Acute abdominal pain may be caused by a myriad of diagnoses, including acute appendicitis, diverticulitis, and cholecystitis. Imaging plays an important role in the treatment management of patients because clinical evaluation results can be inaccurate. Performing computed tomography (CT) is most important because it facilitates an accurate and reproducible diagnosis in urgent conditions. Also, CT findings have been demonstrated to have a marked effect on the management of acute abdominal pain. The cost-effectiveness of CT in the setting of acute appendicitis was studied, and CT proved to be cost-effective. CT can therefore be considered the primary technique for the diagnosis of acute abdominal pain, except in patients clinically suspected of having acute cholecystitis. In these patients, ultrasonography (US) is the primary imaging technique of choice. When costs and ionizing radiation exposure are primary concerns, a possible strategy is to perform US as the initial technique in all patients with acute abdominal pain, with CT performed in all cases of nondiagnostic US. The use of conventional radiography has been surpassed; this examination has only a possible role in the setting of bowel obstruction. However, CT is more accurate and more informative in this setting as well. In cases of bowel perforation, CT is the most sensitive technique for depicting free intraperitoneal air and is valuable for determining the cause of the perforation. Imaging is less useful in cases of bowel ischemia, although some CT signs are highly specific. Magnetic resonance (MR) imaging is a promising alternative to CT in the evaluation of acute abdominal pain and does not involve the use of ionizing radiation exposure. However, data on the use of MR imaging for this indication are still sparse.
Supplemental material: http://radiology.rsna.org/content/253/1/31/suppl/DC1.