Wong 2002.

Study characteristics
Patient sampling	Patients suspected of having appendicitis and scheduled for surgery were recruited. Patients who were pregnant, who were younger than 16 years, or who could not have contrast medium administered via the rectum were excluded. Recruitment period: not stated
Patient characteristics and setting	Age range: 16 years or older. 42% women. 50 participants were included Setting: hospital in Singapore ‐ otherwise unclear. Single‐centre study Disease spectrum: high suspicion of appendicitis
Index tests	1‐slice helical CT of lower abdomen and pelvis with rectally administered colonic contrast material (CT‐X Vision, Toshiba) Slice thickness: 5 mm. Slice interval: 5 mm. Voltage and mAs product: not stated. Additional reconstruction of the axial images to 1‐mm slice interval was done to identify the appendix if there were difficulties locating it from the initial CT images
Target condition and reference standard(s)	Appendicitis. Histological examination of the removed appendix was performed ‐ all patients had surgery with appendectomy
Flow and timing	50 patients were included; all had CT. Surgery was performed in all patients; 37 had appendicitis
Comparative
Criteria for CT diagnosis of appendicitis	If the appendix was visualised: external appendix diameter > 6 mm and/or periappendiceal inflammatory changes (fat stranding, fluid collection, or enlarged mesenteric nodes) If the appendix was not visualised: appendicolith, caecal apical wall thickening, arrowhead sign, or caecal bar sign The appendix was considered normal if the lumen was completely filled with air, contrast material, or both
Assessors of the CT‐scan	Not stated
Notes
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Unclear
Did the study avoid inappropriate exclusions?	Yes
Does the study population represent an unselected sample of adults with suspected appendicitis?	Unclear
		Unclear	Unclear
DOMAIN 2: Index Test All tests
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	Yes
Is the index test described in sufficient detail to permit its replication?	No
Was the analysis based on the initial evaluation of the CT‐scan by the radiologist on call?	Unclear
		Low	High
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Unclear
		Unclear	High
DOMAIN 4: Flow and Timing
Did all patients receive a reference standard?	Yes
Did all patients receive the same reference standard?	Yes
Did all patients with a positive CT‐scan have surgery?	Yes
Did all patients with a negative CT‐scan have clinical follow‐up?	No
Was the choice of reference standard independent of the result of the index test?	Yes
Were all patients included in the analyses?	Yes
		Low