Multidimensional spectral analysis of the ultrasonic radiofrequency signal for characterization of media.

The importance of the analysis of the radiofrequency signal is by now recognized in the field of tissue characterization via ultrasound. The RF signal contains a wealth of information and structural details that are usually lost in the B-Mode representation. The HyperSPACE (Hyper SPectral Analysis for Characterization in Echography) algorithm presented by the authors in previous papers for clinical applications is based on the radiofrequency ultrasonic signal.

Differentiation of Breast Lesions by Use of HyperSPACE: Hyper-Spectral Analysis for Characterization in Echography.

Early diagnosis represents the cornerstone in breast cancer control. Ultrasound is still a valid tool because of its low invasiveness, reduced costs and reduced risk of harm, but better exploitation of its potential is necessary to extract information on tissue features. The proposed method, HyperSPACE (hyper-spectral analysis for characterization in echography), which processes the ultrasonic radiofrequency signal in an N-dimension spectral hyperspace to define several characteristic parameters of the tissue under investigation, was used with the aim of differentiating two types of breast lesion: infiltrating ductal carcinoma and fibroadenoma.

Respiratory rate assessments using a dual-accelerometer device.

Monitoring of respiration-related thoracic movements may be useful to assess respiratory rate (RR) objectively. RR was measured during spontaneous breathing, voluntarily modified breathing, and exercise hyperpnoea in normal subjects via visual inspection, spirometry and a pair of accelerometers positioned on the torso. Spirometric and accelerometric values of RR recorded during relaxed breathing were (mean±SD) 21.

A retrospective study to reduce prostate biopsy cores by a real time interactive tool.

Objective: Prostate carcinoma (PCa) is one of the most frequent neoplasms, with more than 110.000 new cases/year in Europe. As PCa is not clearly demonstrable at transrectal ultrasound (TRUS), guidelines on TRUS guided biopsy suggest to perform a random tissue sampling (at least 8-12 "cores" depending on gland volume).

Multipulse technique exploiting the intermodulation of ultrasound waves in a nonlinear medium.

In recent years, the nonlinear properties of materials have attracted much interest in nondestructive testing and in ultrasound diagnostic applications. Acoustic nonlinear parameters represent an opportunity to improve the information that can be extracted from a medium such as structural organization and pathologic status of tissue. In this paper, a method called pulse subtraction intermodulation (PSI), based on a multipulse technique, is presented and investigated both theoretically and experimentally.

Formation of PCDD and PCDF in the thermal treatment of footwear leather wastes.

The leather waste generated by the footwear industry is considered dangerous due to the presence of trivalent chromium, derived from the salt utilized to tan hides. In Brazil, the majority of this waste is disposed on landfills and only about 3% are recycled. The thermal treatment is an alternative method for purification of such residues.

Accuracy of a new echographic method (RULES, radiofrequency ultrasonic local estimators) in prostate cancer diagnosis.

Background: This study evaluated the accuracy of a new echographic method named RULES (radiofrequency ultrasonic local estimators) in the diagnosis of prostate cancer.

Patients And Methods: A double-blind prospective study was carried out on 105 patients mean age 66.6 years, prostate specific antigen (PSA) >4 ng/ml with clinical and/or biochemical suspicious of prostate cancer.

A novel spectral ultrasonic differentiation method for marking regions of interest in biological tissues. In vivo preliminary results.

Background: "in vivo" application of a new echographic method able to better identify neoplastic tissue. The aim of this study was to evaluate its accuracy in the diagnosis of prostate cancer.

Materials And Methods: Double-blind prospective study on 60 patients (pts) submitted to both transrectal ultrasound (TRUS) of prostate with a traditional echograph connected to a new hardware/software platform named FEMMINA (Fast Echographic Multiparameter Multi Image Novel Apparatus) that processes the echo signal by RULES (Radiofrequency Ultrasonic Local EStimators) algorithm and to a prostatic biopsy (8 to 12 cores).

Stable and transient subharmonic emissions from isolated contrast agent microbubbles.

Ultrasound contrast agents (UCAs) have been widely studied in recent years in order to improve and develop new, sophisticated imaging techniques for clinical applications. In order to improve the understanding of microbubble-ultrasound interactions, an acoustic dynamic characterization of UCA microbubble behavior was performed in this work using a high frame-rate acquiring and processing system. This equipment is connected to a commercial scanner that provides RF beam-formed data with a frame-rate of 30 Hz.

Subharmonic emissions from microbubbles: effect of the driving pulse shape.

The aims of this work are to investigate the response of the ultrasonic contrast agents (UCA) insonified by different arbitrary-shaped pulses at different acoustic pressures and concentration of the contrast agent focusing on subharmonic emission. A transmission setup was developed in order to insonify the contrast agent contained in a measurement chamber. The transmitted ultrasonic signals were generated by an arbitrary wave generator connected to a linear power amplifier able to drive a single-element transducer.

FEMMINA real-time, radio-frequency echo-signal equipment for testing novel investigation methods.

Fast echographic multiparameter multi-image novel apparatus (FEMMINA), is a hardware and software platform dedicated to ultrasonic signal and image processing. FEMMINA is able to operate with sequences of radiofrequency (RF) frames. Its architecture is designed to be modular, expandable, and aimed at implementing different ultrasonic investigation techniques.

Transient subharmonic and ultraharmonic acoustic emission during dissolution of free gas bubbles.

This work concerns the study of free gas bubble behavior, a basic step in contrast agent study. In order to improve the understanding of microbubble-ultrasound interaction, we propose an acoustic dynamic observation of microbubble behavior performed by a high frame-rate acquiring and processing system. Results from ultrasonic observations of free gas microbubbles are discussed and compared with theoretical simulation.

ICARUS: imaging pulse compression algorithm through remapping of ultrasound.

In this work we tackle the problem of applying to echographic imaging those synthetic aperture focusing techniques (SAFT) in the frequency domain commonly used in the field of synthetic aperture radars (SAR). The aim of this research is to improve echographic image resolution by using chirp transmit signals, and by performing pulse compression in both dimensions (depth and lateral). The curved geometry present in the unfocused radio-frequency (RF) ultrasonic image is the main cause of inaccuracy in the direct application of frequency domain SAFT algorithms to echographic imaging.

A novel spectral ultrasonic differentiation method for marking regions of interest in biological tissue: in vitro results for prostate.

Objective: The aim of the present study was to evaluate the effectiveness of a new method of spectral analysis of the radiofrequency (RF) ultrasonic echo signal in discriminating neoplastic from non-neoplastic tissue of the prostate gland.

Material And Methods: The proposed method was previously set up on ten prostatic glands where cancer had been detected by histology in order to correlate the tumour areas with specific spectral parameters. In the present study sixty prostate specimens of patients undergoing radical retropubic prostatectomy for clinically localized prostate cancer were examined.

Toward virtual biopsy through an all fiber optic ultrasonic miniaturized transducer: a proposal.

The present generation of devices based on opto-acoustic and acousto-optic conversion lets us foresee the possibility of realizing complete miniaturized transmitting-receiving transducers, able to generate and detect wideband ultrasounds by laser light. In the present paper, a miniaturized ultrasonic transducer entirely based on fiber optic technology is proposed. Such a device springs from the conjunction between our research, which has produced a highly efficient fiber optic opto-acoustic source, with the results obtained by other researchers concerning the realization of an ultrasonic receiver based on optical interferometry.

Hardware and software platform for real-time processing and visualization of echographic radiofrequency signals.

In this paper the architecture of a hardware and software platform, for ultrasonic investigation is presented. The platform, used in conjunction with an analog front-end hardware for driving the ultrasonic transducers of any commercial echograph, having the radiofrequency echo signal access, make it possible to dispose of a powerful echographic system for experimenting any processing technique, also in a clinical environment in which real-time operation mode is an essential prerequisite. The platform transforms any echograph into a test-system for evaluating the diagnostic effectiveness of new investigation techniques.

A Doppler system for dynamic vector velocity maps.

The aim of the vector Doppler technique is the quantitative reconstruction of a velocity field independently of the ultrasonic probe axis to flow angle. In particular, vector Doppler is interesting for studying vascular pathologies related to complex blood flows. A problem of vector Doppler is data representation in real-time that should be easy to interpret for the physician.