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Diffusion tensor cardiovascular magnetic resonance (DT-CMR) is a non-invasive imaging technique that provides insight into myocardial microstructure. Recently, there has been growing interest in DT-CMR and an increasing number of clinical studies. Due to limited spatial resolution, DT-CMR is often not possible in thinned myocardium due to disorders such as myocardial infarction (MI). The aim of this work is to increase the spatial resolution of DT-CMR and apply this new method in a cohort of MI patients. An interleaved variable-density spiral stimulated echo acquisition mode DT-CMR sequence with two interleaves was implemented and validated in phantoms, healthy volunteers and MI patients at a resolution of 1.8×1.8×8mm3. Corrections for motion-induced phase, off-resonance and T2* were developed. The frequency segmented off-resonance correction used a novel stimulated echo acquisition mode based field-map acquisition with a motion-induced phase correction and a reduced field-of-view. High-resolution DT-CMR was successfully acquired in all subjects. The artefact corrections were essential for high quality spiral DT-CMR data. DT-CMR parameters were similar between the proposed high-resolution sequence and established methods at standard-resolutions in healthy volunteers. Secondary eigenvector angulation (E2A) was evaluated for the first time in MI patients. Systolic E2A decreased with a gradient from highest in the remote, through the peri-infarcted and infarcted regions. The difference in E2A between systole and diastole was reduced in all regions relative to controls suggesting reduced sheetlet mobility and that the whole myocardium is affected by remodeling. This is the first demonstration of DT-CMR at this high-resolution and the work suggests that clinical translation is possible. The artefact corrections developed are essential for spiral DT-CMR and the new technical developments may find use in other spiral applications. In addition to the original aims, the work provides potential new insights into microstructural changes in MI. Open Access |
