1 Carcinoma of the Esophagus and Gastroesophageal Junction -- Technique of Examination -- Normal Anatomy -- Morphology and Staging -- Posttherapeutic Evaluation -- References -- 2 Gastric Carcinoma -- Pathologic Considerations -- Spread of Gastric Cancer and Its Staging -- CT Diagnosis -- >Conclusions Regarding CT Assessment of Surgical Resectability -- References -- 3 Gastrointestinal Lymphoma, Leiomyoma, and Leiomyosarcoma -- Gastrointestinal Lymphoma -- Leiomyomas and Leiomyosarcomas -- References -- 4 Inflammatory Bowel Disease and Related Conditions -- Thickening of the Bowel Wall -- Small Bowel -- Colon -- Differential Diagnosis of Crohnโ{128}{153}s Disease and Ulcerative Colitis -- References -- 5 Subperitoneal Spread of Intra-Abdominal Disease -- CT Demonstration of Normal Anatomy -- CT Demonstration of Pathology -- Conclusion -- References -- 6 Mesenteric Disease -- Anatomy -- Scanning Techniques -- Benign Conditions -- Malignant Conditions -- Acquired Immune Deficiency Syndrome (AIDS) -- References -- 7 Intraperitoneal Fluid Collections -- Anatomic Considerations -- Ascites -- Intra-Abdominal Abscess -- Intraperitoneal Hemorrhage -- Pseudomyxoma Peritonei -- Miscellaneous Fluid Collections -- References -- 8 Acute Appendicitis -- Anatomic Considerations -- Computed Tomography Findings -- References -- 9 Diverticulitis -- Radiologic Diagnosis -- CT Findings: Colonic and Pericolic Changes -- Abscess and Peritonitis -- Fistula Formation -- Correlation of CT Findings and Contrast Enema -- Differential Diagnosis -- Clinical Utility -- References -- 10 Colorectal Carcinoma -- Technique of Examination -- Normal Anatomy -- Primary Diagnosis -- Staging -- Recurrent Carcinoma -- Radiotherapy -- References