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@ARTICLE{Farrher:902165,
author = {Farrher, Ezequiel and Chiang, Chia-Wen and Cho, Kuan-Hung
and Grinberg, Farida and Buschbeck, Richard P. and Chen,
Ming-Jye and Wu, Kuo-Jen and Wang, Yun and Huang, Sheng-Min
and Abbas, Zaheer and Choi, Chang-Hoon and Shah, N. Jon and
Kuo, Li-Wei},
title = {{S}patiotemporal characterisation of ischaemic lesions in
transient stroke animal models using diffusion free water
elimination and mapping {MRI} with echo time dependence},
journal = {NeuroImage},
volume = {244},
issn = {1053-8119},
address = {Orlando, Fla.},
publisher = {Academic Press},
reportid = {FZJ-2021-04074},
pages = {118605 -},
year = {2021},
abstract = {Background and purposeThe excess fluid as a result of
vasogenic oedema and the subsequent tissue cavitation
obscure the microstructural characterisation of ischaemic
tissue by conventional diffusion and relaxometry MRI. They
lead to a pseudo-normalisation of the water diffusivity and
transverse relaxation time maps in the subacute and chronic
phases of stroke. Within the context of diffusion MRI, the
free water elimination and mapping method (FWE) with echo
time dependence has been proposed as a promising approach to
measure the amount of free fluid in brain tissue robustly
and to eliminate its biasing effect on other biomarkers. In
this longitudinal study of transient middle cerebral artery
occlusion (MCAo) in the rat brain, we investigated the use
of FWE MRI with echo time dependence for the
characterisation of the tissue microstructure and explored
the potential of the free water fraction as a novel
biomarker of ischaemic tissue condition.MethodsAdult rats
received a transient MCAo. Diffusion- and transverse
relaxation-weighted MRI experiments were performed
longitudinally, pre-occlusion and on days 1, 3, 4, 5, 6, 7
and 10 after MCAo on four rats. Histology was performed for
non-stroke and 1, 3 and 10 days after MCAo on three
different rats at each time point.ResultsThe free water
fraction was homogeneously increased in the ischaemic cortex
one day after stroke. Between three and ten days after
stroke, the core of the ischaemic tissue showed a
progressive normalisation in the amount of free water,
whereas the inner and outer border zones of the ischaemic
cortex depicted a large, monotonous increase with time. The
specific lesions in brain sections were verified by $H\&E$
and immunostaining. The tissue-specific diffusion and
relaxometry MRI metrics in the ischaemic cortex were
significantly different compared to their conventional
counterpart.ConclusionsOur results demonstrate that the free
water fraction in FWE MRI with echo time dependence is a
valuable biomarker, sensitive to the progressive
degeneration in ischaemic tissue. We showed that part of the
heterogeneity previously observed in conventional parameter
maps can be accounted for by a heterogeneous distribution of
free water in the tissue. Our results suggest that the
temporal evolution of the free fluid fraction map at the
core and inner border zone can be associated with the
pathological changes linked to the evolution of vasogenic
oedema. Namely, the homogeneous increase in free water one
day after stroke and its tendency to normalise in the core
of the ischaemic cortex starting three days after stroke,
followed by a progressive increase in free water at the
inner border zone from three to ten days after stroke.
Finally, the monotonous increase in free fluid in the outer
border zone of the cortex reflects the formation of
fluid-filled cysts.},
cin = {INM-4 / INM-11 / JARA-BRAIN},
ddc = {610},
cid = {I:(DE-Juel1)INM-4-20090406 / I:(DE-Juel1)INM-11-20170113 /
I:(DE-Juel1)VDB1046},
pnm = {5253 - Neuroimaging (POF4-525)},
pid = {G:(DE-HGF)POF4-5253},
typ = {PUB:(DE-HGF)16},
pubmed = {34592438},
UT = {WOS:000710098200001},
doi = {10.1016/j.neuroimage.2021.118605},
url = {https://juser.fz-juelich.de/record/902165},
}