Attempts to achieve absolute quantification of perfusion parameters by standard DSC-MRI have typically been characterized by overestimated absolute values of cerebral blood volume (CBV) and cerebral blood flow (CBF) [1,3,7,8,9], and these observations are attributed, at least in part, to a correspondingly underestimated arterial concentration time integral.
USPIO are investigated as blood pool agents with T1 weighted sequence for angiography, tumour permeability and tumour blood volume or steady-state cerebral blood volume and vessel size index measurements using T2 weighted sequences.
Modalities under development for assessment of brain tissue viability following a stroke include PET imaging, to assess oxygen consumption in compromised tissues; MR diffusion imaging; and assessment of cerebral blood flow, cerebral blood volume, and other hemodynamic parameters using CT imaging.
1 The combination of perfusion MR imaging with diffusion-weighted MR should be a powerful tool in the assessment of the acute stroke patient, but perfusion imaging continues to require significant post-processing, and the most reliable parameters to evaluate (time to peak, mean transit time, cerebral blood volume, etc.
Results demonstrate that two of six patients in the first dosing cohort have exhibited a greater than 25% reduction in relative cerebral blood flow and/or relative cerebral blood volume, compared to baseline.
