Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Default user image.

Linda Knutsson

Professor

Default user image.

Probing brain tissue microstructure with MRI : principles, challenges, and the role of multidimensional diffusion-relaxation encoding

Författare

  • Björn Lampinen
  • Filip Szczepankiewicz
  • Jimmy Lätt
  • Linda Knutsson
  • Johan Mårtensson
  • Isabella M Björkman-Burtscher
  • Danielle van Westen
  • Pia C Sundgren
  • Freddy Ståhlberg
  • Markus Nilsson

Summary, in English

Diffusion MRI uses the random displacement of water molecules to sensitize the signal to brain microstructure and to properties such as the density and shape of cells. Microstructure modeling techniques aim to estimate these properties from acquired data by separating the signal between virtual tissue 'compartments' such as the intra-neurite and the extra-cellular space. A key challenge is that the diffusion MRI signal is relatively featureless compared with the complexity of brain tissue. Another challenge is that the tissue microstructure is wildly different within the gray and white matter of the brain. In this review, we use results from multidimensional diffusion encoding techniques to discuss these challenges and their tentative solutions. Multidimensional encoding increases the information content of the data by varying not only the b-value and the encoding direction but also additional experimental parameters such as the shape of the b-tensor and the echo time. Three main insights have emerged from such encoding. First, multidimensional data contradict common model assumptions on diffusion and T
2 relaxation and illustrates how the use of these assumptions cause erroneous interpretations in both healthy brain and pathology. Second, many model assumptions can be dispensed with if data are acquired with multidimensional encoding. The necessary data can be easily acquired in vivo using protocols optimized to minimize Cramér-Rao lower bounds. Third, microscopic diffusion anisotropy reflects the presence of axons but not dendrites. This insight stands in contrast to current 'neurite models' of brain tissue, which assume that axons in white matter and dendrites in gray matter feature highly similar diffusion. Nevertheless, as an axon-based contrast, microscopic anisotropy can differentiate gray and white matter when myelin alterations confound conventional MRI contrasts.

Avdelning/ar

  • Diagnostisk radiologi, Lund
  • MR Physics
  • Multidimensional microstructure imaging
  • Medicinsk strålningsfysik, Lund
  • eSSENCE: The e-Science Collaboration
  • LU profilområde: Ljus och material
  • MultiPark: Multidisciplinary research focused on Parkinson´s disease
  • LAMiNATE (Language Acquisition, Multilingualism, and Teaching)
  • Logopedi, foniatri och audiologi
  • LU profilområde: Proaktivt åldrande
  • LUCC: Lunds universitets cancercentrum
  • Neuroradiologi
  • Lund University Bioimaging Center

Publiceringsår

2023-08-18

Språk

Engelska

Publikation/Tidskrift/Serie

NeuroImage

Volym

282

Dokumenttyp

Artikel i tidskrift

Förlag

Elsevier

Ämne

  • Other Physics Topics
  • Radiology, Nuclear Medicine and Medical Imaging

Status

Published

Forskningsgrupp

  • MR Physics
  • Multidimensional microstructure imaging
  • LAMiNATE (Language Acquisition, Multilingualism, and Teaching)
  • Neuroradiology

ISBN/ISSN/Övrigt

  • ISSN: 1095-9572