Study designs of evaluations included in the review
Prospective diagnostic accuracy studies were eligible for inclusion.
Specific interventions included in the review
Studies of CT scanning were eligible for inclusion. The studies used unfocused CT with and without contrast; focused CT with and without oral, intravenous or rectal contrast; and focused or unfocused helical CT with and without contrast. The studies used similar criteria to diagnose appendicitis using CT. Such criteria included appendiceal diameter of more than 6 mm with periappendiceal inflammation; nonopacification with oral or rectal contrast material with periappendiceal inflammation; or the presence of an appendicolith. Controlled trials compared CT with either ultrasound or standard treatment.
Reference standard test against which the new test was compared
The inclusion criteria were not specified in terms of a reference standard test. All of the included studies compared CT with pathological diagnosis if the patient underwent appendectomy, or prolonged follow-up (usually 3 months) for patients not undergoing appendectomy.
Participants included in the review
Studies that included adults with suspected appendicitis were eligible for inclusion, whereas studies that recruited only children were excluded.
The included studies were of men, women and children. The studies used different inclusion criteria: many studies excluded patients with typical presentations, while others included patients with typical and atypical presentations. The studies generally defined atypical presentations as missing one of the classical signs of appendicitis (right lower quadrant point tenderness, elevated temperature, raised white blood cell count and anorexia). One study also included women with a clinically suspected acute gynaecological condition, and another was in patients with an acute abdomen. The review aimed to focus on women, but most of the studies did not report the results separately for men and women.
Outcomes assessed in the review
The inclusion criteria were not specified in terms of outcomes. The review assessed the sensitivity, specificity, diagnostic accuracy, and the number of alternative diagnoses and altered treatment plans after CT scanning.
How were decisions on the relevance of primary studies made?
One reviewer selected studies meeting the study design criterion.