The steady-state (SS) approach has been proposed to measure quantitative cerebral blood volume (CBV)- However, it is known that the CBV value in SS (CBVss) is subject to error resulting from the effects of water diffusion from the intra- to extravascular space. CBVss measurements were simulated in both fast-and no-water-exchange limits, and compared with measured CBVss values to determine which limiting case is appropriate. Twenty-eight patients were scanned with a segmented Look-Locker echo-planar imaging (LL-EPI) sequence before and after the injection of 0.1 mmol/kg of a T1-shortening contrast agent. Signal changes and T 1 values of brain parenchyma and the blood pool were measured pre- and postcontrast. These signal changes and T1 values, in combination with the simulated results, were used to estimate water-exchange rates. We found that the intra- to extravascular water-exchange rates in white matter (WM) and gray matter (GM) were 0.9 and 1.6 s-1, respectively. With these water-exchange rates, the fast-water-exchange limit of the CBV values showed good agreement with the simulation (r = 0.86 in WM, and 0.78 in GM). The CBV values with the correction for water-exchange effects were recalculated as 2.73 ± 0.44 and 5.81 ± 1.12 of quantitative cerebral blood water volume (%) in WM and GM, respectively.
- Cerebral perfusion
- Pulse sequence
- Quantitative cerebral blood volume
- Water exchange correction
- Water-exchange rate
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging