Resolution:
## Figure 2.
Example of the effect of verification bias in a hypothetical true distribution of
degree restenosis in patients treated with a carotid artery stent. If a DUS cut-off value of for example 50% stenosis is used to select patients for
a diagnostic study, only the patients in part B and C are included and will undergo
the reference test. Patients in part A are excluded. The number of patients below
a certain threshold, for example 70% is too low (proportion B instead of proportion
A and B) and therefore leads to incorrect estimates of the diagnostic value, the specificity
in particular. Therefore, DUS criteria obtained from a diagnostic study with comparison
with the reference test in part B and C, can not be applied to routine clinical practice
for all stented patients (part A, B, and C).
Nederkoorn and Brown |