Quantitative analysis of cerebral microvascular hemodynamics with T2-weighted dynamic MR imaging.

The purpose of this study was to quantify cerebral microvascular hemodynamics with T2-weighted dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) using a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence. We performed T2-weighted DSC-MRI with HASTE sequence in 19 normal subjects. After bolus injection of gadopentetate dimeglumine, HASTE images of two sections were acquired for the simultaneous creation of concentration-time curves in the internal carotid artery and in brain tissue. Absolute regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and mean transit time (MTT) values of brain tissue were calculated on a base of the indicator dilution theory, and all values were corrected on the assumption that rCBF of white matter is constant in 22 mL/100 g tissue/min without age-dependent alteration. A decrease in rCBV and rCBF of gray matter was age dependent, while rCBV of white matter did not show significant change with aging. The mean rCBF value in gray matter was 37.3 +/- 8.4 mL/100 g tissue/min. The mean rCBV value was 4.1 +/- 0.8 mL/100 g tissue in gray matter and 2.9 + 0.4 mL/100 g tissue in white matter. The rCBV and rCBF values of gray and white matter obtained from T2-weighted DSC-MRI with HASTE sequence were slightly lower than the published data calculated by gradient-echo sequence. We were able to perform absolute quantifications of the capillary blood volume and flow, using a HASTE sequence, which would not have been possible with a gradient-echo sequence. This technique provides a new method for estimating cerebral microvascular hemodynamics.