Focal appendicitis confined to the tip: Diagnosis at US

PURPOSE: To evaluate the diagnostic value of graded-compression ultrasonography (US) for the diagnosis of focal appendicitis confined to the tip. MATERIALS AND METHODS: During a 4-year period, US was performed in 1,450 patients with clinically suspected acute appendicitis. Of these patients, 443 had appendicitis at pathologic examination, 20 of whom had focal appendicitis confined to the tip. Focal appendicitis confined to the tip was defined as occurring when the resected specimen had inflammation only at the distal third of the appendix. RESULTS: Of 20 patients with focal appendicitis confirmed at pathologic examination, 17 patients (85%) had focal appendicitis that was correctly diagnosed at US. The remaining three patients' appendices were diagnosed at US as normal (false-negative cases). Five patients had perforation at the tip, and one patient had an appendicolith. CONCLUSION: Although US appears to be fairly accurate in the diagnosis of focal appendicitis confined to the tip, the entire length of the appendix should be evaluated in order to avoid a false-negative diagnosis.