title: Significance of early CT signs in acute stroke. A CT scan-diffusion MRI study.
abstract: OBJECTIVE
  To study the pathophysiology of early CT signs.
  
  
  BACKGROUND
  Early CT signs, due to an increase in tissue water content, are commonly attributed to cytotoxic edema and development of irreversible injury. This may have important implications for thrombolysis.
  
  
  METHODS
  In patients with acute ischemic stroke in the middle cerebral artery territory, the areas of early CT signs and diffusion weighted imaging (DWI) hypersignal were independently assessed and drawn on a standardized atlas. Then, patients were classified into three groups (early CT signs larger than, similar to or smaller than DWI hypersignal) and compared with perfusion weighted imaging (PWI).
  
  
  RESULTS
  Of 16 patients, CT scanning was performed with a median time of 3 h after onset and early CT scan signs were recorded in 10/16 patients (62.5%). DWI signal hyperintensity was present in 15/16 (94%) patients. In 7/16 (43%) patients, the area with early CT scan signs was larger than the DWI lesion ('CT-larger group'). Only in 2/16 (12%) patients were the areas matching ('matching group'). In 7/16 (43%) the DWI lesion was larger than the early CT scan signs area ('DWI-larger group'). When compared with PWI, the areas of early CT signs were larger than DWI hypersignal and were matching with PWI abnormalities (rMTT) in 2 cases, suggesting that they may represent a reversible process.
  
  
  CONCLUSIONS
  Early CT signs might have a potential dual fate: infarction or reversibility. Other techniques of recognizing reversible ischemic damage, such as DWI-PWI, are needed to improve acute stroke diagnosis and management.
authors.affiliation: Department of Clinical and Biological Neurosciences, Stroke Unit University Hospital, Grenoble, France. Assia.Jaillard@ujf-grenoble.fr
authors.forename: Assia
authors.initials: A
authors.lastname: Jaillard
authors.forename: Marc
authors.initials: M
authors.lastname: Hommel
authors.forename: Alison E
authors.initials: AE
authors.lastname: Baird
authors.forename: Italo
authors.initials: I
authors.lastname: Linfante
authors.forename: Rafael H
authors.initials: RH
authors.lastname: Llinas
authors.forename: Louis R
authors.initials: LR
authors.lastname: Caplan
authors.forename: Robert R
authors.initials: RR
authors.lastname: Edelman
authors.forename: Steven
authors.initials: S
authors.lastname: Warach
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed