title: The evolution of the cerebral blood volume abnormality in patients with ischemic stroke: a CT perfusion study.
abstract: BACKGROUND
  Accurate identification of the acute infarct core abnormality is important for guiding acute stroke treatment. Abnormality volumes from diffusion-weighted MRI (DWI) and CT perfusion (CTP)-cerebral blood volume (CBV) are highly correlated. DWI lesions have been shown to be reversible at 24 h.
  
  
  OBJECTIVE
  To examine the temporal profile of the CT perfusion (CTP)-derived CBV abnormality out to 7 days post ischemic stroke.
  
  
  METHODS
  Twenty-six patients were included. Group A (n = 13) underwent a non-contrast CT (NCCT), CTP/CT angiography (CTA) within 6 h of stroke onset, CTP/CTA at 24 h, and CTP/NCCT at 5-7 days post stroke. Group B (n = 13) underwent a NCCT, CTP/CTA within 6 h of stroke onset, and NCCT at 5-7 days. Recanalization status was established in all patients. For both groups, infarct volumes were traced on 5-7 day NCCT images and superimposed onto all CTP-CBV functional maps to determine CBV. Group B (n = 13) admission images were used to define CBV infarct thresholds for gray and white matter. CBV-lesion over-estimation was determined for Group A using the thresholds from Group B.
  
  
  RESULTS
  CBV (mL·100g(- 1); mean ± stdev) for gray/white matter, within confirmed infarcted regions (CBV(I)) at admission, 24 h, and 5-7 days were 1.82 ± 0.56, 1.56 ± 0.42, 1.75 ± 0.31, and 1.38 ± 0.65, 1.13 ± 0.31, 1.32 ± 0.44, respectively, when averaged over all patients (P > 0.05). Four patients had tissue time-density curves from ischemic lesions (TDC(i)) with an incomplete contrast medium wash-out phase (truncation) at admission and/or 24 h. Compared to admission, gray matter CBV(I) was higher at 5-7 days for patients with TDC(i) truncation (P < 0.05). There were no significant CBV(I) increases for the eight patients without truncation (P > 0.05). Over-estimation of acute CBV lesion was present in 3/4 (75%) and 1/9 (11%) of patients with/without TDC(i) truncation, respectively.
  
  
  CONCLUSIONS
  CTP-derived CBV lesion reversal is associated with TDC(i) truncation during the acute stroke phase.
authors.affiliation: Lawson Health Research Institute, London, Ontario, Canada.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: d'Esterre
authors.forename: Richard I
authors.initials: RI
authors.lastname: Aviv
authors.forename: Ting Yim
authors.initials: TY
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001810:Blood Volume; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography / Q000379:methods*; D002560:Cerebrovascular Circulation; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol