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4-dimensional local radial basis function interpolation of large, uniformly spaced datasets

Thewlis, J.; Stevens, D.; Power, H.; Giddings, D.; Gowland, P.; Vloeberghs, M.


J. Thewlis

D. Stevens

H. Power

M. Vloeberghs


Background and Objective: Large, uniformly spaced, complex and time varying datasets derived from high resolution medical image velocimetry can provide a wealth of information regarding small-scale transient physiological flow phenomena and pulsation of anatomical boundaries. However, there remains a need for interpolation techniques to effectively reconstruct a fully 4-dimensional functional relationship from this data. This paper presents a preliminary evaluation of a 4-dimensional local radial basis function (RBF) algorithm as a means of addressing this problem for laminar flows. Methods: A 4D interpolation algorithm is proposed based on a Local Hermitian Interpolation (LHI) using a combination of multi-quadric RBF with a partition of unity scheme. The domain is divided into uniform sub-systems with size restricted to immediately neighbouring points. The validity of the algorithm is first established on a known 4D analytical dataset and a CFD based laminar flow phantom. Application is then demonstrated through characterisation of a large 4D laminar flow dataset obtained from magnetic resonance imaging (MRI) measurements of cerebrospinal fluid velocities in the brain. Results: Performance of the algorithm is compared to that of a quad-linear interpolation, demonstrating favourable improvement in accuracy. The technique is shown to be robust, computationally efficient and capable of refined interpolation in Euclidean space and time. Application to MR velocimetry data is shown to produce promising results for the 4D reconstruction of the transient flow field and movement of the fluid boundaries at spatial and temporal locations intermediate to the original data. Conclusion: This study has demonstrated feasibility of an accurate, stable and efficient 4-dimensional local RBF interpolation method for large, transient laminar flow velocimetry datasets. The proposed approach does not suffer from ill-conditioning or high computational cost due to domain decomposition into local stencils where the RBF is only ever applied to a limited number of points. This work offers a potential tool to assist medical diagnoses and drug delivery through better understanding of physiological flow fields such as cerebrospinal fluid. Further work will evaluate the technique on a wider range of flow fields and against CFD simulation.

Journal Article Type Article
Acceptance Date Nov 5, 2022
Online Publication Date Nov 7, 2022
Publication Date 2023
Deposit Date Dec 5, 2022
Publicly Available Date Nov 8, 2023
Journal Computer Methods and Programs in Biomedicine
Print ISSN 0169-2607
Electronic ISSN 1872-7565
Publisher Elsevier BV
Peer Reviewed Peer Reviewed
Volume 228
Article Number 107235
Keywords radial basis function; image reconstruction; cerebrospinal fluid
Public URL
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