Darnell 2021.

Study characteristics
Patient Sampling	Aim: to evaluate the diagnostic accuracy of each LI‐RADS category by MRI according to LI‐RADS v2018 in a cohort of people with cirrhosis in whom a solitary nodule ≤ 20 mm was detected during screening US. 315 people with cirrhosis with a single nodule ≤ 20 mm detected by surveillance US were included. 2 participants were excluded due to non‐evaluable results.
Patient characteristics and setting	Patients at risk were screened with US, and suspected cases were referred to MRI.
Index tests	Used the positivity criteria from LI‐RADS v2018, extracted data for the case of LI‐RADS 5 category. Radiologists were unaware of the final diagnosis of the lesion.
Target condition and reference standard(s)	Reference standards: US‐guided biopsy with histology, specific vascular profile (arterial phase hyperenhancement with washout) by MRI and follow‐up. The index test was used as a reference standard and it represents incorporation bias. Further testing was decided based on the index test results.
Flow and timing	Time between index test and reference standard > 90 days. Used different reference standards.
Comparative
Notes	Authors disclosed potential COI and funding was provided by a public institution.
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	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?	Yes
Were positivity criteria clearly defined?	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?	No
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?	No
Did all patients receive the same reference standard?	No
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		High risk