The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Cutaneous Leishmaniasis is a skin infection which is commonly present in underdeveloped countries. The incidence is particularly high in amazonic countries of Latin-America like Brazil, Colombia and Perú and is usually reported as endemic. In Perú, more than one million people are at risk of infection and approximately 6,000 new cases are detected each year. The present work proposes to integrate...
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...
In vivo estimation of attenuation coefficients is useful because of its potential for tissue characterization and relevance in accurate backscatter coefficient estimation. However, current methods based on spectral analysis for ultrasonic attenuation estimation suffer from a severe trade-off between estimation precision and spatial resolution. Recently, the regularized spectral log difference (RSLD)...
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...
In vivo estimation of attenuation coefficients is useful because of its potential for tissue characterization and relevance in accurate backscatter coefficient estimation. Recently, the regularized spectral log difference (RSLD) technique was proposed to extend the trade-off between precision and spatial resolution in attenuation coefficient slope (ACS) estimation. The aim of this pilot study is to...
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...
Pneumonia is one of the major causes of child mortality, but it is curable if one can achieves early diagnostics. Unfortunately, in developing countries there is a lack of infrastructure and medical experts in rural areas to provide the required diagnostics opportunely. Lung ultrasound echography has proved to be an important tool to detect lung consolidates as evidence of pneumonia. The use of ultrasound...
Pneumonia is one of the major causes of child mortality. Unfortunately, in developing countries there is a lack of infrastructure and medical experts in rural areas to provide the required diagnostics opportunely. Lung ultrasound echography has proved to be an important tool to detect lung consolidates as evidence of pneumonia. This paper presents a method for automatic diagnostics of pneumonia using...
Spectral-based techniques for attenuation coefficient slope (ACS) imaging, such as spectral log difference (SLD), experience high estimation variance. A previous work introduced a novel regularized SLD (RSLD) method for the joint estimation of ACS values in all regions of interest (ROIs) within the field of view, in contrast with classic attenuation imaging methods which obtain ACS values from each...
Although the minimum variance (MV) beamformer can provide enhancement in both resolution and contrast of ultrasound images when compared with conventional delay-and-sum (DAS) beamforming, its clinical application is limited by its sensitivity to phase aberrations. Several robust MV beamformers have been proposed, but present limitations when faced with second order phase aberration. Additionally,...
The minimum variance (MV) beamformer is an adaptive beamforming technique that can convey enhancements in resolution and contrast and that can be applied to various ultrasonic sequences, including plane-wave imaging. Despite its improvements, it is still susceptible to clutter. The present work uses the short-lag spatial coherence (SLSC) value as a weighting factor in order to improve over conventional...
Various quantitative ultrasound techniques allow the estimation of elastic parameters in tissues using mechanical or acoustic radiation forces. However, it has previously been reported that the presence of phase aberration compromises elasticity measurement results when propagating in inhomogeneous media. In this study, a comparative evaluation of the effects of phase aberration when estimating shear...
Crawling Wave Sonoelastography (CWS) provides quantitative information of tissue stiffness by the application of two mechanical vibrations into the tissue. However, most of the shear wave speed (SWS) estimators for CWS report lateral artifacts that could undermine the detection accuracy of lesion by increasing the false-positive rate. In previous works, a low-cost estimator (WAVE) based on the crawling...
The use of quantitative ultrasound (QUS) parameters to characterize tissue has shown potential to improve current clinical diagnosis. However, most studies in QUS have used parameters derived from either ultrasonic compressional or low frequency shear wave in isolation, thereby discarding additional information these parameters may carry. In this study, the feasibility of estimating both shear wave...
Pneumonia is a disease which causes high mortality in children under five years old, particularly in developing countries. This paper proposes a novel application of ultrasound video analysis for the detection of pneumonia. This application is based on the processing of small video chunks, in which an image processing algorithm analyzes each frame to get some overall video statistics. Then, based...
Tissue characterization using quantitative ultrasound (QUS) parameters has received significant attention in recent years due to its potential to improve the detection and diagnosis of diseased states. However, the vast majority of studies in QUS tissue typing have used parameters derived from either longitudinal or shear waves in isolation, thereby discarding potentially useful complementary information...
The quantitative estimation of the attenuation coefficient slope (ACS) has the potential to differentiate between healthy and pathological tissues. However, attempts to characterize ACS maps using pulse-echo data using methods such as the spectral log difference (SLD) technique have been limited by the large variability of the estimates. In the present work, ACSs were estimated using a regularized...
Quantitative sonoelastography, through the formation of crawling waves, allows the estimation of elastic parameters in tissues using pulsed wave Doppler techniques. However, this technique's performance may be compromised by aberration effects during in vivo applications. In this study, an experimental evaluation of the effects of aberration when estimating shear wave speed from homogeneous phantoms...
Currently, fine-needle aspiration (FNA) biopsy is the gold standard for the diagnosis of thyroid cancer. Therefore, there is a need to develop non-invasive tools that aid in the identification of malignant tissues in this gland. Quantitative ultrasound imaging using backscatter coefficients (BSCs) has shown potential to characterize thyroid tissues in rodent models ex vivo. As an initial step towards...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.