hsin-yi lai

Diffusion along perivascular spaces as marker for impairment of glymphatic system in PD

The brain glymphatic system is involved in the clearance of misfolding α-synuclein, the impaired glymphatic system may contribute to the progression of Parkinson’s disease (PD). We aimed to analyze the diffusion tensor image along the perivascular space (DTI-ALPS) and perivascular space (PVS) burden to reveal the relationship between the glymphatic system and PD. A cross-sectional study using a 7 T MRI of 76 PD patients and 48 controls was performed to evaluate the brain’s glymphatic system. The DTI-ALPS and PVS burden in basal ganglia were calculated. Correlation analyses were conducted between DTI-ALPS, PVS burden and clinical features. We detected lower DTI-ALPS in the PD subgroup relative to controls, and the differences were more pronounced in patients with Hoehn & Yahr stage greater than two. The decreased DTI-ALPS was only evident in the left hemisphere in patients in the early stage but involved both hemispheres in more advanced PD patients. Decreased DTI-ALPS were also correlated with longer disease duration, higher Unified Parkinson’s Disease Rating Scale motor score (UPDRS III) and UPDRS total scores, as well as higher levodopa equivalent daily dose. Moreover, the decreased DTI-ALPS correlated with increased PVS burden, and both indexes correlated with PD disease severity. This study demonstrated decreased DTI-ALPS in PD, which might initiate from the left hemisphere and progressively involve right hemisphere with the disease progression. Decreased DTI-ALPS index correlated with increased PVS burden, indicating that both metrics could provide supporting evidence of an impaired glymphatic system. MRI evaluation of the PVS burden and diffusion along PVS are potential imaging biomarkers for PD for disease progression.

https://www.nature.com/articles/s41531-022-00437-1

https://mp.weixin.qq.com/s/3r5MRGYZCfx2RTHQ2qIHyQ

Shen, T., Yue, Y., Ba, F. et al. Diffusion along perivascular spaces as marker for impairment of glymphatic system in Parkinson’s disease. npj Parkinsons Dis.8, 174 (2022) https://doi.org/10.1038/s41531-022-00437

2021-Ting SHEN-Diffusion along perivascular spaces as marker for impairment of glymphatic system in Parkinson’s disease.pdf

The role of brain perivascular space burden in early-stage Parkinson’s disease

Perivascular space (PVS) is associated with neurodegenerative diseases, while its effect on Parkinson’s disease (PD) remains unclear. We aimed to investigate the clinical and neuroimaging significance of PVS in basal ganglia (BG) and midbrain in early-stage PD. We recruited 40 early-stage PD patients and 41 healthy controls (HCs). Both PVS number and volume were calculated to evaluate PVS burden on 7 T magnetic resonance imaging images. We compared PVS burden between PD and HC, and conducted partial correlation analysis between PVS burden and clinical and imaging features. PD patients had a significantly more serious PVS burden in BG and midbrain, and the PVS number in BG was significantly correlated to the PD disease severity and L-dopa equivalent dosage. The fractional anisotropy and mean diffusivity values of certain subcortical nuclei and white matter fibers within or nearby the BG and midbrain were significantly correlated with the ipsilateral PVS burden indexes. Regarding to the midbrain, the difference between bilateral PVS burden was, respectively, correlated to the difference between fiber counts of white fiber tract passing through bilateral substantia nigra in PD. Our study suggests that PVS burden indexes in BG are candidate biomarkers to evaluate PD motor symptom severity and aid in predicting medication dosage. And our findings also highlight the potential correlations between PVS burden and both grey and white matter microstructures.

https://www.nature.com/articles/s41531-021-00155-0

https://mp.weixin.qq.com/s/s_RGCHVoFIGCGey0j0eG-A

Shen, T., Yue, Y., Zhao, S. et al. The role of brain perivascular space burden in early-stage Parkinson’s disease. npj Parkinsons Dis. 7, 12 (2021). https://doi.org/10.1038/s41531-021-00155-0

2021-Ting SHEN-The role of brain perivascular space burden in early-stage Parkinson’s disease.pdf

Exploring structural and functional alterations in drug-naïve obsessive-compulsive disorder patients

Background: Brain structural and functional alterations have been reported in obsessive-compulsive disorder (OCD) patients; however, these findings were inconsistent across studies due to several limitations, including small sample sizes, different inclusion/exclusion criteria, varied demographic characteristics and symptom dimensions, comorbidity, and medication status. Prominent and replicable neuroimaging biomarkers remain to be discovered.

Methods: This study explored the gray matter structure, neural activity, and white matter microstructure differences in 40 drug-naïve OCD patients and 57 matched healthy controls using ultrahigh field 7.0 T multimodal magnetic resonance imaging, which increased the spatial resolution and detection power. We also evaluated correlations among different modalities, imaging features and clinical symptoms.

Results: Drug-naïve OCD patients exhibited significantly increased gray matter volume in the frontal cortex, especially in the orbitofrontal cortex, as well as volumetric reduction in the temporal lobe, occipital lobe and cerebellum. Increased neural activities were observed in the cingulate gyri and precuneus. Increased temporal-middle cingulate and posterior cingulate-precuneus functional connectivities and decreased frontal-middle cingulate connectivity were further detected. Decreased fractional anisotropy values were found in the cingulum-hippocampus gyrus and inferior fronto-occipital fascicle in OCD patients. Moreover, significantly altered imaging features were related to OCD symptom severity. Altered functional and structural neural connectivity might influence compulsive and obsessive features, respectively.

Conclusions: Altered structure and function of the classical cortico-striato-thalamo-cortical circuit, limbic system, default mode network, visual, language and sensorimotor networks play important roles in the neurophysiology of OCD.

Keywords: Magnetic resonance imaging; Multimodal; Obsessive-compulsive disorder; Ultrahigh field.

https://www.sciencedirect.com/science/article/pii/S1876201822004294?via%3Dihub

https://mp.weixin.qq.com/s/sPTC_FLYJ85o-vvLjz5kvg

Wenxin Tang, Ting Shen, Yueqi Huang, Wenjing Zhu, Shujun You, Cheng Zhu, Luyue Zhang, Jiehua Ma, Yiquan Wang, Jingping Zhao, Tao Li, Hsin-Yi Lai, Exploring structural and functional alterations in drug-naïve obsessive-compulsive disorder patients: An ultrahigh field multimodal MRI study, Asian Journal of Psychiatry, Volume 81, 2023, 103431, ISSN 1876-2018, https://doi.org/10.1016/j.ajp.2022.103431.

2023-Wenxin TANG- Exploring structural and functional alterations in drug-naïve obsessive-compulsive disorder patients An ultrahigh field multimodal MRI study.pdf

Normal-sized basal ganglia perivascular space related to motor phenotype in Parkinson freezers

Changes in basal ganglia (BG) perivascular spaces (PVSs) are related to motor and cognitive behaviors in Parkinson's disease (PD). However, the correlation between the initial motor phenotype and PVSs distribution/burden in PD freezing of gait (FOG) remains unclear. In addition, the normal-sized PVSs (nPVSs) have not been well-studied. With high-resolution 7T-MRI, we studied nPVSs burden in BG, thalamus, midbrain and centrum semiovale. The numbers and volume of nPVSs were assessed in 10 healthy controls, 10 PD patients without FOG, 20 with FOG [10 tremor dominant (TD), 10 non-TD subtype]. Correlation analyses were further performed in relation to clinical parameters. In this proof of concept study, we found that the nPVS burden of bilateral and right BG were significantly higher in freezers. A negative correlation existed between the tremor score and BG-nPVSs count. A positive correlation existed between the levodopa equivalent daily dose and BG-nPVSs count. The nPVS burden correlated with the progression to FOG in PD, but the distribution and burden of nPVS differ in TD vs. non-TD subtypes. High resolution 7T-MRI is a sensitive and reliable tool to evaluate BG-nPVS, and may be a useful imaging marker for predicting gait impairment that may evolve into FOG in PD.

https://pubmed.ncbi.nlm.nih.gov/34314380/

https://mp.weixin.qq.com/s/sB5Noib9VL2bCrhUw7r-TQ

Lv W, Yue Y, Shen T, Hu X, Chen L, Xie F, Zhang W, Zhang B, Gui Y, Lai HY, Ba F. Normal-sized basal ganglia perivascular space related to motor phenotype in Parkinson freezers. Aging (Albany NY). 2021 Jul 27;13(14):18912-18923. doi: 10.18632/aging.203343. Epub 2021 Jul 27. PMID: 34314380; PMCID: PMC8351731.

2021-Wen LV- Normal-sized basal ganglia perivascular space related to motor phenotype in Parkinson freezers.pdf

7T MRI with post-processing for the presurgical evaluation of pharmacoresistant focal epilepsy

Background: We aimed to evaluate the diagnostic yield of seven-tesla (7T) magnetic resonance imaging (MRI) with post-processing of three-dimensional (3D) T1-weighted (T1W) images by the morphometric analysis program (MAP) in epilepsy surgical candidates whose 3T MRI results were inconclusive or negative.

Methods: We recruited 35 patients with pharmacoresistant focal epilepsy. A multidisciplinary team including an experienced neuroradiologist evaluated their seizure semiology, video-electroencephalography data, 3T MRI and post-processing results, and co-registered FDG-PET. Eleven patients had suspicious lesions on 3T MRI and the other 24 patients were strictly MRI-negative. 7T MRI evaluation was then performed to aid clinical decision. Among patients with pathologically proven focal cortical dysplasia (FCD) type II, signs of FCD were retrospectively evaluated in each MRI sequence (T1W, T2W, and FLAIR), and positive rates were analyzed in each MAP feature map (junction, extension, and thickness).

Results: 7T MRI evaluation confirmed the lesion in nine of the 11 (81.8%) patients with suspicious lesions on 3T MRI. It also revealed new lesions in four of the 24 (16.7%) strictly MRI-negative patients. Histopathology showed FCD type II in 11 of the 13 (84.6%) 7T MRI-positive cases. Unexpectedly, three of the four newly identified FCD lesions were located in the posterior quadrant. Blurred gray-white boundary was the most frequently observed sign of FCD, appearing on 7T T1W image in all cases and on T2W and FLAIR images in only about half cases. The 7T junction map successfully detected FCD (10/11) in more cases than the extension (1/11) and thickness (0/11) maps. The 3D T1W images at 7T exhibited superior cerebral gray-white matter contrast, more obviously blurred gray-white boundary of FCD, and larger and brighter positive zones in post-processing than 3T T1W images.

Conclusion: 7T MRI with post-processing can enhance the detection of subtle epileptogenic lesions for MRI-negative epilepsy and may optimize surgical strategies for patients with focal epilepsy.

https://pubmed.ncbi.nlm.nih.gov/34163537/

https://mp.weixin.qq.com/s/7x73Is4bKadfHAS2GIrrIw

Chen C, Xie JJ, Ding F, Jiang YS, Jin B, Wang S, Ding Y, Li H, Jiang B, Zhu JM, Ding MP, Chen Z, Wu ZY, Zhang BR, Hsu YC, Lai HY, Wang S. 7T MRI with post-processing for the presurgical evaluation of pharmacoresistant focal epilepsy. Ther Adv Neurol Disord. 2021 Jun 8;14:17562864211021181. doi: 10.1177/17562864211021181. PMID: 34163537; PMCID: PMC8191069.

2021 - Cong CHEN - 7T MRI with post-processing for the presurgical evaluation of pharmacoresistant focal epilepsy.pdf