Relaxation along a fictitious field (RAFF) and Z-spectroscopy using alternating-phase irradiation (ZAPI) in permanent focal cerebral ischemia in rat

K.T. Jokivarsi, T. Liimatainen, R.A. Kauppinen, O.H.J. Gröhn, Johanna Närväinen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

Abstract

Cerebral ischemia alters the molecular dynamics and content of water in brain tissue, which is reflected in NMR relaxation, diffusion and magnetization transfer (MT) parameters. In this study, the behavior of two new MRI contrasts, Relaxation Along a Fictitious Field (RAFF) and Z-spectroscopy using Alternating-Phase Irradiation (ZAPI), were quantified together with conventional relaxation parameters (T1, T2 and T) and MT ratios in acute cerebral ischemia in rat. The right middle cerebral artery was permanently occluded and quantitative MRI data was acquired sequentially for the above parameters for up to 6 hours. The following conclusions were drawn: 1) Time-dependent changes in RAFF and T relaxation are not coupled to those in MT. 2) RAFF relaxation evolves more like transverse, rather than longitudinal relaxation. 3) MT measured with ZAPI is less sensitive to ischemia than conventional MT. 4) ZAPI data suggest alterations in the T2 distribution of macromolecules in acute cerebral ischemia. It was shown that both RAFF and ZAPI provide complementary MRI information from acute ischemic brain tissue. The presented multiparametric MRI data may aid in the assessment of brain tissue status early in ischemic stroke.
Original languageEnglish
Article number69157
JournalPLoS ONE
Volume8
Issue number7
DOIs
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed

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ischemia
Brain Ischemia
Rats
spectroscopy
Magnetization
Spectrum Analysis
irradiation
Magnetic resonance imaging
Irradiation
Spectroscopy
rats
Brain
brain
Tissue
molecular dynamics
Middle Cerebral Artery
Molecular Dynamics Simulation
stroke
arteries
Macromolecules

Cite this

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title = "Relaxation along a fictitious field (RAFF) and Z-spectroscopy using alternating-phase irradiation (ZAPI) in permanent focal cerebral ischemia in rat",
abstract = "Cerebral ischemia alters the molecular dynamics and content of water in brain tissue, which is reflected in NMR relaxation, diffusion and magnetization transfer (MT) parameters. In this study, the behavior of two new MRI contrasts, Relaxation Along a Fictitious Field (RAFF) and Z-spectroscopy using Alternating-Phase Irradiation (ZAPI), were quantified together with conventional relaxation parameters (T1, T2 and T1ρ) and MT ratios in acute cerebral ischemia in rat. The right middle cerebral artery was permanently occluded and quantitative MRI data was acquired sequentially for the above parameters for up to 6 hours. The following conclusions were drawn: 1) Time-dependent changes in RAFF and T1ρ relaxation are not coupled to those in MT. 2) RAFF relaxation evolves more like transverse, rather than longitudinal relaxation. 3) MT measured with ZAPI is less sensitive to ischemia than conventional MT. 4) ZAPI data suggest alterations in the T2 distribution of macromolecules in acute cerebral ischemia. It was shown that both RAFF and ZAPI provide complementary MRI information from acute ischemic brain tissue. The presented multiparametric MRI data may aid in the assessment of brain tissue status early in ischemic stroke.",
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Relaxation along a fictitious field (RAFF) and Z-spectroscopy using alternating-phase irradiation (ZAPI) in permanent focal cerebral ischemia in rat. / Jokivarsi, K.T.; Liimatainen, T.; Kauppinen, R.A.; Gröhn, O.H.J.; Närväinen, Johanna (Corresponding Author).

In: PLoS ONE, Vol. 8, No. 7, 69157, 2013.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Relaxation along a fictitious field (RAFF) and Z-spectroscopy using alternating-phase irradiation (ZAPI) in permanent focal cerebral ischemia in rat

AU - Jokivarsi, K.T.

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AU - Kauppinen, R.A.

AU - Gröhn, O.H.J.

AU - Närväinen, Johanna

PY - 2013

Y1 - 2013

N2 - Cerebral ischemia alters the molecular dynamics and content of water in brain tissue, which is reflected in NMR relaxation, diffusion and magnetization transfer (MT) parameters. In this study, the behavior of two new MRI contrasts, Relaxation Along a Fictitious Field (RAFF) and Z-spectroscopy using Alternating-Phase Irradiation (ZAPI), were quantified together with conventional relaxation parameters (T1, T2 and T1ρ) and MT ratios in acute cerebral ischemia in rat. The right middle cerebral artery was permanently occluded and quantitative MRI data was acquired sequentially for the above parameters for up to 6 hours. The following conclusions were drawn: 1) Time-dependent changes in RAFF and T1ρ relaxation are not coupled to those in MT. 2) RAFF relaxation evolves more like transverse, rather than longitudinal relaxation. 3) MT measured with ZAPI is less sensitive to ischemia than conventional MT. 4) ZAPI data suggest alterations in the T2 distribution of macromolecules in acute cerebral ischemia. It was shown that both RAFF and ZAPI provide complementary MRI information from acute ischemic brain tissue. The presented multiparametric MRI data may aid in the assessment of brain tissue status early in ischemic stroke.

AB - Cerebral ischemia alters the molecular dynamics and content of water in brain tissue, which is reflected in NMR relaxation, diffusion and magnetization transfer (MT) parameters. In this study, the behavior of two new MRI contrasts, Relaxation Along a Fictitious Field (RAFF) and Z-spectroscopy using Alternating-Phase Irradiation (ZAPI), were quantified together with conventional relaxation parameters (T1, T2 and T1ρ) and MT ratios in acute cerebral ischemia in rat. The right middle cerebral artery was permanently occluded and quantitative MRI data was acquired sequentially for the above parameters for up to 6 hours. The following conclusions were drawn: 1) Time-dependent changes in RAFF and T1ρ relaxation are not coupled to those in MT. 2) RAFF relaxation evolves more like transverse, rather than longitudinal relaxation. 3) MT measured with ZAPI is less sensitive to ischemia than conventional MT. 4) ZAPI data suggest alterations in the T2 distribution of macromolecules in acute cerebral ischemia. It was shown that both RAFF and ZAPI provide complementary MRI information from acute ischemic brain tissue. The presented multiparametric MRI data may aid in the assessment of brain tissue status early in ischemic stroke.

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