2. QUADAS methodological items and operational definitions.

Item definition	Item question	Assessment
1. Representative spectrum (spectrum bias)	Was the spectrum of participants representative of the patients who will receive the test in practice?	Yes: if the study includes a consecutive series of participants referred for follow‐up to detect potential endoleaks. No: if the referred participants were not under follow‐up for endoleak detection. Unclear: insufficient information to make a judgement.
2. Acceptable reference standard	Was the reference standard likely to classify the target condition correctly?	Yes: CT scan test with contrast agents performed and images evaluated by a radiologist. No: reference standard did not meet criteria outlined above.  Unclear: insufficient information to make a judgement.
3. Acceptable delay between tests	Was time period between reference standard and index test short enough to be reasonably sure that target condition did not change between the 2 tests?	Yes: time period between index test and reference standard ≤ 4 weeks. No: time period > 4 weeks. Unclear: insufficient information to make a judgement.
4. Partial verification avoided	Did the whole sample or a random selection of the sample, receive verification using a reference standard of diagnosis?	Yes: all study participants accounted for and results of reference standard reported for all. No: not all participants who received index test received verification by reference standard. Unclear: insufficient information to make a judgement.
5. Differential verification avoided	Did participants receive the same reference standard regardless of the index test result?	Yes: all participants who received index test were subjected to same reference standard. No: not all participants who received index test were subjected to same reference standard.; Unclear: insufficient information to make a judgement.
6. Incorporation avoided	Was the reference standard independent of the index test (i.e. the index test did not form part of the reference standard)?	Yes: index test was not part of reference standard. No: index test was clearly part of reference standard. Unclear: insufficient information was given to make a judgement.
7. Reference standard results blinded	Were the index test results interpreted without knowledge of the results of the reference standard?	Yes: explicitly stated that index test was interpreted without knowledge of reference standard. No: if assessor of index test was aware of results of reference standard. Unclear: insufficient information to make a judgement.
8. Index test results blinded	Was the execution of the reference standard described in sufficient detail to permit its replication?	Yes: explicitly stated that reference standard was interpreted without knowledge of index test. No: if assessor of reference standard was aware of results of index test. Unclear: insufficient information to make a judgement.
9. Relevant clinical information	Were the same clinical data available when the index test results were interpreted as would be available when the test is used in practice?	Yes: clinical data (age, gender, symptoms, type of stent) would ordinarily be available in clinical practice when index test was being interpreted AND these same clinical data were available in this study when index test was being interpreted. No: above clinical data were not available when index test and reference standard were interpreted. Unclear: insufficient information to make a judgement.
10. Uninterpretable results reported	Were uninterpretable/intermediate test results reported?	Yes: reported results for all study participants, including those with uninterpretable, indeterminate, or intermediate results of index test and reference standard. No: uninterpretable, indeterminate, or intermediate results of index test or reference standard were not reported OR results of index test and reference standard were not reported for all study participants. Unclear: insufficient information to make a judgement.
11. Withdrawals explained	Were withdrawals from the study explained?	Yes: clear what happened to all participants who entered study, e.g. if a flow diagram of study participants reported explaining any withdrawals or exclusions, or numbers recruited match those in analysis. No: appeared that some participants who entered study did not complete study, i.e. did not receive both index test and reference standard, and these participants were not accounted for. Unclear: insufficient information to make a judgement.

CT: computed tomography.