Effects of Flip Angle Variations on the Accuracy of Perfusion Parameters in DCE-MRI

Introduction: Dynamic contrast-enhanced (DCE-) MRI has become a valuable tool in the assessment of tumors and in the evaluation of the effects of treatment. Kinetic modeling with two or three (including tumor vascular component vp) compartments is commonly used to measure the parameter K, a first order rate constant that describes tumor perfusion and vascular permeability. In its calculation, the flip angles used for DCE-MRI and for computing the tumor’s intrinsic T1 (if variable flip angle (VFA) technique is used), must be known. However, flip angle inaccuracies can often occur due to inhomogeneous RF fields and slice profile effects [1]. The goal of our current work is to evaluate to what extent deviations in flip angle can occur in a large FOV DCE-MRI protocol and determine how those variations affect the measurement accuracy of perfusion parameters (K, ve).