Signal characteristics of FLAIR related to water content: comparison with conventional spin echo imaging in infarcted rat brain.
To examine the correlation between tissue water content and signal intensity on fluid-attenuated inversion recovery (FLAIR) images, we analyzed infarcted rat brain, verified the results by theoretical simulation, and compared them with conventional spin-echo images. We produced brain infarction with cavitation in five rats by middle cerebral artery occlusion. After in vivo MRI, histologic sections of the MRI plane were obtained. We measured the signal intensity of regions on FLAIR and spin-echo images, and measured the area of cavitation on histologic sections. We plotted curves of cavity percentage to signal intensity. Theoretical values were calculated using a two-compartment model. On the curve of cavity area to signal intensity, the signal on FLAIR images peaked in tissues with 20% to 30% area of cavitation. On the theoretical curve, the signal on FLAIR images peaked at 90% tissue water content. These results seem to be characteristic of FLAIR.
Department of Radiology, Nara Medical University, Nara, Japan. ttaoka@naramed-u.ac.jp
Toshiaki
T
Taoka
Masayuki
M
Fujioka
Yoshiyuki
Y
Matsuo
Mitsuru
M
Notoya
Satoru
S
Iwasaki
Akio
A
Fukusumi
Hiroyuki
H
Nakagawa
Masahiko
M
Sakamoto
Kimihiko
K
Kichikawa
Hajime
H
Ohishi
D000818:Animals; D001834:Body Water / Q000378:metabolism*; D001921:Brain / Q000473:pathology; D001923:Brain Chemistry; D002544:Cerebral Infarction / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051381:Rats; D017208:Rats, Wistar