Radiologic definition of lateral pelvic nodal compartments-The next frontier in rectal imaging.

The accurate localization of lateral pelvic nodes is essential for staging and surgical planning in rectal cancer. The objective of this article is to review existing radiologic and surgical definitions of the boundaries of lateral pelvic lymph node compartments on cross-sectional CT/MR images. In addition, we propose a simplified approach to facilitate the application of these boundaries to CT/MR images. We also discuss a few pitfalls in the localization of pelvic nodes in rectal cancer.