Dynamic Flow Velocity Mapping from Fluorescent Dye Transit Times in the Brain Surface Microcirculation of Anesthetized Rats and Mice.
This study aimed to develop a new method for mapping blood flow velocity based on the spatial evolution of fluorescent dye transit times captured with CLSFM in the cerebral microcirculation of anesthetized rodents.



The animals were anesthetized with isoflurane, and a small amount of fluorescent dye was intravenously injected to label blood plasma. The CLSFM was conducted through a closed cranial window to capture propagation of the dye in the cortical vessels. The transit time of the dye over a certain distance in a single vessel was determined with automated image analyses, and average flow velocity was mapped in each vessel.



The average flow velocity measured in the rat pial artery and vein was 4.4 ± 1.2 and 2.4 ± 0.5 mm/sec, respectively. A similar range of flow velocity to those of the rats was observed in the mice; 4.9 ± 1.4 and 2.0 ± 0.9 mm/sec, respectively, although the vessel diameter in the mice was about half of that in the rats.



Flow velocity in the cerebral microcirculation can be mapped based on fluorescent dye transit time measurements with conventional CLSFM in experimental animals.
Faculty of Informatics and Engineering, University of Electro-Communications, Tokyo, Japan.
Ryo
R
Hoshikawa
Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
Hiroshi
H
Kawaguchi
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Hiroyuki
H
Takuwa
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Yoko
Y
Ikoma
Department of Neurology, Keio University School of Medicine, Tokyo, Japan.
Yutaka
Y
Tomita
Department of Neurology, Keio University School of Medicine, Tokyo, Japan.
Miyuki
M
Unekawa
Department of Neurology, Keio University School of Medicine, Tokyo, Japan.
Norihiro
N
Suzuki
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Iwao
I
Kanno
Faculty of Informatics and Engineering, University of Electro-Communications, Tokyo, Japan.|Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.|Brain Science Inspired Life Support Research Center, University of Electro-Communications, Tokyo, Japan.
Kazuto
K
Masamoto
D000758:Anesthesia; D000818:Animals; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003952:Diagnostic Imaging / Q000379:methods; D005456:Fluorescent Dyes; D008722:Methods; D051379:Mice; D008833:Microcirculation / Q000502:physiology*; D018613:Microscopy, Confocal / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods; D051381:Rats
D005456:Fluorescent Dyes
capillary heterogeneity; cerebral blood flow; dilution technique; fluorescent imaging; neurovascular unit