The utility of CT scan for the diagnostic evaluation of acute abdominal pain.

AbdCT for the evaluation of AAP in the ED in the US may be excessive and is potentially (although rarely) misleading and harmful. A selective policy of 'AbdUS first' combined with an observation unit and/or surgeon evaluation prior to AbdCT is preferred to a 'routine AbdCT' policy. Repeated AbdCTs for abdominal pain are not recommended because of cumulative radiation exposure. Standardized and complete history and physical examination, such as that originally designed for computer-aided diagnosis of AAP, along with select laboratory testing and higher utilization of AbdUS lessens the necessity of AbdCT. 'Routine AbdCT' is particularly not necessary for the evaluation of suspected appendicitis. 'Routine AbdCT' lowers the negative appendectomy rate but at the expense of exposure to radiation. Right lower quadrant US and selective use of observation prior to AbdCT for suspected appendicitis, particularly in children, adolescents, and young adults, are warranted. MRI should substitute for AbdCT for the evaluation of suspected appendicitis during pregnancy.