title: Cerebral hemodynamic evaluation using perfusion-weighted magnetic resonance imaging: comparison with positron emission tomography values in chronic occlusive carotid disease.
abstract: OBJECTIVE
  Perfusion-weighted magnetic resonance imaging (PWI) is a reliable and semiquantitative method for estimating cerebral hemodynamics. We sought to evaluate the potential of PWI for assessing cerebral blood flow (CBF) and metabolism compared with positron emission tomography (PET) in patients with chronic occlusive carotid disease.
  
  
  METHODS
  In 24 patients with chronic unilateral occlusive carotid disease, time-to-peak (TTP) delay (TTP-D) measured by PWI was compared with CBF, cerebral blood volume (CBV), and oxygen extraction fraction (OEF) obtained by PET. TTP indicates the time from the start of PWI to the bolus peak. TTP-D indicates the difference in TTP values between the occlusive and contralateral hemispheres. TTP-D was compared between patients with normal and reduced CBF/CBV and also between patients with normal and elevated OEF.
  
  
  RESULTS
  TTP-D in patients with reduced CBF/CBV was significantly longer than that in patients with normal CBF/CBV (3.4+/-1.8 versus 1.4+/-0.7 seconds; P<0.001). In the patients with reduced CBF/CBV, TTP-D correlated with OEF significantly (r=0.710, P<0.0001). TTP-D in patients with elevated OEF was significantly longer than that in patients with normal OEF (4.8+/-2.2 versus 2.0+/-0.9 seconds; P<0.01). In all 5 patients with TTP-D >or=4 seconds, OEF was elevated markedly.
  
  
  CONCLUSIONS
  TTP-D >or=4 seconds is considered to indicate a high risk of hemodynamic failure. The measurement of TTP-D by PWI appears to provide important clinical information for evaluating cerebral hemodynamics in chronic occlusive carotid disease.
authors.affiliation: Department of Cerebrovascular Medicine, National Cardiovascular Center, 5-7-1 Fujishirodai, Suita City, Osaka 565-8565, Japan. kkajimot@hsp.ncvc.go.jp.
authors.forename: Katsufumi
authors.initials: K
authors.lastname: Kajimoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Moriwaki
authors.forename: Naoaki
authors.initials: N
authors.lastname: Yamada
authors.forename: Kohei
authors.initials: K
authors.lastname: Hayashida
authors.forename: Junya
authors.initials: J
authors.lastname: Kobayashi
authors.forename: Kotaro
authors.initials: K
authors.lastname: Miyashita
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Naritomi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000378:metabolism; D002340:Carotid Artery Diseases / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation; D002908:Chronic Disease; D005260:Female; D006439:Hemodynamics; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D010104:Oxygen Radioisotopes; D011237:Predictive Value of Tests; D011859:Radiography; D015203:Reproducibility of Results; D020521:Stroke / Q000150:complications / Q000503:physiopathology*; D013997:Time Factors; D014055:Tomography, Emission-Computed
chemical_list: D010104:Oxygen Radioisotopes; D010100:Oxygen