Imaging right lower quadrant pain: Not always appendicitis.

Although acute appendicitis (AA) is one of the commonest causes of right lower quadrant abdominal pain (RLQP), there are numerous other conditions in the abdomen and pelvis that can simulate the clinical presentation of AA for which imaging is essential in detection. We discuss the approach to evaluation of patients presenting with acute onset RLQP and the choice of various imaging modalities that can be utilized. Although CT remains the workhorse in evaluation, US and MRI, given lack of radiation, play an important ancillary role, particularly in the pediatric and pregnant patients. We present a spectrum of conditions presenting with RLQP which we have classified systematically ranging from conditions affecting the bowel, mesentery/omentum/peritoneum, vasculature, urinary and reproductive systems to give the reader a checklist of conditions to consider when evaluating a case of RLQP.