy clearly depicted the macroscopic type of carcinoma, including gross configuration and tumor ulceration (r = 0.916, P < .001). High-spatial-resolution 3D CISS MR imaging has high diagnostic accuracy in the in vitro evaluation of mural invasion and macroscopic features of colorectal carcinomas.