Cerebral blood volume measurements by rapid contrast infusion and T2*-weighted echo planar MRI.
Cerebral blood volume (CBV) provides information complementary to that of cerebral blood flow in cerebral ischemia, tumors, and other conditions. We have developed an alternative theory and method for measuring CBV based on dynamic imaging by MRI or CT during a short contrast infusion. This method avoids several limitations of traditional approaches that involve waiting for steady state or measuring the area under the curve (AUC) during bolus contrast injection. Anesthetized dogs were studied by T2*-weighted echo planar imaging during gadolinium-DTPA infusions lasting 30-60 sec. CBV was calculated from the ratio of the signal changes in tissue and artery. Method responsiveness was compared to AUC measurements using the vasodilator acepromazine. The ratio of signal change in tissue to that in artery rapidly approached an asymptotic value even while the amount of contrast in artery continued to increase. Using 30-sec infusions, the mean (+/- SD) of CBV for control animals was 3.6 +/- 0.9 ml blood/100 g tissue in gray matter and 2.3 +/- 0.8 ml blood/100 g tissue in white matter (ratio = 1.6). Acepromazine increased CBV to 5.7 +/- 1.5 ml blood/100 g tissue in gray matter and 3.1 +/- 0.8 ml blood/100 g tissue in white matter (ratio = 2.0). AUC measurements after bolus injection yielded similar values for control animals but failed to demonstrate any change after acepromazine. It is possible to measure CBV using dynamic MRI or CT during 30-60-sec contrast infusions. This method may be more sensitive to changes in CBV than traditional AUC methods.
Tudorica
Alina
A
Department of Chemistry, SUNY at Stony Brook, Stony Brook, New York, USA.
Fang Li
Hai
H
Hospod
Frank
F
Delucia-Deranja
Evan
E
Huang
Wei
W
Patlak
Clifford S
CS
Newman
George C
GC
D000075:Acepromazine / Q000008:administration & dosage; D000818:Animals; D019540:Area Under Curve; D001783:Blood Flow Velocity / Q000502:physiology*; D001811:Blood Volume Determination / Q000379:methods*; D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D003287:Contrast Media / Q000008:administration & dosage*; D004285:Dogs; D019786:Gadolinium DTPA; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male
D003287:Contrast Media; D000075:Acepromazine; D019786:Gadolinium DTPA