Evaluation of the 3D fractal dimension as a marker of structural brain complexity in multiple-acquisition MRI
Krohn, Stephan; Froeling, Martijn; Leemans, Alexander; Ostwald, Dirk; Villoslada, Pablo; Finke, Carsten; Esteban, Francisco J.
(2019) Human Brain Mapping, volume 40, issue 11, pp. 3299 - 3320
(Article)
Abstract
Fractal analysis represents a promising new approach to structural neuroimaging data, yet systematic evaluation of the fractal dimension (FD) as a marker of structural brain complexity is scarce. Here we present in-depth methodological assessment of FD estimation in structural brain MRI. On the computational side, we show that spatial scale
... read more
optimization can significantly improve FD estimation accuracy, as suggested by simulation studies with known FD values. For empirical evaluation, we analyzed two recent open-access neuroimaging data sets (MASSIVE and Midnight Scan Club), stratified by fundamental image characteristics including registration, sequence weighting, spatial resolution, segmentation procedures, tissue type, and image complexity. Deviation analyses showed high repeated-acquisition stability of the FD estimates across both data sets, with differential deviation susceptibility according to image characteristics. While less frequently studied in the literature, FD estimation in T2-weighted images yielded robust outcomes. Importantly, we observed a significant impact of image registration on absolute FD estimates. Applying different registration schemes, we found that unbalanced registration induced (a) repeated-measurement deviation clusters around the registration target, (b) strong bidirectional correlations among image analysis groups, and (c) spurious associations between the FD and an index of structural similarity, and these effects were strongly attenuated by reregistration in both data sets. Indeed, differences in FD between scans did not simply track differences in structure per se, suggesting that structural complexity and structural similarity represent distinct aspects of structural brain MRI. In conclusion, scale optimization can improve FD estimation accuracy, and empirical FD estimates are reliable yet sensitive to image characteristics.
show less
Download/Full Text
The full text of this publication is not available.
Keywords: fractal analysis, MRI biomarker, structural brain complexity, structural similarity, imaging validation, Clinical Neurology, Neurology, Radiological and Ultrasound Technology, Radiology Nuclear Medicine and imaging, Anatomy
ISSN: 1065-9471
Publisher: Wiley-Liss Inc.
Note: Funding Information: S.K. and C.F. are supported by the German Federal Ministry for Education and Research (BMBF grant 13GW0206D). The research of A.L. is supported by VIDI Grant 639.072.411 from the Netherlands Organization for Scientific Research (NWO). P.V. is employed by Gen-entech Inc. for work unrelated to this project. P.V. has stocks and is serving in the advisory board of Health Engineering SL (who has licensed a platform for measuring the FD from brain images from the University of Jaén and IDIBAPS), QMenta SL and Bionure SL. The work of F.J.E. is supported by Junta de Andalucía (BIO-302) and MEIC (Systems Medicine Excellence Network SAF2015-70270-REDT). Finally, the authors are grateful to Jakob Ludewig and Leonhard Waschke for inspiring discussions regarding the current work. Funding Information: Bundesministerium für Bildung und Forschung, Grant/Award Number: 13GW0206D; Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía, Grant/Award Number: BIO-302; MEIC Systems Medicine Excellence Network, Grant/Award Number: SAF2015-70270-REDT; Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Grant/Award Number: VIDI Grant 639.072.411 Funding Information: S.K. and C.F. are supported by the German Federal Ministry for Education and Research (BMBF grant 13GW0206D). The research of A.L. is supported by VIDI Grant 639.072.411 from the Netherlands Organization for Scientific Research (NWO). P.V. is employed by Genentech Inc. for work unrelated to this project. P.V. has stocks and is serving in the advisory board of Health Engineering SL (who has licensed a platform for measuring the FD from brain images from the University of Ja?n and IDIBAPS), QMenta SL and Bionure SL. The work of F.J.E. is supported by Junta de Andaluc?a (BIO-302) and MEIC (Systems Medicine Excellence Network SAF2015-70270-REDT). Finally, the authors are grateful to Jakob Ludewig and Leonhard Waschke for inspiring discussions regarding the current work. Publisher Copyright: © 2019 Wiley Periodicals, Inc.
(Peer reviewed)