High frequency ultrasonic scattering by biological tissues

Shung, K. Kirk; Maruvada, Subha

doi:10.1121/1.4778503

Cited by 18 publications

(29 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…QUS methods have been used to diagnose prostate cancer, ocular tumors, liver and cardiac abnormalities (15 -18); differentiate benign fibroadenomas from mammary carcinomas and sarcomas (19); and have provided good diagnostic accuracy in prostate cancer detection and lesion localization (20). QUS methods, specifically spectral parameters, can be used to detect structural alterations induced by ultrasonically induced hyperthermia in tumor xenografts (21), discern between different types of ocular tumors (22,23), and classify these depending on their lethality potential (16,24).…”

Section: Discussionmentioning

confidence: 99%

Quantitative Ultrasound Characterization of Responses to Radiotherapy in Cancer Mouse Models

Vlad

Brand²,

Giles

et al. 2009

Clinical Cancer Research

View full text Add to dashboard Cite

Purpose: Currently, no imaging modality is used routinely to assess tumor responses to radiotherapy within hours to days after the delivery of treatment. In this study, we show the application of quantitative ultrasound methods to characterize tumor responses to cancer radiotherapy in vivo, as early as 24 hours after treatment administration. Experimental Design:Three mouse models of head and neck cancer were exposed to radiation doses of 0, 2, 4, and 8 Gray. Data were collected with an ultrasound scanner using frequencies of 10 to 30 MHz. Ultrasound estimates calculated from normalized power spectra and parametric images (spatial maps of local estimates of ultrasound parameters) were used as indicators of response. Results: Two of the mouse models (FaDu and C666-1) exhibited large hyperechoic regions at 24 hours after radiotherapy. The ultrasound integrated backscatter increased by 6.5 to 8.2 dB (P < 0.001) and the spectral slopes increased from 0.77 to 0.90 dB/MHz for the C666-1tumors and from 0.54 to 0.78 dB/MHz for the FaDu tumors (P < 0.05), in these regions compared with preirradiated tumors.The hyperechoic regions in the ultrasound images corresponded in histology to areas of cell death. Parametric images could discern the tumor regions that responded to treatment. The other cancer mouse model (Hep-2) was resistant to radiotherapy. Conclusions:The results indicate that cell structural changes after radiotherapy have a significant influence on ultrasound spectral parameters. This provides a foundation for future investigations regarding the use of ultrasound in cancer patients to individualize treatments noninvasively based on their responses to specific interventions.

show abstract

Section: Discussionmentioning

confidence: 99%

Quantitative Ultrasound Characterization of Responses to Radiotherapy in Cancer Mouse Models

Vlad

Brand²,

Giles

et al. 2009

Clinical Cancer Research

View full text Add to dashboard Cite

show abstract

“…The chambers of the human heart therefore appear as dark regions in echocardiography (the echo from the myocardium is typically 32 dB stronger than that from blood at 5 MHz). 27 However, Figure 5a shows that we can still obtain a strong echo signal from blood within the ventricle of the zebrafish at an ultrasound frequency of 80 MHz. Therefore, separating blood and tissue signals using an amplitude threshold is also not suitable in TDI of the zebrafish heart (as is also the case for the frequency-filter principle).…”

Section: Fig 5 Typical B-mode Image Of a Normal Zebrafish Heart Obtmentioning

confidence: 99%

High-Resolution Tissue Doppler Imaging of the Zebrafish Heart During Its Regeneration

Huang

Shih

2015

Zebrafish

View full text Add to dashboard Cite

The human heart cannot regenerate after injury, whereas the adult zebrafish can fully regenerate its heart even after 20% of the ventricle is amputated. Many studies have begun to reveal the cellular and molecular mechanisms underlying this regenerative process, which have exciting implications for human cardiac diseases. However, the dynamic functions of the zebrafish heart during regeneration are not yet understood. This study established a high-resolution echocardiography for tissue Doppler imaging (TDI) of the zebrafish heart to explore the cardiac functions during different regeneration phases. Experiments were performed on AB-line adult zebrafish (n = 40) in which 15% of the ventricle was surgically removed. An 80-MHz ultrasound TDI based on color M-mode imaging technology was employed. The cardiac flow velocities and patterns from both the ventricular chamber and myocardium were measured at different regeneration phases relative to the day of amputation. The peak velocities of early diastolic inflow, early diastolic myocardial motion, late diastolic myocardial motion, early diastolic deceleration slope, and heart rate were increased at 3 days after the myocardium amputation, but these parameters gradually returned to close to their baseline values for the normal heart at 7 days after amputation. The peak velocities of late diastolic inflow, ventricular systolic outflow, and systolic myocardial motion did not significantly differ during the heart regeneration.

show abstract

“…When the number density of scatterers is increased, the effect of constructive wave interference causes the distribution of the backscattered statistics to vary toward the Rayleigh distribution [13] and also leads to larger backscattered echoes [33]. Strong scatterers or an aggregation of scatterers also result in the formation of high-amplitude signals [34]. Obviously, in the conventional definition of entropy, the relevance of signal amplitude in information interpretation is neglected.…”

Section: Ultrasound Weighted Entropymentioning

confidence: 99%

Ultrasound Detection of Scatterer Concentration by Weighted Entropy

Tsui

2015

Entropy

View full text Add to dashboard Cite

Abstract:Ultrasound backscattering signals depend on the microstructures of tissues. Some studies have applied Shannon entropy to analyze the uncertainty of raw radiofrequency (RF) data. However, we found that the sensitivity of entropy in detecting various scatterer concentrations is limited; thus, we propose a weighted entropy as a new information entropy-based approach to enhance the performance of scatterer characterization. A standard simulation model of ultrasound backscattering was used to generate backscattered RF signals with different number densities of scatterers. The RF signals were used to estimate the weighted entropy according to the proposed algorithmic scheme. The weighted entropy increased from 0.08 to 0.23 (representing a dynamic range of 0.15) when the number density of scatterers increased from 2 to 32 scatterers/mm 2 . In the same range of scatterer concentration, the conventional entropy increased from 0.16 to 0.19 (a dynamic range of 0.03). The results indicated that the weighted entropy enables achieving a more sensitive detection of the variation of scatterer concentrations by ultrasound.

show abstract

High frequency ultrasonic scattering by biological tissues

Cited by 18 publications

References 0 publications

Quantitative Ultrasound Characterization of Responses to Radiotherapy in Cancer Mouse Models

Quantitative Ultrasound Characterization of Responses to Radiotherapy in Cancer Mouse Models

High-Resolution Tissue Doppler Imaging of the Zebrafish Heart During Its Regeneration

Ultrasound Detection of Scatterer Concentration by Weighted Entropy

Contact Info

Product

Resources

About