T2-*weighted perfusion MRI.

T2*-weighted perfusion MRI is based on the so-called "first passage" approach: the modifications in the T2-weighted MRI signal are followed during the first passage of a bolus of contrast agent. The pixel-by-pixel analysis of the curves is used to obtain parametric maps (time of arrival, time of the peak, mean transit time, relative volume and blood flow). Further analysis, with deconvolution by arterial input function (concentration of contrast agent in the blood), helps improve the quantification. It is possible to pre-inject a small dose of contrast agent to limit the impact of the extravasation of the contrast agent.