Correlated regions of cerebral blood flow with clinical parameters in Parkinson’s disease; comparison using ‘Anatomy’ and ‘Talairach Daemon’ software

Damaged Insula Network Contributes to Depression in Parkinson's Disease

BACKGROUND

Depression is common in patients with Parkinson's disease (PD). Our previous studies suggest that depressed PD patients have altered insula structures. It is, however, still unknown whether the altered structures cause disruption of insula functional networks, further contributing to depression in PD.

METHODS

In the present study, 17 depressed PD patients, 17 non-depressed PD patients, and 17 normal controls were enrolled. All subjects went through neurological and psychiatric clinical assessments. Resting-state functional magnetic resonance imaging and seed-based insula functional analyses were performed to examine the insula functional connectivity alterations in PD patients.

RESULTS

We found that compared with normal controls, PD patients exhibited significantly decreased insula functional connectivity widely across the whole brain. Compared with non-depressed PD patients, depressed patients showed further decreased functional connectivity in the middle frontal gyrus and inferior parietal lobe. Furthermore, connectivity between the left anterior insula and middle frontal gyrus was positively correlated with the cognitive scale score.

CONCLUSION

These results suggest that insula networks were severely damaged in PD patients, and that the disrupted connection between the salience network and executive control network might contribute to depression in PD.

Early diagnosis of Alzheimer's disease and Parkinson's disease associated with dementia using cerebral perfusion SPECT

BACKGROUND

Since patterns of cognitive dysfunction in mild Parkinson's disease associated with dementia (PDD) are similar to those in mild Alzheimer's disease (AD), it is difficult to accurately differentiate between these two types of dementia in their early phases using neuropsychological tests. The purpose of the current study was to investigate differences in cerebral perfusion patterns of patients with AD and PDD at the earliest stages using single photon emission computed tomography (SPECT).

METHODS

We consecutively recruited 31 patients with mild PDD, 32 patients with mild probable AD and 33 age-matched healthy subjects. All subjects underwent (99m)Tc-hexamethylpropyleneamine oxime perfusion SPECT and completed general neuropsychological tests.

RESULTS

We found that both mild PDD and AD patients showed distinct hypoperfusion in frontal, parietal and temporal regions, compared with healthy subjects. More importantly, hypoperfusion in occipital and cerebellar regions was observed only in mild PDD.

CONCLUSION

The observation of a significant decrease in cerebral perfusion in occipital and cerebellar regions in patients with mild PDD is likely useful to differentiate between PDD and AD at the earliest stages.

Image coregistration: quantitative processing framework for the assessment of brain lesions

The quantitative, multiparametric assessment of brain lesions requires coregistering different parameters derived from MRI sequences. This will be followed by analysis of the voxel values of the ROI within the sequences and calculated parametric maps, and deriving multiparametric models to classify imaging data. There is a need for an intuitive, automated quantitative processing framework that is generalized and adaptable to different clinical and research questions. As such flexible frameworks have not been previously described, we proceeded to construct a quantitative post-processing framework with commonly available software components. Matlab was chosen as the programming/integration environment, and SPM was chosen as the coregistration component. Matlab routines were created to extract and concatenate the coregistration transforms, take the coregistered MRI sequences as inputs to the process, allow specification of the ROI, and store the voxel values to the database for statistical analysis. The functionality of the framework was validated using brain tumor MRI cases. The implementation of this quantitative post-processing framework enables intuitive creation of multiple parameters for each voxel, facilitating near real-time in-depth voxel-wise analysis. Our initial empirical evaluation of the framework is an increased usage of analysis requiring post-processing and increased number of simultaneous research activities by clinicians and researchers with non-technical backgrounds. We show that common software components can be utilized to implement an intuitive real-time quantitative post-processing framework, resulting in improved scalability and increased adoption of post-processing needed to answer important diagnostic questions.

Significant correlation between cerebral hypoperfusion and neuropsychological assessment scores of patients with mild cognitive impairment

PURPOSE

The regions of significant correlation between cerebral hypoperfusion and neuropsychological assessment scores were evaluated using (99m)Tc-HMPAO SPECT in patients with mild cognitive impairment (MCI) on the basis of its three subtypes, namely, single-domain amnestic MCI (aMCI-s), multiple-domain amnestic MCI (aMCI-m), and nonamnestic MCI (naMCI), following which comparisons were made among the three subtypes of MCI.

METHODS

Regions of hypoperfusion were determined by comparing the three groups with the normal group. Neuropsychological assessment included tests to evaluate attention, language and related functions, visuospatial function, memory, frontal-executive function, and mini-mental state examination and depression scores. Regions of cerebral hypoperfusion were identified by comparing the three groups of MCI patients with the normal group (P<0.05, uncorrected). One-way analysis of variance was used to examine differences across groups, and post-hoc a-priori pairwise comparisons were used for between-group analyses. The regions of significant correlation, related to the neuropsychological assessment scores, were identified by simple regression of SPM8 within the masking image of the area of cerebral hypoperfusion (P<0.05, uncorrected).

RESULTS

The regions of cerebral hypoperfusion were identified by comparing members of the normal group with patients with aMCI-s, aMCI-m, and naMCI. The patients with aMCI-m showed significant correlation with all neuropsychological assessment scores, but the patients with aMCI-s correlated with four neuropsychological assessment scores of attention. The patients with naMCI revealed no significantly correlated regions (P<0.05, uncorrected). The regions that correlated with neuropsychological assessment scores in patients with aMCI-s were very small compared with those in patients with aMCI-m. The correlated regions in patients with aMCI-m were restricted to the left cerebrum and cerebellum. Brain areas showed significant correlation between neuropsychological assessment scores and hypoperfusion, which was evaluated by simple regression with the threshold being P less than 0.05, uncorrected. Rey complex figure test 20 min delayed, Korean-color word stroop test word reading, and Korean mini-mental state examination scores correlated more strongly with cerebral hypoperfusion compared with other assessment scores.

CONCLUSION

The specific pattern of significant correlation of cerebral hypoperfusion with neuropsychological assessment scores was classified into three subtypes (aMCI-s, aMCI-m, and naMCI) according to the patients' deficits in their cognitive domains.