Validation of Quantitative Human Brain Perfusion Measurement with Intravoxel Incoherent Motion (IVIM), with a Hypercapnia and Hyperoxygenation Challenge.

Christian Federau¹, Philippe Maeder¹, Kieran O'Brien², Patrick Browaeys¹, Markus Klarhoefer³, Reto Meuli¹, Patric Hagmann¹

Quantitative brain perfusion measurement remains a major challenge to currently available MR perfusion methods. The intravoxel incoherent motion (IVIM) method offers a non-invasive, alternative method to measure brain perfusion quantitatively, based on a bi-exponential fit of the relative signal obtained with an standard diffusion sequence for multiple b-values, usually between 0 and about 1000 s/mm2. We challenged the IVIM method with graded hypercapnia and hyperoxgenation in 7 healthy volunteers and report a statistically significant, graded increase of the IVIM perfusion parameters under hypercapnia, namely of the perfusion fraction f and of the pseudo-diffusion coefficient D*.