Through-plane dark-rim artefacts in 3D first-pass myocardial perfusion
KeywordsBritish Heart Foundation Biomedical Research Unit Pass Peak Endocardial Wall Cardiovascular Biomedical
The dark-rim artefact (DRA) is well known in 2D first-pass perfusion (FPP). The in-plane features of DRA are understood, but DRA has not been examined along the second phase-encoding (partition) direction for 3D FPP. The Gibbs contribution to DRAs in 2D FPP is minimised by finer resolution, but low through-plane resolutions of 3D FPP imply risk of partition axis DRAs. We investigated these new partition DRAs ("PDRAs") and partial volume effects due to coarse resolution of this direction.
A numerical phantom modelled a conical LV at intensity ratio 5:2 (blood:myocardium at first pass peak). Np, and the angle between endocardial wall and image plane, θB, were varied while plotting width of PDRAs.
In-vivo investigation: single-frame high-resolution data (1.3x1.3x2.0mm) was acquired by navigator-gated bSSFP at high flip-angle for similar blood:myocardium intensity ratio (approx 2:1).
LV blood and myocardium were manually segmented and the intensity of each tissue uniformly set to the 5:2 ratio of the numerical phantom. This gave more anatomically realistic data than the uniform cone, with changing θB along and around the LV.
Contrary to expectation that increased resolution reduces DRAs, at the low through-plane resolutions of 3D FPP increasing the resolution in this direction may increase Gibbs-induced DRAs due to sharper through-plane boundaries. However, this is a trade-off against partial volume blurring at low partition resolution. Further in-vivo investigations should optimise compromise between these two effects.
Supported by the NIHR Cardiovascular Biomedical Research Unit of Royal Brompton and Harefield NHS Foundation Trust and Imperial College London, UK.
MF is funded by a British Heart Foundation (BHF) PhD Studentship Grant - FS/13/21/30143.
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