Associate Professor of Biomedical Imaging
Improving disease diagnosis using Cardiac MRI and MRS at high field strength.
Cardiac Magnetic Resonance Imaging is a technology that has emerged as an incredibly powerful tool for visualising the human heart. In the last 15 years the method has gone from an approach that was academically interesting to one that is used clinically on hundreds of patients every day. In oxford we enjoy being part of this revolution. Specifically Oxford is pioneering the use of high magnetic field MRI to push forward the boundaries of what is possible with MR of the entire cardiovascular system.
The cardiac physics team, which I presently lead, works in a number of areas. These include the use of MRS (magnetic resonance spectroscopy) for directly measuring the concentration of metabolites in the heart (using both the proton and the phosphorus signatures), which benefits greatly to our access to our 3 Tesla and 7 Tesla human scanners. We are also investigating how we can use our 7 Tesla human scanner (one of only 2 in the UK, and 30 worldwide) to better diagnose cardiac disease. Cardiac spectroscopy is an area that was first pioneered in Oxford over 20 years ago and with these latest technical innovations we hope that we will at last make is clinically useful.
Another area of expertise lies in the characterising tissue using its MR properties. Specifically we are interested in the relaxation times of the tissues which we have found demonstrate remarkable correlations with disease. (figure ShMOLLI provides an accurate T1 map in a single breath-hold). The new methods that we have developed make it very easy to perform precise diagnoses that makes cardiac MRI much easier to perform. We believe that these mapping methods are set to revolutionise cardiac MRI and now we have validated the applicability of these methods in the clinic (with our clinical partners in Oxford and beyond) we are working closely with Siemens Healthcare to make these methods available to routine clinical MRI sites.
A further area with which I have worked is in Ultra-Short Echo Time (UTE) imaging, in which we reduce the imaging time down from milliseconds to microseconds. This enables us to image hydrogen nuclei that previously were invisible to MRI. Usefully the protons associated with collagen fall into this category and consequently these approaches have found great utility when imaging the musculo skeletal systems of the body. Although this isn’t a direct area of research for me, I am fortunate enough to be able to collaborate with groups using my methods, which is very exciting.
Cardiac gating using scattering of an 8-channel parallel transmit coil at 7T.
Jaeschke SHF. et al, (2018), Magn Reson Med, 80, 633 - 640
Diaphragm position can be accurately estimated from the scattering of a parallel transmit RF coil at 7 T.
Hess AT. et al, (2018), Magn Reson Med, 79, 2164 - 2169
Phosphodiester content measured in human liver by in vivo 31 P MR spectroscopy at 7 tesla.
Purvis LAB. et al, (2017), Magn Reson Med, 78, 2095 - 2105
Quantitative ultrashort echo time imaging for assessment of massive iron overload at 1.5 and 3 Tesla.
Krafft AJ. et al, (2017), Magn Reson Med, 78, 1839 - 1851
Adiabatic excitation for 31 P MR spectroscopy in the human heart at 7 T: A feasibility study.
Valkovič L. et al, (2017), Magn Reson Med, 78, 1667 - 1673