The average pathlength map: A diffusion MRI tractography-derived index for studying brain pathology

Pannek, Kerstin; Mathias, Jane L.; Bigler, Erin D.; Brown, G. A.; Taylor, Jamie; Rose, Stephen

doi:10.1016/j.neuroimage.2010.12.010

Cited by 58 publications

(45 citation statements)

References 26 publications

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“…TWI is a recently developed DWI technique that uses properties of tractography streamlines, such as density, curvature, and length, to provide additional measures that may be sensitive to white matter pathology 55, 56. TWI measures have previously been shown to be altered in preclinical mTBI23, 24 and repeated mTBI25 models that involved the use of anesthetic and/or craniotomy.…”

Section: Discussionmentioning

confidence: 99%

Diffusion MRI abnormalities in adolescent rats given repeated mild traumatic brain injury

Wortman

Meconi

Neale

et al. 2018

Ann Clin Transl Neurol

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ObjectiveMild traumatic brain injury (mTBI) is a serious health concern in the adolescent population. Repeated mTBI may result in more pronounced deficits, and has been associated with long‐term neurological consequences including neurodegeneration. As such, there is a critical need for the development of objective mTBI biomarkers to help guide medical management. Diffusion‐weighted imaging (DWI) is an advanced magnetic resonance imaging (MRI) technique that may detect brain abnormalities after mTBI. Diffusion tensor imaging (DTI) is the most commonly applied DWI method, and initial studies have reported DTI changes in mTBI patients. Furthermore, new DWI methods (e.g., track‐weighted imaging; TWI) are being developed that may also be sensitive to mTBIs, but remain to be comprehensively studied.MethodsThis study utilized the Awake Closed Head Injury (ACHI) model of mTBI to investigate changes in DTI and TWI following repeated mTBI in adolescent male and female rats. A total of four ACHI impacts, two/day over two consecutive days, were delivered beginning on postnatal day 25. At 1 day and 7 days postinjury, rats were euthanized and brains were collected for DWI analyses.ResultsRats given repeated mTBI displayed changes in fractional anisotropy and radial diffusivity (i.e., DTI measures), as well as track density (i.e., TWI).InterpretationThese findings are consistent with initial DTI findings in mTBI patients, suggest that TWI may complement DTI, support the utility of DWI measures as biomarkers in mTBI, and further validate the ACHI rat model of mTBI.

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Section: Discussionmentioning

confidence: 99%

Diffusion MRI abnormalities in adolescent rats given repeated mild traumatic brain injury

Wortman

Meconi

Neale

et al. 2018

Ann Clin Transl Neurol

View full text Add to dashboard Cite

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“…14 Given these limitations, it could be argued that the power of super-resolution TDI is not as a quantitative tool but rather in the high anatomic contrast and detail it provides (as illustrated by the results from Hoch et al, 1 and other related studies 3,4,15,16 ). Quantification is therefore better performed on the basis of, for example, other complementary track-based parameters, such as track-weighted apparent diffusion coefficient (TW-ADC), trackweighted fractional anisotropy (TW-FA), and track-weighted fiber-orientation distribution (TW-FOD), 12,17 or even on the basis of other properties of the streamlines themselves (such as their lengths in the average pathlength map [APM] method) 13 or on measures of the voxelwise fiber-orientation distribution (such as those related to the apparent fiber density [AFD] method). 14,18 While these maps have reduced anatomic contrast relative to that seen in TDI maps, they have more reliable quantitative properties 12,13 and are therefore more suitable for quantitative analysis in clinical applications.…”

Section: -14mentioning

confidence: 99%

Super-Resolution Track Density Imaging: Anatomic Detail versus Quantification

Calamante

2016

AJNR Am J Neuroradiol

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“…In another interesting use of tractography to infer connectivity changes, Pannek et al (2011) compared average path length maps in normal and severe TBI cases. The present work builds on our own previous work on WM connectivity importance maps, which demonstrated the use of network-centric methods applied to WM lesion maps (Kuceyeski et al, 2011), as well as another recent work that modeled disease propagation as a diffusion process on the normal brain connectivity network (Raj et al, 2012).…”

Section: Previous Workmentioning

confidence: 99%

The Network Modification (NeMo) Tool: Elucidating the Effect of White Matter Integrity Changes on Cortical and Subcortical Structural Connectivity

et al. 2013

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Accurate prediction of brain dysfunction caused by disease or injury requires the quantification of resultant neural connectivity changes compared with the normal state. There are many methods with which to assess anatomical changes in structural or diffusion magnetic resonance imaging, but most overlook the topology of white matter (WM) connections that make up the healthy brain network. Here, a new neuroimaging software pipeline called the Network Modification (NeMo) Tool is presented that associates alterations in WM integrity with expected changes in neural connectivity between gray matter regions. The NeMo Tool uses a large reference set of healthy tractograms to assess implied network changes arising from a particular pattern of WM alteration on a region-and network-wise level. In this way, WM integrity changes can be extrapolated to the cortices and deep brain nuclei, enabling assessment of functional and cognitive alterations. Unlike current techniques that assess network dysfunction, the NeMo tool does not require tractography in pathological brains for which the algorithms may be unreliable or diffusion data are unavailable. The versatility of the NeMo Tool is demonstrated by applying it to data from patients with Alzheimer's disease, fronto-temporal dementia, normal pressure hydrocephalus, and mild traumatic brain injury. This tool fills a gap in the quantitative neuroimaging field by enabling an investigation of morphological and functional implications of changes in structural WM integrity.

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The average pathlength map: A diffusion MRI tractography-derived index for studying brain pathology

Cited by 58 publications

References 26 publications

Diffusion MRI abnormalities in adolescent rats given repeated mild traumatic brain injury

Diffusion MRI abnormalities in adolescent rats given repeated mild traumatic brain injury

Super-Resolution Track Density Imaging: Anatomic Detail versus Quantification

The Network Modification (NeMo) Tool: Elucidating the Effect of White Matter Integrity Changes on Cortical and Subcortical Structural Connectivity

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