Jiuquan Zhang

Characterizing iron deposition in Parkinson's disease using susceptibility-weighted imaging: an in vivo MR study.

Brain-iron deposition has been proposed to play an important role in the pathophysiology of Parkinsons disease (PD). The aim of this study was to evaluate the feasibility of characterizing iron deposition in PD using susceptibility-weighted imaging (SWI), and to investigate the correlation of brain-iron accumulation with the clinical status in patients with PD. Forty patients with PD without dementia and 26 age- and sex-matched healthy controls underwent high-resolution susceptibility-weighted magnetic resonance (MR) imaging. The phase shift values of the bilateral red nucleus (RN), substantia nigra (SN), caudate nucleus (CA), globus pallidus (GP), putamen (PU), thalamus (TH) and frontal white matter (FWM) were examined for their relationship with the clinical status. The iron concentrations of the regions involved in PD, such as the SN, increased more significantly, while those in other regions of interest (ROI) did not elevate significantly. No correlation between the increase of the iron concentrations of the SN and duration of PD was observed. PD, however, was closely associated with the Unified Parkinsons Disease Rating Scale motor score (UPDRS-III). No significant differences were found between earlier-onset and later-onset PD patients in terms of the iron concentrations of the SN. Brain-iron concentration can be evaluated by SWI. Also, the brain-iron concentration in the SN correlated with UPDRS motor score, indicating that iron concentration can function as an in vivo biomarker to objectively evaluate the status of PD.

The correlation between apparent diffusion coefficient and tumor cellularity in patients: a meta-analysis.

Objective To perform a meta-analysis exploring the correlation between the apparent diffusion coefficient (ADC) and tumor cellularity in patients. Materials and Methods We searched medical and scientific literature databases for studies discussing the correlation between the ADC and tumor cellularity in patients. Only studies that were published in English or Chinese prior to November 2012 were considered for inclusion. Summary correlation coefficient (r) values were extracted from each study, and 95% confidence intervals (CIs) were calculated. Sensitivity and subgroup analyses were performed to investigate potential heterogeneity. Results Of 189 studies, 28 were included in the meta-analysis, comprising 729 patients. The pooled r for all studies was −0.57 (95% CI: −0.62, −0.52), indicating notable heterogeneity (P<0.001). After the sensitivity analysis, two studies were excluded, and the pooled r was −0.61 (95% CI: −0.66, −0.56) and was not significantly heterogeneous (P = 0.127). Regarding tumor type subgroup analysis, there were sufficient data to support a strong negative correlation between the ADC and cellularity for brain tumors. There was no notable evidence of publication bias. Conclusions There is a strong negative correlation between the ADC and tumor cellularity in patients, particularly in the brain. However, larger, prospective studies are warranted to validate these findings in other cancer types.

Voxel-based morphometry of the visual-related cortex in primary open angle glaucoma.

Purpose: To study changes in the morphometric characteristics of the whole brain visual-related cortex in various stages of primary open angle glaucoma (POAG) in vivo. Materials and methods: Thirty POAG patients (nine early stage cases and 21 advanced-late stage cases) and 30 gender-, education-, and age-matched healthy controls were enrolled in the study. Image data were obtained with a T1 weighted three-dimensional magnetization prepared rapid acquisition gradient echo sequence (T1WI 3D MP RAGE). Voxel-based morphometry (VBM) analysis was used to assess regional differences in gray matter (GM) densities on T1WI 3D MP RAGE scans of patients versus controls. Results: Compared with controls, brain regions with GM density changes were not found in the early stage of POAG patients but were found in the advanced-late stage of POAG patients. These changes with GM density reduction were mainly located in the bilateral primary visual cortex (BA17 and BA18), bilateral paracentral lobule (BA5), right precentral gyrus (BA6), right middle frontal gyrus (BA9), right inferior temporal gyrus (BA20), right angular gyrus (BA39), left praecuneus (BA7), left middle temporal gyrus (BA21), and superior temporal gyrus (BA22). Conversely, patients showed increased GM density in BA39 near the most damaged regions. In addition, in the advanced-late stage of POAG, some reduced GM density areas were related to binocular mean defect (MD) and disease duration (ranging from r = −0.761 to r = –0.458). Conclusions: Our results suggest that there are different types of pathogenesis at different stages of POAG. Atrophy and degeneration of the visual-related cortex existed in the dorsal and ventral visual pathways in the advanced-late stage of POAG but were not found in the early stage of POAG using VBM. Such GM density changes are likely associated with the pathogenesis of POAG.

Specific frequency band of amplitude low-frequency fluctuation predicts Parkinson's disease

Resting-state functional magnetic resonance imaging (RS-fMRI) has been considered for development as a biomarker and analytical tool for evaluation of Parkinsons disease (PD). Here we utilized analysis of the amplitude low-frequency fluctuations (ALFF) to determine changes in intrinsic neural oscillations in 72 patients with PD. Two different frequency bands (slow-5: 0.01-0.027 Hz; slow-4: 0.027-0.073 Hz) were analyzed. In the slow-5 band, PD patients compared with controls had increased ALFF values mainly in the caudate and several temporal regions, as well as decreased ALFF values in the cerebellum and the parieto-temporo-occipital cortex. Additionally, in the slow-4 band, PD patients relative to controls exhibited reduced ALFF value in the thalamus, cerebellum, and several occipital regions. Together, our data demonstrate that PD patients have widespread abnormal intrinsic neural oscillations in the corticostriatal network in line with the pathophysiology of PD, and further suggest that the abnormalities are dependent on specific frequency bands. Thus, frequency domain analyses of resting state BOLD signals may provide a useful means to study the pathophysiology of PD and the physiology of the brains dopaminergic pathways.

Akinetic-rigid and tremor-dominant Parkinson's disease patients show different patterns of intrinsic brain activity

BACKGROUND Parkinsons disease (PD) is a surprisingly heterogeneous neurodegenerative disorder. It is well established that different subtypes of PD present with different clinical courses and prognoses. However, the neural mechanism underlying these disparate presentations is uncertain. METHODS Here we used resting-state fMRI (rs-fMRI) and the regional homogeneity (ReHo) method to determine neural activity patterns in the two main clinical subgroups of PD (akinetic-rigid and tremor-dominant). RESULTS Compared with healthy controls, akinetic-rigid (AR) subjects had increased ReHo mainly in right amygdala, left putamen, bilateral angular gyrus, bilateral medial prefrontal cortex (MPFC), and decreased ReHo in left post cingulate gyrus/precuneus (PCC/PCu) and bilateral thalamus. In contrast, tremor-dominant (TD) patients showed higher ReHo mostly in bilateral angular gyrus, left PCC, cerebellum_crus1, and cerebellum_6, while ReHo was decreased in right putamen, primary sensory cortex (S1), vermis_3, and cerebellum_4_5. These results indicate that AR and TD subgroups both represent altered spontaneous neural activity in default-mode regions and striatum, and AR subjects exhibit more changed neural activity in the mesolimbic cortex (amygdala) but TD in the cerebellar regions. Of note, direct comparison of the two subgroups revealed a distinct ReHo pattern primarily located in the striatal-thalamo-cortical (STC) and cerebello-thalamo-cortical (CTC) loops. CONCLUSION Overall, our findings highlight the involvement of default mode network (DMN) and STC circuit both in AR and TD subtypes, but also underscore the importance of integrating mesolimbic-striatal and CTC loops in understanding neural systems of akinesia and rigidity, as well as resting tremor in PD. This study provides improved understanding of the pathophysiological models of different subtypes of PD.

Meta‐analysis of diffusion‐weighted MRI in the differential diagnosis of lung lesions

To perform a meta‐analysis to evaluate the diagnostic performance of the diffusion‐weighted imaging (DWI) technique in differentiating malignant from benign lung lesions.

Gray matter volume abnormalities in type 2 diabetes mellitus with and without mild cognitive impairment.

This study sought to evaluate the potential brain gray matter (GM) volume changes that occur with the transition from normal cognition to mild cognitive impairment (MCI) in patients with type 2 diabetes mellitus (T2DM) using voxel-based morphometry (VBM). VBM analyses of brain GM based on magnetic resonance imaging (MRI) data were performed on 28 T2DM patients with MCI, 25 T2DM patients without MCI, 28 MCI patients and 29 healthy controls (HC). Compared with the HC, the T2DM patients both with and without MCI showed significantly decreased total GM volume. Furthermore, the VBM results indicated that the T2DM patients without MCI exhibited extensively decreased GM volume compared with the HC in certain brain regions, including the superior and middle temporal gyrus (MTG), the superior and medial frontal gyrus and the middle occipital gyrus. In addition to more extensive GM atrophy in the aforementioned brain regions, the medial temporal lobe also exhibited GM loss in the T2DM patients with MCI. Furthermore, relative to the patients without MCI, only the left MTG exhibited a lower GM volume in the T2DM patients with MCI, which was positively correlated with the total MoCA score (r=0.699, P<0.01). Finally, relative to MCI, the left MTG atrophy was also found in the T2DM patients with MCI. Our findings suggest that MTG atrophy was associated with an increased risk for MCI in T2DM patients. The brain structural changes in many brain regions may underlie the transition from normal cognition to MCI in T2DM patients.

Regional alterations in cortical thickness and white matter integrity in amyotrophic lateral sclerosis

Abstract Previous neuroimaging studies have revealed that both gray matter (GM) and white matter (WM) are altered in several morphological aspects in amyotrophic lateral sclerosis (ALS). However, the relations between GM and WM measures and their contributions to clinical features remain in doubt. In this study, we acquired high-resolution diffusion tensor imaging along with structural magnetic resonance imaging data on 20 patients with clinical evidence of ALS and 21 matched healthy controls. WM microstructural metrics and cortical thickness were measured to characterize the whole brain WM and GM degenerative patterns. Probabilistic diffusion tractography was used to reconstruct the tracts from the WM regions characterized by fractional anisotropy (FA) decrease in patients. Decreased FA and increased radial diffusivity was observed in WM regions of the bilateral corticospinal tracts (CST) and callosal motor fibers in the ALS patients, while the superior longitudinal fasciculus exhibited a changing trend. Cortical thinning was found in the anatomically congruent regions, including the motor-related cortices (i.e., bilateral precentral gyri, dorsal premotor cortices, and left supplementary motor area), prefrontal and occipito-parietal regions. However, there was no significant relationship between FA reduction and cortical thinning. Finally, patients with faster clinical progression showed more severe cortical thinning of the left precentral gyrus and FA reduction of the left CST. Together, these findings suggest that ALS is multisystem degeneration involving both the widespread cortices and the underlying WM fibers. GM and WM changes might play distinct roles in the disease progression.

Relationship between apparent diffusion coefficient and tumour cellularity in lung cancer.

Background and objective To prospectively investigate the relationship between the apparent diffusion coefficient (ADC) and cellularity in lung cancer. Methods Sixty patients histopathologically confirmed with lung cancer (41 men, 19 women) underwent diffusion-weighted magnetic resonance imaging of the chest (with b values of 50 and 1000 s/mm2). The median mean ADC (ADCmean) value and median minimum ADC (ADCmin) value within each primary tumour were calculated and compared with the median nucleo-cytoplasmic ratio (NCR), which was selected to represent the cellularity. The correlation between the NCR and ADCmean/ADCmin was calculated with SPSS 18.0 software. Results The mean ADCmean values, ADCmin values and median NCR were (1.07±0.12)×10−3 mm2/s, (0.86±0.14)×10−3 mm2/s, and (14.9±2.6) %, respectively, in adenocarcinoma; (0.88±0.10)×10−3 mm2/s, (0.73±0.12)×10−3 mm2/s, and (20.6±4.4) %, respectively, in squamous cell carcinoma; and (0.89±0.13)×10−3 mm2/s, (0.67±0.13)×10−3 mm2/s, and (18.3±3.5) %, respectively in small cell lung cancer. The NCR of squamous cell carcinoma and small cell lung cancer is greater than that of adenocarcinoma (P<0.01 and P = 0.002, respectively). There was an inverse relationship between ADCmean/NCR and ADCmin/NCR (r = −0.60, P = 0.001 and r = −0.47, P<0.001, respectively). Conclusion There is a significant inverse relationship between tumour cellularity and ADC in lung cancer. However, tumour cellularity most likely is not the sole determinant of the ADC.

Cortical Gyrification Reductions and Subcortical Atrophy in Parkinson's Disease

Parkinsons disease (PD) is a neurodegenerative disorder characterized by both motor and non‐motor symptoms. Previous morphometric studies of PD were mainly conducted by measuring gray matter volume and cortical thickness, and little attention has been paid to the morphology of the cortical surface.