McLafferty 2002.

Clinical features and settings	People with AAAs who received stent graft. Type of stents received: AneuRx graft (Medtronics AVE, Sunnyvale, CA, USA). Aneurysm diameter: not reported. Setting: vascular laboratory (Intersocietal Commission for the Accreditation of Vascular Laboratories) at Memorial Medical Center (Springfield, IL, USA).
Participants	No further description about basic characteristics of participants provided. Comorbidities: not reported. Geography: USA. Period of recruitment: June 1997 to July 1999.
Study design	Prospective design. Whole sample included.
Target condition and reference standard(s)	Target condition: endoleak. Definition of endoleak: "According to protocol, endoleaks were classified as arising from proximal, distal, or junctional graft attachment sites (types I and III), from branch vessel flow (Type II), or from undetermined source." Endoleak (absolute n): 7. Prevalence of endoleak: 9.2% (7/20). Reference standard: helical CT scan. Image acquisition: "from the origin of the celiac artery to the bifurcation of the femoral arteries with 3 mm collimation and 2 mm reconstruction;" thickness: 2‐mm slices. Type of CT scanner: unclear. Use of contrast: yes (type not reported).
Index and comparator tests	Index test: CDUS. Image production: "Imaging of the aorta was performed from the coeliac artery to the iliac bifurcation in the longitudinal and transverse axes. The iliac and common femoral arteries were scanned in a similar fashion. Transverse measurements, relative to the vessel, were made just proximal to the coeliac artery, at the level of the renal arteries, at the maximal aneurysm diameter, and just proximal to the iliac bifurcation. Measurement of the proximal, middle, and distal common and external iliac arteries in the transverse axis was performed. Similarly, Doppler scan waveforms and velocity measurements were obtained proximally, within, and distal to the endograft. Colour‐flow mode was used to help identify endoleaks with further focus on determining the origin." Type of US: "Low frequency transducers ranging from 2.0 to 3.5 MHz were used with either the Quantum 2000 scanner (Quantum Medical Systems, Issaquah, Wash) or the Philips P800 scanner (Philips, North American Corp, Itasca, Ill)." Use of contrast: no. Operator: registered vascular technologists.
Follow‐up	No missing data or adverse events.
Notes	"According to the AneuRx phase II and III protocols, CT scan was routinely obtained at baseline, before discharge after erAAA, 6 months, 12 months, and yearly thereafter." "Between June 1997 and July 1999, all erAAAs were performed with the AneuRx graft (Medtronics AVE, Sunnyvale, Calif) with prospective phase II and phase III Food and Drug Administration protocols." "When compared with CT scan at 6 months, CFD scan had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 100%, 99%, 88%, 100%, and 99%, respectively."
Table of Methodological Quality
Item	Authors' judgement	Description
Representative spectrum? All tests	Yes	Participants represent average patients who after receiving EVAR are exposed to endoleak surveillance.
Acceptable reference standard? All tests	Yes	Reference standard was CTA.
Acceptable delay between tests? All tests	Unclear	Not reported.
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	Unclear	Not reported.
Index test results blinded? All tests	Unclear	Not reported.
Relevant clinical information? All tests	Yes	Yes.
Uninterpretable results reported? All tests	Yes	"Three patients (3.6%) had to have CT scan at the 1‐month follow‐up examination because the CFD scan could not be performed as a result of the presence of large body habitus or bowel gas. These patients had negative results for endoleak with CT scan at 1 month of follow‐up study."
Withdrawals explained? All tests	Yes	"Five patients who had negative results for endoleak at 1 month with CFD scan did not have CT scan at 6 months. One patient died of congestive heart failure before 6 months, one patient was unable to return, and three patients had lapses in scheduling. These remaining four patients had negative results for endoleak at 12 months. Four patients who had positive results for endoleak with CFD scan at 1 month did not have a CT scan at 3 months because of scheduling problems. All of these patients still had positive results for endoleak at 6 months with CT scan."