Quantifying brain iron deposition in patients with Parkinson's disease using quantitative susceptibility mapping, R2 and R2*

PURPOSE: To evaluate the sensitivity and specificity of quantitative magnetic resonance (MR) iron mapping including R2, R2* and magnetic susceptibility to differentiate patients with Parkinson's disease (PD) from healthy controls. MATERIALS AND METHODS: Thirty (30) healthy controls (HC) (64±7years old) and 20 patients with idiopathic PD (66±8years old) were studied using a 3T MR imaging scanner. R2 maps were generated from GRASE sequence while R2*, and quantitative susceptibility mapping (QSM) were obtained from a conventional multi-echo gradient-echo sequence. R2, R2* and relative susceptibility (Δχ) values of structures in the basal ganglia were measured for each patient and control. An analysis of sensitivity and specificity and unpaired t-test was applied to the two groups. RESULTS: A significant difference (p<0.05) was found for R2 and ∆χ values in the substantia nigra as a whole and in the pars compacta for PD patients. The R2* values were different significantly (p<0.05) only on the substantia nigra pars compacta. QSM presented the highest sensitivity and specificity to differentiate the two populations. CONCLUSION: The QSM map was the most sensitive quantitative technique for detecting a significant increase of iron for PD. The highest significant difference between controls and patients was found in the substantia nigra pars compacta using QSM.