 This study evaluated the accuracy of diagnostic modalities on gastrointestinal cancers. It found that positron emission tomography, computed tomography, PET-CT, and our magnetic resonance imaging, MRI, are the best modalities to assess distant metastases. Additionally, fat and fiber mode of computed tomography, CT, may be useful for T4 staging of esophageal cancer, while CT alone is a partially reliable modality for lymph nodes staging endastric cancer, and CT combined with MRI is the most reliable modality for liver metastases from colorectal cancer. This article was authored by Hideaki Shimada, Takeo Fukagawa, Yoshio Heiga, and others.