Purpose: Diffusion tensor cardiovascular magnetic resonance (DT-CMR) has a limited spatial resolution. The
purpose of this study was to demonstrate high-resolution DT-CMR using a segmented variable density spiral
sequence with correction for motion, off-resonance and T2* related blurring.
Methods: A single-shot STEAM EPI DT-CMR sequence at 2.8x2.8x8mm3 and 1.8x1.8x8mm3 was compared to a
single shot spiral at 2.8x2.8x8mm3 and an interleaved spiral sequence at 1.8x1.8x8mm3
resolution in 10 healthy
volunteers at peak-systole and diastasis. Motion-induced phase was corrected using the densely sampled
central k-space data of the spirals. STEAM field maps and T2* measures were obtained using a pair of
stimulated echoes each with a double spiral readout, the first used to correct the motion-induced phase of the
second.
Results: The high resolution spiral sequence produced similar DT-CMR results and quality measures to the
standard resolution sequence in both cardiac phases. Residual differences in fractional anisotropy and helix
angle gradient between the resolutions could be due to spatial resolution and/or signal to noise ratio. The data
quality increased after both motion-induced phase correction and off-resonance correction and sharpness
increased after T2* correction. The high resolution EPI sequence failed to provide sufficient data quality for
DT-CMR reconstruction.
Conclusion: In this study an in-vivo DT-CMR acquisition at 1.8x1.8mm2
in-plane resolution was demonstrated
using a segmented spiral STEAM sequence. The motion-induced phase and off-resonance corrections are
essential for high resolution spiral DT-CMR. Segmented variable density spiral STEAM was found to be the
optimal method for acquiring high resolution DT-CMR data.