Investigation of relationships between transverse relaxation rate, diffusion coefficient, and labeled cell concentration in ischemic rat brain using MRI.
MRI has been used to evaluate labeled cell migration and distribution. However, quantitative determination of labeled cell concentration using MRI has not been systematically investigated. In the current study, we investigated the relationships between labeled cell concentration and MRI parameters of transverse relaxation rate, R(2), and apparent diffusion coefficient (ADC), in vitro in phantoms and in vivo in rats after stroke. Significant correlations were detected between iron concentration or labeled cell concentration and MRI measurements of R(2), ADC, and ADC x R(2) in vitro. In contrast, in vivo labeled cell concentration did not significantly correlate with R(2), ADC, and ADC x R(2). A major factor for the absence of a significant correlation between labeled cell concentration and MRI measurements in vivo may be attributed to background effects of ischemic tissue. By correcting the background effects caused by ischemic damage, DeltaR(2) (difference in R(2) values in the ischemic tissue with and without labeled cells) exhibited a significant correlation to labeled cell concentration. Our study suggests that MRI parameters have the potential to quantitatively determine labeled cell concentration in vivo.
Athiraman
Hemanthkumar
H
Department of Neurology, Henry Ford Health System, Detroit, Michigan 48202, USA.
Jiang
Quan
Q
Ding
Guang Liang
GL
Zhang
Li
L
Zhang
Zheng Gang
ZG
Wang
Lei
L
Arbab
Ali S
AS
Li
Qingjiang
Q
Panda
Swayam
S
Ledbetter
Karen
K
Rad
Ali M
AM
Chopp
Michael
M
D000818:Animals; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology*; D002478:Cells, Cultured; D003287:Contrast Media; D003911:Dextrans; D052203:Ferrosoferric Oxide; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007501:Iron; D058185:Magnetite Nanoparticles; D008297:Male; D009474:Neurons / Q000473:pathology*; D010087:Oxides; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods; D020521:Stroke / Q000473:pathology*
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide