Pediatric Cardiac Shear Wave Elastography for Quantitative Assessment of Myocardial Stiffness: A Pilot Study in Healthy Controls

Abstract

The long-term goal of this study is to assess chemotherapy-induced cardiotoxicity for pediatric cancer patients using cardiac ultrasound shear wave (SW) elastography. This pilot study aimed to systematically investigate the feasibility of using cardiac SW elastography in children and provide myocardial stiffness control data for cancer patients. Twenty healthy volunteers (ages 5-18) were recruited. A novel cardiac SW elastography sequence with pulse-inversion harmonic imaging and time-aligned sequential tracking was developed for this study. Cardiac SW elastography produces and detects transient SWs propagating in the myocardium in late-diastole, which can be used to quantify myocardial stiffness. The parasternal long-axis (L-A) and short-axis (S-A) views of the interventricular septum (IVS) were feasible for pediatric cardiac SW elastography. The L-A and S-A views of the basal and mid IVS provided better success rates than those of the apical IVS. Success rates decreased with increased body mass index (BMI), but did not differ with age or gender. Two-dimensional SW speed measurements were 1.26, 1.22, 1.71 and 1.67 m/s for L-A base, L-A mid, S-A base and S-A mid IVS, respectively. All S-A SW speed values were significantly higher (p < 0.01) than L-A values due to myocardial anisotropy. No SW speed difference was observed for different ages and genders. This pilot study demonstrated, for the first time, the feasibility of using cardiac SW elastography to measure quantitative myocardial stiffness in children, and established control SW speed values for using SW elastography to assess chemo-induced cardiotoxicity for pediatric cancer patients. The results showed that the myocardial anisotropy needs to be accounted for when comparing SW speed from different imaging axes.

Cardiac MR elastography for quantitative assessment of elevated myocardial stiffness in cardiac amyloidosis

“…Wassenaar et al described a quantitative cardiac MRE technique, using 80 Hz vibration frequency and a 2D MRE approach, but to date they have only reported results on normal volunteers and have not demonstrated the ability to distinguish normal subjects from patient populations. Likewise, the cardiac ultrasound elastography literature has primarily focused on demonstrating feasibility in healthy adult and pediatric volunteers and has not been tested in patient populations …”

“…Likewise, the cardiac ultrasound elastography literature has primarily focused on demonstrating feasibility in healthy adult and pediatric volunteers and has not been tested in patient populations. 35,36 The cardiac amyloid patients in this study had numerous findings traditionally associated with increased myocardial stiffness and served as an excellent group for preliminary validation for cardiac MRE. The cardiac amyloid patients had increased E/e' ratio and left atrial volume index, which are associated with increased LV filling pressures.…”

Non-contact single shot elastography using line field low coherence holography

“…In this case, if the degree of wavefront deformation exceeds the coherence length, interference will not occur at the corresponding spatial pixels. Gating has been successfully used for supersonic shear imaging applications [28,29] and is a promising technique for in vivo elastographic application with the presented system. Also, we utilized a 10 nm bandpass filter to increase the coherence length for maintaining interference across the line beam.…”

A direct comparison of natural and acoustic-radiation-force-induced cardiac mechanical waves

“…In theory, higher propagation speeds are expected for stiffer materials, resulting in a quantitative measure of tissue stiffness. Natural SWE analyzes the natural transverse vibrations induced in the myocardium after aortic and mitral valve closure (AVC and MVC) 7 – 13 , whereas active SWE uses a focused high-energy ultrasonic beam generating an acoustic radiation force (ARF) to induce a perturbation in the tissue of interest 14 – 18 . In this study, we will focus on the relationship between the natural vibrations after AVC and MVC and active SWE.…”