Forskning
Udskriv Udskriv
Switch language
Region Hovedstaden - en del af Københavns Universitetshospital
Udgivet

ActiveAxADD: Toward non-parametric and orientationally invariant axon diameter distribution mapping using PGSE

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

DOI

  1. Quantification of cerebral perfusion and cerebrovascular reserve using Turbo-QUASAR arterial spin labeling MRI

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  2. Coil profile estimation strategies for parallel imaging with hyperpolarized 13 C MRI

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  3. Gamma-aminobutyric acid edited echo-planar spectroscopic imaging (EPSI) with MEGA-sLASER at 7T

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  1. Ex vivo diffusion-weighted MRI tractography of the Göttingen minipig limbic system

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  2. Uncovering a Role for the Dorsal Hippocampal Commissure in Recognition Memory

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  3. Differences in frontal network anatomy across primate species

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  4. Limited colocalization of microbleeds and microstructural changes after severe traumatic brain injury

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  5. Validation of structural brain connectivity networks: The impact of scanning parameters

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Vis graf over relationer

PURPOSE: Non-invasive axon diameter distribution (ADD) mapping using diffusion MRI is an ill-posed problem. Current ADD mapping methods require knowledge of axon orientation before performing the acquisition. Instead, ActiveAx uses a 3D sampling scheme to estimate the orientation from the signal, providing orientationally invariant estimates. The mean diameter is estimated instead of the distribution for the solution to be tractable. Here, we propose an extension (ActiveAxADD ) that provides non-parametric and orientationally invariant estimates of the whole distribution.

THEORY: The accelerated microstructure imaging with convex optimization (AMICO) framework accelerates mean diameter estimation using a linear formulation combined with Tikhonov regularization to stabilize the solution. Here, we implement a new formulation (ActiveAxADD ) that uses Laplacian regularization to provide robust estimates of the whole ADD.

METHODS: The performance of ActiveAxADD was evaluated using Monte Carlo simulations on synthetic white matter samples mimicking axon distributions reported in histological studies.

RESULTS: ActiveAxADD provided robust ADD reconstructions when considering the isolated intra-axonal signal. However, our formulation inherited some common microstructure imaging limitations. When accounting for the extra axonal compartment, estimated ADDs showed spurious peaks and increased variability because of the difficulty of disentangling intra and extra axonal contributions.

CONCLUSION: Laplacian regularization solves the ill-posedness regarding the intra axonal compartment. ActiveAxADD can potentially provide non-parametric and orientationally invariant ADDs from isolated intra-axonal signals. However, further work is required before ActiveAxADD can be applied to real data containing extra-axonal contributions, as disentangling the 2 compartment appears to be an overlooked challenge that affects microstructure imaging methods in general.

OriginalsprogEngelsk
TidsskriftMagnetic Resonance in Medicine
Vol/bind83
Udgave nummer6
Sider (fra-til)2322-2330
Antal sider9
ISSN0740-3194
DOI
StatusUdgivet - jun. 2020

Bibliografisk note

© 2019 International Society for Magnetic Resonance in Medicine.

ID: 58330004