Novel approach to the measurement of absolute cerebral blood volume using vascular-space-occupancy magnetic resonance imaging.
Quantitative determination of cerebral blood volume (CBV) is important for understanding brain physiology and pathophysiology. In this work, a novel approach is presented for accurate measurement of absolute CBV (aCBV) using vascular-space-occupancy (VASO) MRI, a blood-nulling pulse sequence, in combination with the T(1) shortening property of Gd-DTPA. Two VASO images with identical imaging parameters are acquired before and after contrast agent injection, resulting in a subtracted image that reflects the amount of blood present in the brain, i.e., CBV. With an additional normalizing factor, aCBV in units of milliliters of blood per 100 mL of brain can be estimated. Experimental results at 1.5 and 3 T systems showed that aCBV maps with high spatial resolution can be obtained with high reproducibility. The averaged aCBV values in gray and white matter were 5.5 +/- 0.2 and 1.4 +/- 0.1 mL of blood/100 mL of brain, respectively. Compared to dynamic susceptibility contrast techniques, VASO MRI is based upon a relatively straightforward theory and the calculation of CBV does not require measurement of an arterial input function. In comparison with previous pre/postcontrast difference approaches, VASO MRI provides maximal signal difference between pre- and postcontrast situation and does not require the use of whole blood for signal normalization.
Lu
Hanzhang
H
Center of Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York 10016, USA. h.lu@med.nyu.edu
Law
Meng
M
Johnson
Glyn
G
Ge
Yulin
Y
van Zijl
Peter C M
PC
Helpern
Joseph A
JA
D000328:Adult; D000465:Algorithms; D001810:Blood Volume; D001811:Blood Volume Determination / Q000379:methods*; D001921:Brain / Q000098:blood supply* / Q000473:pathology*; D001927:Brain Diseases / Q000175:diagnosis*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity