Objective:To devise an appropriate measure of the quality of a magnetic resonance imaging (MRI) signal for the assessment of dynamic cerebral autoregulation, and propose simple strategies to improve its quality. Materials and methods: Magnetic resonance images of 11 healthy subjects were scanned during a transient decrease in arterial blood pressure (BP). Mean signals were extracted from non-overlapping brain regions for each image. An ad-hoc contrast-to-noise ratio (CNR) was used to evaluate the quality of these regional signals. Global mean signals were obtained by averaging the set of regional signals resulting after applying a Hampel filter and discarding a proportion of the lower quality component signals. Results: Significant improvements in CNR values of global mean signals were obtained, whilst maintaining significant correlation with the original ones. A Hampel filter with a small moving window and a low rejection threshold combined with a selection of the 50% component signals seems a recommendable option. Conclusions: This work has demonstrated the possibility of improving the quality of MRI signals acquired during transient drops in BP. This approach needs validation at a voxel level, which could help to consolidate MRI as a technological alternative to the standard techniques for the study of cerebral autoregulation.
CITATION STYLE
Jara, J. L., Saeed, N. P., Panerai, R. B., & Robinson, T. G. (2018). Increasing the contrast-to-noise ratio of MRI signals for regional assessment of dynamic cerebral autoregulation. In Acta Neurochirurgica, Supplementum (Vol. 126, pp. 153–157). Springer-Verlag Wien. https://doi.org/10.1007/978-3-319-65798-1_32
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