Sangam Gurudas Shet Kanekar MD, Presenter: Nothing to Disclose

Guangwei Du MD, PhD, Abstract Co-Author: Employee, Siemens AG, China

Mechelle Lewis, Abstract Co-Author: Nothing to Disclose

Lan Kong, Abstract Co-Author: Nothing to Disclose

Xuemei Huang, Abstract Co-Author: Nothing to Disclose

To investigate the discriminability of combined MRI R2* and diffusion tensor imaging (DTI) in differentiating Parkinson’s disease (PD) from two atypical Parkinsonisms (PSM): multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). 

High resolution MRI (T1-, T2-weighted, T2*, and DTI) were obtained from 15 Controls, 15 PD patients, 13 MSA-P patients, and 14 PSP patients. R2*, fractional anisotropy (FA), and mean diffusivity (MD) values in the putamen, caudate, global pallidus, substantia nigra (SN), and red nucleus (RN) were obtained from each subject using an automatic labeling software followed by manual correction of the regions of interest. Repeated measures MANCOVA was used to assess differences in imaging measurements between groups adjusting for age and gender. Logistic regression and receiver operational characteristic curves then were used to quantify discrimination ability of R2* and DTI measures individually and in combination.

Compared with Controls, both PD and PSM showed increased R2* values (p=0.0137 for PD; p=0.0014 for MSA; p<0.0001 for PSP) and decreased FA values (p=0.0088 for PD; p=0.0004 for MSA; p<0.0096 for PSP) in the SN. Only PD demonstrated increased R2* values the RN (p=0.0105) compared to Controls. Interestingly, only PSM showed decreased FA values in the putamen (p<0.0001 for MSA, p<0.0001 for PSP) and the caudate (p<0.0001 for MSA, p<0.0001 for PSP) compared to Controls. Combined R2* and DTI (c-statistic=0.763) showed an improved performance in differentiating PD from PSM compared to either R2* (c-statistic=0.615) or DTI (c-statistic=0.71) alone. 

The pattern of MRI changes (across modalities and locations) in PD and PSM suggests that MSA and PSP involve more diffuse MRI alterations that include the putamen and caudate, whereas the changes in PD are more focused on the SN. Combining R2* and DTI measures improved the discrimination between PD and PSM.

The current study highlights that imaging measurements, in particular R2* and DTI measures, may reflect different aspects of the neurodegenerative process and may be useful to separate PD from MSA-P and PSP.

Kanekar, S, Du, G, Lewis, M, Kong, L, Huang, X, Combined R2* and Diffusion Tensor Imaging Differentiate Parkinson’s Disease from Atypical Parkinsonism.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018567.html