title: Early x-ray hypoattenuation of brain parenchyma indicates extended critical hypoperfusion in acute stroke.
abstract: OBJECTIVE
  The presence of early x-ray hypoattenuation is an important selection criterion for thrombolytic therapy. However, knowledge about the pathophysiological constellation reflected by this hypoattenuation is lacking. Our objective was to study the relationship between the presence of early CT hypoattenuation and the volumes of critical cortical hypoperfusion.
  
  
  METHODS
  In 32 patients with acute ischemic stroke, CT was performed 20 to 170 minutes (mean, 94 minutes) after symptom onset, and [(15)O]H(2)O-PET 20 to 120 minutes (mean, 67 minutes) later. CTs were scrutinized for the presence of hypoattenuation. On the PET scans, the volumes of critical cortical hypoperfusion were assessed.
  
  
  RESULTS
  CT hypoattenuation was present in 18 patients (56%), all of whom had critical cortical hypoperfusion and developed infarction. Of the 14 patients with normal CTs, critical hypoperfusion was found in 6, and 7 developed infarction. The mean volumes of critically hypoperfused tissue differed significantly (P=0.0001, Wilcoxon test) between the CT normal (mean 13.9 cm(3), range 0 to 71 cm(3)) and the CT abnormal (mean 116.3 cm(3), range 4 to 389 cm(3)) groups.
  
  
  CONCLUSIONS
  Early presence of hypoattenuation is indicative of extended volumes of critically hypoperfused cortical tissue. The extent of hypoperfusion may exceed that of hypoattenuation, and some of that tissue might still be salvageable.
authors.affiliation: Klinik und Poliklinik für Neurologie, Institut und Poliklinik für radiologische Diagnostik der Universität zu Köln, Germany. martin.grond@pet.mpin-koeln.mpg.de
authors.forename: M
authors.initials: M
authors.lastname: Grond
authors.forename: R
authors.initials: R
authors.lastname: von Kummer
authors.forename: J
authors.initials: J
authors.lastname: Sobesky
authors.forename: S
authors.initials: S
authors.lastname: Schmülling
authors.forename: J
authors.initials: J
authors.lastname: Rudolf
authors.forename: K
authors.initials: K
authors.lastname: Terstegge
authors.forename: W
authors.initials: W
authors.lastname: Heiss
mesh_terms: D000208:Acute Disease; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D020521:Stroke / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed