01 Feb 21. Featured Paper

A four-dimensional computational model of dynamic contrast-enhanced magnetic resonance imaging measurement of subtle blood-brain barrier leakage.

Link to paper on NeuroImage

Authors

Jose Bernal, Maria d.C. Valdés-Hernández, Javier Escudero, Anna K. Heye, Eleni Sakka, Paul A. Armitage, Stephen Makin, Rhian M. Touyz, Joanna M. Wardlaw, Michael J. Thrippleton

Abstract

Dynamic contrast-enhanced MRI (DCE-MRI) is increasingly used to quantify & map the spatial distribution of blood-brain barrier (BBB) leakage in neurodegenerative disease, including cerebral small vessel disease & dementia.

However, the subtle nature of leakage & resulting small signal changes make quantification challenging.

While simplified one-dimensional simulations have probed the impact of noise, scanner drift, & model assumptions, the impact of spatio-temporal effects such as gross motion, k-space sampling & motion artefacts on parametric leakage maps has been overlooked.

Moreover, evidence on which to base the design of imaging protocols is lacking due to practical difficulties & the lack of a reference method.

To address these problems, we present an open-source computational model of the DCE-MRI acquisition process for generating four dimensional Digital Reference Objects (DROs), using a high-resolution brain atlas & incorporating realistic patient motion, extra-cerebral signals, noise & k-space sampling.

Simulations using the DROs demonstrated a dominant influence of spatio-temporal effects on both the visual appearance of parameter maps & on measured tissue leakage rates.

The computational model permits greater understanding of the sensitivity & limitations of subtle BBB leakage measurement & provides a non-invasive means of testing & optimising imaging protocols for future studies.

Keywords

• Blood-brain barrier permeability
• Cerebral small vessel disease
• DCE-MRI
• Digital reference object
• Endothelial dysfunction
• Spatio-temporal imaging artefacts