Toward understanding transverse relaxation in human brain through its field dependence

Fumiyuki Mitsumori, Hidehiro Watanabe, Nobuhiro Takaya, Michael Garwood, Edward J Auerbach, Shalom Michaeli, Silvia Mangia

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Apparent transverse-relaxation rate constants (R 2 = 1/T 2) were measured in various regions of the healthy human brain using a multiecho adiabatic spin-echo sequence at five different magnetic fields, 1.5, 1.9, 3, 4.7, and 7 T. The R 2 values showed a clear dependence on magnetic field strength (B 0 ). The regional distribution of the R 2 was well explained by the sum of three components: (1) regional nonhemin iron concentration ([Fe]), (2) regional macromolecular mass fraction (f M ), and (3) a region-independent factor. Accordingly, R 2 = α[Fe] + βf M + γ, where coefficients α, β, and γ were experimentally determined at each magnetic field by a least square fitting method using multiple regression analysis. Although the coefficient α linearly increased with B 0 , β showed a quadratic dependence on top of a field-independent component. The coefficient γ also increased slightly with B 0 on top of a field-independent component. The linear dependence of α on B 0 was consistent with that observed for the transverse-relaxation rate of water protons in ferritin solutions as found previously by others. The quadratic dependence of β on B 0 was accounted for by isochronous and anisochronous exchange mechanisms using intrinsic-relaxation parameters obtained from the literature.

Original languageEnglish (US)
Pages (from-to)947-953
Number of pages7
JournalMagnetic resonance in medicine
Volume68
Issue number3
DOIs
StatePublished - Sep 1 2012

Fingerprint

Magnetic Fields
Brain
Ferritins
Least-Squares Analysis
Protons
Iron
Regression Analysis
Water

Keywords

  • field dependence
  • human brain
  • iron
  • macromolecule
  • transverse relaxation

Cite this

Toward understanding transverse relaxation in human brain through its field dependence. / Mitsumori, Fumiyuki; Watanabe, Hidehiro; Takaya, Nobuhiro; Garwood, Michael; Auerbach, Edward J; Michaeli, Shalom; Mangia, Silvia.

In: Magnetic resonance in medicine, Vol. 68, No. 3, 01.09.2012, p. 947-953.

Research output: Contribution to journalArticle

@article{0e81adb23f0d42d9b362126ada28916b,
title = "Toward understanding transverse relaxation in human brain through its field dependence",
abstract = "Apparent transverse-relaxation rate constants (R 2 = 1/T 2) were measured in various regions of the healthy human brain using a multiecho adiabatic spin-echo sequence at five different magnetic fields, 1.5, 1.9, 3, 4.7, and 7 T. The R 2 values showed a clear dependence on magnetic field strength (B 0 ). The regional distribution of the R 2 was well explained by the sum of three components: (1) regional nonhemin iron concentration ([Fe]), (2) regional macromolecular mass fraction (f M ), and (3) a region-independent factor. Accordingly, R 2 = α[Fe] + βf M + γ, where coefficients α, β, and γ were experimentally determined at each magnetic field by a least square fitting method using multiple regression analysis. Although the coefficient α linearly increased with B 0 , β showed a quadratic dependence on top of a field-independent component. The coefficient γ also increased slightly with B 0 on top of a field-independent component. The linear dependence of α on B 0 was consistent with that observed for the transverse-relaxation rate of water protons in ferritin solutions as found previously by others. The quadratic dependence of β on B 0 was accounted for by isochronous and anisochronous exchange mechanisms using intrinsic-relaxation parameters obtained from the literature.",
keywords = "field dependence, human brain, iron, macromolecule, transverse relaxation",
author = "Fumiyuki Mitsumori and Hidehiro Watanabe and Nobuhiro Takaya and Michael Garwood and Auerbach, {Edward J} and Shalom Michaeli and Silvia Mangia",
year = "2012",
month = "9",
day = "1",
doi = "10.1002/mrm.23301",
language = "English (US)",
volume = "68",
pages = "947--953",
journal = "Magnetic Resonance in Medicine",
issn = "0740-3194",
publisher = "John Wiley and Sons Inc.",
number = "3",

}

TY - JOUR

T1 - Toward understanding transverse relaxation in human brain through its field dependence

AU - Mitsumori, Fumiyuki

AU - Watanabe, Hidehiro

AU - Takaya, Nobuhiro

AU - Garwood, Michael

AU - Auerbach, Edward J

AU - Michaeli, Shalom

AU - Mangia, Silvia

PY - 2012/9/1

Y1 - 2012/9/1

N2 - Apparent transverse-relaxation rate constants (R 2 = 1/T 2) were measured in various regions of the healthy human brain using a multiecho adiabatic spin-echo sequence at five different magnetic fields, 1.5, 1.9, 3, 4.7, and 7 T. The R 2 values showed a clear dependence on magnetic field strength (B 0 ). The regional distribution of the R 2 was well explained by the sum of three components: (1) regional nonhemin iron concentration ([Fe]), (2) regional macromolecular mass fraction (f M ), and (3) a region-independent factor. Accordingly, R 2 = α[Fe] + βf M + γ, where coefficients α, β, and γ were experimentally determined at each magnetic field by a least square fitting method using multiple regression analysis. Although the coefficient α linearly increased with B 0 , β showed a quadratic dependence on top of a field-independent component. The coefficient γ also increased slightly with B 0 on top of a field-independent component. The linear dependence of α on B 0 was consistent with that observed for the transverse-relaxation rate of water protons in ferritin solutions as found previously by others. The quadratic dependence of β on B 0 was accounted for by isochronous and anisochronous exchange mechanisms using intrinsic-relaxation parameters obtained from the literature.

AB - Apparent transverse-relaxation rate constants (R 2 = 1/T 2) were measured in various regions of the healthy human brain using a multiecho adiabatic spin-echo sequence at five different magnetic fields, 1.5, 1.9, 3, 4.7, and 7 T. The R 2 values showed a clear dependence on magnetic field strength (B 0 ). The regional distribution of the R 2 was well explained by the sum of three components: (1) regional nonhemin iron concentration ([Fe]), (2) regional macromolecular mass fraction (f M ), and (3) a region-independent factor. Accordingly, R 2 = α[Fe] + βf M + γ, where coefficients α, β, and γ were experimentally determined at each magnetic field by a least square fitting method using multiple regression analysis. Although the coefficient α linearly increased with B 0 , β showed a quadratic dependence on top of a field-independent component. The coefficient γ also increased slightly with B 0 on top of a field-independent component. The linear dependence of α on B 0 was consistent with that observed for the transverse-relaxation rate of water protons in ferritin solutions as found previously by others. The quadratic dependence of β on B 0 was accounted for by isochronous and anisochronous exchange mechanisms using intrinsic-relaxation parameters obtained from the literature.

KW - field dependence

KW - human brain

KW - iron

KW - macromolecule

KW - transverse relaxation

UR - http://www.scopus.com/inward/record.url?scp=84865489172&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84865489172&partnerID=8YFLogxK

U2 - 10.1002/mrm.23301

DO - 10.1002/mrm.23301

M3 - Article

C2 - 22161735

AN - SCOPUS:84865489172

VL - 68

SP - 947

EP - 953

JO - Magnetic Resonance in Medicine

JF - Magnetic Resonance in Medicine

SN - 0740-3194

IS - 3

ER -