3D Magnetization Prepared Double Inversion Recovery (3D MP-DIR) at 7 Tesla

Introduction: Double Inversion Recovery (DIR) [1] is a valuable tool for the diagnosis of cortical and/or sub cortical lesions [2]. By introducing non-selective 3D acquisitions the problem of inherent CSF-inflow artifacts and partial volume effects in DIR images have been reduced, substantially improving the sensitivity and specificity of detecting sub-millimeter lesions . Successful implementations of 3D DIR sequences have been reported for 3T and lower field strengths [3]. At 7T, the implementation of 3D DIR is less straightforward [4] due to SAR constraints, high sensitivity to susceptibility , short T2 components and RF in-homogeneity. Moreover, whereas the T1 of CSF is relatively constant, lengthening of T1 relaxation times [5] of grey and white matter (GM and WM) at 7T, introduces more T1 weighting (Fig. 1) compromising the desired T2 contrast. The aim of the present study is to develop a 3D DIR sequence with high T2 contrast and high SNR by using dedicated Magnetization Preparation pre-pulses (MP) for 7Tesla.