Moment analysis of microflow histogram in focal ischemic lesion to evaluate microvascular derangement after small pial arterial occlusion in rats.
The authors' high-spatial-resolution optical method was used to examine microvascular derangement in a focal cerebral cortex lesion in 12 Sprague-Dawley rats anesthetized with alpha-chloralose-urethane. A pial artery (approximately 40- to 50 microm diameter) was occluded by laser-beam cauterization (n = 6). Diluted carbon black suspension was injected into the internal carotid artery, and images in a 2-mm x 2-mm region of interest during tissue dye-dilution were recorded. Sequential frames were analyzed with Matlab software to evaluate blood distribution and mean transit time, affording a two-dimensional microflow map and histogram with first, second, third, and fourth moments. In the early phase of ischemia, blood distribution and average flow decreased (both P < 0.01), and the second moment (microflow heterogeneity) and third moment (skew to the left owing to increase in low-flow components) increased (P < 0.05 and P < 0.01, respectively). At approximately 2 hours, blood distribution decreased further in 3 cases, apparently because capillary stasis prevented carbon black filling. However, average microflow unexpectedly increased in 4 of 5 rats, presumably due to exclusion of unperfused (low flow at the earlier stage) channels from the calculation. The authors conclude that flow in ischemic tissue is quite heterogeneous and that an averaged flow value tends to smear important information about ischemic microvascular derangement.
Tomita
Yutaka
Y
Department of Neurology, Saitama Municipal Hospital, Saitama-city, Saitama, Japan. y-tomita@sc.itc.keio.ac.jp
Tomita
Minoru
M
Schiszler
Istvan
I
Amano
Takahiro
T
Tanahashi
Norio
N
Kobari
Masahiro
M
Takeda
Hidetaka
H
Ohtomo
Manabu
M
Fukuuchi
Yasuo
Y
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000503:physiopathology; D002545:Brain Ischemia / Q000503:physiopathology*; D002343:Carotid Artery, Internal; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004396:Coloring Agents / Q000493:pharmacokinetics; D017075:Laser Coagulation; D008297:Male; D008833:Microcirculation / Q000502:physiology; D010841:Pia Mater / Q000098:blood supply*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004396:Coloring Agents