Fig 1.
Example of Helical Angle (HA) map.
This shows a smooth progression from a left-handed helical pattern in the epicardium (blue) to a circumferential orientation in the mesocardium (green) and right-handed helical pattern in the endocardium (red).
Fig 2.
Colour coded Bullseye plot of mean helical angle values per transmural layer and regional wall.
The inner, middle and outer rings represent the endo, meso and epicardium respectively. The upper, right, lower and left segments represent the anterior, lateral, inferior and septal walls respectively.
Fig 3.
Example of regional HA line profiles.
The x-axis shows the percentage distance from the endocardial surface. A relative reduction in the transmural helical angle gradient can be appreciated in the mesocardium.
Fig 4.
Typical examples of fractional anisotropy (FA) maps.
The maps show a circumferential increase in FA (red) in the mesocardium, indicating a more anisotropic composition of myocytes compared to the endo- and epicardium.
Fig 5.
Colour Bullseye maps showing the significant heterogeneity in the distribution of FA, MD, SNR and e1-e3.
The outer ring shows results from the epicardium, the middle ring shows the mesocardium, and the inner ring shows the endocardium of the single left ventricular slice. The four walls are also shown in their usual positions: Upper- anterior wall; left- septum; lower- inferior wall; right- lateral wall.
Table 1.
Fractional Anisotropy Regional Analysis.
Lateral wall used as the reference for statistical comparisons.
Fig 6.
Typical Mean Diffusivity (MD) map.
There is a subtle increased in the septal MD compared to the other regions.
Table 2.
Mean Diffusivity Regional Analysis (×10-3mm2s-1) Lateral wall used as the reference for statistical comparisons.
Table 3.
E1 Regional Analysis (×10-3mm2s-1).
Lateral wall used as the reference for statistical comparisons.
Table 4.
E2 Regional Analysis (×10-3mm2s-1).
Lateral wall used as the reference for statistical comparisons.
Table 5.
E3 Regional Analysis (×10-3mm2s-1).
Lateral wall used as the reference for statistical comparisons.
Table 6.
Lateral wall used as the reference for statistical comparisons.
Fig 7.
HA, FA, MD and SNR maps for 2 subjects at standard resolution (2.8x2.8x8mm2) and higher resolution (1.9x1.9x6mm2).
In both cases the SNR is reduced in the higher resolution scan, especially in the lateral and inferior walls. There is no difference in the transmural helical angle patterns. In regions of poor SNR in the higher resolution scans, the FA is increased and the MD is decreased. Transmurally there is little change in the FA heterogeneity between standard and higher resolution imaging.