Cardiac Hydatid cyst without liver involvement: A case report

Hydatid disease is a rare parasitic disease, which mainly involves liver then lung tissues. Cardiac involvement is very rare, especially when there is not hepatic in-volvement. We describe a 47-year-old woman with a history of a lung hydatid cyst who was referred to Rajaei Heart Center, Tehran, Iran in 2012. Her chest computed tomographic scan showed a cardiac mass. Echocardiographic exami-nation illustrated a large, well-defined heterogeneous mass (4.5 � 2.5 cm) in the roof of the right atrium with attachment to the crista terminalis without com-pressive effect on the inferior and superior venae cavae. The patient was candi-date for open-heart surgery via median sternotomy. A cystic mass was observed in the lateral aspect of the right atrial wall. After an injection of hypertonic nor-mal saline into the cystic lesion, the mass was excised totally. The right atrial de-fect was reconstructed with autologous pericardium. The patient was discharged from the hospital in good condition. Histological examination confirmed the di-agnosis of the hydatid cyst. © 2016, Tehran University of Medical Sciences (TUMS). All rights reserved

Design and Analysis of Full-Duplex Massive MIMO Cellular Networks

This paper provides a theoretical framework for the study of full-duplex (FD) massive multiple-input multiple-output (MIMO) cellular networks over Rician self-interference (SI) and Rayleigh intended and other-interference fading channels. To facilitate bi-directional wireless functionality, we incorporate (i) a downlink (DL) linear zero-forcing with self-interference-nulling (ZF-SIN) precoding scheme at the FD base stations (BSs), and (ii) an uplink (UL) self-interference-aware (SIA) fractional power control mechanism at the FD user equipments (UEs). Linear ZF receivers are further utilized for signal detection in the UL. The results indicate that the UL rate bottleneck in the baseline FD single-antenna system can be elevated by several hundred times via exploiting massive MIMO. On the other hand, the findings may be viewed as a reality-check as the largest spectral efficiency gain from the FD massive MIMO cellular network over its half-duplex (HD) counterpart under state-of-the-art system parameters is shown to be in the region of ~40%

Novel approach for automatic mid-diastole frame detection in 2D echocardiography sequences for performing planimetry of the mitral valve orifice

The mitral valve orifice area is a reliable measure for evaluating mitral valve stenosis (MS) severity, which is obtained by the planimetry of the mid-diastole frame in the echocardiography sequences. Since the manual method for determining this frame is time-consuming and user-dependent, a novel automatic method has been proposed in this study. First, the region of interest (ROI) containing the mitral valve orifice region is detected using circular Hough transform and k-means algorithms. Then, the dimension reduction method is applied to the ROI of each frame to map it into a point in a 2D space. The performance of the local linear embedding (LLE), isometric mapping, kernel principal component analysis (PCA), and linear PCA algorithms has been evaluated in this study. Finally, a distance curve is obtained by calculating the Euclidean distance between consecutive points in 2D space, and the mid-diastole frame is determined by interpreting this curve. The proposed algorithm was validated using 2D echocardiography of the 20 MS patients. Finally, the LLE method showed the best result, and the average frame difference for 20 cases using the proposed method compared with the gold standard (the echo-cardiologist opinion) was 1.40. © The Institution of Engineering and Technology 2020

Optimization for Maximizing Sum Secrecy Rate in SWIPT-enabled NOMA Systems

OAPA In this paper, we study secrecy simultaneous wireless information and power transfer (SWIPT) in downlink nonorthogonal multiple access (NOMA) systems comprising a base station (BS), multiple information receivers (IRs), and multiple energy receivers (ERs) that have potential to wiretap the IRs. The goal of this paper is to maximize the sum secrecy rate (SSR) of the system subject to the individual IR’s minimum data rate requirement and the individual ER’s minimum harvested energy requirement. The corresponding problem involves resource allocation via max-min function, which is non-convex and difficult to solve directly. In order to tackle this, we first transform the original non-convex problem to a sequence of convex subproblems which can be solved simultaneously. Hence, a closedform solution of the optimal power allocation policy is derived based on the Karush-Kuhn-Tucker (KKT) conditions. Numerical results validate the theoretical findings and demonstrate that significant performance gain over the orthogonal multiple access (OMA) scheme in terms of SSR can be achieved by the proposed algorithm in a SWIPT-enabled NOMA system

Assessment of normal hemodynamic profile of mechanical pulmonary prosthesis by doppler echocardiography: a prospective cross-sectional study

OBJECTIVES: Very few reports have described the Doppler-derived echocardiographic parameters for mechanical pulmonary valve prosthesis (MPVP). This study aims to describe the normal Doppler hemodynamic profile of MPVP using Doppler echocardiography. METHODS: The current prospective, single center observational study enrolled 108 patients who underwent pulmonary valve replacement (PVR) surgery for the first time and had a normally functioning prosthesis post-operation. The hemodynamic performance of MPVPs, considering flow dependent and flow independent parameters, was evaluated at two follow-up points, at week one and week four post-operation. All assessments were conducted by an experienced echocardiographer. RESULTS: The mean age (±SD) of the participants was 26.4 (±8.98). Tetralogy of Fallot (ToF) was the most common underlying disease leading to PVR, with a prevalence of 88. At first week post-operation, measurement of indices reported the following values (±SD): peak pressure gradient (PPG): 18.51(±7.64) mm Hg; mean pressure gradient (MPG): 10.88(±5.62) mm Hg; peak velocity (PV): 1.97(±0.43)m/s; doppler velocity index (DVI): 0.61(±18); pulmonary velocity acceleration time (PVAT): 87.35(±15.16) ms; effective orifice area (EOA): 2.98(±1.02) cm2;and effective orifice area to body surface area ratio (EOA/ BSA): 1.81(±0.62) cm2/m2. Comparing these measurements with those obtained from the second follow-up (at week four post-op) failed to hold significant difference in all values except for PVAT, which had increased from its primary value (p�=�0.038). Also, right ventricular (RV) function showed significant improvement throughout the follow up period. CONCLUSION: The findings of this study help strengthen the previously scarce data pool and better establish the normal values for Doppler hemodynamics in mechanical pulmonary prosthesis

Assessment of left ventricular mechanical dyssynchrony by phase analysis of gated-SPECT myocardial perfusion imaging and tissue Doppler imaging: Comparison between QGS and ECTb software packages

Background: Recently, the phase analysis of gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has become feasible via several software packages for the evaluation of left ventricular mechanical dyssynchrony. We compared two quantitative software packages, quantitative gated SPECT (QGS) and Emory cardiac toolbox (ECTb), with tissue Doppler imaging (TDI) as the conventional method for the evaluation of left ventricular mechanical dyssynchrony. Methods and Results: Thirty-one patients with severe heart failure (ejection fraction ≤35%) and regular heart rhythm, who referred for gated-SPECT MPI, were enrolled. TDI was performed within 3 days after MPI. Dyssynchrony parameters derived from gated-SPECT MPI were analyzed by QGS and ECTb and were compared with the Yu index and septal-lateral wall delay measured by TDI. QGS and ECTb showed a good correlation for assessment of phase histogram bandwidth (PHB) and phase standard deviation (PSD) (r = 0.664 and r = 0.731, P < .001, respectively). However, the mean value of PHB and PSD by ECTb was significantly higher than that of QGS. No significant correlation was found between ECTb and QGS and the Yu index. Nevertheless, PHB, PSD, and entropy derived from QGS revealed a significant (r = 0.424, r = 0.478, r = 0.543, respectively; P < .02) correlation with septal-lateral wall delay. Conclusion: Despite a good correlation between QGS and ECTb software packages, different normal cut-off values of PSD and PHB should be defined for each software package. There was only a modest correlation between phase analysis of gated-SPECT MPI and TDI data, especially in the population of heart failure patients with both narrow and wide QRS complex. © 2014, American Society of Nuclear Cardiology

Echocardiography image enhancement using texture-cartoon separation

Due to the speckled nature of cardiac ultrasound imaging, it is not easy to process and extract useful information directly from the acquired image. In this work, we have proposed a method to reduce the effect of speckle artifacts through the decomposition of echocardiography images into cartoon and texture components. The first component (i.e., cartoon image) contains image structures containing smooth areas and sharp edges, and the texture component is mainly composed of highly oscillating and repetitive patterns. To decompose the image into these two subcomponents, convolutional sparse coding has been utilized as a solid tool for solving the decomposition optimization function. The significant advantage of using convolutional sparse coding, compared to classical sparse coding methods, is image quality enhancement due to not using the block coding, making the classic solutions computationally feasible. The original image has been masked with the cartoon part leading to suppress speckle artifacts which result in image quality enhancement. Besides, it has been shown that using this speckle reduction scenario, considerable accuracy enhancement of the segmentation task can be achieved, compared to segmentation of the original image. Numerical results provide acceptable reasons to prove the efficiency of the proposed algorithm. Resulting echocardiography videos show a mean segmentation enhancement of 15.98 for Hausdorff distance (in pixels) and 0.0632 for the Dice similarity coefficient. © 2021 Elsevier Lt

Temporal super resolution of ultrasound images using compressive sensing

Increasing the frame rate is a challenging problem for tracking the fast transient motions of the heart in ultrasound imaging with diagnostic goals. In this paper, compressive sensing (CS) is used for super temporal resolution. Compressive sensing is an acquisition method where only a few random samples of a signal are blindly measured, and the full signal is reconstructed under certain conditions. The proposed method uses spatial and temporal information of radio frequency (RF) signals for reconstruction of the entire image sequence so; the reconstruction is performed in both spatial and temporal directions. Three sparsity bases are used for the sparse representation of the signals in the Spatio-Temporal domain, including fixed sparsity basis, fixed overcomplete dictionary and learned overcomplete dictionary. This approach is evaluated on the In-vivo 2-dimensional (2D) data of the carotid artery and the 3-dimensional (3D) simulated echocardiographic data. The qualitative and quantitative results show that images, which are reconstructed by the proposed Spatio-Temporal method have a far low error and so much better quality than those that reconstructed by conventional spatial compressive sensing method. The proposed approach via the learned overcomplete dictionary in temporal and spatial direction increases the frame rate based on the different subsampling rates. For instance, the frame rate up to two times the original sequence is achievable, while Root Mean Square Error (RMSE) is approximately 1.5 and 3 for 2D and 3D data, respectively. © 2019 Elsevier Lt