Fractal Analysis of MRI Data at 7 T: How Much Complex Is the Cerebral Cortex?
The human brain is a highly complex structure, which can be only partially described by conventional metrics derived from magnetic resonance imaging (MRI), such as volume, cortical thickness, and gyrification index. In the last years, the fractal dimension (FD) – a useful quantitative ind...
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doaj-9bf5447b41454cb9aa01e279e474d27c2021-05-13T23:00:53ZengIEEEIEEE Access2169-35362021-01-019692266923410.1109/ACCESS.2021.30773709422711Fractal Analysis of MRI Data at 7 T: How Much Complex Is the Cerebral Cortex?Chiara Marzi0https://orcid.org/0000-0002-1791-3573Marco Giannelli1https://orcid.org/0000-0002-4061-0490Carlo Tessa2Mario Mascalchi3Stefano Diciotti4https://orcid.org/0000-0001-8778-7819Department of Electrical, Electronic, and Information Engineering “Guglielmo Marconi,”, University of Bologna, Cesena, ItalyUnit of Medical Physics, Pisa University Hospital “Azienda Ospedaliero-Universitaria Pisana,”, Pisa, ItalyRadiology Unit Apuane e Lunigiana, Azienda USL Toscana Nord Ovest, Massa, ItalyDepartment of Experimental and Clinical Biomedical Sciences “Mario Serio,”, University of Florence, Florence, ItalyDepartment of Electrical, Electronic, and Information Engineering “Guglielmo Marconi,”, University of Bologna, Cesena, ItalyThe human brain is a highly complex structure, which can be only partially described by conventional metrics derived from magnetic resonance imaging (MRI), such as volume, cortical thickness, and gyrification index. In the last years, the fractal dimension (FD) – a useful quantitative index of fractal geometry – has proven to well express the morphological complexity of the cerebral cortex. However, this complexity is likely higher than that we can observe using MRI scanners with 1.5 T or 3 T field strength. Ultrahigh-field MRI (UHF-MRI) improves imaging of smaller anatomical brain structures by exploring down to a submillimetric spatial resolution with higher signal-to-noise and contrast-to-noise ratios. Accordingly, we hypothesized that UHF-MRI might reveal a higher level of the structural complexity of the cerebral cortex. In this study, using an improved box-counting algorithm, we estimated the FD of the cerebral cortex in six public or private T1-weighted MRI datasets of young healthy subjects (for a total of 87 subjects), acquired at different field strengths (1.5 T, 3 T, and 7 T). Our results showed, for the first time, that MRI-derived FD values of the cerebral cortex imaged at 7 T were significantly higher than those observed at lower field strengths. UHF-MRI provides an anatomical definition not achievable at lower field strengths and can improve unveiling the real structural complexity of the human brain.https://ieeexplore.ieee.org/document/9422711/Braincerebral cortexcomplexityfractal dimensionultrahigh-field magnetic resonance imaging |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Chiara Marzi Marco Giannelli Carlo Tessa Mario Mascalchi Stefano Diciotti |
spellingShingle |
Chiara Marzi Marco Giannelli Carlo Tessa Mario Mascalchi Stefano Diciotti Fractal Analysis of MRI Data at 7 T: How Much Complex Is the Cerebral Cortex? IEEE Access Brain cerebral cortex complexity fractal dimension ultrahigh-field magnetic resonance imaging |
author_facet |
Chiara Marzi Marco Giannelli Carlo Tessa Mario Mascalchi Stefano Diciotti |
author_sort |
Chiara Marzi |
title |
Fractal Analysis of MRI Data at 7 T: How Much Complex Is the Cerebral Cortex? |
title_short |
Fractal Analysis of MRI Data at 7 T: How Much Complex Is the Cerebral Cortex? |
title_full |
Fractal Analysis of MRI Data at 7 T: How Much Complex Is the Cerebral Cortex? |
title_fullStr |
Fractal Analysis of MRI Data at 7 T: How Much Complex Is the Cerebral Cortex? |
title_full_unstemmed |
Fractal Analysis of MRI Data at 7 T: How Much Complex Is the Cerebral Cortex? |
title_sort |
fractal analysis of mri data at 7 t: how much complex is the cerebral cortex? |
publisher |
IEEE |
series |
IEEE Access |
issn |
2169-3536 |
publishDate |
2021-01-01 |
description |
The human brain is a highly complex structure, which can be only partially described by conventional metrics derived from magnetic resonance imaging (MRI), such as volume, cortical thickness, and gyrification index. In the last years, the fractal dimension (FD) – a useful quantitative index of fractal geometry – has proven to well express the morphological complexity of the cerebral cortex. However, this complexity is likely higher than that we can observe using MRI scanners with 1.5 T or 3 T field strength. Ultrahigh-field MRI (UHF-MRI) improves imaging of smaller anatomical brain structures by exploring down to a submillimetric spatial resolution with higher signal-to-noise and contrast-to-noise ratios. Accordingly, we hypothesized that UHF-MRI might reveal a higher level of the structural complexity of the cerebral cortex. In this study, using an improved box-counting algorithm, we estimated the FD of the cerebral cortex in six public or private T1-weighted MRI datasets of young healthy subjects (for a total of 87 subjects), acquired at different field strengths (1.5 T, 3 T, and 7 T). Our results showed, for the first time, that MRI-derived FD values of the cerebral cortex imaged at 7 T were significantly higher than those observed at lower field strengths. UHF-MRI provides an anatomical definition not achievable at lower field strengths and can improve unveiling the real structural complexity of the human brain. |
topic |
Brain cerebral cortex complexity fractal dimension ultrahigh-field magnetic resonance imaging |
url |
https://ieeexplore.ieee.org/document/9422711/ |
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