Barlinn 2016.

Study characteristics
Patient Sampling	Retrospectively evaluated 346 consecutive patients with acute cerebral ischemia who were admitted to a tertiary stroke center. Patients were eligible if their diagnostic workup included DUS and CTA performed within 5 days of each other Exclusion criteria: quote "Patients who underwent acute revascularization therapy of the extracranial ICA prior to completion of both diagnostic studies were excluded from our analysis".
Patient characteristics and setting	All patients were symptomatic, 346 patients with acute Ischemic stroke (n = 284) or transient ischemic attack (n = 62) 303 acute cerebral Ischemic patients included in analyses Mean age, 72 ± 12 years. 58% men and 42% women; median baseline National Institutes of Health Stroke Scale score, 4 [IQR 7] No information on risk factor
Index tests	DUS . Image production: Duplex ultrasonography (Toshiba Aplio MX SSA‐780a System®, Toshiba Medical Systems, Germany) with a 7.5–10‐MHz linear array transducer was used for examinations of the extracranial carotid arteries. Contrast: No Criteria used to determine grade of stenosis: DEGUM ultrasound criteria (Appendix 9Arning 2010)
Target condition and reference standard(s)	Reference standard: CTA Target condition: assessment of extracranial ICA steno‐occlusive disease in patients with acute cerebral ischemia Criteria used to determine grade of stenosis: NASCET criteria Complications: Not described
Flow and timing	43 patients (12%) were not eligible for the final analysis due to the following reasons: ultrasonographic assessment after acute revascularization therapy, n = 13; elapsed time between DUS and CTA > 5 days, n = 23; and only one vascular imaging modality assessable (e.g. streak artefacts from dental implants on CTA), n = 7. The median elapsed time between DUS and CTA was 1 (IQR, 2) day
Comparative
Methods	Study design: Retrospective design; participants identified retrospectively based on availability of complete records, if their diagnostic workup included DUS and CTA performed within 5 days Study location: Germany Year and language of publication: Published in 2016 in English Study period: from January 2012 to December 2012 Participants enrolled: 303 patients Carotids included in analyses: 593 DUS and CTA carotid artery pairs available for comparison
Notes	Only included retrospectively patients that had undergone the index and the reference tests; unclear if DUS results were used to select patients to CTA
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Unclear
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Yes
Could the selection of patients have introduced bias?		Unclear risk
Are there concerns that the included patients and setting do not match the review question?			Low concern
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
Could the conduct or interpretation of the index test have introduced bias?		Low risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
Could the reference standard, its conduct, or its interpretation have introduced bias?		Low risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			Low concern
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	No
Could the patient flow have introduced bias?		High risk