Reproducibility of diffusion tensor image analysis along the perivascular space (DTI-ALPS) for evaluating interstitial fluid diffusivity and glymphatic function: CHanges in Alps index on Multiple conditiON acquIsition eXperiment (CHAMONIX) study

Abstract Purpose The diffusion tensor image analysis along the perivascular space (DTI-ALPS) method was developed to evaluate the brain’s glymphatic function or interstitial fluid dynamics. This study aimed to evaluate the reproducibility of the DTI-ALPS method and the effect of modifications in the imaging method and data evaluation. Materials and methods Seven healthy volunteers were enrolled in this study. Image acquisition was performed for this test–retest study using a fixed imaging sequence and modified imaging methods which included the placement of region of interest (ROI), imaging plane, head position, averaging, number of motion-proving gradients, echo time (TE), and a different scanner. The ALPS-index values were evaluated for the change of conditions listed above. Results This test–retest study by a fixed imaging sequence showed very high reproducibility (intraclass coefficient = 0.828) for the ALPS-index value. The bilateral ROI placement showed higher reproducibility. The number of averaging and the difference of the scanner did not influence the ALPS-index values. However, modification of the imaging plane and head position impaired reproducibility, and the number of motion-proving gradients affected the ALPS-index value. The ALPS-index values from 12-axis DTI and 3-axis diffusion-weighted image (DWI) showed good correlation (r = 0.86). Also, a shorter TE resulted in a larger value of the ALPS-index. Conclusion ALPS index was robust under the fixed imaging method even when different scanners were used. ALPS index was influenced by the imaging plane, the number of motion-proving gradient axes, and TE in the imaging sequence. These factors should be uniformed in the planning ALPS method studies. The possibility to develop a 3-axis DWI-ALPS method using three axes of the motion-proving gradient was also suggested.

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The Influence of Demographics and Vascular Risk Factors on Glymphatic Function Measured by Diffusion Along Perivascular Space

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.693787 ◽

2021 ◽

Vol 13 ◽

Author(s):

Yao Zhang ◽

Ruiting Zhang ◽

Yongquan Ye ◽

Shuyue Wang ◽

Yeerfan Jiaerken ◽

...

Keyword(s):

Risk Factors ◽

Animal Studies ◽

Diffusion Tensor ◽

Perivascular Space ◽

Brain Diseases ◽

Imaging Method ◽

Imaging Data ◽

Potential Index ◽

The Alps

Assessing glymphatic function using in-vivo imaging method is of great value for understanding its contribution to major brain diseases. In the present study, we aim to validate the association between a variety of risk factors and a potential index of glymphatic function—Diffusion Tensor Image Analysis Along the Perivascular Space (ALPS index). We enrolled 142 subjects from communities and performed multi-modality magnetic resonance imaging scans. The ALPS index was calculated from diffusion tensor imaging data, and its associations with demographic factors, vascular factors were investigated using regression analyses. We found that the ALPS index was negatively associated with age (β = −0.284, p < 0.001). Compared to males, females had significantly higher ALPS index (β = −0.243, p = 0.001). Hypertensive subjects had significantly lower ALPS index compared to non-hypertensive subjects (β = −0.189, p = 0.013). Furthermore, venous disruption could decrease ALPS index (β = −0.215, p = 0.003). In general, our results are in consistent with previous conceptions and results from animal studies about the pathophysiology of glymphatic dysfunction. Future studies utilizing this method should consider introducing the above-mentioned factors as important covariates.

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Evaluation of glymphatic system activity with the diffusion MR technique: diffusion tensor image analysis along the perivascular space (DTI-ALPS) in Alzheimer’s disease cases

Japanese Journal of Radiology ◽

10.1007/s11604-017-0617-z ◽

2017 ◽

Vol 35 (4) ◽

pp. 172-178 ◽

Cited By ~ 51

Author(s):

Toshiaki Taoka ◽

Yoshitaka Masutani ◽

Hisashi Kawai ◽

Toshiki Nakane ◽

Kiwamu Matsuoka ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Image Analysis ◽

Diffusion Tensor ◽

Perivascular Space ◽

Diffusion Tensor Image ◽

System Activity ◽

Glymphatic System ◽

Diffusion Mr

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Glymphatic Dysfunction in Patients With Ischemic Stroke

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.756249 ◽

2021 ◽

Vol 13 ◽

Author(s):

Cheng Hong Toh ◽

Tiing Yee Siow

Keyword(s):

Ischemic Stroke ◽

Linear Regression ◽

Diffusion Tensor ◽

Normal Subjects ◽

Perivascular Space ◽

Cerebral Infarct ◽

Stroke Onset ◽

Analysis Of Covariance ◽

Factors Associated ◽

The Alps

Objectives: Rodent experiments have provided some insight into the changes of glymphatic function in ischemic stroke. The diffusion tensor image analysis along the perivascular space (DTI-ALPS) method offers an opportunity for the noninvasive investigation of the glymphatic system in patients with ischemic stroke. We aimed to investigate the changes of glymphatic function in ischemic stroke and the factors associated with the changes.Materials and Methods: A total of 50 patients (mean age 56.7 years; 30 men) and 44 normal subjects (mean age 53.3 years; 23 men) who had preoperative diffusion-tensor imaging for calculation of the analysis along the perivascular space (ALPS) index were retrospectively included. Information collected from each patient included sex, age, time since stroke onset, infarct location, hemorrhagic change, infarct volume, infarct apparent diffusion coefficient (ADC), infarct fractional anisotropy (FA), and ALPS index of both hemispheres. Interhemispheric differences in ALPS index (infarct side vs. contralateral normal side) were assessed with a paired t-test in all patients. ALPS index was normalized by calculating ALPS ratios (right-to-left and left-to-right) for comparisons between patients and normal subjects. Comparisons of ALPS ratios between patients and normal subjects were performed using analysis of covariance with adjustments for age and sex. Linear regression analyses were performed to identify factors associated with the ALPS index.Results: In patients, the mean ALPS index ipsilateral to infarct was 1.162 ± 0.126, significantly lower (P < 0.001) than that of the contralateral side (1.335 ± 0.160). The right-to-left ALPS index ratio of patients with right cerebral infarct was 0.84 ± 0.08, significantly lower (P < 0.001) than that of normal subjects (0.95 ± 0.07). The left-to-right ALPS ratio of patients with left cerebral infarct was 0.92 ± 0.09, significantly (P < 0.001) lower than that of normal subjects (1.05 ± 0.08). On multiple linear regression analysis, time since stroke onset (β = 0.794, P < 0.001) was the only factor associated with the ALPS index.Conclusion: The ALPS index showed lower values in ischemic stroke suggesting impaired glymphatic function. Following initial impairment, the ALPS index increased with the time since stroke onset, which is suggestive of glymphatic function recovery.

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Deep white matter hyperintensity is associated with the dilation of perivascular space

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x211002279 ◽

2021 ◽

pp. 0271678X2110022

Author(s):

Peiyu Huang ◽

Ruiting Zhang ◽

Yeerfan Jiaerken ◽

Shuyue Wang ◽

Wenke Yu ◽

...

Keyword(s):

Diffusion Tensor Imaging ◽

White Matter ◽

Interstitial Fluid ◽

Diffusion Tensor ◽

Free Water ◽

Perivascular Space ◽

White Matter Hyperintensity ◽

Deep White Matter ◽

Free Water Content ◽

Tight Association

Understanding the pathophysiology of white matter hyperintensity (WMH) is necessary to reduce its harmfulness. Dilated perivascular space (PVS) had been found related to WMH. In the present study, we aimed to examine the topological connections between WMH and PVS, and to investigate whether increased interstitial fluid mediates the correlation between PVS and WMH volumes. One hundred and thirty-six healthy elder subjects were retrospectively included from a prospectively collected community cohort. Sub-millimeter T2 weighted and FLAIR images were acquired for assessing the association between PVS and WMH. Diffusion tensor imaging and free-water (FW) analytical methods were used to quantify white matter free water content, and to explore whether it mediates the PVS-WMH association. We found that most (89%) of the deep WMH lesions were spatially connected with PVS, exhibiting several interesting topological types. PVS and WMH volumes were also significantly correlated (r = 0.222, p < 0.001). FW mediated this association in the whole sample (β = 0.069, p = 0.037) and in subjects with relatively high WMH load (β = 0.118, p = 0.006). These findings suggest a tight association between PVS dilation and WMH formation, which might be linked by the impaired glymphatic drainage function and accumulated local interstitial fluid.

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Preoperative identification of the facial nerve in patients with large cerebellopontine angle tumors using high-density diffusion tensor imaging

Journal of Neurosurgery ◽

10.3171/2011.12.jns111404 ◽

2012 ◽

Vol 116 (4) ◽

pp. 697-702 ◽

Cited By ~ 32

Author(s):

Neil Roundy ◽

Johnny B. Delashaw ◽

Justin S. Cetas

Keyword(s):

Diffusion Tensor Imaging ◽

Facial Nerve ◽

Cerebellopontine Angle ◽

Diffusion Tensor ◽

Tumor Resection ◽

High Density ◽

Imaging Method ◽

Study Objective ◽

Nerve Preservation ◽

Imaging Results

Object Facial nerve paresis can be a devastating complication following resection of large (> 2.5 cm) cerebellopontine angle (CPA) tumors. The authors have developed and used a new high-density diffusion tensor imaging (HD-DT imaging) method, aimed at preoperatively identifying the location and course of the facial nerve in relation to large CPA tumors. Their study objective was to preoperatively identify the facial nerve in patients with large CPA tumors and compare their HD-DT imaging method with a traditional standard DT imaging method and correlate with intraoperative findings. Methods The authors prospectively studied 5 patients with large (> 2.5 cm) CPA tumors. All patients underwent preoperative traditional standard- and HD-DT imaging. Imaging results were correlated with intraoperative findings. Results Utilizing their HD-DT imaging method, the authors positively identified the location and course of the facial nerve in all patients. In contrast, using a standard DT imaging method, the authors were unable to identify the facial nerve in 4 of the 5 patients. Conclusions The HD-DT imaging method that the authors describe and use has proven to be a powerful, accurate, and rapid method for preoperatively identifying the facial nerve in relation to large CPA tumors. Routine integration of HD-DT imaging in preoperative planning for CPA tumor resection could lead to improved facial nerve preservation.

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The Translational Role of Diffusion Tensor Image Analysis in Animal Models of Developmental Pathologies

Developmental Neuroscience ◽

10.1159/000336825 ◽

2012 ◽

Vol 34 (1) ◽

pp. 5-19 ◽

Cited By ~ 9

Author(s):

Ipek Oguz ◽

Matthew S. McMurray ◽

Martin Styner ◽

Josephine M. Johns

Keyword(s):

Image Analysis ◽

Animal Models ◽

Diffusion Tensor ◽

Diffusion Tensor Image

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Diffusion Tensor Imaging Along the Perivascular Space Index in Different Stages of Parkinson’s Disease

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.773951 ◽

2021 ◽

Vol 13 ◽

Author(s):

Xinxin Ma ◽

Shuhua Li ◽

Chunmei Li ◽

Rui Wang ◽

Min Chen ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Diffusion Tensor ◽

Multivariate Logistic Regression Analysis ◽

Perivascular Space ◽

Periventricular White Matter ◽

Perivascular Spaces ◽

Glymphatic System ◽

Multiple Variables ◽

Association Fibers

Background: The aim of this study was to evaluate the glymphatic system activity in patients with Parkinson’s disease (PD) using the diffusion tensor image analysis along the perivascular space (DTI-ALPS) methods.Methods: In total, 71 patients with idiopathic PD and 36 age- and sex-matched normal controls (NCs) were involved. Patients with PD were divided into early (n = 35) and late (n = 36) subgroups, based on Hoehn and Yahr (HY) stages. We calculated the diffusivity along the perivascular spaces (ALPS), as well as projection fibers and association fibers separately, to acquire the ALPS index. Enlarged perivascular spaces (EPVS) and periventricular white matter hyperintensities were also rated. Differences in ALPS index between the PD group and NCs and between two PD subgroups and NCs were compared. In addition, a multivariate logistic regression analysis was conducted to investigate the association between ALPS index and clinical variables.Results: Patients with PD revealed lower ALPS index than NCs (p = 0.010). The late PD group exhibited significantly lower ALPS index than NCs (p = 0.006). However, there were no marked differences noticed in ALPS index between NCs and early PD group and between the two PD subgroups. In the early PD group, there was a significantly positive correlation between ALPS index and Mini-Mental State Examination (MMSE) score (β = 0.021, p = 0.029) and a negative correlation between ALPS index and EPVS score (β = −0.050, p = 0.034), after controlling for multiple variables. In the late PD group, ALPS index was inversely associated with age (β = −0.012, p = 0.004).Conclusion: Impairment of the glymphatic system is involved in PD. DTI-ALPS index could be a promising biomarker of glymphatic system in PD.

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