Christian Denk1, Samantha Palmer2,
Martin J. McKeown3, Alexander Rauscher1
1UBC MRI Research Centre, University of
British Columbia, Vancouver, BC, Canada; 2Brain Research Centre,
Vancouver, BC, Canada; 3Pacific Parkinson's Research Centre,
Vancouver, BC, Canada
The
main pathologic feature of Parkinson's disease (PD) is the loss of
dopaminergic neurons in the substantia nigra pars compacta (Snc). There is
increasing evidence that iron-mediated oxidative stress via the Fenton
reaction is responsible for this loss of neurons. Iron's paramagnetism leads
to changes in the relaxation rates R1, R2 and R2* and the phase of
susceptibility weighted images (SWI). 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. The strongest correlation with
phase to the UPDRS score of -0.5 was found in the medial SN pars compacta as
well as the largest phase differences between PD patients and controls. A
smaller correlation was found with R2*, which is in agreement with previous
studies of cerebral R2* in patients with PD.