Ex vivo Study of Quantitative Ultrasound Parameters in Fatty Rabbit Livers

Ghoshal, Goutam; Lavarello, Roberto; Kemmerer, Jeremy P.; Miller, Rita J.; Oelze, Michael L.

doi:10.1016/j.ultrasmedbio.2012.08.010

Cited by 107 publications

(79 citation statements)

References 56 publications

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“…20 In that study, a significant and positive correlation was observed between the parameters of the homodyned K-distribution and the FLD stage in rabbits. Another study that used rat models employed Nakagami imaging to examine the relationship between the ultrasound backscattered statistics and the stage of FLD.…”

Section: Research Significancementioning

confidence: 75%

Effects of fatty infiltration in human livers on the backscattered statistics of ultrasound imaging

Wan

Tai

et al. 2015

Proc Inst Mech Eng H

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Ultrasound imaging has been widely applied to screen fatty liver disease. Fatty liver disease is a condition where large vacuoles of triglyceride fat accumulate in liver cells, thereby altering the arrangement of scatterers and the corresponding backscattered statistics. In this study, we used ultrasound Nakagami imaging to explore the effects of fatty infiltration in human livers on the statistical distribution of backscattered signals. A total of 107 patients volunteered to participate in the experiments. The livers were scanned using a clinical ultrasound scanner to obtain the raw backscattered signals for ultrasound B-mode and Nakagami imaging. Clinical scores of fatty liver disease for each patient were determined according to a well-accepted sonographic scoring system. The results showed that the Nakagami image can visualize the local backscattering properties of liver tissues. The Nakagami parameter increased from 0.62 ± 0.11 to 1.02 ± 0.07 as the fatty liver disease stage increased from normal to severe, indicating that the backscattered statistics vary from pre-Rayleigh to Rayleigh distributions. A significant positive correlation (correlation coefficient ρ = 0.84; probability value (p value) < 0.0001) exists between the degree of fatty infiltration and the Nakagami parameter, suggesting that ultrasound Nakagami imaging has potentials in future applications in fatty liver disease diagnosis.

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Section: Research Significancementioning

confidence: 75%

Effects of fatty infiltration in human livers on the backscattered statistics of ultrasound imaging

Wan

Tai

et al. 2015

Proc Inst Mech Eng H

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“…The second method uses statistical distributions to model the echo amplitude distribution for a more accurate statistical analysis. This concept has been realized using statistical models, such as K [26] and Nakagami distributions [27,28], indicating that the echo amplitude distribution varies from pre-Rayleigh to Rayleigh with the formation of fatty liver.…”

Section: Introductionmentioning

confidence: 99%

Effects of Fatty Infiltration of the Liver on the Shannon Entropy of Ultrasound Backscattered Signals

Tsui

Wan

2016

Entropy

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This study explored the effects of fatty infiltration on the signal uncertainty of ultrasound backscattered echoes from the liver. Standard ultrasound examinations were performed on 107 volunteers. For each participant, raw ultrasound image data of the right lobe of liver were acquired using a clinical scanner equipped with a 3.5-MHz convex transducer. An algorithmic scheme was proposed for ultrasound B-mode and entropy imaging. Fatty liver stage was evaluated using a sonographic scoring system. Entropy values constructed using the ultrasound radiofrequency (RF) and uncompressed envelope signals (denoted by H R and H E , respectively) as a function of fatty liver stage were analyzed using the Pearson correlation coefficient. Data were expressed as the median and interquartile range (IQR). Receiver operating characteristic (ROC) curve analysis with 95% confidence intervals (CIs) was performed to obtain the area under the ROC curve (AUC). The brightness of the entropy image typically increased as the fatty stage varied from mild to severe. The median value of H R monotonically increased from 4.69 (IQR: 4.60-4.79) to 4.90 (IQR: 4.87-4.92) as the severity of fatty liver increased (r = 0.63, p < 0.0001). Concurrently, the median value of H E increased from 4.80 (IQR: 4.69-4.89) to 5.05 (IQR: 5.02-5.07) (r = 0.69, p < 0.0001). In particular, the AUCs obtained using H E (95% CI) were 0. 93 (0.87-0.99), 0.88 (0.82-0.94), and 0.76 (0.65-0.87) for fatty stages ≥mild, ≥moderate, and ≥severe, respectively. The sensitivity, specificity, and accuracy were 93.33%, 83.11%, and 86.00%, respectively (≥mild). Fatty infiltration increases the uncertainty of backscattered signals from livers. Ultrasound entropy imaging has potential for the routine examination of fatty liver disease.

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“…Several of these techniques use models of scattering for characterization of tissue disease or response to therapy. [3][4][5][6][7][8][9][10][11] The choice of scattering models is influenced by certain a priori assumptions about the sources of scattering in tissues, such as the assumptions of weak scattering and scattering sites that are physically small compared to a wavelength and, consequently, small compared to the transducer beam width for a weakly focused transducer. This later assumption allows the spatial autocorrelation function of a random medium to be decoupled from the transducer beam.…”

Section: Introductionmentioning

confidence: 99%

Scattering by single physically large and weak scatterers in the beam of a single-element transducer

Kemmerer

Oelze

Gyöngy

2015

The Journal of the Acoustical Society of America

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Quantitative ultrasound techniques are generally applied to characterize media whose scattering sites are considered to be small compared to a wavelength. In this study, the backscattered response of single weakly scattering spheres and cylinders with diameters comparable to the beam width of a 2.25 MHz single-element transducer were simulated and measured in the transducer focal plane to investigate the impact of physically large scatterers. The responses from large single spherical scatterers at the focus were found to closely match the plane-wave response. The responses from large cylindrical scatterers at the focus were found to differ from the plane-wave response by a factor of f(-1). Normalized spectra from simulations and measurements were in close agreement: the fall-off of the responses as a function of lateral position agreed to within 2 dB for spherical scatterers and to within 3.5 dB for cylindrical scatterers. In both measurement and simulation, single scatterer diameter estimates were biased by less than 3% for a more highly focused transducer compared to estimates for a more weakly focused transducer. The results suggest that quantitative ultrasound techniques may produce physically meaningful size estimates for media whose response is dominated by scatterers comparable in size to the transducer beam.

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Ex vivo Study of Quantitative Ultrasound Parameters in Fatty Rabbit Livers

Cited by 107 publications

References 56 publications

Effects of fatty infiltration in human livers on the backscattered statistics of ultrasound imaging

Effects of fatty infiltration in human livers on the backscattered statistics of ultrasound imaging

Effects of Fatty Infiltration of the Liver on the Shannon Entropy of Ultrasound Backscattered Signals

Scattering by single physically large and weak scatterers in the beam of a single-element transducer

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