In a recent report, Auer et aldescribed the clinical and imaging findings in 19 cases of extracranial vertebral artery dissection retrospectively.1 We make the following comments.

Firstly, the authors described the “sensitivity” and “specificity” of digital subtraction angiography (DSA), magnetic resonance imaging/angiography (MRI/A), and duplex sonography for diagnosing extracranial vertebral artery dissection.1These figures were based on the percentage of probable and definite features among the 19 patients. Nevertheless, sensitivity of a test is the number of cases with true positive results divided by the total number of positive results (including both true and false positives), and specificity is the number of cases with true negative results over the sum of true and false negatives. The authors misquoted the terms “sensitivity” and “specificity” in their report, as …