Commercial 4-Dimensional Echocardiography for Murine Heart Volumetric Evaluation after Myocardial Infarction

Abstract

Background: Traditional preclinical echocardiography (ECHO) modalities, including 1-dimensional motion-mode (M-Mode) and 2-dimensional long axis (2D-US), rely on geometric and temporal assumptions about the heart for volumetric measurements. Surgical animal models, such as the mouse coronary artery ligation (CAL) model of myocardial infarction, result in morphologic changes that do not fit these geometric assumptions. New ECHO technology, including 4-dimensional ultrasound (4D-US), improves on these traditional models. This paper aims to compare commercially available 4D-US to M-mode and 2D-US in a mouse model of CAL.Methods: 37 mice underwent CAL surgery, of which 32 survived to a 4 week post-operative time point. ECHO was completed at baseline, 1 week, and 4 weeks after CAL. M-mode, 2D-US, and 4D-US were taken at each time point and evaluated by two separate echocardiographers. At 4 weeks a subset of mice underwent cardiac magnetic resonance (CMR) imaging to serve as a reference standard. End systolic volume (ESV), end diastolic volume (EDV), and ejection fraction (EF) were compared between imaging modalities. Hearts were also collected for histologic evaluation of scar size and compared to wall motion severity index (WMSI).Results: 4D-US provides closer agreement of ESV (Bias: -2.55%) and EF (US Bias: 11.23%) 4 weeks after CAL when compared to CMR, outperforming 2D-US and M-mode estimations. 4D-US is also more reliable than other modalities when estimating EDV (r=0.88), ESV (r=0.86) and EF (r=0.74) at 1 week when compared to 4 week imaging. 4D-US also allows for rapid assessment of WMSI, which correlates strongly with infarct size by histology (r=0.77).Conclusion: 4D-US outperforms M-Mode and 2D-US for volumetric analysis 4 weeks after CAL. 4D-US also provides more reliable measurements at 1 week after CAL and has less inter-user variability that other modalities. 4D-US allows for rapid calculation of WMSI, which correlates well with histologic scar size.

A novel ultrasound-guided mouse model of sudden cardiac arrest

“…Echocardiography was performed at baseline, 1 day, 1 week, and 4 weeks as previously described [10] and measured by a blinded operator. Briefly, transthoracic echocardiography was performed using the Vevo 3100 system and analyzed using VevoLab v3.2.5 (Visual Sonics).…”

Real-time visualisation of peripheral nerve trauma during subepineural injection in pig brachial plexus using micro-ultrasound

“…16 In this study we used a VisualSonics Vevo 2100 micro-US system capable of realtime imaging to visualise dynamic motion of the nerve. The Vevo micro-US systems have been used extensively for real-time in vivo small animal imaging in many pre-clinical studies, 17 such as phenotyping, 18 echocardiography, 19 and oncology. 20 The Visualsonics Vevo MD version of the system is now approved for clinical applications including vascular, 21 dermatology, 22 and neonatology.…”

Biomedical Imaging in Experimental Models of Cardiovascular Disease

“…12,13 Acquiring and measuring 3 (base, mid, and apex) or multiple short-axis views separated by a known distance may be more precise but is more time consuming. 13–15 The 3-dimensional (3D) reconstruction of the LV from short-axis views has been applied both to transthoracic and transesophageal echocardiography and can allow measurement of LV and RV volumes 14–18 ; however, they are time consuming and rarely used. This method can also be useful in measuring a wall motion score index, or a percentage of akinetic myocardium, which reflects MI scar in nonreperfused myocardial infarction models.…”