Spectral CT imaging of myocardial infarction: preliminary animal experience.

Objectives: To evaluate the capability of spectral CT imaging to detect the different stages and angiogenesis of myocardial infarction (MI).

Methods: MI was surgically induced in 40 rabbits that were evenly divided into four stages of MI: 6 h (6H), 3 days (3D), 7 days (7D) and 14 days (14D). Spectral CT was performed at 10 s, 1 min and 3 min after intravenous contrast medium administration. CD31 immunohistochemistry was used for the microvessel density (MVD) measurement. Iodine concentrations in the myocardium were measured and normalised to the aorta as nIC. The relationships between infarcted myocardial nIC and MVD were analysed.

Results: The nIC of infarct myocardium decreased at 10 s and increased in late-phase CT images. There were significant differences between the 6H and other groups (P ( 6H-3D )  = 0.01, P ( 6H-7D )  = 0.01, P ( 6H-14D )  = 0.00). There was a significant difference in the MVD of infarct myocardium between the two groups except in the 7D and 14D groups (P = 0.08). In the 10-s phase, the nIC of infarct myocardium was negatively correlated with MVD (r = -0.54, P = 0.00), whereas in the late phases, there was a positive correlation between them (r = 0.57, P = 0.00 in the 1-min phase, r = 0.48, P = 0.00 in the 3-min phase).

Conclusion: Spectral CT imaging of the myocardium can be used to evaluate the different stages and angiogenesis of MI.