Sato 1998.

Clinical features and settings	People who were implanted with the Endovascular Technologies stent graft device. Type of stents received: not reported. Aneurysm diameter: not reported. Setting: division of vascular surgery.
Participants	79 participants; no demographic information provided. Comorbidities: not reported. Geography: USA.
Study design	Retrospective review of records. "The EnACT Core Laboratory records were reviewed from CDU [CDUS] and CT studies that were performed in patients who were implanted with the Endovascular Technologies stent graft device. All of the studies were evaluated by the Core Laboratory for endoleak and interpreted as having an endoleak present or absent or recorded as an indeterminate study as a result of technical factors. Data were entered into a computerized database and analyzed for diagnostic accuracy of CDU studies as compared with CTs."
Target condition and reference standard(s)	Target condition: endoleak. Definition of endoleak: not reported. Endoleaks have been reported at a rate of 13‐44%. Endoleak (absolute n): unclear. Prevalence of endoleak: 34.0% (34/100). Reference standard: contrast‐enhanced CT scan. "The CTs were obtained according to study protocol. A scout CT was obtained without contrast to identify the superior mesenteric artery. This was followed by a contrast‐enhanced CT with 3‐mm‐thick slices from above the superior mesenteric artery to the level of the profunda femoris and the superficial femoral artery. No delayed images were required with the study protocol. The CDUs were performed according to the study protocol, which included the evaluation of the flow through the endograft, the perigraft flow, the renal and the iliac arterial flow, the maximum diameter of aneurysm, and the presence of branch vessel flow." Type of scanner: not reported. Use of contrast: yes (type not reported).
Index and comparator tests	Index test: CDUS. Image production: B‐mode image performed to assess graft, proximal and distal stents, and AAA sac and size measurements of the AAA sac. Colour Doppler scan added, and settings optimized to avoid excessive overgain. Doppler scan may be added to assist in detection of perigraft flow. Type of US:low‐frequency (range: 2.25‐5 MHz), curved array, phased array or mechanical sector, and pulsed Doppler scan transducers. Use of contrast: not used. Operator: > 1.
Follow‐up	Unclear.
Notes
Table of Methodological Quality
Item	Authors' judgement	Description
Representative spectrum? All tests	Yes	Yes.
Acceptable reference standard? All tests	Yes	Reference standard was CT scan.
Acceptable delay between tests? All tests	Unclear	No information provided.
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	Interpretation of all CDUS and CT scans blinded to all concurrent and prior studies.
Index test results blinded? All tests	Yes	Interpretation of all CDUS and CT scans blinded to all concurrent and prior studies.
Relevant clinical information? All tests	Yes	Yes.
Uninterpretable results reported? All tests	Yes	Of 117 studies, 103 CDUs (88%) and 114 CTs (97%) were recorded as having presence or absence of an endoleak and 14 CDUs (12%) and 3 CTs (3%) were indeterminate. The 14 indeterminate CDUs caused by suboptimal imaging technique. The 3 indeterminate CTs caused by unsatisfactory contrast administration in 2 studies and by extensive calcification in the third study. In 18 studies (18%), CTs and CDUs were conflicting for endoleaks.
Withdrawals explained? All tests	Unclear	Unclear whether missing data or adverse events occurred.