Morphology and signal changes of the lentiform nucleus based on susceptibility weighted imaging in parkinsonism-predominant multiple system atrophy.

Introduction: It remains challenging to make a differential diagnosis between atypical parkinsonism and Parkinson's disease (PD) from routine neuroimaging. This case-control study aimed to quantitatively investigate both morphological and signal intensity changes in susceptibility weighted imaging (SWI) of the lentiform nucleus (LN) for discriminating parkinsonism-predominant multiple system atrophy (MSA-P) from PD.

Methods: We retrospectively enrolled patients with MSA-P, PD, and sex- and age-matched controls between January 2016 and November 2019 at the Movement Disorder Center who underwent 3T MR imaging of brain with SWI sequence. Two specialists at the center reviewed the medical records and made the final diagnosis, and two experienced neuroradiologists performed MRI image analysis based on a defined radiological protocol to conduct the ROI-based morphological measurements of the LN and the signal intensity.

Results: A total of 19 patients with MSA-P, 19 patients with PD and 19 controls were enrolled in this study. We found that patients with MSA-P had significant decreases size in the short line (SL) and the ratio of the SL and the long line (SLLr) and increased value in the signal intensity standard deviation of the LN (SIsd_LN) compared with the patients with PD and with the controls (P < 0.05). Combining these three indexes, this finding had a sensitivity of 94.7% and a specificity of 63.2% to distinguish MSA-P from PD.

Conclusion: As compared to PD and control subjects, the SA-P patients are characterized by narrowing morphology and the inhomogeneous signal intensity of the posterior region of LN. The quantitative morphological change is a possible potential marker to differentiate MSA-P from PD on SWI.