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Analysis of human fibroadenomas using threedimensional impedance maps
 IEEE Trans. Med. Imag
"... Abstract—Threedimensional impedance maps (3DZMs) are virtual volumes of acoustic impedance values constructed from histology to represent tissue microstructure acoustically. From the 3DZM, the ultrasonic backscattered power spectrum can be predicted and model based scatterer properties, such as eff ..."
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Abstract—Threedimensional impedance maps (3DZMs) are virtual volumes of acoustic impedance values constructed from histology to represent tissue microstructure acoustically. From the 3DZM, the ultrasonic backscattered power spectrum can be predicted and model based scatterer properties, such as effective scatterer diameter (ESD), can be estimated. Additionally, the 3DZM can be exploited to visualize and identify possible scattering sites, which may aid in the development of more effective scattering models to better represent the ultrasonic interaction with underlying tissue microstructure. In this study, 3DZMs were created from a set of human fibroadenoma samples. ESD estimates were made assuming a fluidfilled sphere form factor model from 3DZMs of volume 300 300 300 m. For a collection of 33 independent human fibroadenoma tissue samples, the ESD was estimated to be 111 40 7 m. The 3DZMs were then investigated visually to identify possible scattering sources which conformed to the estimated model scatterer dimensions. This estimation technique allowed a better understanding of the spatial distribution and variability of the estimates throughout the volume. Index Terms—Biomedical ultrasound, tissue modeling, ultrasonic backscatter analysis, ultrasound simulation. I.
A noninvasive expert system for diagnosis of intraocular tumours: the system concept
"... The aim of the project is to developand introduce to the market a new safe, noninvasive expert system for analysis and diagnosis of intraocular tumours. It will consist of a novel noninvasive ultrasonic tissue characterisation instrument attachment to the conventional ultrasound diagnostic system ..."
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The aim of the project is to developand introduce to the market a new safe, noninvasive expert system for analysis and diagnosis of intraocular tumours. It will consist of a novel noninvasive ultrasonic tissue characterisation instrument attachment to the conventional ultrasound diagnostic system for acquisition of ultrasound RF signals, sophisticated software for ultrasonic data analysis and the innovative digital ophthalmoscope for acquiring, processing and parameterisation of images of intraocular tumours.
Improved diagnostics through quantitative ultrasound imaging
 in Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009
"... AbstractConventional Bmode imaging in ultrasound consists of displaying the logcompressed envelope of the backscattered signal. While clinical ultrasonic Bmode images have good spatial resolution, i.e., better than a millimeter, the contrast resolution of ultrasonic Bmode images is typically l ..."
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AbstractConventional Bmode imaging in ultrasound consists of displaying the logcompressed envelope of the backscattered signal. While clinical ultrasonic Bmode images have good spatial resolution, i.e., better than a millimeter, the contrast resolution of ultrasonic Bmode images is typically low. However, additional information is contained in the ultrasonic backscattered signal, which can be used to create images related to tissue microstructure. Because diagnosis of disease is typically based on histological examination of tissue microstructure, the ability to quantify and describe tissue microstructure through ultrasound may result in improved diagnostic capabilities of ultrasound. Tissuemimicking phantoms and animal models of breast cancer were used to assess the ability of novel ultrasonic imaging techniques to quantify microstructure. Four parameters were extracted from the ultrasonic backscattered signal and related to the microstructure. The effective scatterer diameter (ESD) and the effective acoustic concentration (EAC) parameters were based on modeling the frequency dependence of the backscatter. The k parameter (which quantifies the periodicity of scatterer locations) and the μ parameter (which estimates the number of scatterers per resolution cell) were based on modeling the statistics of the backscattered envelope. Images constructed with these parameters resulted in an increase in contrast between diseased tissue and normal tissues but at the expense of spatial resolution. Specifically, in simulation, quantitative ultrasound (QUS) increased the contrasttonoise ratio (CNR) between targets and background by more than 10 times in some cases. Statistically significant differences were observed between three kinds of tumors using the ESD, EAC, and k parameters. QUS imaging was also improved with the addition of coded excitation. A novel coded excitation technique was used that improved the variance of estimates over conventional pulsing methods, e.g, the variance of ESD estimates were reduced by a factor of up to 10.
Development and application of threedimensional impedance maps related to tissue pathology
 M.S. thesis, Univ. Illinois UrbanaChampaign
, 2007
"... ii Threedimensional acoustic tissue models are a unique means to study ultrasonic scattering by tissue microstructure. In this work, the previous methods used to create and analyze these models were evaluated and refined. These techniques were then applied to a set of 10 human fibroadenomas, a beni ..."
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ii Threedimensional acoustic tissue models are a unique means to study ultrasonic scattering by tissue microstructure. In this work, the previous methods used to create and analyze these models were evaluated and refined. These techniques were then applied to a set of 10 human fibroadenomas, a benign tumor of the breast. These models, called threedimensional impedance maps (3DZMs), are created from serial sets of histological images which must be properly transformed to recreate the original tissue volume. A properly reconstructed 3DZM can then be used to estimate properties, such as the effective scatterer size, of the ultrasonic scattering sites in the underlying tissue. These estimates can, in turn, be related to histological features of the tissue. For the fibroadenoma datasets, the average effective scatterer diameter was estimated to be 84 ± 40 µm when the entire volume was used for analysis. This result compared roughly to the size of the acini in the tissue, although a wide variation was observed in the histological layout of the tissue. iii
The cientificWorldJOURNAL Research Article Algorithms and Results of Eye Tissues Differentiation Based on RF Ultrasound
"... Algorithms and software were developed for analysis of Bscan ultrasonic signals acquired from commercial diagnostic ultrasound system. The algorithms process raw ultrasonic signals in backscattered spectrum domain, which is obtained using two timefrequency methods: shorttime Fourier and HilbertH ..."
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Algorithms and software were developed for analysis of Bscan ultrasonic signals acquired from commercial diagnostic ultrasound system. The algorithms process raw ultrasonic signals in backscattered spectrum domain, which is obtained using two timefrequency methods: shorttime Fourier and HilbertHuang transformations. The signals from selected regions of eye tissues are characterized by parameters: Bscan envelope amplitude, approximated spectral slope, approximated spectral intercept, mean instantaneous frequency, mean instantaneous bandwidth, and parameters of Nakagami distribution characterizing HilbertHuang transformation output. The backscattered ultrasound signal parameters characterizing intraocular and orbit tissues were processed by decision tree data mining algorithm. The pilot trial proved that applied methods are able to correctly classify signals from corpus vitreum blood, extraocular muscle, and orbit tissues. In 26 cases of ocular tissues classification, one error occurred, when tissues were classified into classes of corpus vitreum blood, extraocular muscle, and orbit tissue. In this pilot classification parameters of spectral intercept and Nakagami parameter for instantaneous frequencies distribution of the 1st intrinsic mode function were found specific for corpus vitreum blood, orbit and extraocular muscle tissues. We conclude that ultrasound data should be further collected in clinical database to establish background for decision support system for ocular tissue noninvasive differentiation.
IMPROVED TECHNIQUES FOR STATISTICAL ANALYSIS OF THE ENVELOPE OF BACKSCATTERED ULTRASOUND USING THE HOMODYNED K DISTRIBUTION BY
"... Biomedical ultrasound is a prominent imaging modality for diagnostics. Conventional ultrasonic imaging is qualitative in nature with spatial resolution up to hundreds of micrometers. Quantitative ultrasound techniques based on ultrasonic backscatter can provide estimates describing tissue microstruc ..."
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Biomedical ultrasound is a prominent imaging modality for diagnostics. Conventional ultrasonic imaging is qualitative in nature with spatial resolution up to hundreds of micrometers. Quantitative ultrasound techniques based on ultrasonic backscatter can provide estimates describing tissue microstructure. Improving quantitative ultrasound techniques will result in improved diagnostic capabilities of ultrasound. Quantitative techniques were developed and assessed based on the envelope of backscattered ultrasound. The envelope of backscattered ultrasound can be modeled as the superposition of the scattered signals from individual scatterers in the medium being interrogated. As such, the envelope signal is statistical in nature. By applying a model to the amplitude distribution of the envelope, information about the subresolution material properties such as the scatterer number density and organizational structure can be obtained. The homodyned K distribution was used to model the envelope of backscattered ultrasound. An efficient parameter estimation algorithm was developed and tested through simulations and experiments. Techniques to reduce estimate bias and variance were assessed. The diagnostic potential of tissue characterization based on envelope statistics was evaluated. ii ACKNOWLEDGMENTS
© 2011 Alexander D. PawlickiTHREEDIMENSIONAL IMPEDANCE MAP ANALYSIS OF BIOLOGICAL TISSUE TO ELUCIDATE SMALLSCALE ACOUSTIC SCATTERING BEHAVIOR BY
"... Threedimensional impedance maps (3DZMs) are computational models of acoustic impedance of tissue constructed from a series of adjacent histology images. The power spectrum of a 3DZM can be analyzed to estimate modelbased quantitative ultrasound parameters such as effective scatterer diameter (ESD) ..."
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Threedimensional impedance maps (3DZMs) are computational models of acoustic impedance of tissue constructed from a series of adjacent histology images. The power spectrum of a 3DZM can be analyzed to estimate modelbased quantitative ultrasound parameters such as effective scatterer diameter (ESD) and effective acoustic concentration (EAC). The goal in this approach is to determine a link between the quantitative ultrasound estimates made from tissue and actual tissue structures seen in histology as a means of identifying the ultrasonic scattering sites in different types of tissue. The 3DZM construction and analysis routines have been updated in order to increase speed and overall performance. In particular, the map creation algorithm was structured in a parallel implementation to greatly increase speed. The ESD analysis algorithm was modified to increase both speed and accuracy, and an EAC estimator has been implemented also. The new analysis algorithm was tested through simulating 3DZMs and was found to be very accurate for estimating ESD, but only accurate up to an offset for EAC. The 3DZM method was then applied to rabbit liver and rat cervix tissue. ESD estimates for both normal and fatty rabbit liver were made with average values of 7.5 ± 1.3 µm and 7.0 ±
c ○ 2010 Alexander J. DaporeTHREEDIMENSIONAL ACOUSTIC IMPEDANCE MAP ANALYSIS OF SOFT TISSUE BY
"... Threedimensional impedance maps (3DZMs) are virtual volumes of acoustic impedance values constructed from histology to represent tissue microstructure acoustically. From the 3DZM, the ultrasonic backscattered power spectrum can be predicted and model based scatterer properties, such as effective sc ..."
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Threedimensional impedance maps (3DZMs) are virtual volumes of acoustic impedance values constructed from histology to represent tissue microstructure acoustically. From the 3DZM, the ultrasonic backscattered power spectrum can be predicted and model based scatterer properties, such as effective scatterer diameter (ESD), can be estimated. Additionally, the 3DZM can be exploited to visualize and identify possible scattering sites, which may aid in the development of more effective scattering models to better represent the ultrasonic interaction with underlying tissue microstructure. The 3DZM construction and analysis algorithms have been improved both in terms of performance and cost. A multiresolution registration scheme has been implemented in order to robustly reconstruct the 3DZM from real tissue. Additional processing, such as photometric correction and automatic detection of damaged histology sections, has been applied to ensure the reconstructed volume is faithful to the properties of the orignal tissue. In this work, 3DZMs were created from a set of human fibroadenoma samples. ESD estimates were made assuming a fluidfilled sphere form factor model from 3DZMs of volume
c © 2010 Alexander J. Dapore THREEDIMENSIONAL ACOUSTIC IMPEDANCE MAP ANALYSIS OF SOFT TISSUE BY
"... Threedimensional impedance maps (3DZMs) are virtual volumes of acoustic impedance values constructed from histology to represent tissue microstructure acoustically. From the 3DZM, the ultrasonic backscattered power spectrum can be predicted and model based scatterer properties, such as effective s ..."
Abstract
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Threedimensional impedance maps (3DZMs) are virtual volumes of acoustic impedance values constructed from histology to represent tissue microstructure acoustically. From the 3DZM, the ultrasonic backscattered power spectrum can be predicted and model based scatterer properties, such as effective scatterer diameter (ESD), can be estimated. Additionally, the 3DZM can be exploited to visualize and identify possible scattering sites, which may aid in the development of more effective scattering models to better represent the ultrasonic interaction with underlying tissue microstructure. The 3DZM construction and analysis algorithms have been improved both in terms of performance and cost. A multiresolution registration scheme has been implemented in order to robustly reconstruct the 3DZM from real tissue. Additional processing, such as photometric correction and automatic detection of damaged histology sections, has been applied to ensure the reconstructed volume is faithful to the properties of the orignal tissue. In this work, 3DZMs were created from a set of human fibroadenoma samples. ESD estimates were made assuming a fluidfilled sphere form factor model from 3DZMs of volume