Studies were then graded according to the Quality
Assessment of Diagnostic Accuracy Studies (QUADAS)
tool [24], which was modified for the purpose of the
review. This tool considers 14 criteria relevant to diagnostic
studies accounting for bias (items 3 to 7, 10 to 12),
variability (items 1 and 2) and reporting (items 8 and 9).
Items 4 (regarding the time period between index and
reference test) and 7 (regarding the independency of the
reference test) were omitted with regard to the selection
criteria and the previously applied CEBM criteria. Additionally,
item 3 (regarding the ability of the reference test
to correctly classify the target condition) was applied to
CT findings, ICI and neurosurgery separately.