Investigation of brain iron content in patients with Parkinson's disease using phase and R2 obtained with multi echo susceptibility weighted imaging

Introduction: The main pathologic feature of Parkinson's disease (PD) is the loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) [1]. There is increasing evidence that iron-mediated oxidative stress via the Fenton reaction is responsible for this loss of neurons [2]. Iron's paramagnetism leads to changes in the relaxation rates R1, R2 and R2* [3] and the phase of susceptibility weighted images (SWI) [3,4]. While R2* has been previously used to assess iron deposition in the SNc in PD [5], the advantage of phase is that it is independent of relaxation mechanisms and has a higher signal to noise ratio (SNR). The aim of this study was therefore to use multi echo SWI for the investigation of both phase and R2* relaxation in deep brain structures of patients with PD.