Xilun Ma1, Jitian Guan1, Zhiyan Zhang1, Miaomiao Chen1, Yanzi Chen1, Zhiwei Shen1, and Renhua Wu1
1Department of Medical Imaging, the 2nd Affiliated Hospital, Medical College of Shantou University, Shantou 515041, China, Shantou, China, People's Republic of
Synopsis
Eighteen
Parkinson Disease’s (PD) patients and four healthy controls(HC) underwent the
diffusional kurtosis imaging (DKI) and then we tested the PD’s patients with Hoehn-Yahr scale and Unified Parkinson Disease Rating Scale(UPDRS). As a result, we found a significant decrease of Mean kurtosis (MK) values in the left substantia
nigra between PD’s patients and healthy controls. Moreover, the kurtosis
fractional anisotropy (KFA) values in right red nucleus of the PD’s patients
were positively associated with the UPDRS
scores in our study.Purpose
To evaluate the minimal
changes in the substantia
nigra and red nucleus of
PD’s patients by DKI , a new MRI technique
for assessing tissue microstructure.
Introduction
The diagnosis of Parkinson Disease (PD) is based on the cardinal signs such as bradykinesia, resting tremors and muscular rigidity which are evident only after the loss of 80% DA in
the striatum.1,2 DKI technique has been proposed as an extension of diffusion tensor imaging (DTI).Not only did the DKI technique obtained all the conventional diffusion tensor metrics,
including axial diffusivity, radial diffusivity, and fractional anisotropy, but
also provided another metrics related to non-Gaussian water diffusion such as Mean kurtosis (MK) , kurtosis
fractional
anisotropy (KFA) and kurtosis mean
diffusivity(KMD) 3. Therefore, we evaluated the minimal changes in the
substantia nigra and red nucleus of
PD’s patients by diffusional kurtosis
imaging (DKI).
Method
Eighteen PD’s patients (six females,
twelve males, mean
age 63.2±8.5 years, Hoehn-Yahr stage 0 to 3.0, mean UPDRS scores 27.5±15.0)
and four healthy controls (one female, three males, mean age 58.5±11.0 years)underwent
the DKI which were performed
on a General Electric (GE) Signa 3.0 Tesla MR Imaging System.We accessed the
severity of the patients with Hoehn-Yahr scale and Unified
Parkinson Disease Rating Scale(UPDRS) scale. All participants had no personal or familiar history of other
neurological disease or history of diabetes. All
DKI data processing operations were performed with commercial workstations (GE,
ADW 4.6) using
Functool software to generate color-coded and parametric maps of MK, KFA, KMD. All data were analyzed and graphs were
designed on SPSS 20.0 statistical software. An independent sample t test was conducted
to compare the diffusion
indexes between PD and Healthy Controls（HC）subjects. The associations between the diffusion indexes and UPDRS
scores were calculated by using Pearson Correlation Coefficients.
Result
In consequence, a significant decline of MK values (P<0.05)
in the left substantia nigra was seen in the PD’s patients compare with the healthy
controls. No significant change of MK values in right substantia nigra, KFA or
KMD in bilateral red nucleus and substantia nigra was observed in our
reseaech Besides, we found a positive
correlation between KFA values of right red nucleus and UPDRS scores in the PD’s
patients (P<0.01). However, we didn’t observe any association between the MK
values of bilateral red nucleus or substantia nigra and UPDRS scores.
Discussion
Diffusion Kurtosis Imaging
is proposed as a new MRI technique of quantifying non-Gaussian water diffusion4,5.
Mean kurtosis, a distinct parameter obtained in DKI, reflects the changes in
structural complexity. In addition to MK, another parameter called KFA,
mathematically analogous to fractional anisotropy (FA),is also calculated in our study. Then we found that the KFA values of right red
nucleus were positively associated with the UPDRS scores, a most common scale for PD's severity, in PD’s patients which suggest
that the changes of complexity in right red nucleus may affect the daily living ability of PD’s patients. Another important finding is the decline
of MK values in the left substantia nigra
of the patients. This observation may due to the neuronal loss and gliosis in
the left substantia nigra as a result of
reduced structural complexity.
Acknowledgements
This
work was sponsored by the National Natural Science Foundation of China (Grant
No. 81471730), and the National High Technology Research and Development
Program (863 Program) of China (Program No. 2014AA021101).References
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