title: Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.
abstract: OBJECTIVE
  Diffusion- and perfusion-weighted magnetic resonance imaging can identify ischemic brain injury in the hyperacute stage. For neuroprotection during thoracic aortic surgery, we developed a novel retrograde cerebral perfusion with intermittent pressure augmentation. The purpose of this study was to assess the efficiency of this novel method for neuroprotection in real time by using diffusion- and perfusion-weighted magnetic resonance imaging.
  
  
  METHODS
  Sixteen beagle dogs were randomly divided into 4 groups: the antegrade selective cerebral perfusion group (n = 4; antegrade selective cerebral perfusion at a flow rate of 10 mL x kg(-1) x min(-1)); the intermittent retrograde cerebral perfusion group (n = 4; retrograde cerebral perfusion at a baseline pressure of 15 mm Hg with intermittent pressure augmentation to 45 mm Hg every 30 seconds); the conventional retrograde cerebral perfusion group (n = 4; conventional retrograde cerebral perfusion at a fixed pressure of 25 mm Hg); and the circulatory arrest group (n = 4; only circulatory arrest). Diffusion- and perfusion-weighted magnetic resonance images were acquired during each session of cerebral perfusion. Regions of interest were defined, and the apparent diffusion coefficient and relative regional cerebral blood volume were calculated in these regions of interest. Finally, the brain was evaluated for its histopathologic damage score.
  
  
  RESULTS
  The best apparent diffusion coefficient values were observed in the intermittent retrograde cerebral perfusion group in all the regions of interest, although the relative regional cerebral blood volume values were mostly lower than those in the antegrade selective cerebral perfusion group. The total Histopathologic Damage Score (0, normal; 32, worst) in the intermittent retrograde cerebral perfusion group (8.0 +/- 0.6) was significantly lower than that in the conventional retrograde cerebral perfusion (17.5 +/- 1.7; P < .01) and circulatory arrest (25 +/- 1.0; P < 0.01) groups and was equivalent to that in the antegrade selective cerebral perfusion group (7.8 +/- 0.8; P = .9).
  
  
  CONCLUSIONS
  Intermittent retrograde cerebral perfusion provides adequate neuroprotection by allowing high apparent diffusion coefficient values to be maintained.
authors.affiliation: Department of Cardiothoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. mkawata-ths@umin.ac.jp
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kawata
authors.forename: Masaki
authors.initials: M
authors.lastname: Sekino
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takamoto
authors.forename: Shoogo
authors.initials: S
authors.lastname: Ueno
authors.forename: Sachiko
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kitahori
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsukihara
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Suematsu
authors.forename: Minoru
authors.initials: M
authors.lastname: Ono
authors.forename: Noboru
authors.initials: N
authors.lastname: Motomura
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Morota
authors.forename: Arata
authors.initials: A
authors.lastname: Murakami
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000601:surgery*; D050792:Circulatory Arrest, Deep Hypothermia Induced / Q000009:adverse effects*; D038524:Diffusion Magnetic Resonance Imaging; D004195:Disease Models, Animal; D004285:Dogs; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control*; D010477:Perfusion / Q000379:methods; D011312:Pressure