Comparison of theoretical scattering results and ultrasonic data from clinical liver examinations

Lizzi, Frederic L.; King, Donald L.; Rorke, M; Hui, Joanne; Ostromogilsky, M.; Yaremko, Mykola M.; Feleppa, Ernest J.; Wai, Peter

doi:10.1016/0301-5629(88)90073-7

Cited by 124 publications

(69 citation statements)

References 9 publications

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“…irradiation, by measuring the linear rate of decrease in UIB with increasing depth (17). This attenuation coefficient was similar to the attenuation coefficients measured in vitro from corresponding cell samples, viable and after exposure to radiotherapy (31).…”

Section: Mouse Tumorssupporting

confidence: 68%

Quantitative Ultrasound Characterization of Responses to Radiotherapy in Cancer Mouse Models

Vlad

Brand²,

Giles

et al. 2009

Clinical Cancer Research

100

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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.

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Section: Mouse Tumorssupporting

confidence: 68%

Quantitative Ultrasound Characterization of Responses to Radiotherapy in Cancer Mouse Models

Vlad

Brand²,

Giles

et al. 2009

Clinical Cancer Research

100

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“…Another alternative approach is to use the same principles of ultrasound spectroscopic analysis with conventional midfrequency ultrasound. Lower frequency ultrasound penetrates much deeper, and the backscattered data could be potentially subjected to the same analysis to provide information about structural changes in the tissue at the cellular level (41)(42)(43)(44)(45)(46).…”

Section: Discussionmentioning

confidence: 99%

Ultrasound Imaging of Apoptosis in Tumor Response: Novel Preclinical Monitoring of Photodynamic Therapy Effects

Banihashemi

Vlad²,

Debeljevic³

et al. 2008

Cancer Research

137

157

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High-frequency ultrasound is a novel method to detect apoptotic cell death based on changes in cell morphology that cause alterations in the viscoelastic and, consequently, the acoustic properties of cell ensembles and tissues. In this study, we evaluated the first preclinical tumor-based use of highfrequency ultrasound spectroscopy to noninvasively monitor tumor treatment by following xenograft malignant melanoma tumor responses to photodynamic therapy (PDT) in vivo. We observed a time-dependant increase in ultrasound backscatter variables after treatment. The observed increases in spectroscopic variables correlated with morphologic findings, indicating increases in apoptotic cell death, which peaked at 24 hours after PDT. We analyzed the changes in spectral slope and backscatter in relation to apoptosis and histologic variations in cell nuclear size. Changes in spectral slope strongly correlated with the changes in mean nuclear size over time, associated with apoptosis, after PDT (P < 0.05). At 48 hours, a decrease in ultrasound backscatter was observed, which could be explained by an increase in cell nuclear degradation. In summary, we show that high-frequency ultrasound spectroscopic variables can be used noninvasively to monitor response after treatment in a preclinical tumor cancer model. These findings provide a foundation for future investigations regarding the use of ultrasound to monitor and aid the customization of treatments noninvasively based on responses to specific interventions. [Cancer Res 2008;68(20):8590-6]

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“…Each scan line was digitized with 3400 eight-bit samples. Data were acquired with the transducer focus placed at the front (near) surface of the phantom, that is, at a depth of 0 mm, then at depths of 5,10,15,20,25,30,35, and 40 mm, that is, at the rear (far) surface of the phantom.…”

Section: Laboratorymentioning

confidence: 99%

Interlaboratory Comparison of Ultrasonic Backscatter Coefficient Measurements From 2 to 9 MHz

Wear

Stiles²,

Frank³

et al. 2005

Journal of Ultrasound in Medicine

Self Cite

143

119

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Objective. As are the attenuation coefficient and sound speed, the backscatter coefficient is a fundamental ultrasonic property that has been used to characterize many tissues. Unfortunately, there is currently far less standardization for the ultrasonic backscatter measurement than for the other two, as evidenced by a previous American Institute of Ultrasound in Medicine (AIUM)-sponsored interlaboratory comparison of ultrasonic backscatter, attenuation, and speed measurements (J Ultrasound Med 1999; 18:615-631). To explore reasons for these disparities, the AIUM Endowment for Education and Research recently supported this second interlaboratory comparison, which extends the upper limit of the frequency range from 7 to 9 MHz. Methods. Eleven laboratories were provided with standard test objects designed and manufactured at the University of Wisconsin (Madison, WI). Each laboratory was asked to perform ultrasonic measurements of sound speed, attenuation coefficients, and backscatter coefficients. Each laboratory was blinded to the values of the ultrasonic properties of the test objects at the time the measurements were performed. Results. Eight of the 11 laboratories submitted results. The range of variation of absolute magnitude of backscatter coefficient measurements was about 2 orders of magnitude. If the results of 1 outlier laboratory are excluded, then the range is reduced to about 1 order of magnitude. Agreement regarding frequency dependence of backscatter was better than reported in the previous interlaboratory comparison. For example, when scatterers were small compared with the ultrasonic wavelength, experimental frequency-dependent backscatter coefficient data obtained by the participating laboratories were usually consistent with the expected Rayleigh scattering behavior (proportional to frequency to the fourth power). Conclusions. Greater standardization of backscatter measurement methods is needed. Measurements of frequency dependence of backscatter are more consistent than measurements of absolute magnitude.

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Comparison of theoretical scattering results and ultrasonic data from clinical liver examinations

Cited by 124 publications

References 9 publications

Quantitative Ultrasound Characterization of Responses to Radiotherapy in Cancer Mouse Models

Quantitative Ultrasound Characterization of Responses to Radiotherapy in Cancer Mouse Models

Ultrasound Imaging of Apoptosis in Tumor Response: Novel Preclinical Monitoring of Photodynamic Therapy Effects

Interlaboratory Comparison of Ultrasonic Backscatter Coefficient Measurements From 2 to 9 MHz

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