Direct Measurement of Arterial Input Function in White Matter

Vishal Patil¹, Jens H. Jensen¹, Glyn Johnson¹

Estimating the arterial input function (AIF) is the first step in most DSC and DCE MRI analyses. Problems associated with measuring an AIF in a large vessel are partially resolved by AIF measurements in normal white matter. However, an accurate relationship between relaxivity and contrast agent concentration, C, has never been determined in white matter in vivo. In this study we compared AIFs derived from blood and white matter using two relaxivity models: 1) A nonlinear model which interpolates between both short and long static dephasing regime times. 2) A linear model while only considers long dephasing times. The results demonstrate that the nonlinear model provides an accurate relationship between relaxivity and C.