Abstract
Introduction
Susceptibility-weighted imaging (SWI) with high- and ultra-high-field magnetic resonance is a very helpful tool for evaluating brain gliomas and intratumoral structures, including microvasculature. Here, we test whether objective quantification of intratumoral SWI patterns by applying fractal analysis can offer reliable indexes capable of differentiating glial tumor grades.
Methods
Thirty-six patients affected by brain gliomas (grades II–IV, according to the WHO classification system) underwent MRI at 7 T using a SWI protocol. All images were collected and analyzed by applying a computer-aided fractal image analysis, which applies the fractal dimension as a measure of geometrical complexity of intratumoral SWI patterns. The results were subsequently statistically correlated to the histopathological tumor grade.
Results
The mean value of the fractal dimension of the intratumoral SWI patterns was 2.086 ± 0.413. We found a trend of higher fractal dimension values in groups of higher histologic grade. The values ranged from a mean value of 1.682 ± 0.278 for grade II gliomas to 2.247 ± 0.358 for grade IV gliomas (p = 0.013); there was an overall statistically significant difference between histopathological groups.
Conclusion
The present study confirms that SWI at 7 T is a useful method for detecting intratumoral vascular architecture of brain gliomas and that SWI pattern quantification by means of fractal dimension offers a potential objective morphometric image biomarker of tumor grade.
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Abbreviations
- FD:
-
Fractal dimension
- FDSWI :
-
Fractal dimension of the intratumoral SWI pattern
- WHO:
-
World Health Organization
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Acknowledgments
ADI received a 2010 research grant from the Italian Society of Neurosurgery (SINch) and a 2011 Aesculap European Association of Neurosurgical Societies Laboratory Research Prize. This study was supported by the Jubiläumsfonds of the Austrian National Bank (grant no. 13457). The authors wish to thank FMEA (the Society for the Promotion of Research in Microsurgical and Endoscopic Anatomy) for funding the production of this article. We would like to give special thanks to the Virtual Fractal Lab Team (www.fractal-lab.org) for developing the software used here and for their continued technical support beyond image and fractal analyses.
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We declare that we have no conflict of interest.
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The preliminary results of this study were presented at the 59th Congress of the Italian Society of Neurosurgery (SINch) in Milan, Italy; the Research Course of the European Association of Neurosurgical Societies (EANS) in Lausanne, Switzerland; and the 16th Congress of the Italian Society of Neurooncology (AINO) in Milan, Italy.
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Di Ieva, A., Göd, S., Grabner, G. et al. Three-dimensional susceptibility-weighted imaging at 7 T using fractal-based quantitative analysis to grade gliomas. Neuroradiology 55, 35–40 (2013). https://doi.org/10.1007/s00234-012-1081-1
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DOI: https://doi.org/10.1007/s00234-012-1081-1