Perfusion by magnetic resonance imaging: its physical foundations and clinical application

We review one of the most important functional techniques in magnetic resonance imaging, perfusion MRI (pMRI) with emphasis in its applications, particularly in the diagnosis and follow up of brain lesions. First, we discuss the physical principles and results of the technique, then, we discuss its major applications. In clinical settings, two different contrast-based MRI techniques are used: T2*-weighted dynamic susceptibility contrast MRI (DSC) and T1-weighted dynamic contrast enhancement imaging (DCE). DSC measures the pharmacokinetics of first pass contrast bolus through a predefined volume. In contrast, DCE measures capillary permeability, derived it from an assumed compartment model in a time-series of T1-weighted images. The major usefulness of pMRI has been reported in brain tumors, brain ischemia and inflammation, and degenerative disorders. In this paper we review the physical basis and the contribution of MRI perfusion to the diagnosis and prognosis of several diseases of the central nervous system.