Impact of Presence of Oral Contrast Material in the Large Intestine on the Recognition of Appendix During an Ultrasound Exam

Acute appendicitis is the most common cause of abdominal pain requiring surgical intervention.

The gold standard test for the diagnosis of acute appendicitis is the CT scan. Despite its effectiveness, the test involves exposure to a high dose of radiation.

Using ultrasound to diagnose this condition has been described extensively in the medical literature, and this test has a very high specificity (over 95%), however sensitivity of the test is not as good and varies between 40% and 90%. Major limitations of the Ultrasound test include operator dependency as well as factors such as body habitus of the patient, presence of technical disturbances (artifacts) caused by gas in the large intestine and inadequate cooperation from the patient during the exam. All of these factors may affect the ability to detect sonographic signs of appendicitis.

The investigators believe that it is possible to reduce the amount of artifacts caused by the presence of gas in the intestine by filling of the colon with liquid suspension that is routinely given in the investigators' hospital before performing an abdominal CT and performing an additional ultrasound scan to those patients in which the initial ultrasound examination (without any preparation) proved to be equivocal or not diagnostic.

The target population for the study is any patient who arrives to the emergency room with complaints of right lower quadrant abdominal pain and it is decided by the referring physician in the ER to start diagnostic workup for suspected appendicitis by performing an ultrasound, if the ultrasound exam proves to be equivocal or not diagnostic and it is decided that the patient needs to continue investigation by performing a CT scan, the patient will receive contrast material orally for approximately 180 minutes and prior to the CT the investigators intend to repeat the ultrasound. The investigators hypothesize that the repeat ultrasound will allow a statistically significant improvement in the detection rate of the appendix.