Quantitation and localization of blood-to-brain influx by magnetic resonance imaging and quantitative autoradiography in a model of transient focal ischemia.
The ability of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) enhanced MRI to localize and quantitate blood-brain barrier (BBB) opening was evaluated against quantitative autoradiographic (QAR) imaging of (14)C-alpha-aminoisobutyric acid (AIB) distribution. The blood-to-brain transfer constant (K(i)) for Gd-DTPA was determined by MRI in rats after 3 h of focal cerebral ischemia plus 2.5 h of reperfusion (n = 9), and that of AIB was determined by QAR shortly thereafter. Tissue regions of interest (ROIs) for Gd-DTPA leakage were identified by ISODATA segmentation of pre- and post-Gd-DTPA Look-Locker (L-L) T(1) maps. Patlak plots were constructed using time course of blood and tissue T(1) changes induced by Gd for estimating K(i). Among the nine rats, 14 sizable regions of AIB uptake were found; 13 were also identified by ISODATA segmentation. Although the 13 MRI-ROIs spatially approximated those of AIB uptake, the segmentation sometimes missed small areas of lesser AIB uptake that did not extend through more than 60% of the 2.0-mm-thick slice. Mean K(i)'s of AIB were highly correlated with those of Gd-DTPA across the 13 regions; the group means (+/-SD) were similar for the two tracers (7.1 +/- 3.3 x 10(-3) and 6.8 +/- 3.5 x 10(-3) ml.g(-1) . min(-1), respectively). In most instances, Gd-DTPA MRI accurately localized areas of BBB opening.
Knight
Robert A
RA
Department of Neurology, Henry Ford Health Sciences Center, Detroit, MI 48202, USA. knight@neurnis.neuro.hfh.edu
Nagaraja
Tavarekere N
TN
Ewing
James R
JR
Nagesh
Vijaya
V
Whitton
Polly A
PA
Bershad
Eric
E
Fagan
Susan C
SC
Fenstermacher
Joseph D
JD
D000818:Animals; D001345:Autoradiography / Q000379:methods*; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging / Q000473:pathology*; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D003287:Contrast Media; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011877:Radionuclide Imaging; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
D003287:Contrast Media; D019786:Gadolinium DTPA