In vivo quantification of the bound pool T1 in human white matter using the binary spin-bath model of progressive magnetization transfer saturation
(2009) In Physics in Medicine and Biology 54(23). p.529-540- Abstract
- The relative size and relaxation of the invisible pool of bound spins (T1b) underlying magnetization transfer (MT) was quantified in eight subjects in vivo at 1.5 T from progressive saturation experiments using repetitive MT pulses. The evolution of the binary spin–bath was sampled by increasing the repetition period from 8 to 200 ms. Single-shot echo-planar images at TE=50ms were evaluated in the central white matter. Three models were fitted: the general solution, and with constraints of equal relaxation and T1b=1s for the invisible pool. The general solution of unconstrained T1b provided a significantly better fit, indicating fast-to-intermediate exchange. The bound pool fraction was 17±4%, the relaxation times T1f=1.6±0.2s for free... (More)
- The relative size and relaxation of the invisible pool of bound spins (T1b) underlying magnetization transfer (MT) was quantified in eight subjects in vivo at 1.5 T from progressive saturation experiments using repetitive MT pulses. The evolution of the binary spin–bath was sampled by increasing the repetition period from 8 to 200 ms. Single-shot echo-planar images at TE=50ms were evaluated in the central white matter. Three models were fitted: the general solution, and with constraints of equal relaxation and T1b=1s for the invisible pool. The general solution of unconstrained T1b provided a significantly better fit, indicating fast-to-intermediate exchange. The bound pool fraction was 17±4%, the relaxation times T1f=1.6±0.2s for free water and T1b=171±22ms for the bound pool. The constrained models did not differ from each other, since here T1b was similar to the observed T1 of 1.1±0.1s. They underestimate the bound pool fraction and its relaxation. Thus, the standard assumption of continuous-wave MT models may underestimate the relaxation via the bound pool by more than a factor of five. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/8773608
- author
- Helms, Gunther LU and Hagberg, Gisela E.
- organization
- publishing date
- 2009
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physics in Medicine and Biology
- volume
- 54
- issue
- 23
- pages
- 529 - 540
- publisher
- IOP Publishing
- external identifiers
-
- scopus:70449715236
- ISSN
- 1361-6560
- DOI
- 10.1088/0031-9155/54/23/N01
- language
- English
- LU publication?
- yes
- additional info
- 23
- id
- 859ccde2-00a8-4021-a64c-d059925ab6b6 (old id 8773608)
- date added to LUP
- 2016-04-01 12:14:01
- date last changed
- 2022-03-28 22:07:47
@article{859ccde2-00a8-4021-a64c-d059925ab6b6, abstract = {{The relative size and relaxation of the invisible pool of bound spins (T1b) underlying magnetization transfer (MT) was quantified in eight subjects in vivo at 1.5 T from progressive saturation experiments using repetitive MT pulses. The evolution of the binary spin–bath was sampled by increasing the repetition period from 8 to 200 ms. Single-shot echo-planar images at TE=50ms were evaluated in the central white matter. Three models were fitted: the general solution, and with constraints of equal relaxation and T1b=1s for the invisible pool. The general solution of unconstrained T1b provided a significantly better fit, indicating fast-to-intermediate exchange. The bound pool fraction was 17±4%, the relaxation times T1f=1.6±0.2s for free water and T1b=171±22ms for the bound pool. The constrained models did not differ from each other, since here T1b was similar to the observed T1 of 1.1±0.1s. They underestimate the bound pool fraction and its relaxation. Thus, the standard assumption of continuous-wave MT models may underestimate the relaxation via the bound pool by more than a factor of five.}}, author = {{Helms, Gunther and Hagberg, Gisela E.}}, issn = {{1361-6560}}, language = {{eng}}, number = {{23}}, pages = {{529--540}}, publisher = {{IOP Publishing}}, series = {{Physics in Medicine and Biology}}, title = {{In vivo quantification of the bound pool T1 in human white matter using the binary spin-bath model of progressive magnetization transfer saturation}}, url = {{http://dx.doi.org/10.1088/0031-9155/54/23/N01}}, doi = {{10.1088/0031-9155/54/23/N01}}, volume = {{54}}, year = {{2009}}, }