MRI relaxation in the presence of fictitious fields correlates with myelin content in normal rat brain

Hanne Hakkarainen, Alejandra Sierra, Silvia Mangia, Michael Garwood, Shalom Michaeli, Olli Gröhn, Timo Liimatainen

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Purpose Brain myelin plays an important role in normal brain function. Demyelination is involved in many degenerative brain diseases, thus quantitative imaging of myelin has been under active investigation. In previous work, we demonstrated the capability of the method known as Relaxation Along a Fictitious Field (RAFF) in the rotating frame of rank n (RAFFn) to provide image contrast between white and gray matter in human and rat brains. Here, we provide evidence pointing to myelin being the major source of this contrast. Methods RAFFn relaxation time constant (TRAFFn) was mapped in rat brain ex vivo. TRAFFn was quantified in 12 different brain areas. TRAFFn values were compared with multiple other MRI metrics (T1, T2, continuous wave T, adiabatic T and T, magnetization transfer ratio), and with histologic measurements of cell density, myelin and iron content. Results Highest contrast between white and grey matter was obtained with TRAFFn in the rotating frames of ranks n = 4 and 5. TRAFFn values correlated strongly with myelin content, whereas no associations between TRAFFn and iron content or cell density were found. Conclusion TRAFFn with n = 4 or 5 provides a high sensitivity for selective myelin mapping in the rat brain.

Original languageEnglish (US)
Pages (from-to)161-168
Number of pages8
JournalMagnetic resonance in medicine
Volume75
Issue number1
DOIs
StatePublished - Jan 1 2016

Fingerprint

Myelin Sheath
Brain
Iron
Cell Count
Brain Diseases
Demyelinating Diseases

Keywords

  • brain
  • contrast imaging
  • fictitious field
  • myelin
  • relaxation
  • rotating frame

Cite this

MRI relaxation in the presence of fictitious fields correlates with myelin content in normal rat brain. / Hakkarainen, Hanne; Sierra, Alejandra; Mangia, Silvia; Garwood, Michael; Michaeli, Shalom; Gröhn, Olli; Liimatainen, Timo.

In: Magnetic resonance in medicine, Vol. 75, No. 1, 01.01.2016, p. 161-168.

Research output: Contribution to journalArticle

@article{101dc7f4b5e74f7ca001e2f42b79b289,
title = "MRI relaxation in the presence of fictitious fields correlates with myelin content in normal rat brain",
abstract = "Purpose Brain myelin plays an important role in normal brain function. Demyelination is involved in many degenerative brain diseases, thus quantitative imaging of myelin has been under active investigation. In previous work, we demonstrated the capability of the method known as Relaxation Along a Fictitious Field (RAFF) in the rotating frame of rank n (RAFFn) to provide image contrast between white and gray matter in human and rat brains. Here, we provide evidence pointing to myelin being the major source of this contrast. Methods RAFFn relaxation time constant (TRAFFn) was mapped in rat brain ex vivo. TRAFFn was quantified in 12 different brain areas. TRAFFn values were compared with multiple other MRI metrics (T1, T2, continuous wave T1ρ, adiabatic T1ρ and T2ρ, magnetization transfer ratio), and with histologic measurements of cell density, myelin and iron content. Results Highest contrast between white and grey matter was obtained with TRAFFn in the rotating frames of ranks n = 4 and 5. TRAFFn values correlated strongly with myelin content, whereas no associations between TRAFFn and iron content or cell density were found. Conclusion TRAFFn with n = 4 or 5 provides a high sensitivity for selective myelin mapping in the rat brain.",
keywords = "brain, contrast imaging, fictitious field, myelin, relaxation, rotating frame",
author = "Hanne Hakkarainen and Alejandra Sierra and Silvia Mangia and Michael Garwood and Shalom Michaeli and Olli Gr{\"o}hn and Timo Liimatainen",
year = "2016",
month = "1",
day = "1",
doi = "10.1002/mrm.25590",
language = "English (US)",
volume = "75",
pages = "161--168",
journal = "Magnetic Resonance in Medicine",
issn = "0740-3194",
publisher = "John Wiley and Sons Inc.",
number = "1",

}

TY - JOUR

T1 - MRI relaxation in the presence of fictitious fields correlates with myelin content in normal rat brain

AU - Hakkarainen, Hanne

AU - Sierra, Alejandra

AU - Mangia, Silvia

AU - Garwood, Michael

AU - Michaeli, Shalom

AU - Gröhn, Olli

AU - Liimatainen, Timo

PY - 2016/1/1

Y1 - 2016/1/1

N2 - Purpose Brain myelin plays an important role in normal brain function. Demyelination is involved in many degenerative brain diseases, thus quantitative imaging of myelin has been under active investigation. In previous work, we demonstrated the capability of the method known as Relaxation Along a Fictitious Field (RAFF) in the rotating frame of rank n (RAFFn) to provide image contrast between white and gray matter in human and rat brains. Here, we provide evidence pointing to myelin being the major source of this contrast. Methods RAFFn relaxation time constant (TRAFFn) was mapped in rat brain ex vivo. TRAFFn was quantified in 12 different brain areas. TRAFFn values were compared with multiple other MRI metrics (T1, T2, continuous wave T1ρ, adiabatic T1ρ and T2ρ, magnetization transfer ratio), and with histologic measurements of cell density, myelin and iron content. Results Highest contrast between white and grey matter was obtained with TRAFFn in the rotating frames of ranks n = 4 and 5. TRAFFn values correlated strongly with myelin content, whereas no associations between TRAFFn and iron content or cell density were found. Conclusion TRAFFn with n = 4 or 5 provides a high sensitivity for selective myelin mapping in the rat brain.

AB - Purpose Brain myelin plays an important role in normal brain function. Demyelination is involved in many degenerative brain diseases, thus quantitative imaging of myelin has been under active investigation. In previous work, we demonstrated the capability of the method known as Relaxation Along a Fictitious Field (RAFF) in the rotating frame of rank n (RAFFn) to provide image contrast between white and gray matter in human and rat brains. Here, we provide evidence pointing to myelin being the major source of this contrast. Methods RAFFn relaxation time constant (TRAFFn) was mapped in rat brain ex vivo. TRAFFn was quantified in 12 different brain areas. TRAFFn values were compared with multiple other MRI metrics (T1, T2, continuous wave T1ρ, adiabatic T1ρ and T2ρ, magnetization transfer ratio), and with histologic measurements of cell density, myelin and iron content. Results Highest contrast between white and grey matter was obtained with TRAFFn in the rotating frames of ranks n = 4 and 5. TRAFFn values correlated strongly with myelin content, whereas no associations between TRAFFn and iron content or cell density were found. Conclusion TRAFFn with n = 4 or 5 provides a high sensitivity for selective myelin mapping in the rat brain.

KW - brain

KW - contrast imaging

KW - fictitious field

KW - myelin

KW - relaxation

KW - rotating frame

UR - http://www.scopus.com/inward/record.url?scp=84922204584&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84922204584&partnerID=8YFLogxK

U2 - 10.1002/mrm.25590

DO - 10.1002/mrm.25590

M3 - Article

C2 - 25648507

AN - SCOPUS:84922204584

VL - 75

SP - 161

EP - 168

JO - Magnetic Resonance in Medicine

JF - Magnetic Resonance in Medicine

SN - 0740-3194

IS - 1

ER -