Can stroke physicians and neuroradiologists identify signs of early cerebral infarction on CT?

Doctors managing acute stroke are expected to recognise signs of early infa rction on CT before choosing thrombolytic treatment, according to recent tr ials and guidelines. The ability of 13 physicians and two neuroradiologists to recognise early infarct signs and decide whether patients should be ran domised in a hypothetical stroke treatment trial was tested. Only 65% of th e CT scans from 14 stroke patients were correctly identified as normal or a bnormal (95% CI 60-69%). Neither observer experience nor knowledge of sympt oms significantly improved recognition of abnormality, although experience did significantly improve the observers' ability to reproduce their results . Parenchymal hypodensity was the least well recognised sign. Only 45% (95% CI 40%-50%) of patients were identified correctly for the hypothetical acu te stroke treatment trial. Early infarction on CT is not well recognised ev en by experienced doctors. Part of the problem may be in understanding the definitions of the extent of infarction. These difficulties should be consi dered in the design of acute stroke treatment trials and in the introductio n of any new acute stroke treatments.