title: A new threshold of apparent diffusion coefficient values in white matter after successful tissue plasminogen activator treatment for acute brain ischemia.
abstract: OBJECTIVE
  Tissue plasminogen activator (tPA) is effective for the treatment of acute brain ischemia, but may trigger fatal brain edema or hemorrhage if the brain ischemia results in a large infarct. Herein, we attempted to predict the extent of infarcts by determining the optimal threshold of ADC values on DWI that predictively distinguishes between infarct and reversible areas, and by reconstructing color-coded images based on this threshold.
  
  
  METHODS
  The study subjects consisted of 36 patients with acute brain ischemia in whom MRA had confirmed reopening of the occluded arteries in a short time (mean: 99min) after tPA treatment. We measured the apparetnt diffusion coefficient (ADC) values in several small regions of interest over the white matter within high-intensity areas on the initial diffusion weighted image (DWI); then, by comparing the findings to the follow-up images, we obtained the optimal threshold of ADC values using receiver-operating characteristic analysis.
  
  
  RESULTS
  The threshold obtained (583×10-6m2/s) was lower than those previously reported; this threshold could distinguish between infarct and reversible areas with considerable accuracy (sensitivity: 0.87, specificity: 0.94).
  
  
  CONCLUSIONS
  The threshold obtained and the reconstructed images were predictive of the final radiological result of tPA treatment, and this threshold may be helpful in determining the appropriate management of patients with acute brain ischemia.
authors.affiliation: Division of Neurosurgery, Ina Central Hospital, Ina, Japan. Electronic address: asato@inahp.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sato
authors.affiliation: Division of Neurology, Ina Central Hospital, Ina, Japan.
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Division of Neurosurgery, Ina Central Hospital, Ina, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Koyama
authors.affiliation: Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hongo
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D016896:Treatment Outcome; D066127:White Matter / Q000473:pathology*
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator
keywords: Apparent diffusion coefficient; Early recanalization; Ischemia; Threshold; Tissue plasminogen activator