Dynamic susceptibility contrast perfusion MRI (with pitfalls)

Since the first studies in the late 1980s and early 1990s, dynamic susceptibility contrast MRI (DSC-MRI, also known as ‘bolus tracking’) has become a very powerful technique for the assessment of perfusion, and perfusion-related parameters (see (1,2) for recent reviews). Despite the need of an exogenous MR agent (cf. arterial spin labeling techniques), DSC-MRI is currently the most common MR perfusion methodology in clinical studies. It relies on the injection of a bolus of a paramagnetic contrast agent (usually gadolinium-DTPA), which produces a transient decrease in signal intensity on a series of gradient-echo or spin-echo images acquired during its passage through the brain (3). The loss in signal intensity is due to the decrease in T2* (or T2) associated with the susceptibility-induced gradients surrounding the paramagnetic contrast agent (4). This effect is more significant in areas where the contrast agent is compartmentalized (since this increases the induced gradients) and makes quantification of cerebral perfusion in areas with blood-brain barrier (BBB) leakage more complex (see later).