Brusner et al. take on an extremely important issue of diagnostic test evaluation. In this era of changing definition of stroke from clinical to tissue based definition they compare one of the most commonly used diagnostic methods in stroke, positive diffusion weighted image to a reference standard. It is a single center study and neuroradiologists were unblinded which are limitations of this study but it was prospective and included more than 700 patients. It verifies that DWI if positive overwhelming supports the diagnosis of acute ischemic stroke. The likelihood ratio is more than 10 in this case. And if negative, diagnosis of acute ischemic stroke should be questioned.
Given this finding this article is a good read before morning report and or stroke rounds to get the details on positive diffusion imaging.