Brain Iron Deposition and Sequence Characteristics in Parkinsonism Comparison of SWI, T2* Maps, T2-Weighted-, and FLAIR-SPACE

Objectives: To compare quantitatively T-2- and T-2*-based magnetic resonance imaging sequences in patients with symptoms of Parkinson disease and to evaluate the information content of those sequences regarding brain iron concentration. Materials and Methods: We imaged 51 patients with symptoms of Parkinson disease on 3-T magnetic resonance imaging with T-2-weighted sampling perfection with application optimized contrasts using different flip-angle evolution (SPACE), fluid attenuation inversion recovery (FLAIR)-SPACE, susceptibility-weighted imaging (SWI), and parametric T-2* sequence (MapIt). Signal analysis was performed in 22 regions of interest in the brain. Results: Correlations (r(2) = 0.82...0.96) with brain iron concentration were excellent. Contrast and tissue separability ratios were best in the T-2* maps and FLAIR-SPACE, respectively. Good correlations of contrast were reached between SWI and both T-2-weighted SPACE and FLAIR-SPACE. Their relation to quantitative T-2* values was reminiscent of a quadratic curve shape. However, separation into gray and white matter revealed a linear positive and negative correlation, respectively. Conclusions: SWI showed potential in differentiating illnesses characterized by brain iron deposition. Closely similar information was given by T 2 weighted SPACE and FLAIR-SPACE, whereas other sequence comparisons revealed dispersion from intersequence agreement.