Abstract 769: Quantification and MRI Validation of Regional Contractile Dysfunction in Mice Post Myocardial Infarction Using High Resolution Ultrasound
Background: This study quantifies 2D regional contractile function of the left ventricle (LV) in mice 24h after myocardial infarction (MI) using high resolution ultrasound (US) imaging, and compares the results to DENSE cardiac MRI.
Methods: Fifteen C57BL/6 mice were scanned at high frame rate by cardiac ultrasound (Vevo 770, VisualSonics) 24h after MI induced by coronary occlusion. Four normal mice were examined as controls. Regional myocardial contractile measurements, including displacement, radial strain (RS) and circumferential strain (CS), were measured using an optimized, computationally-efficient 2D speckle-tracking algorithm. Strain analyses from the US images were compared to DENSE MRI performed on the same mice.
Results: Panel A: ED to ES displacements from speckle-tracking (infarct indicated by large arrow). B: Displacement loops from inset in A indicating both displacement tracks and velocities. Note twist during systole and recoil during diastole. C&D: CS maps from US (C) and DENSE MRI (D). Comparisons between US and MRI yielded promising correlations for RS and CS (R = 0.91 & R = 0.84, respectively). Also, analysis of US images yielded significantly decreased maximum systolic velocity (Vmax) and maximum systolic strain rate (SRmax) in the infarcted and adjacent myocardium, revealing post-MI contractile dysfunction.
Conclusions: US imaging, followed by 2D speckle tracking on B-mode images, can accurately quantify regional myocardial contractile dysfunction in mice post-MI, with the advantages of being an effective, low cost, versatile and mobile alternative to MRI for non-invasive, accurate and reliable quantification of murine cardiac function.