The Role of Intravascular Effects in Phase Contrast Between Gray and White Matter

Natalia Petridou¹, Samuel J. Wharton¹, Ashley Lotfipour¹, Penny Gowland¹, Richard Bowtell¹

MR phase images exhibit exceptional contrast between Gray and White Matter. Here we examine the contribution of blood-related sources to this contrast by modulating the blood susceptibility with a gadolinium-based contrast agent during time-series phase imaging. We found that the GM/WM phase difference increased during the bolus pass but returned approximately to pre-contrast values after recirculation, while the GM/vasculature phase difference remained enhanced. Thus the significantly elevated susceptibility of blood due to the steady-state concentration of gadolinium had no significant effect on the GM/WM susceptibility difference, indicating that the latter is not explained by deoxyhaemoglobin in blood.