Hershko 2007.

Study characteristics
Patient sampling	Consecutive patients with suspected acute appendicitis were randomly assigned to 1 of 3 CT‐protocols. Patients who were pregnant or who had contraindications to intravenous contrast material, severe asthma, or chronic renal failure were excluded Recruitment period: June 2002 to January 2005
Patient characteristics and setting	Age range (mean): 16 to 83 years (30). 54% women Department of Surgery in Haifa, Israel. Single‐centre study Disease spectrum: unclear
Index tests	Included patients were randomly allocated to 1 of the following 3 helical CT‐protocols: • Unenhanced CT of the lower abdomen • CT of the lower abdomen with rectal contrast material • CT of the lower abdomen with oral and intravenous contrast material All CT‐scans were performed with a multi‐slice CT‐scanner (NIX8000 ‐ IDT TM, Philips). Slice thickness: 2.5 mm. Voltage: 120 kV. Slice interval and mAs product: not stated
Target condition and reference standard(s)	Appendicitis. Surgical and histopathological findings were reported for patients who had surgery with or without appendectomy. Patients who did not have surgery were followed up clinically. Follow‐up procedures and timing are not described
Flow and timing	• Unenhanced CT of the lower abdomen 70 patients were allocated. 14 were excluded due to inconclusive CT findings. 21 of the remaining 56 patients had appendicitis. Numbers who had surgery and follow‐up were not reported • CT of the lower abdomen with rectal contrast material 78 patients were allocated. There were no inconclusive CT‐scans. Appendicitis was found in 39 patients. Numbers who had surgery and follow‐up were not reported • CT of the lower abdomen with oral and intravenous contrast material 84 patients were allocated. There were no inconclusive CT‐scans. Surgery was performed in 48 patients with positive CT‐scans; 43 had appendicitis confirmed histologically. All patients with negative CT‐scans had uneventful follow‐up
Comparative
Criteria for CT diagnosis of appendicitis	Findings were interpreted as acute appendicitis if the appendix was > 6 mm in diameter and/or had surrounding signs of inflammation The appendix was interpreted as normal if it was < 7 mm in diameter or was filled to the tip with contrast material or air. Similarly, when the appendix was not visualised, the scan was interpreted as normal
Assessors of the CT‐scan	6 radiology residents who were at least 2 years into their training programmes
Notes	3 randomised groups were considered as individual studies in the meta‐analyses
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Did the study avoid inappropriate exclusions?	Yes
Does the study population represent an unselected sample of adults with suspected appendicitis?	Yes
		Low	Low
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?	Yes
		Low	High
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Unclear
Were the reference standard results interpreted without knowledge of the results of the index tests?	Unclear
		Unclear	Low
DOMAIN 4: Flow and Timing
Did all patients receive a reference standard?	Unclear
Did all patients receive the same reference standard?	No
Did all patients with a positive CT‐scan have surgery?	Unclear
Did all patients with a negative CT‐scan have clinical follow‐up?	Yes
Was the choice of reference standard independent of the result of the index test?	No
Were all patients included in the analyses?	No
		High