- All consecutive emergency department patients undergoing abdominal CT for non-traumatic abdominal pain and tenderness will be prospectively enrolled, with the following exceptions. For study purposes, "abdominal pain and tenderness" is defined as pain and tenderness to direct palpation in the region anterior to the mid-axillary line bilaterally, and extending from the costal margins to the inguinal ligaments. Consequently, patients undergoing CT for indications such as isolated vomiting, fever without source, staging of malignancies, isolated flank pain or suspected renal colic, or other indications that do not meet the above definition will not be enrolled.