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Public Engagement Officer Closing date 6th February 2022
We are currently recruiting for the following role(s):
Magnetic Resonance Imaging (MRI) is an important step in many clinical pathways, and a crucial resource in brain imaging research. Currently, up to 37% of patients undergoing MRI report moderate to high anxiety levels, with reasons including claustrophobia, loud acoustic noise, and length of scan, while up to 30% of in-patient or emergency MR examinations are corrupted beyond use due to motion artefacts, and 14% of subjects require sedation. These issues waste significant quantities of money and can make recruitment of patients into long-term studies difficult. A simple way to reduce anxiety, and hence improve the patient experience, is to reduce the acoustic noise level of an MR scan.
The physics team in the Department of Neuroimaging at Denmark Hill have together with collaborators at GE Healthcare pioneered development of novel MRI techniques with reduced acoustic noise. In the first half of 2020, we saw several projects in silent MRI come to a conclusion, marking an important step forward in our research in silent MRI.
The project is largely divided into development of silent structural and silent functional MRI methods, both of which have demonstrated impressive leaps forward this year.
Emil Ljungberg successfully defended his PhD thesis which focused on how to generate useful image contrast with silent MRI. Part of his thesis was published in Magnetic Resonance in Medicine, demonstrating silent T1 mapping using the VFA method . Emil is now working on implementing motion correction into silent MRI in a postdoctoral fellowship supported by the CME.
Postdoctoral CME fellow Dr. Tobias Wood published his first silent MRI paper, focusing on magnetisation transfer (MT), and more specifically on myelin-weighted imaging using the recently proposed inhomogeneous MT (ihMT) contrast .
Nikou Damestani, an NIHR Maudsley BRC PhD student, is working on the development of silent fMRI using a sequence known as Looping Star. She presented initial results of using Looping Star with an auditory oddball paradigm, highlighting the benefits of minimising the confound of acoustic noise .
In collaboration with GE Healthcare, our team has also demonstrated the utility of a multi-contrast silent method which can capture T1, T2, and proton density images in one combined acquisition.
The team is now busy wrapping up the year with some really exciting results to share early next year. Watch this space!
Magnetic resonance imaging (MRI) is considered the gold standard for the assessment of cardiac anatomy, left ventricular (LF) function (CINE-MRI), myocardial viability (LGE-MRI), myocardial tissue characterization (T1 and T2 relaxation time mapping) and perfusion (MR-perfusion) due to its excellent soft tissue contrast, high spatial resolution and lack of ionizing radiation according to a Society for Magnetic Resonance (SCMR) expert consensus statement. However, a key limitation of the current MRI acquisition scheme is that all imaging sequences (e.g. CINE, LGE, T1 and T2 mapping, coronary MR angiography (MRA), etc.) are acquired sequentially, in different geometric orientations, at different breath-hold positions or using time inefficient navigator gating methods.
To address this limitation, we developed a novel non-invasive, radiation-free and contrast-free Magnetic Resonance Imaging (MRI) framework for comprehensive assessment of coronary and myocardial disease in a single multi-contrast and multi-parametric high-resolution 3D whole-heart scan.
This novel framework includes advanced respiratory motion correction methods which include beat-to-beat translational motion correction using image navigators (iNAV) and bin-to-bin non-rigid motion correction using the imaging data itself thereby allowing for shorter and predictable scan time resulting in improved image quality. In addition, novel imaging sequences were developed which allow the simultaneous visualization of the coronary vessels, coronary thrombus, high intensity plaque and myocardial scar (BOOST sequence) (1-3). These techniques now have been combined with advanced undersampling reconstruction techniques (ORCCA (4) and PROST (5)), which allow respiratory motion resolved reconstruction and highly undersampled reconstruction (3-4 fold) of non-rigid motion corrected whole heart coronary MR angiography (CMRA) datasets(6). To enable multi centric clinical validation we have developed works in progress packages (WIPs) together with Siemens Healthineers for our CMRA and BOOST sequence. The CMRA WIP also includes the option of performing free-breathing high-resolution motion corrected 3D myocardial viability imaging with and without black blood option, which is important for the detection of small infarctions or arrhythmic substrate. The multi-contrast BOOST sequence has also been extended to allow joint T1/T2 mapping(7) and was combined with the latest motion correction and image reconstruction developments to further increase image resolution and shorten scan time. We also have developed a motion corrected free running 3D whole heart T1 (8) and joint T1/T2 mapping technique(9) for simultaneous assessment of fibrosis and edema and which is based on a 3D radial trajectory and a low rank patched based reconstruction. All sequences are currently tested in patients with cardiovascular disease. Specifically, we have scanned 50 patients referred from the CTCA list with our high resolution CMRA protocol (0.9mm3) with the CMRA images approaching CT image quality but without the need for radiation or nephrotoxic contrast agents. The highlight of this clinical study is that all CMRA were completed successfully and that 97% of the proximal and 94% of the middle coronary segments were of diagnostic image quality (vs 99% and 98% for CTCA). Specificity and negative predicative value for identification of coronary artery disease were 93-98% and 95-100% for LM, LAD, RCA and LCx.