BackgroundConventional echocardiography is not sensitive enough to assess left ventricular (LV) dysfunction in hypertrophic cardiomyopathy (HCM) patients. This research attempts to find a new ultrasonic technology to better assess LV diastolic function, systolic function, and myocardial longitudinal and circumferential systolic strain of segments with different thicknesses in HCM patients.MethodsThis study included 50 patients with HCM and 40 healthy subjects as controls. The peak early and late mitral annulus diastolic velocities at six loci (Ea′ and Aa′, respectively) and the Ea′/Aa′ ratio were measured using real-time tri-plane echocardiography and quantitative tissue velocity imaging (RT-3PE-QTVI). The mean value of Ea′ at six loci (Em′) was obtained for the calculation of E/Em′ ratio. The LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), LV stroke volume (LVSV), and LV ejection fraction (LVEF) were measured using real-time three-dimensional echocardiography (RT-3DE). LV myocardial longitudinal peak systolic strain (LPSS) and circumferential peak systolic strain (CPSS) in the apical-middle-basal segments (LPSS-api, LPSS-mid, LPSS-bas; CPSS-api, CPSS-mid, and CPSS-bas, respectively) were obtained using a software for two-dimensional speckle tracking imaging (2D-STI). According to the different segmental thicknesses (STs) in each HCM patient, the values (LPSS and CPSS) of all the myocardial segments were categorized into three groups and the respective averages were computed.ResultsThe Ea′, Aa′, and, Ea′/Aa’ ratio in HCM patients were lower than those in the controls (all p < 0.001), while the E/Em′ ratio in HCM patients was higher than that in the controls (p < 0.001). The LVEDV, LVSV, and LVEF were significantly lower in HCM patients than in controls (all p < 0.001). In HCM patients, the LPSS-api, LPSS-mid, LPSS-bas, CPSS-api, CPSS-mid, and CPSS-bas and the LPSS and CPSS of LV segments with different thicknesses were all significantly reduced (all p < 0.001).ConclusionsIn HCM patients, myocardial dysfunction was widespread not only in the obviously hypertrophic segments but also in the non-hypertrophic segments; the LV systolic and diastolic functions were damaged, even with a normal LVEF. LV diastolic dysfunction, systolic dysfunction, and myocardial deformation impairment in HCM patients can be sensitively revealed by RT-3PE-QTVI, RT-3DE, and 2D-STI.

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The plane wave compounding (PWC) is a promising modality to improve the imaging quality and maintain the high frame rate for ultrafast ultrasound imaging. In this paper, a novel beamforming method is proposed to achieve higher resolution and contrast with low complexity. A minimum variance (MV) weight calculated by the partial generalized sidelobe canceler is adopted to beamform the receiving array signals. The dimension reduction technique is introduced to project the data into lower dimensional space, which also contributes to a large subarray length. Estimation of multi-wave receiving covariance matrix is performed and then utilized to determine only one weight. Afterwards, a fast second-order reformulation of the delay multiply and sum (DMAS) is developed as nonlinear compounding to composite the beamforming output of multiple transmissions. Simulations, phantom, in vivo, and robustness experiments were carried out to evaluate the performance of the proposed method. Compared with the delay and sum (DAS) beamformer, the proposed method achieved 86.3% narrower main lobe width and 112% higher contrast ratio in simulations. The robustness to the channel noise of the proposed method is effectively enhanced at the same time. Furthermore, it maintains a linear computational complexity, which means that it has the potential to be implemented for real-time response.

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