Figure 1.
Study design. (a) Fifteen adult male mice were randomly assigned into three surgical groups: (i) sham-operated controls, (ii) 30 min ischaemia–reperfusion (I/R), and (iii) permanent ligation (PL) of the left coronary artery (yellow arrow). A Vevo2100 ultrasound system was used to acquire 4D ultrasound data and flow information of the left ventricle at baseline and on days 1, 2, 3, 5, 7, 14, 21 and 28 post-surgery. At the end of the study, the heart was stained with haematoxylin–eosin (H&E) and Masson's trichrome (MTC). Yellow dashed outlines highlight the infarcted myocardium. (b) We reconstructed 4D ultrasound data from ECG and respiratory-gated 2D short-axis ultrasound images of the left ventricle. (c) Three-dimensional endocardial (red), epicardial (blue) and sternal artefact (white) boundaries were segmented at end-diastole and peak-systole. (d) Maximum principal 3D Green–Lagrange strain (EI) was calculated using a direct deformation estimation technique. (e) Strain was then localized within the myocardium using segmented boundaries and presented as bullseye maps (f). A, anterior; S, septal; L, lateral; B, base. Scale bar: 1 mm. (Online version in colour.)