Can ultrasound compete with CT in evaluation of possible appendicitis?

In most situations, the diagnosis or exclusion of acute appendicitis will be apparent clinically. However, in equivocal cases, either CT or US may be utilized to assist in definitive diagnosis or establish an alternative etiology for the patients' RLQ pain. In most adult patients, when CT is performed at the authors' institution, the entire abdomen is examined using 5-mm slice increments with intravenous contrast enhancement. However, in women and children, especially those who are thin, US may prove very useful. Ultrasound is best performed using a 4- to 5-MHz curved sector scanner examining the entire abdomen. After performing this portion of the study, graded compression US using a 7.5-MHz linear probe is performed in the right lower abdomen. If a gynecological process is suspected or cannot be excluded, endovaginal scanning may be performed. By a meticulous examination performed by well-trained personnel, US will have a fairly high accuracy in diagnosing appendicitis. Either sonography or CT may be used to drain periappendiceal or pelvic abscesses associated with appendicitis.