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World J Gastroenterol. Dec 7, 2014; 20(45): 16964-16975
Published online Dec 7, 2014. doi: 10.3748/wjg.v20.i45.16964
Preoperative evaluation of colorectal cancer using CT colonography, MRI, and PET/CT
Shigeyoshi Kijima, Takahiro Sasaki, Koichi Nagata, Kenichi Utano, Alan T Lefor, Hideharu Sugimoto
Shigeyoshi Kijima, Takahiro Sasaki, Koichi Nagata, Kenichi Utano, Hideharu Sugimoto, Department of Radiology, Jichi Medical University, Tochigi 329-0498, Japan
Alan T Lefor, Department of Surgery, Jichi Medical University, Tochigi 329-0498, Japan
Author contributions: Kijima S and Sasaki T have contributed equally in collecting the data, drafting of the manuscript and preparing the final manuscript; Nagata K contributed to manuscript edition, critical scientific concepts, and preparing the final manuscript; Lefor AT was involved in editing the manuscript; Utano K and Sugimoto H designed the study.
Correspondence to: Koichi Nagata, MD, PhD, Department of Radiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan. nagata7@aol.com
Telephone: +81-285-442111 Fax: +81-285-444296
Received: March 16, 2014
Revised: July 13, 2014
Accepted: August 13, 2014
Published online: December 7, 2014
Abstract

Imaging studies are a major component in the evaluation of patients for the screening, staging and surveillance of colorectal cancer. This review presents commonly encountered findings in the diagnosis and staging of patients with colorectal cancer using computed tomography (CT) colonography, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT colonography. CT colonography provides important information for the preoperative assessment of T staging. Wall deformities are associated with muscular or subserosal invasion. Lymph node metastases from colorectal cancer often present with calcifications. CT is superior to detect calcified metastases. Three-dimensional CT to image the vascular anatomy facilitates laparoscopic surgery. T staging of rectal cancer by MRI is an established modality because MRI can diagnose rectal wall laminar structure. N staging in patients with colorectal cancer is still challenging using any imaging modality. MRI is more accurate than CT for the evaluation of liver metastases. PET/CT colonography is valuable in the evaluation of extra-colonic and hepatic disease. PET/CT colonography is useful for obstructing colorectal cancers that cannot be traversed colonoscopically. PET/CT colonography is able to localize synchronous colon cancers proximal to the obstruction precisely. However, there is no definite evidence to support the routine clinical use of PET/CT colonography.

Keywords: Colorectal cancer, Preoperative evaluation, T staging, N staging, Liver metastasis, Magnetic resonance imaging, Computed tomography colonography, Positron emission tomography

Core tip: We review recent advances in the preoperative imaging of colorectal cancer especially regarding computed tomography (CT) colonography, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT colonography. CT colonography can provide information for the preoperative assessment of T staging in colorectal cancer by morphological analysis of wall deformities. CT colonography with contrast enhancement is useful for imaging the vascular anatomy prior to laparoscopic surgery. MRI is widely used for the T staging of rectal cancer. N staging in patients with colorectal cancer is still challenging. The combination of MRI and PET/CT colonography may be useful for N staging. Gadolinium ethoxybenzyl diethlenetriamine pentaacetic acid - enhanced MRI is more accurate than CT and ultrasound for the evaluation of liver metastases.