Cerebral small vessel disease (SVD) is a major underlying contributor to ischaemic and
haemorrhagic stroke, cognitive decline, and dementia. Neuroimaging features of SVD have
been shown to be associated with increased risk of stroke occurrence, reoccurrence, and
cognitive decline post-stroke. New approaches are needed that target SVD diagnosis,
monitoring, and treatment, to improve outcomes across the stroke and cognitive decline
care pathways. However, providing equitable access to advanced medical technologies
across the Scottish population is becoming a significant burden on the NHS and wider
clinical community. Low-field MRI, which is both more cost-effective and less complex to
operate, has the potential to address this growing societal burden at a whole-population
level. Whilst on-going research efforts remain focussed on developing new interventions
to slow progression of SVD and improve treatment outcomes, work is also needed to improve
approaches to assess SVD pathophysiology, severity, progression, and treatment outcome.
Repeated assessment with magnetic resonance imaging (MRI), is recognised as the best
solution to detect the multiple features that combine to produce SVD. This has the
potential to identify markers of stroke risk and cognitive decline and, in future, guide
tailored treatments to better manage stroke risk and improve post-stroke long-term
outcomes. No other imaging technique, blood test or other assessment can provide the
necessary information. However, the high cost and infrastructure demands of conventional
MRI means that while it is feasible for clinical trials and research, it cannot
realistically be used for widespread repeated brain imaging assessment, or screening, for
SVD. For this reason, robust and reliable imaging methods that can be easily implemented
across the whole Scottish population, rural/urban, wealthy/deprived must be developed.
Operating at magnetic field strengths up to 10,000 times lower than conventional MRI,
low-field MRI technologies provide a unique opportunity to make repeated brain imaging
cost-effective and accessible in community and outpatient settings. The utility of
commercially available portable low-field MRI technology, operating at a fixed field of
64 mT (milliTesla), has already been proven for imaging acute stroke at the bedside of
patients and recent preliminary findings have indicated its feasibility to detect
moderate and severe SVD. However, the novelty of portable low-field MRI means that its
full potential has yet to be realised, and work is now required to develop low-field
quantitative imaging approaches to enhance the capabilities of low-field MRI to extract
underlying features related to brain health and SVD severity. We aim to provide a
stepping-stone to optimised fixed low-field MRI technology by leveraging the unique
capabilities of field-cycling imaging (FCI), a unique whole-body MRI technology developed
at the University of Aberdeen. IRAS Form Reference: 25/PR/0216 IRAS Version 6.4.1 Date:
13/02/2025 350553/1711955/37/104 7Investigations using field-cycling technologies, which
vary the strength of the magnetic field during acquisition, have shown unique sensitivity
to tissue features and contrast mechanisms that are invisible at higher, fixed, magnetic
fields such as 1.5 and 3T. Furthermore, using FCI, differences between healthy tissue and
stroke pathology have been observed. Our own preliminary results, using the mark 2 FCI
scanner to image patients with SVD at field strengths between 0.2 and 200 mT have shown a
significant positive linear correlation between the volume of SVD extracted from FCI
images and from 3T MRI images. However, these preliminary results, limited to a single
slice acquisition at 3.1 x 3.1 x 10 mm resolution, do not provide the full evidence
needed to design new, cost-effective and accessible, lowfield MRI scanners that would
enable widespread, repeated brain imaging assessment for SVD. The objective of this
proposal is therefore to address this evidence gap and to inform the design of new
low-field MRI technologies tailored to extracting key markers of SVD. First, by utilising
the unique capabilities of the new mark 3 FCI scanner, now onsite at Aberdeen Royal
Infirmary, imaging data will be acquired at multiple different field strengths, and a
higher pixel resolution. This data will be used to determine the most effective low-field
approach to identify markers of SVD (e.g., white matter changes, reduced perfusion,
microbleeds, recent lacunar infarcts) and SVD progression. Second, by acquiring imaging
data from both field-cycling imaging (FCI) and a separate fixed low-field MRI scanner,
the extent of agreement between assessments of SVD will be examined.
