Computed tomography in the diagnosis of equivocal appendicitis

The clinically obscure right iliac fossa (RIF) pain remains a diagnostic problem. The present study examines the use of computed tomography (CT) in improving the accuracy of clinical assessment in these difficult surgical cases.

The trial design was a retrospective review of all patients admitted under one surgeon with suspected acute appendicitis, between 1 January 1995 and 30 June 1997. The study setting was a district hospital (Calvary Hospital) that received patients from both an urban and rural environment. The patient cohort was identified from the Unit Registry and an International Classification of Diseases-based review of medical records. Twenty-one prospective data points were obtained from patient records. Those patients admitted with RIF pain and equivocal symptoms and signs subsequently underwent a CT and/or ultrasound (US) examination, conducted by the attending radiologist. For those patients who proceeded to appendicectomy, the histopathological findings were correlated with the imaging report. Those patients who were discharged after imaging without proceeding to operation were not readmitted to any regional hospital during the course of the study.

A total of 84 patients were identified. Thirty-three patients (39%) underwent appendicectomy without imaging and were excluded from further analysis. A total of 51 patients (61%) underwent 61 imaging procedures. The CT scan was correct in 35/36 patients (97%), while US was correct in 17/25 patients (68%).

The present study suggests that CT can be used to improve the accuracy of diagnosis of obscure RIF pain. As a pilot study, it supports the development of a randomized controlled trial in a multicentre regional study.