Why emergency XeCT-CBF should become routine in acute ischemic stroke before thrombolytic therapy.
Intravenous thrombolytic therapy using recombinant tissue plasminogen activator (rtpa) has been approved for the treatment of acute ischemic stroke in the USA, if treatment is initiated within 3-hours (NINDS tpa Stroke Study Group) but not 6 hours (ECASS II) after time of onset. Favorable outcome in the placebo arm was much higher than expected possibly because patients with TIA's are likely to be included as progressive ischemic stroke subjects when a brief 3-6 hours duration of stroke is defined as the therapeutic window. Yonas' group at the University of Pittsburg demonstrated that adding stable xenon inhalation to routine CT scanning performed during emergency screening of acute stroke, predicted which cases became irreversibly infarcted if thrombolytic therapy was not administered within a few hours of stroke onset, since non-contrasted CT scans are usually normal this early. Adding a few minutes for inhalation of 26% xenon is justified in order to measure LCBF values which predict size, severity and volumes of impending cerebral infarctions and rule out TIA's which have relatively normal CT-CBF values. CT-CBF measures provide positive indications for thrombolytic therapy. This is not possible by MRI and SPECT methods which are not sufficiently quantitative to discern LCBF values persistently below ischemic thresholds of 16 mls/100 gm/min, thereby predicting impending infarction.
Meyer
J S
JS
Cerebrovascular Research Laboratories, Veterans Administration Medical Center, Houston, Texas, USA.
Rauch
G M
GM
D020520:Brain Infarction / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D004632:Emergency Medical Services; D006801:Humans; D020521:Stroke / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D014057:Tomography, X-Ray Computed; D014978:Xenon
D014978:Xenon; D010959:Tissue Plasminogen Activator