Fig 1.
Diagram of the proposed 3D self-gating CMR method for detecting MI in mouse.
(a) The stack-of-stars sampling scheme comprises Cartesian encoding along kz direction and radial projections filling in kx-ky plane. All partition encodes for a given projection angle are collected sequentially before switching to the next projection angle. This partition-first sampling scheme enables the projection centers (denoted as black solid circles) to be used as self-gating data for extracting cardiac and respiratory motion signals; (b) Corresponding 3D GRE sequence with stack-of-stars sampling trajectories.
Fig 2.
Pipeline of extracting the cardiac and respiratory motion signals.
(a) The central points (black solid circles) of each projection angle denote a self-gating data profile. (b) Z-intensity profile generated by performing 1D Fourier transform of the self-gating data profiles. (c) Mixed cardiac and respiratory motion signals were obtained by calculating the center of mass from (b). (d) The respiratory and cardiac motion signals extracted by bandpass filtering of (c) and used for data realignment.
Fig 3.
Illustration of contouring the MI areas on both MR and histological images.
The boundaries (yellow solid lines) were first determined by Image-Pro Plus software and then manually outlined for reducing the measurement bias.
Table 1.
Heart and respiratory rates obtained by the proposed self-gating method and the rodent ventilator.
Fig 4.
Representative images reconstructed by conventional regridding method and the proposed CS method.
Compared with the conventional regridding method, the images reconstructed by the proposed CS method show much less streaking artifacts.
Table 2.
CNRs between the blood and myocardium for images obtained by conventional regridding method and the proposed CS method.
Fig 5.
Representative histological pictures and reconstructed MR images from two mice with MI induction.
The regions of MI (yellow arrows) matched between the histology analysis and the proposed method.
Fig 6.
Comparisons of cross-sectional infarction and myocardial size ratio in six subjects obtained with the proposed method and the standard histological analysis approach.
(a) Infarction and myocardial area ratio linear regression analysis of the two approaches. (b) Bland-Altman plots of the measurements. Mean difference values are represented by a solid line and the confidence intervals by dashed lines.