Chua 2007.

Study characteristics
Patient Sampling	Evaluated 114 patients who presented within 120 days of the onset of ischemic symptoms (transient ischemic attack or non‐disabling stroke), 20 were excluded Exclusion criteria: Patients with cardiac embolism and prior ipsilateral carotid endarterectomy were excluded. Occlusion of one or both ICA and atypical flow patterns within vessels, such as low velocities in near‐occlusion, and extensive calcified plaques resulting in long segments of acoustic shadowing
Patient characteristics and setting	94 patients ranged from 53 to 76 years (mean, 64; standard deviation, 8.8). The male‐to‐female sex ratio was 2.9:1 No information on risk factors
Index tests	DUS Image production: Diasonics Spectra (Diasonics Inc, Milpatas, California) using a 7.5‐MHz transducer Contrast: No Criteria used to determine grade of stenosis: ROC curve analysis
Target condition and reference standard(s)	Reference standard: DSA Target condition: evaluate optimal criteria for determination of ICA stenosis in symptomatic patients Criteria used to determine grade of stenosis: NASCET criteria Complications: None
Flow and timing	20 were excluded from the study because of the occlusion of one or both ICA and atypical flow patterns within vessels, such as low velocities in near‐occlusion, and extensive calcified plaques resulting in long segments of acoustic shadowing. Carotid duplex ultrasonography and DSA within 1 month of each other
Comparative
Methods	Study design: Prospective, not consecutive, accuracy cohort study Study location: Singapore Year and language of publication: Published in 2007 in English Study period: January 1995 to December 2003 Participants enrolled: 94 Carotids included in analyses: 188
Notes
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	No
Could the selection of patients have introduced bias?		High 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?	No
If a threshold was used, was it pre‐specified?	No
Could the conduct or interpretation of the index test have introduced bias?		High 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?	No
Could the reference standard, its conduct, or its interpretation have introduced bias?		High 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