Gray 2012.

Clinical features and settings	People who underwent EVAR at the Mater Hospital from 1 June 2003 to 1 July 2010 retrospectively reviewed. Type of stents received: not reported. Aneurysm diameter: not reported. Setting: department of vascular surgery.
Participants	145 participants; 122 (84.1%) male; mean (± SD) age: 77.1 ± 7.9 years. Comorbidities: not reported. Geography: Ireland.
Study design	Retrospective design.
Target condition and reference standard(s)	Target condition: endoleak. Definition of endoleak: type I, evidence of high jet flow; type II, endoleak or low velocity flow within the old aneurysm sac demonstrating forward and reversed flow. Endoleak (absolute n): 25. Prevalence of endoleak: 5.4% (25/459). Reference standard: CT scan. Image acquisition: not reported. thickness: 0.75‐mm slices. Type of CT scanner: Somatom Definition AS 128‐slice scanner (Siemens AG, Erlangen, Germany). Use of contrast: not reported.
Index and comparator tests	Index test: CDUS. Image production: all CDUS began with visualisation of aorta immediately inferior to diaphragm. Residual aneurysm imaged in B‐mode in both transverse and longitudinal planes from diaphragm to iliac bifurcation. Multiple measurements obtained of residual aneurysm sac in transverse plane. Maximum measurements of residual aneurysm sac recorded and compared to last scan report to ensure there was no significant increase in sac size. Careful note made in B‐mode of stent walls to ensure there was no evidence of obvious defects or kinking of metal exoskeleton. Iliac arteries imaged in B‐mode throughout entire length. Multiple transverse and anteroposterior measurements obtained and maximum of the 2 measurements recorded for follow‐up purposes. Type of US: 6‐mHz curvilinear broadband transducer: Sequoia 512 Ultrasound system and later in study an S200 Ultrasound system (Siemens AG, Erlangen, Germany). Use of contrast: no. Operator: 1 accredited vascular technologist.
Follow‐up	CDUS and CT scans of 31 (21.4%) participants not compared due to inconsistent timing of imaging modalities (scans performed > 90 days apart excluded), failure to attend and CT being contraindicated due to IV contrast allergy.
Notes	After discharge, all participants CDUS scan at 1 month and then CDUS scan and CT scan at 6 months, 12 months, and annually thereafter provided there was no documented endoleak on either CDUS or CT.
Table of Methodological Quality
Item	Authors' judgement	Description
Representative spectrum? All tests	Yes	Participants represented average patients who after receiving EVAR are exposed to endoleak surveillance.
Acceptable reference standard? All tests	Yes	Reference standard was CT scan.
Acceptable delay between tests? All tests	Unclear	Number of participants with delays between the 2 test > 28 days unclear. However, study reported "scans performed greater than 90 days apart were excluded."
Partial verification avoided? All tests	Yes	All study participants accounted for and results of reference standard reported for all.
Differential verification avoided? All tests	Yes	All participants who received index test subjected to same reference standard.
Incorporation avoided? All tests	Yes	Index test not part of reference standard.
Reference standard results blinded? All tests	Yes	In all cases, technologist was blind to CT results.
Index test results blinded? All tests	Unclear	No clear information provided.
Relevant clinical information? All tests	Yes	Yes.
Uninterpretable results reported? All tests	Yes	Of the 2 participants who had type I endoleak on CDUS and not on CT, 1 was anatomical abnormality and misinterpreted on the CDUS scan. The second participant was documented as type II endoleak on CT. 4/5 participants who had type I endoleak detected on CDUS underwent further intervention.
Withdrawals explained? All tests	Yes	"The CDUS and CT scans of the remaining 31 (21.4%) patients were not compared due to inconsistent timing of imaging modalities (scans performed greater than 90 days apart were excluded), failure to attend and CT being contra‐indicated due to i.v. contrast allergy. Of the 426 CDUS scans carried out 26 (6.1%) scans were reported as limited, due to the presence of excess bowel gas and body habitus curtailing the determination of residual sac size and endoleak detection. The maximum residual aneurysm size was documented on the remaining 400 (93.9%) CDUS scans. Of the 289 CT’s performed 107 (37%) did not have the maximum residual aneurysm sac size documented in the report. The maximum residual aneurysm size was documented on the remaining 182 (63%) of CT scan reports."