A cross-comparative analysis of in vivo versus ex vivo MRI indices in a mouse model of concussion.
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BORIS DOI
Publisher DOI
PubMed ID
37673379
Description
BACKGROUND
We present a cross-sectional, case-matched, and pair-wise comparison of structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), and neurite orientation dispersion and density imaging (NODDI) measures in vivo and ex vivo in a mouse model of concussion, thus aiming to establish the concordance of structural and diffusion imaging findings in living brain and after fixation.
METHODS
We allocated 28 male mice aged 3-4 months to sham injury and concussion (CON) groups. CON mice had received a single concussive impact on day 0 and underwent MRI at day 2 (n=9) or 7 (n=10) post-impact, and sham control mice likewise underwent imaging at day 2 (n=5) or 7 (n=4). Immediately after the final scanning, we collected the perfusion-fixed brains, which were stored for imaging ex vivo 6-12 months later. We then compared the structural imaging, DTI, and NODDI results between different methods.
RESULTS
In vivo to ex vivo structural and DTI/NODDI findings were in notably poor agreement regarding the effects of concussion on structural integrity of the brain. Comparison with existing methods ex vivo imaging was frequently done to study the effects of diseases and treatments, but our results showed that ex vivo and in vivo imaging can detect completely opposite and contradictory results. This is also the first study that compares in vivo and ex vivo NODDI.
CONCLUSION
Our findings call for caution in extrapolating translational capabilities obtained ex vivo to physiological measurements in vivo. The divergent findings may reflect fixation artefacts and the contribution of the glymphatic system changes.
We present a cross-sectional, case-matched, and pair-wise comparison of structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), and neurite orientation dispersion and density imaging (NODDI) measures in vivo and ex vivo in a mouse model of concussion, thus aiming to establish the concordance of structural and diffusion imaging findings in living brain and after fixation.
METHODS
We allocated 28 male mice aged 3-4 months to sham injury and concussion (CON) groups. CON mice had received a single concussive impact on day 0 and underwent MRI at day 2 (n=9) or 7 (n=10) post-impact, and sham control mice likewise underwent imaging at day 2 (n=5) or 7 (n=4). Immediately after the final scanning, we collected the perfusion-fixed brains, which were stored for imaging ex vivo 6-12 months later. We then compared the structural imaging, DTI, and NODDI results between different methods.
RESULTS
In vivo to ex vivo structural and DTI/NODDI findings were in notably poor agreement regarding the effects of concussion on structural integrity of the brain. Comparison with existing methods ex vivo imaging was frequently done to study the effects of diseases and treatments, but our results showed that ex vivo and in vivo imaging can detect completely opposite and contradictory results. This is also the first study that compares in vivo and ex vivo NODDI.
CONCLUSION
Our findings call for caution in extrapolating translational capabilities obtained ex vivo to physiological measurements in vivo. The divergent findings may reflect fixation artefacts and the contribution of the glymphatic system changes.
Date of Publication
2023-12-01
Publication Type
Article
Subject(s)
600 - Technology::610 - Medicine & health
Keyword(s)
Concussion DTI NODDI ex vivo in vivo mice structural imaging
Language(s)
en
Contributor(s)
Vinh To, Xuan | |
Kurniawan, Nyoman D | |
Nasrallah, Fatima A |
Additional Credits
Universitätsklinik für Nuklearmedizin
Series
Brain research
Publisher
Elsevier
ISSN
0006-8993
Access(Rights)
open.access