White matter segmentation based on a skeletonized atlas: Effects on diffusion tensor imaging studies of regions of interest

Zhang, Shengwei; Arfanakis, Konstantinos

doi:10.1002/jmri.24445

Cited by 11 publications

(13 citation statements)

References 35 publications

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“…Previous evaluations have found skele-tonization to improve performance in deep white matter ROIs [37]; however, the improvement in models with FA here were not significant. This may support other results showing that high quality registration is as important as skeletonization in improving sensitivity [68] and related findings showing more heterogeneous results [37]. Smoothing tended to increase the size of the significant clusters, although the effect size did not change.…”

Section: Discussioncontrasting

confidence: 64%

“…Voxel-based analysis has also been evaluated to quantify the effects of filter size [33], software package [34], and to compare results with ROI-based methods [35] [36]. There has also been extensive testing of skeleton-based analysis to understand its strengths and limitations [28] [26] [37] as well as comparing to voxel-based analysis and region-based analysis [20] [21]. Previous work has also evaluated the choice of template type, showing the advantages of study-specific and high-quality templates [38] [39] [40] [41].…”

Section: Introductionmentioning

confidence: 99%

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A Comparative evaluation of voxel-based spatial mapping in diffusion tensor imaging

2017

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This paper presents a comparative evaluation of methods for automated voxel-based spatial mapping in diffusion tensor imaging studies. Such methods are an essential step in computational pipelines and provide anatomically comparable measurements across a population in atlas-based studies. To better understand their strengths and weaknesses, we tested a total of eight methods for voxel-based spatial mapping in two types of diffusion tensor templates. The methods were evaluated with respect to scan-rescan reliability and an application to normal aging. The methods included voxel-based analysis with and without smoothing, two types of region-based analysis, and combinations thereof with skeletonization. The templates included a study-specific template created with DTI-TK and the IIT template serving as a standard template. To control for other factors in the pipeline, the experiments used a common dataset, acquired at 1.5T with a single shell high angular resolution diffusion MR imaging protocol, and tensor-based spatial normalization with DTI-TK. Scan-rescan reliability was assessed using the coefficient of variation (CV) and intraclass correlation (ICC) in eight subjects with three scans each. Sensitivity to normal aging was assessed in a population of 80 subjects aged 25 to 65 years old, and methods were compared with respect to the anatomical agreement of significant findings and the R2 of the associated models of fractional anisotropy. The results show that reliability depended greatly on the method used for spatial mapping. The largest differences in reliability were found when adding smoothing and comparing voxel-based and region-based analyses. Skeletonization and template type were found to have either a small or negligible effect on reliability. The aging results showed agreement among the methods in nine brain areas, with some methods showing more sensitivity than others. Skeletonization and smoothing were not major factors affecting sensitivity to aging, but the standard template showed higher R2 in several conditions. A structural comparison of the templates showed that large deformations between them may be related to observed differences in patterns of significant voxels. Most areas showed significantly higher R2 with voxel-based analysis, particularly when clusters were smaller than the available regions-of-interest. Looking forward, these results can potentially help to interpret results from existing white matter imaging studies, as well as provide a resource to help in planning future studies to maximize reliability and sensitivity with regard to the scientific goals at hand.

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Section: Discussioncontrasting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

A Comparative evaluation of voxel-based spatial mapping in diffusion tensor imaging

2017

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“…Notably, this approach depends on the accuracy of the ROI’s in the template as well as the reliability of the within-subject registration to the template. Although there are both advantages and disadvantages to using a standard template (Zhang and Arfanakis, 2013), we focused on the reliability of the standard atlas for extracting ROI’s, particularly given the need to account for white matter hyperintensity (WMH) extraction (masked from FLAIR T2-weighted images) in the study. Finally, one MRI time point was available, thereby limiting further analysis of longitudinal change in brain structure.…”

Section: Discussionmentioning

confidence: 99%

Declines in inflammation predict greater white matter microstructure in older adults

Bettcher

Yaffe

Boudreau

et al. 2015

Neurobiology of Aging

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Objective Protracted, systemic inflammation has been associated with adverse effects on cognition and brain structure, and may accelerate neurodegenerative disease processes; however, it is less clear whether changes in inflammation are associated with brain structure. Methods We studied 276 black and white older adults (mean age=83 years at time of imaging) enrolled in a prospective study of aging. Inflammation (measured with CRP) was assessed repeatedly over 6 years (i.e. Year 2, 4, 6, & 8). Brain MRIs were obtained at years 10–11 with DTI; regions of interest included late-myelinating areas vulnerable to aging, including frontal-parietal [superior longitudinal fasciculus (SLF)-dorsal] and temporal (SLF-temporal; uncinate) white matter tracts. Results Mean CRP values significantly declined (t=−5.54, p<.0001) over 6 years, and subject-specific slopes (BLUPs) all showed a decline (mean=−.57, SD=.53) for our participant sample. More than 50% of study participants were still in the moderate to high cardiovascular risk range based on CRP values at Year 8. After controlling for demographics, vascular risk factors and MRI white matter hyperintensities, larger decreases in CRP values over time were significantly associated with higher fractional anisotropy in the SLF-dorsal [Beta=−0.0052, standard error (SE)=0.003; 95% confidence interval (CI)= −0.0103 to −0.0025, p=.04], SLF-temporal (Beta=−0.0109, SE=0.004; 95%CI=−0.0189 to −0.0029, p=.008), and uncinate (Beta=−0.0067, SE=0.003; 95%CI=−0.0132 to −0.0001, p=.05) fasciculi. Conclusions Results suggest that in a prospective cohort of older individuals, faster declines in inflammation over time are related to indicators of white matter health, even after accounting for vascular risk factors.

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“…Digital diffusion tensor imaging (DTI) templates of the adult human brain are indispensable neuroimaging tools. The most common applications of DTI templates are in voxel-wise analyses, where they are used as references for inter-subject spatial normalization (Zhang and Arfanakis, 2013)(Smith et al, 2006), and in region of interest analyses, where they are used for conventional or skeletonized atlas-based segmentation (Zhang and Arfanakis, 2014). DTI templates are also used in automated seed selection for fiber-tracking (Y.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of standardized and study-specific diffusion tensor imaging templates of the adult human brain: Template characteristics, spatial normalization accuracy, and detection of small inter-group FA differences

Zhang

Arfanakis

2018

NeuroImage

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Digital diffusion tensor imaging (DTI) templates of the adult human brain are commonly used in neuroimaging research, and their characteristics influence the accuracy of the application. However, a systematic evaluation of the characteristics and performance of standardized and study-specific DTI templates has not been conducted. The purpose of this work was to compare eight available standardized DTI templates to each other (ICBM81, ENIGMA, FMRIB58, SRI24, IIT2, NTU-DSI-122-DTI, IIT v.3.0, Eve), as well as to study-specific templates, in terms of template characteristics (image sharpness, ability to identify small brain structures, artifacts, mean values, noise properties) and performance in spatial normalization and detection of small inter-group FA differences. The IIT v.3.0 template was shown to combine a number of desirable characteristics: includes full-tensor information, is population-based, has high image sharpness, shows no visible artifacts, has low noise levels, has diffusion tensor properties and spatial features representative of data from the average individual adult brain. Furthermore, the IIT v.3.0 template was shown to allow higher inter-subject DTI spatial normalization accuracy, and detection of smaller inter-group FA differences, compared to all other templates, including study-specific templates. These findings were consistent when evaluating the templates in younger as well as older adult cohorts.

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White matter segmentation based on a skeletonized atlas: Effects on diffusion tensor imaging studies of regions of interest

Abstract: Conventional and skeletonized atlas-based segmentation probe different portions of brain tissue and lead to different statistical summaries of diffusion characteristics in WM labels. Careful selection of segmentation approach is required for DTI investigations of WM ROIs.

Cited by 11 publications

References 35 publications

A Comparative evaluation of voxel-based spatial mapping in diffusion tensor imaging

A Comparative evaluation of voxel-based spatial mapping in diffusion tensor imaging

Declines in inflammation predict greater white matter microstructure in older adults

Evaluation of standardized and study-specific diffusion tensor imaging templates of the adult human brain: Template characteristics, spatial normalization accuracy, and detection of small inter-group FA differences

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