02931nas a2200385   4500000000100000008004100001100001500042700001300057700001800070700001500088700001200103700001200115700001800127700001500145700001100160700001300171700001300184700001300197700001500210700001400225700001700239700001600256700001700272700001300289700001300302700001300315700001400328700001300342245013500355250001500490300000800505490000700513520197400520020005102494       2015                            d1 aLindley R.1 aCohen G.1 aSandercock P.1 aWardlaw J.1 aMair G.1 aBoyd E.1 avon Kummer R.1 aDemchuk A.1 aYan B.1 aAdami A.1 aWhite P.1 aAdams M.1 aFarrall A.1 aSellar R.1 aRamaswamy R.1 aMollison D.1 aRodrigues M.1 aSamji K.1 aBaird A.1 aSakka E.1 aPalmer J.1 aPerry D.00aObserver reliability of CT angiography in the assessment of acute ischaemic stroke: data from the Third International Stroke Trial  a2014/10/08  a1-90 v573 a<p>
INTRODUCTION: CT angiography (CTA) is often used for assessing patients with acute ischaemic stroke. Only limited observer reliability data exist. We tested inter- and intra-observer reliability for the assessment of CTA in acute ischaemic stroke. METHODS: We selected 15 cases from the Third International Stroke Trial (IST-3, ISRCTN25765518) with various degrees of arterial obstruction in different intracranial locations on CTA. To assess inter-observer reliability, seven members of the IST-3 expert image reading panel (&gt;5 years experience reading CTA) and seven radiology trainees (&lt;2 years experience) rated all 15 scans independently and blind to clinical data for: presence (versus absence) of any intracranial arterial abnormality (stenosis or occlusion), severity of arterial abnormality using relevant scales (IST-3 angiography score, Thrombolysis in Cerebral Infarction (TICI) score, Clot Burden Score), collateral supply and visibility of a perfusion defect on CTA source images (CTA-SI). Intra-observer reliability was assessed using independently repeated expert panel scan ratings. We assessed observer agreement with Krippendorff's-alpha (K-alpha). RESULTS: Among experienced observers, inter-observer agreement was substantial for the identification of any angiographic abnormality (K-alpha = 0.70) and with an angiography assessment scale (K-alpha = 0.60-0.66). There was less agreement for grades of collateral supply (K-alpha = 0.56) or for identification of a perfusion defect on CTA-SI (K-alpha = 0.32). Radiology trainees performed as well as expert readers when additional training was undertaken (neuroradiology specialist trainees). Intra-observer agreement among experts provided similar results (K-alpha = 0.33-0.72). CONCLUSION: For most imaging characteristics assessed, CTA has moderate to substantial observer agreement in acute ischaemic stroke. Experienced readers and those with specialist training perform best.
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  a1432-1920 (Electronic)<br/>0028-3940 (Linking)