Improvements in High Field MRI of Carotid Artery Wall
Carotid vessel wall with evidence
of an atherosclerotic plaque with
a necrotic core & fibrous cap
Significant research activity is underway in Oxford and elsewhere to develop imaging methods that can map the extent of tissue damage following acute vascular events, such as stroke. However, whilst imaging in the brain of the ‘downstream’ consequences of vascular disease is able to characterize potential and actual tissue damage, it is also important to develop improved strategies for characterizing the ‘upstream’ vascular pathology that leads to acute tissue damage. Unlike x-ray arteriography, ultrasound, and CT technologies, that have thus far been used as the principal methods of assessing atherosclerosis, MRI offers the capability to image both the vessel lumen and the arterial wall composition. By combining different MRI weightings to images of atherosclerotic plaque it has been shown that multi-contrast MRI is able to distinguish the lipid-rich core, thin fibrous cap, and intra-plaque haemorrhage, that all indicate unstable plaques at risk of causing stroke.
However, the vascular imaging tools that are currently available on commercial MRI scanners have poor slice coverage and long acquisition times, compromising our ability to characterise the vessel wall using MRI in patients, particularly in the acute setting. In this project we propose new approaches to vascular imaging at high field (3 Tesla) that will improve the slice coverage and substantially reduce the scan acquisition time. The techniques will be used in the newly constructed Oxford Acute Vascular Imaging Centre that incorporates a state-of-the-ar 3 Tesla MRI scanner and a biplanar angiography suite. The techniques we develop will also be optimized with ultra-high magnetic field in mind, such that they can be sent to the 7 Tesla system when this becomes available, and where we think that 7 Tesla atherosclerotic imaging may be a valuable clinical tool. Although the focus of this project is to study carotid artery wall, the methods will also have application in imaging the walls of other intracranial/-extracranial and cardiac vessels.
