Quantitative Ex Vivo MRI Changes due to Progressive Formalin Fixation in Whole Human Brain Specimens: Longitudinal Characterization of Diffusion, Relaxometry, and Myelin Water Fraction Measurements at 3T
| العنوان: | Quantitative Ex Vivo MRI Changes due to Progressive Formalin Fixation in Whole Human Brain Specimens: Longitudinal Characterization of Diffusion, Relaxometry, and Myelin Water Fraction Measurements at 3T |
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| المؤلفون: | Anwar S. Shatil, Md Nasir Uddin, Kant M. Matsuda, Chase R. Figley |
| المصدر: | Frontiers in Medicine, Vol 5 (2018) Frontiers in Medicine |
| بيانات النشر: | Frontiers Media SA, 2018. |
| سنة النشر: | 2018 |
| مصطلحات موضوعية: | Relaxometry, longitudinal, Brain mapping, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Nuclear magnetic resonance, In vivo, Fractional anisotropy, medicine, human brain, Original Research, Fixation (histology), postmortem, lcsh:R5-920, T2, T1, fixation, Chemistry, diffusion, General Medicine, Human brain, formalin, myelin, medicine.anatomical_structure, ex vivo, Medicine, lcsh:Medicine (General), 030217 neurology & neurosurgery, Ex vivo, MRI, Diffusion MRI |
| الوصف: | Purpose: Postmortem MRI can be used to reveal important pathologies and establish radiology-pathology correlations. However, quantitative MRI values are altered by tissue fixation. Therefore, the purpose of this study was to investigate time-dependent effects of formalin fixation on MRI relaxometry (T1 and T2), diffusion tensor imaging (fractional anisotropy, FA; and mean diffusivity, MD), and myelin water fraction (MWF) measurements throughout intact human brain specimens. Methods: Two whole, neurologically-healthy human brains were immersed in 10% formalin solution and scanned at 13 time-points between 0 and 1032 hours. Whole brain maps of longitudinal (T1) and transverse (T2) relaxation times, FA, MD, and MWF were generated at each time-point to illustrate spatiotemporal changes, and region-of-interest analyses were then performed in eight brain structures to quantify temporal changes with progressive fixation. Results: Although neither of the diffusion measures (FA nor MD) showed significant changes as a function of formalin fixation time, both T1 and T2-relaxation times significantly decreased, and MWF estimates significantly increased with progressive fixation until (and likely beyond) our final measurements were taken at 1032 hours. Conclusions: These results suggest that T1-relaxation, T2-relaxation and MWF estimates must be performed quite early in the fixation process to avoid formalin-induced changes compared to in vivo values; and furthermore, that different ex vivo scans within an experiment must be acquired at consistent (albeit still early) fixation intervals to avoid fixative-related differences between samples. Conversely, ex vivo diffusion measures (FA and MD) appear to depend more on other factors (e.g., pulse sequence optimization, sample temperature, etc.). |
| تدمد: | 2296-858X |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cd058c55a89b55ec10410ca3c8048e44Test https://doi.org/10.3389/fmed.2018.00031Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....cd058c55a89b55ec10410ca3c8048e44 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 2296858X |
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