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The Resolution Enhancement Compression (REC) technique is a coded excitation method developed for improving the axial resolution of ultrasound images. It consists on emitting an amplitude modulated chirp signal that transmits more energy at the frequencies where the ultrasound transducer is less efficient. The focus of this study is to elaborate a new beamforming strategy, which consists of implementing...
The image quality provided by current ultrasound (US) scanners can be increased by extending the effective bandwidth of the US transducers. In 2007, a promising technique, called Resolution Enhancement Compression (REC), was proposed. Combining chirp modulated signals in emission and Modified Wiener Filters (MTF) in reception, REC allows bandwidth enhancement by boosting the energy of the emitted/received...
Echocardiography is the most used modality for the evaluation of cardiac function. To obtain a time-resolved volumetric quantification of cardiac motion, ultrafast 3-D imaging is required. Ultrafast ultrasound imaging with diverging waves has demonstrated its potential for clinical 2-D echocardiography. It has been shown that MoCo (motion compensation) strategies based on a triangle transmit arrangement...
To improve the quality of focused ultrasound images, in the last decade several beamforming algorithms have been proposed as an alternative to the common Delay-And-Sum (DAS), as for example adaptive or non-linear beamformers, which achieve improved imaging performance at the expense of an increased computational load. In this paper, we propose a computationally efficient algorithm based on nonlinear...
A novel ultrasound (US) platform with high channels density is a pre-requisite to open new frontiers in diagnostic and/or therapy by experimental implementation of new enabled advanced techniques. To date, few systems in the world permit to have a full and simultaneous control both in transmit and receive of all single elements of arrays with more than 1000 transducers. This paper presents a powerful...
This work shows the feasibility of performing ultrafast 3D ultrasound imaging by producing diverging waves (DW) with 2D sparse arrays. The 3D volumes were experimentally acquired by individually driving the 1024 elements of a full 32×32 matrix array. The volumes obtained with different sparse configurations were compared to those obtained with two references arrays: the full 32×32 array and a dense...
Ultrafast imaging based on plane wave (PW) / diverging wave (DW) is an active area of research in ultrasound acquisitions because of its capacity of reaching high frame rate. Beamforming of received echoes in Fourier domain provides comparable image quality but lower computational complexity with respect to the conventional DAS approach [Zhang et al., UFFC, 2016]. However, the current state-of-the-art...
One of the objectives in ultrasonic imaging is to improve the spatial resolution of the acquired images. The axial resolution is determined by the transducer bandwidth and the beamforming process. The resolution enhancement compression (REC) technique allows extending the bandwidth by combining the concepts of frequency and amplitude modulated excitation with modified Wiener filter compression. More...
Echocardiography is one of the most widely spread modality for non-invasive 2-D imaging of the heart. However, to fully observe and quantify left ventricular function and morphology, 3-D imaging is required. The observation of the whole left ventricle remains limited by the temporal resolution of conventional 3-D echocardiography. Indeed, the only way to get wide-angle volumetric images is to merge...
In ultrafast imaging using pulse compression, the image quality is limited by the bandwidth of the ultrasonic (US) transducer. Thus extending the effective bandwidth of the US transducers could improve the performance of the current US imaging methods. Resolution Enhancement Compression (REC) allows bandwidth enhancement by exciting the ultrasound transducer with frequency and amplitude modulated...
Ultrasound (US) therapy is, for a large panel of application, a promising technique which still requires an accurate monitoring system. Therefore, the passive acoustic mapping (PAM) beamforming technique is outlined. It reconstructs cavitation activity maps by beamforming acoustic signals passively recorded by an array. This method has already been explored in 2D with optimizations as phase coherence...
Ultrafast imaging based on diverging wave (DW) is an active area of research in ultrasound sectorial acquisition because of its capacity of reaching high frame rate. Recently, we have introduced a 3D Fourier-based formalism for the reconstruction of 3D sectorial images with DW insonifications and validated with numerical simulations [Zhang et al. IUS 2016]. The proposed method can provide comparable...
The heart, like skeletal muscles, is made up of muscular cells arranged regularly and packed into sort of bundles commonly called cardiac fibers. After a myocardial infarction (MI) both during the acute phase and the reperfusion of the myocardium, several cells die and some local fibers orientation modifications appear. Consequently, the heart does not contract properly anymore. The evaluation of...
There is an increasing interest for sparse 2D arrays as an alternative to full gridded arrays used in commercial systems. This work presents an effective and straightforward solution to perform 3D ultrasound imaging by driving a reduced number of elements of a commercial 2D array. The selection of 128, 192 or 256 elements out of a 32×32 array was based on simulated annealing to produce radiated beam...
After a myocardium infarction, cell loss is irremediable leading to a progressive local disorganization and change in the tissue structure altering heart function. An imaging method able to render the local tissue directivity would be a powerful tool to characterize the extent of the lesion. In this field, diffusion MRI is the reference. Because of its long acquisition time and the difficulty to tackle...
Very high frame rates can be reached both in 2D and 3D ultrasound imaging thanks to diverging waves (DWs) transmission. Up to now 3D ultrafast imaging has been performed controlling full 2D arrays with thousands of active elements which cannot be directly controlled by scanners with limited number of channels. The motivation here is to perform 3D ultrafast imaging with 128, 192 or 256 active elements...
In parallel with the increasing interest for 3D ultrasound imaging, different design techniques have been investigated to find the best configurations of 2D sparse arrays to scan an entire volume of interest [Trucco, IEEE UFFC99], [Diarra, IEEE TBME13]. In particular, we recently addressed the issue of driving a full 2D array of 1024 elements with a reduced number of channels (128, 192 or 256): the...
A novel ultrasound (US) platform with high channels density that offers flexibility, precision and open access is a pre-requisite to open new frontiers in diagnostic and/or therapy by experimental implementation of new enabled advanced techniques: dual-mode US imaging/therapies in the heart, new approaches to study the myocardial tissue (structure/characterization), fast sparse array strategies, multi-line...
Photoacoustic imaging is a hybrid modality used to image biological tissues. Multispectral optical excitation permits to obtain functional images thanks to the tissue specific optical absorption that depends on the light wavelength. The aim of this study is to propose a clustering method for photoacoustic multispectral images based on both spatial neighbourhood and spectral behaviour. The proposed...
Ultrafast imaging based on diverging wave is an active area of research in ultrasound sectorial acquisition because of its capacity of reaching high frame rate. The current state-of-the-art technique in 3D sectorial ultrafast imaging is based on diverging wave transmission and a reconstruction strategy using delay and sum (DAS). Recently, we have introduced a Fourier-based technique for the reconstruction...
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