Abstract
Purpose Magnetic resonance T1-weighted images are routinely used for human brain segmentation, brain parcellation, and clinical diagnosis of demyelinating diseases. Myelin is thought to influence the longitudinal relaxation commonly described by a mono-exponential recovery, although reports of bi-exponential longitudinal relaxation have been published. The purpose of this work was to investigate if a myelin water T1 contribution could be separated in geometrically sampled Look-Locker trains of low flip angle gradient echoes. Methods T1 relaxograms from normal human brain were computed by a spatially regularized inverse Laplace transform after estimating the apparent inversion efficiency. Results With sufficiently long inversion-time sampling (ca. 5 × T1 of cerebrospinal fluid), the T 1 relaxogram revealed a short-T1 peak (106-225 ms). The apparent fraction of this water component increased in human brain white matter from 8.3% at 3 T, to 11.3% at 4 T and 15.0% at 7 T. The T2* of the short-T1 peak at 3 T was shorter, 27.9 ± 13.0 ms, than that of the long-T1 peak, 51.3 ± 5.6 ms. Conclusion The short-T1 fraction is interpreted as the water resident in myelin. Its detection is facilitated by longer T1 of axoplasmic water at higher magnetic field.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 375-387 |
| Number of pages | 13 |
| Journal | Magnetic Resonance in Medicine |
| Volume | 71 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2014 |
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Keywords
- inverse Laplace transform
- longitudinal relaxation
- myelin water
- regularization
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
Cite this
Myelin water mapping by spatially regularized longitudinal relaxographic imaging at high magnetic fields. / Labadie, Christian; Lee, Jing Huei; Rooney, William; Jarchow, Silvia; Aubert-Frécon, Monique; Springer, Charles Jr; Möller, Harald E.
In: Magnetic Resonance in Medicine, Vol. 71, No. 1, 01.2014, p. 375-387.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Myelin water mapping by spatially regularized longitudinal relaxographic imaging at high magnetic fields
AU - Labadie, Christian
AU - Lee, Jing Huei
AU - Rooney, William
AU - Jarchow, Silvia
AU - Aubert-Frécon, Monique
AU - Springer, Charles Jr
AU - Möller, Harald E.
PY - 2014/1
Y1 - 2014/1
N2 - Purpose Magnetic resonance T1-weighted images are routinely used for human brain segmentation, brain parcellation, and clinical diagnosis of demyelinating diseases. Myelin is thought to influence the longitudinal relaxation commonly described by a mono-exponential recovery, although reports of bi-exponential longitudinal relaxation have been published. The purpose of this work was to investigate if a myelin water T1 contribution could be separated in geometrically sampled Look-Locker trains of low flip angle gradient echoes. Methods T1 relaxograms from normal human brain were computed by a spatially regularized inverse Laplace transform after estimating the apparent inversion efficiency. Results With sufficiently long inversion-time sampling (ca. 5 × T1 of cerebrospinal fluid), the T 1 relaxogram revealed a short-T1 peak (106-225 ms). The apparent fraction of this water component increased in human brain white matter from 8.3% at 3 T, to 11.3% at 4 T and 15.0% at 7 T. The T2* of the short-T1 peak at 3 T was shorter, 27.9 ± 13.0 ms, than that of the long-T1 peak, 51.3 ± 5.6 ms. Conclusion The short-T1 fraction is interpreted as the water resident in myelin. Its detection is facilitated by longer T1 of axoplasmic water at higher magnetic field.
AB - Purpose Magnetic resonance T1-weighted images are routinely used for human brain segmentation, brain parcellation, and clinical diagnosis of demyelinating diseases. Myelin is thought to influence the longitudinal relaxation commonly described by a mono-exponential recovery, although reports of bi-exponential longitudinal relaxation have been published. The purpose of this work was to investigate if a myelin water T1 contribution could be separated in geometrically sampled Look-Locker trains of low flip angle gradient echoes. Methods T1 relaxograms from normal human brain were computed by a spatially regularized inverse Laplace transform after estimating the apparent inversion efficiency. Results With sufficiently long inversion-time sampling (ca. 5 × T1 of cerebrospinal fluid), the T 1 relaxogram revealed a short-T1 peak (106-225 ms). The apparent fraction of this water component increased in human brain white matter from 8.3% at 3 T, to 11.3% at 4 T and 15.0% at 7 T. The T2* of the short-T1 peak at 3 T was shorter, 27.9 ± 13.0 ms, than that of the long-T1 peak, 51.3 ± 5.6 ms. Conclusion The short-T1 fraction is interpreted as the water resident in myelin. Its detection is facilitated by longer T1 of axoplasmic water at higher magnetic field.
KW - inverse Laplace transform
KW - longitudinal relaxation
KW - myelin water
KW - regularization
UR - http://www.scopus.com/inward/record.url?scp=84890797506&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84890797506&partnerID=8YFLogxK
U2 - 10.1002/mrm.24670
DO - 10.1002/mrm.24670
M3 - Article
C2 - 23468414
AN - SCOPUS:84890797506
VL - 71
SP - 375
EP - 387
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
SN - 0740-3194
IS - 1
ER -