Dynamic-contrast-enhanced-MRI with extravasating contrast reagent: rat cerebral glioma blood volume determination.
The accurate mapping of the tumor blood volume (TBV) fraction (vb) is a highly desired imaging biometric goal. It is commonly thought that achieving this is difficult, if not impossible, when small molecule contrast reagents (CRs) are used for the T1-weighted (Dynamic-Contrast-Enhanced) DCE-MRI technique. This is because angiogenic malignant tumor vessels allow facile CR extravasation. Here, a three-site equilibrium water exchange model is applied to DCE-MRI data from the cerebrally-implanted rat brain U87 glioma, a tumor exhibiting rapid CR extravasation. Analyses of segments of the (and the entire) DCE data time-course with this "shutter-speed" pharmacokinetic model, which admits finite water exchange kinetics, allow TBV estimation from the first-pass segment. Pairwise parameter determinances were tested with grid searches of 2D parametric error surfaces. Tumor blood volume (vb), as well as ve (the extracellular, extravascular space volume fraction), and Ktrans (a CR extravasation rate measure) parametric maps are presented. The role of the Patlak Plot in DCE-MRI is also considered.
Li
Xin
X
W.M. Keck Foundation High-Field MRI Laboratory-Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR 97239, United States. lxin@ohsu.edu
Rooney
William D
WD
Várallyay
Csanád G
CG
Gahramanov
Seymur
S
Muldoon
Leslie L
LL
Goodman
James A
JA
Tagge
Ian J
IJ
Selzer
Audrey H
AH
Pike
Martin M
MM
Neuwelt
Edward A
EA
Springer
Charles S
CS
D000818:Animals; D001810:Blood Volume; D001811:Blood Volume Determination / Q000379:methods*; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D005910:Glioma / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008657:Metabolic Clearance Rate; D008959:Models, Neurological; D051381:Rats; D011923:Rats, Nude
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA