DWI Fiber Tracking with Functional MRI of White Matter

Object Resecting brain tumors involves the risk of damaging the descending motor pathway. Diffusion tensor (DT)–imaged fiber tracking is a noninvasive magnetic resonance (MR) technique that can delineate the subcortical course of the motor pathway. The goal of this study was to use intraoperative subcortical stimulation mapping of the motor tract and magnetic source imaging to validate the utility of DT-imaged fiber tracking as a tool for presurgical planning. Methods Diffusion tensor-imaged fiber tracks of the motor tract were generated preoperatively in nine patients with gliomas. A mask of the resultant fiber tracks was overlaid on high-resolution T1- and T2-weighted anatomical MR images and used for stereotactic surgical navigation. Magnetic source imaging was performed in seven of the patients to identify functional somatosensory cortices. During resection, subcortical stimulation mapping of the motor pathway was performed within the white matter using a bipolar electrode. Results A total of 16 subcortical motor stimulations were stereotactically identified in nine patients. The mean distance between the stimulation sites and the DT-imaged fiber tracks was 8.7 ±3.1 mm (±standard deviation). The measured distance between subcortical stimulation sites and DT-imaged fiber tracks combines tracking technique errors and all errors encountered with stereotactic navigation. Conclusions Fiber tracks delineated using DT imaging can be used to identify the motor tract in deep white matter and define a safety margin around the tract.

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Neuroimaging Anomalies in Community-Dwelling Asymptomatic Adults With Very Early-Stage White Matter Hyperintensity

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.715434 ◽

2021 ◽

Vol 13 ◽

Author(s):

Shuai Guan ◽

Xiangyu Kong ◽

Shifei Duan ◽

Qingguo Ren ◽

Zhaodi Huang ◽

...

Keyword(s):

White Matter ◽

Functional Mri ◽

Resting State ◽

Early Stage ◽

Structural Mri ◽

Resting State Fmri ◽

Community Dwelling ◽

White Matter Hyperintensity ◽

Age Related ◽

Comparative Results

White matter hyperintensity (WMH) is common in healthy adults in their 60s and can be seen as early as in their 30s and 40s. Alterations in the brain structural and functional profiles in adults with WMH have been repeatedly studied but with a focus on late-stage WMH. To date, structural and functional MRI profiles during the very early stage of WMH remain largely unexplored. To address this, we investigated multimodal MRI (structural, diffusion, and resting-state functional MRI) profiles of community-dwelling asymptomatic adults with very early-stage WMH relative to age-, sex-, and education-matched non-WMH controls. The comparative results showed significant age-related and age-independent changes in structural MRI-based morphometric measures and resting-state fMRI-based measures in a set of specific gray matter (GM) regions but no global white matter changes. The observed structural and functional anomalies in specific GM regions in community-dwelling asymptomatic adults with very early-stage WMH provide novel data regarding very early-stage WMH and enhance understanding of the pathogenesis of WMH.

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Functional MRI and resting state connectivity in white matter - a mini-review

Magnetic Resonance Imaging ◽

10.1016/j.mri.2019.07.017 ◽

2019 ◽

Vol 63 ◽

pp. 1-11 ◽

Cited By ~ 15

Author(s):

John C. Gore ◽

Muwei Li ◽

Yurui Gao ◽

Tung-Lin Wu ◽

Kurt G. Schilling ◽

...

Keyword(s):

White Matter ◽

Functional Mri ◽

Resting State ◽

Resting State Connectivity

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Combining fiber tracking and functional brain imaging for revealing brain networks involved in auditory–visual integration in humans

Seeing and Perceiving ◽

10.1163/187847612x646280 ◽

2012 ◽

Vol 25 (0) ◽

pp. 5 ◽

Cited By ~ 1

Author(s):

Anton L. Beer ◽

Tina Plank ◽

Evangelia-Regkina Symeonidou ◽

Georg Meyer ◽

Mark W. Greenlee

Keyword(s):

White Matter ◽

Functional Activity ◽

Occipital Lobe ◽

Object Perception ◽

Occipital Cortex ◽

Fiber Tracking ◽

Visual Object ◽

Body Movements ◽

Body Area ◽

Probabilistic Tracking

Previous functional magnetic resonance imaging (MRI) found various brain areas in the temporal and occipital lobe involved in integrating auditory and visual object information. Fiber tracking based on diffusion-weighted MRI suggested neuroanatomical connections between auditory cortex and sub-regions of the temporal and occipital lobe. However, the relationship between functional activity and white-matter tracks remained unclear. Here, we combined probabilistic tracking and functional MRI in order to reveal the structural connections related to auditory–visual object perception. Ten healthy people were examined by diffusion-weighted and functional MRI. During functional examinations they viewed either movies of lip or body movements, listened to corresponding sounds (phonological sounds or body action sounds), or a combination of both. We found that phonological sounds elicited stronger activity in the lateral superior temporal gyrus (STG) than body action sounds. Body movements elicited stronger activity in the lateral occipital cortex than lip movements. Functional activity in the phonological STG region and the lateral occipital body area were mutually modulated (sub-additive) by combined auditory–visual stimulation. Moreover, bimodal stimuli engaged a region in the posterior superior temporal sulcus (STS). Probabilistic tracking revealed white-matter tracks between the auditory cortex and sub-regions of the STS (anterior and posterior) and occipital cortex. The posterior STS region was also found to be relevant for auditory–visual object perception. The anterior STS region showed connections to the phonological STG area and to the lateral occipital body area. Our findings suggest that multisensory networks in the temporal lobe are best revealed by combining functional and structural measures.

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Tactile direction discrimination in humans after stroke

Brain Communications ◽

10.1093/braincomms/fcaa088 ◽

2020 ◽

Vol 2 (2) ◽

Author(s):

Linda C Lundblad ◽

Håkan Olausson ◽

Pontus Wasling ◽

Katarina Jood ◽

Anna Wysocka ◽

...

Keyword(s):

White Matter ◽

Functional Mri ◽

Sensory System ◽

Insular Cortex ◽

Structural Mri ◽

Skin Surface ◽

Direction Discrimination ◽

Healthy Humans ◽

Tactile Stimuli ◽

Hands And Feet

Abstract Sensing movements across the skin surface is a complex task for the tactile sensory system, relying on sophisticated cortical processing. Functional MRI has shown that judgements of the direction of tactile stimuli moving across the skin are processed in distributed cortical areas in healthy humans. To further study which brain areas are important for tactile direction discrimination, we performed a lesion study, examining a group of patients with first-time stroke. We measured tactile direction discrimination in 44 patients, bilaterally on the dorsum of the hands and feet, within 2 weeks (acute), and again in 28 patients 3 months after stroke. The 3-month follow-up also included a structural MRI scan for lesion delineation. Fifty-nine healthy participants were examined for normative direction discrimination values. We found abnormal tactile direction discrimination in 29/44 patients in the acute phase, and in 21/28 3 months after stroke. Lesions that included the opercular parietal area 1 of the secondary somatosensory cortex, the dorsolateral prefrontal cortex or the insular cortex were always associated with abnormal tactile direction discrimination, consistent with previous functional MRI results. Abnormal tactile direction discrimination was also present with lesions including white matter and subcortical regions. We have thus delineated cortical, subcortical and white matter areas important for tactile direction discrimination function. The findings also suggest that tactile dysfunction is common following stroke.

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