T1 measurement of flowing blood and arterial input function determination for quantitative 3D T1-weighted DCE-MRI.
OBJECTIVE
To propose a simple, accurate method for measuring T(1) in flowing blood and the arterial input function (AIF), and to evaluate the impact on dynamic contrast-enhanced MRI (DCE-MRI) quantification of pharmacokinetic parameters.


METHODS
A total of 10 rabbits were scanned at 1.5 Tesla and administered a bolus of Gadomer. Preinjection T(1) and AIF measurements were acquired in the iliac arteries using a rapid three-dimensional (3D) spoiled gradient recalled echo (SPGR) approach. Correction was made for imperfect B(1) fields, in-flow, and partial volume effects. DCE-MRI parameters blood volume (v(b)) and endothelial transfer constant (K(trans)) in resting skeletal muscle were estimated from pharmacokinetic analysis using individually measured AIFs. Literature comparisons were made to assess accuracy.


RESULTS
Blood T(1) was more accurate and precise after correction for B(1) and partial volume errors (1267 +/- 72 msec). Measured AIFs followed reported biexponential decay characteristics for Gadomer clearance in rabbits. Parameters v(b) (2.47 +/- 0.65%) and K(trans) (3.6 +/- 1.0 x 10(-3) minute(-1)) derived from AIFs based on corrected blood T(1)s were more reproducible and in better agreement with literature values.


CONCLUSIONS
The proposed method enables accurate in vivo blood T(1) and AIF measurements and can be easily implemented in a range of DCE-MRI applications to improve both the accuracy and reproducibility of pharmacokinetic parameters.
Cheng
Hai-Ling Margaret
HL
Department of Diagnostic Imaging, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada. hai-ling,cheng@sickkids.ca
D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D003287:Contrast Media / Q000493:pharmacokinetics*; D050091:Dendrimers / Q000493:pharmacokinetics*; D005260:Female; D007083:Iliac Artery; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D018482:Muscle, Skeletal / Q000098:blood supply*; D011817:Rabbits
D003287:Contrast Media; D050091:Dendrimers; C513348:gadomer 24