Graded compression ultrasound in the diagnosis of appendicitis. A comparison of diagnostic criteria.

Four sonographic diagnostic criteria for appendicitis, (1) any visualization, (2) appendiceal diameter greater than 6.0 mm, (3) muscular wall thickness greater than or equal to 3.0 mm, and (4) presence of a complex mass, were compared in a series of 200 patients clinically suspected of having appendicitis. The diagnosis of appendicitis was confirmed histopathologically and included all forms of appendicitis with mucosal invasion by inflammatory cells. The sensitivities of all the criteria were low (11% to 75%) and the usefulness of this test as a screening procedure is questioned. The combined criteria of an appendix with a muscular wall thickness (MWT) greater than or equal to 3.0 mm and visualization of a complex mass (CM) separate from the adnexa in females proved most useful as a diagnostic test (sensitivity, 68%; specificity, 98%). We conclude that the diagnosis of appendicitis is still difficult, despite the addition of graded compression ultrasound as a diagnostic test. We do not recommend its use as the only screening test, but do recommend it, rather, in a diagnostic role after the initial clinical screening.