Keywords: Parkinson's Disease, Parkinson's Disease

Motivation: Parkinson disease patients show alterations in their vascular system, exhibiting lower perfusion than healthy subjects.

Goal(s): Here, we harness a mouse model exhibiting extensive human α-syn deposition to investigate cerebral blood flow properties in PD. 

Approach: We use a novel setup enabling high resolution Pseudo-Continuous Arterial Spin Labelling, a non-invasive technique for perfusion mapping in-vivo without injection of contrast agentes.

Results: We found that not only the PD mouse line but also their WT littermates have altered perfusion properties across the brain compared to control c57bl/6 mice.
 
 

Impact: Our findings highlight the importance of accounting for these potential sources of variability in future work with these lines.

Keywords: Parkinson's Disease, Parkinson's Disease

Motivation: Delayed detection of wearing off (WO) in Parkinson’s disease (PD) has a negative impact on quality of life. However, there is currently no method for WO prediction prior to treatment.  

Goal(s): To investigate whether resting-state functional MRI (rs-fMRI) could aid in WO prediction.

Approach: Fractional amplitude of low-frequency fluctuation (fALFF) was quantified from rs-fMRI to determine whether spontaneous activity dysfunction could be a predisposing vulnerability related to WO.

Results: Putaminal fALFF reduction was the independent predictor of WO development.

Impact: Detection of putaminal fALFF reduction prior to treatment provides a quantitative metric to facilitate WO prediction and improve prognosis.

Keywords: Parkinson's Disease, Parkinson's Disease

Motivation: The influence of gender on the brain morphology of PD-RBD patients remains unclear. 

Goal(s): We aimed to investigate gender differences in PD-RBD patients in terms of cortical morphology and individual structural covariance network.

Approach: We firstly conducted volume- and surface-based morphometry analyses, followed by further exploration of the topological characteristics of individual level morphological similarity networks based on Kullback-Leibler Divergence.

Results: Male patients presented decreased cortical indicators in salience, along with increased volume, cortical complexity and sulcus depth increase. Furthermore, in the individual morphological networks, we found significant differences between male and female patients in terms of both global and nodal properties.

Impact: PD-RBD patients exhibit significantly gender-specific differences in brain morphology and covariant patterns, which may reflect distinct clinical treatment needs and disease progression patterns. Further exploration is needed to enhance clinical management efficiency.

Keywords: Parkinson's Disease, Brain Connectivity, Parkinson's disease, fMRI

Motivation: Currently there are no effective non-invasive neuroimaging biomarkers to evaluate the progression of Parkinson's disease (PD).

Goal(s): To use graph theory analysis of resting-state functional MRI (rs-fMRI) to investigate the abnormalities of brain functional network in PD at different disease stages.

Approach: We evaluated the global and nodal indicators changes between PD at different disease stages by comparison with healthy control.

Results: Brain functional network topology was disrupted to a varying extent in patients with PD at different disease stages.

Impact: The findings of this study may enhance our understanding of the mechanisms underlying the progression of Parkinson's disease and contribute to the development of non-invasive neuroimaging biomarkers for monitoring disease progression.

Keywords: Parkinson's Disease, Parkinson's Disease

Motivation: Early detection of Parkinson's disease (PD) is crucial, and MRI has been a valuable tool. Synthetic MRI, allows for comprehensive analysis of brain regions, offering potential for early diagnosis.

Goal(s): Evaluate the feasibility of synthetic MRI in early PD diagnosis by studying brain regions.

Approach: 31 PD patients and 25 controls underwent MRI. Synthetic MRI provided T1, T2, and PrD maps. Brain regions were analyzed and a combined diagnostic model was developed.

Results: Differences in T1 and T2 values were found in the calcarine, cuneus, and hippocampus. The model achieved an AUC of 0.930, suggesting synthetic MRI-derived parameters can serve as  biomarkers.

Impact: The combined diagnosis using T1 and T2 values in specific brain regions effectively distinguished early-stage Parkinson's disease (ESP) from healthy controls (HC). This suggests that synthetic MRI-derived parameters have the potential to serve as precise early PD diagnostic biomarkers.

Keywords: Parkinson's Disease, Parkinson's Disease, glymphatic system

Motivation: In this study,we aimed to investigate the activity of the glymphatic system in PD using DTI-ALPS method and to further explore the correlation patterns of DTI-ALPS indexes with aging and cognitive impairment.

Goal(s): To explores the correlation between glymphatic system impairment and cognitive impairment.

Approach: Diffusion tensor image analysis along the perivascular space (DTI-ALPS) index offers a noninvasive alternative and the method has been validated well with standard glymphatic MRI.

Results: Our study found that glymphatic system function was impaired in PD as reflected by DTI-ALPS. Glymphatic dysfunction may lead to cognitive impairment,which was affected by aging and disease state.

Impact: Our study explores the correlation between glymphatic system impairment and cognitive impairment.This finding provides new perspectives on cognitive impairment in patients with PD and suggests potential strategies for treating cognitive impairment in such patients.

Keywords: Parkinson's Disease, Parkinson's Disease

Motivation: Early diagnosis of Parkinson's disease (PD) remains challenging.

Goal(s): Aimed to identify new imaging features in the basal ganglia of PD by 7T iron-sensitive MRI, and to investigate the diagnostic performance of the new imaging features in distinguishing early-stage PD patients from healthy subjects.

Approach: 129 participants were prospectively recruited between May 2021 and September 2023. All participants were scanned at Tiantan Neuroimaging Center using 7-Tesla MRI. Two neuroradiologist separately evaluated the visual rating scale of iron deposition signs in basal ganglia.

Results: The newly developed basal ganglia sign scoring scale showed high sensitivity and excellent specificity for diagnosis of early-stage PD.

Impact: The distribution characteristics of iron deposition in basal ganglia might be a promising marker of the diagnosis of early-stage PD.

Keywords: Parkinson's Disease, Parkinson's Disease, Neuromelanin contrast MRI, AI, clinical trial, longitudinal

Motivation: Neuromelanin (NM) MRI is a proposed biomarker of dopaminergic neurodegeneration in the substantia nigra pars compacta (SNpc).

Goal(s): To automate post-hoc analysis on NM-MRI data acquired from a large multi-center clinical trial. 

Approach: A deep dynamic u-net model was built to segment the SNpc and the background region automatically and was used to analyze a large multi-center longitudinal PD dataset. 

Results: Within-subject change from baseline effects were significant at the population level for SNpc volume (left and right). These results suggest an AI-derived SNpc volume, estimating the atrophied hyperintense region on an NM-MRI scan, is a viable marker of disease progression in PD.

Impact: The dynamic AI model on NM-MRI trained/tested on multiple sites/scanners accurately and robustly delineates the SNpc and may have applicability in trials where NM-MRI is used as a marker of nigrostriatal degeneration.

Keywords: Parkinson's Disease, Parkinson's Disease, Normal aging; Gradient; Quantitative susceptibility mapping; Nigrostriatal

Motivation: The gradient characterization of microenvironment in nigrostriatal system is key to understanding striatal dysfunction in PD.

Goal(s): To investigate the gradients of neurodegeneration in nigrostriatal system in normal aging and PD.

Approach: Quantitative susceptibility mapping (QSM) and spatial method were used to detect the spatial gradient of iron deposition in healthy young people, normal elderly and PD in vivo.

Results: During normal aging, iron deposition was significant in almost all segments of the striatum, and iron content was even higher in some segments of the caudate than in PD. Iron deposition in PD is mainly in the central substantia nigra.

Impact: The present study reveals the spatial gradient of iron deposition in the nigrostriatal system in normal aging and PD, providing more subtle and profound insights into the pathological changes in subcortical nuclei during neurodegeneration.

Keywords: Parkinson's Disease, Parkinson's Disease, neuromelanin

Motivation: Differential diagnosis of parkinsonism is difficult in early stage. Neuromelanin of SN plays an important role in the development of PD, PSP and MSA with iron.

Goal(s): To find more neuroimage biomarkers to differentiate early parkinsonism by altered neuromelanin and iron in the level of SN subregions.

Approach: We applied the 3D-ME-MTC-NM sequence to differentiate subregions based on the distribution of neuromelanin and iron, measured the volume, CR and/or susceptibility of neuromelanin accumulation, iron deposition and overlap regions.

Results: The susceptibility of overlap region increased in early PSP, while no significant difference was seen between PD and MSA. 

Impact: The alteration of susceptibility in the overlap region may be helpful to identify characteristic changes in parkinsonism via different pathological proteins.

Keywords: Parkinson's Disease, Parkinson's Disease

Motivation: Susceptibility map-weighted imaging (SMWI) of the substantia nigra is a novel MRI sequence that has the potential to aid the diagnosis of patients with clinically uncertain parkinsonian syndromes (CUPS).

Goal(s): To investigate the accuracy of AI-driven automated SMWI software in a clinically relevant population.

Approach: We acquired SMWI in patients who received a dopamine transporter (DAT)-SPECT because of CUPS. The diagnostic software (Heuron IPD) results were compared with the DAT-SPECT results as a reference. 

Results: Preliminary analysis of 120 patients demonstrated an accuracy of 88% for the diagnostic software to differentiate neurodegenerative from non-neurodegenerative parkinsonism in patients who presented with CUPS.

Impact: Susceptibility map-weighted imaging (SMWI) demonstrates a diagnostic accuracy of 88% in patients with clinically uncertain parkinsonian syndromes (CUPS). These findings are promising for the use of SWMI as diagnostic marker and warrant prospective studies in CUPS patients.

Keywords: Parkinson's Disease, Arterial spin labelling, Neurodegenration, Neuroscience

Motivation: Investigating cerebral blood flow (CBF) alterations between idiopathic REM sleep behavior disorder (iRBD) and Parkinson's disease (PD) using arterial spin labeling (ASL) can provide crucial insights into the shared neurobiological underpinnings of these conditions, facilitating effective disease management and treatment.

Goal(s): Analyzing the cerebral blood flow (CBF) variations and CBF-connectivity and evaluating their diagnostic utility.

Approach: By employing ASL, we conducted a detailed analysis of CBF variations and constructed a CBF-connectivity network. 

Results: Observed increased CBF in PD vs iRBD in specific regions, as well as elevated connectivity.

Impact: The present study provides objective biomarkers for the progression of iRBD and PD through the study of cerebral perfusion. It also provides direction for adjunctive treatment of microcirculatory abnormalities to further inhibit the progression of associated dysfunction.

Keywords: Parkinson's Disease, Quantitative Imaging, MEGA-PRESS

Motivation: Altered λ-aminobutyric acid (GABA) levels have been observed in Parkinson's disease (PD), and these discrepancies may depend in differences of clinical symptoms. However, the role o GABA and glutamate concentrations of depression in Parkinson's disease (DPD) remains unexplored.

Goal(s): To explore the changes of GABA+, glutamate and glutamate (Glx) in DPD.

Approach: We utilized MEGA-PRESS to measure GABA+ and Glx levels in the medial frontal cortex (MFC) and thalamus among PD patients with and without depression, along with aged-matched healthy participants.

Results: GABA+ levels were found to be elevated within MFC in individuals with DPD, independent of the presence of Parkinson’s disease.

Impact: These findings suggest that GABAergic alterations in specific brain regions might be linked to the clinical symptoms of PD. Modulating GABAergic function could be a potential approach for treating DPD.

Keywords: Parkinson's Disease, Diffusion Tensor Imaging

Motivation: The genetic variant rs9638616, is associated with Parkinson’s Disease (PD) risk in Asian populations.

Goal(s): To provide insight into the neural correlates of rs9638616 in Asian PD, to inform risk models and idiopathic PD aetiology.

Approach: Using imaging and genotyping data from 116 early-PD patients and 57 controls of Chinese ethnicity, we performed voxelwise analyses to assess rs9638616 T-allele association with brain microstructure, morphology and function.

Results: Our results suggest that rs9638616 may confer PD risk in Asian cohorts via lower white matter fractional anisotropy and reduced supplementary motor area functional connectivity.

Impact: In an imaging-genetics analysis, the Asian PD risk variant rs9638616 was associated with altered brain structure/function. This rationalises rs9638616’s role in PD risk, and may be useful in improving PD stratification and risk modeling.

Keywords: Parkinson's Disease, Parkinson's Disease, 7T MRI; dorsal nigral hyperintensity

Motivation: The dorsal nigral hyperintensity (DNH) abnormality is a characteristic feature of PD and 7T MRI has proved useful for its  visualization.

Goal(s): To investigate the diagnostic efficiency of DNH abnormality at different stages of PD and in atypical parkinsonisms using 7T MRI.

Approach: PD, RBD, MSA-P, MSA-C, and PSP patients and controls underwent 7T T2* with DNH abnormality assessed for diagnostic performance. R2* mapping and principal component analysis were performed in substantia nigra.

Results: MSA-C and RBD demonstrated higher preservation rate of DNH than PD, MSA-P, and PSP. DNH scoring criteria proved an optimal diagnostic method of PD, RBD, MSA-P, MSA-C, and PSP.

Impact: MSA-C and RBD patients had higher dorsal nigral hyperintensity (DNH) preservation rate compared with PD, MSA-P, and PSP. The DNH scoring criteria proved an optimal diagnostic method of PD, RBD, MSA-P, MSA-C, and PSP.

Keywords: Parkinson's Disease, Parkinson's Disease

Motivation: SMWI is an advanced SWI method capable of detecting nigral hyperintensity in the substantia nigra. Due to the long scan time, a reduced FOV sequence was proposed to decrease the scan time from 4min 15sec to 2min 45sec, along with the application of denoising techniques. However, when evaluated with the original classifier, the results showed changes, reporting increased FN, which may be a problem in clinic.

Goal(s): Maintaining diagnostic results for the reduced FOV with denoised SMWI images.

Approach: Optimizing classifier to denoised FOV-simulated SMWI images.

Results: The diagnostic result of denoised FOV 64.5% SMWI images is comparable to FOV 100% SMWI images.

Impact:  The diagnostic result of denoised FOV 64.5% SMWI images is comparable to FOV 100% SMWI images with the optimizing classifier based on denoised FOV-simulated SMWI images.