Fiber orientation dependance of T2* relaxation time in the whole human brain at 3T

Introduction: An orientation dependency of T2*-weighted images at high field strengths was described in recent publications. Wiggins et al. [1] first demonstrated a direct change in the intensity of the Corpus Callosum and the Cingulum when tilting the head and Cherubini et al. [2] demonstrated a relationship between R2* and main fiber direction when comparing R2*-maps with DTI data and suggests that fiber orientation might play an important role in all WM. Several tissues show a relationship with B0, for example peripheral nerves [3] and blood vessels [4,5]. In this study it is examined whether a real angle dependency exists for all of the WM and the results are compared with the relationships found for peripheral nerves and for blood vessels.