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Li S, Tsui PH, Wu W, Wu S, Zhou Z. Ultrasound k-nearest neighbor entropy imaging: Theory, algorithm, and applications. ULTRASONICS 2024; 138:107256. [PMID: 38325231 DOI: 10.1016/j.ultras.2024.107256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/09/2024]
Abstract
Ultrasound information entropy is a flexible approach for analyzing ultrasound backscattering. Shannon entropy imaging based on probability distribution histograms (PDHs) has been implemented as a promising method for tissue characterization and diagnosis. However, the bin number affects the stability of entropy estimation. In this study, we introduced the k-nearest neighbor (KNN) algorithm to estimate entropy values and proposed ultrasound KNN entropy imaging. The proposed KNN estimator leveraged the Euclidean distance between data samples, rather than the histogram bins by conventional PDH estimators. We also proposed cumulative relative entropy (CRE) imaging to analyze time-series radiofrequency signals and applied it to monitor thermal lesions induced by microwave ablation (MWA). Computer simulation phantom experiments were conducted to validate and compare the performance of the proposed KNN entropy imaging, the conventional PDH entropy imaging, and Nakagami-m parametric imaging in detecting the variations of scatterer densities and visualizing inclusions. Clinical data of breast lesions were analyzed, and porcine liver MWA experiments ex vivo were conducted to validate the performance of KNN entropy imaging in classifying benign and malignant breast tumors and monitoring thermal lesions, respectively. Compared with PDH, the entropy estimation based on KNN was less affected by the tuning parameters. KNN entropy imaging was more sensitive to changes in scatterer densities and performed better visualizable capability than typical Shannon entropy (TSE) and Nakagami-m parametric imaging. Among different imaging methods, KNN-based Shannon entropy (KSE) imaging achieved the higher accuracy in classification of benign and malignant breast tumors and KNN-based CRE imaging had larger lesion-to-normal contrast when monitoring the ablated areas during MWA at different powers and treatment durations. Ultrasound KNN entropy imaging is a potential quantitative ultrasound approach for tissue characterization.
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Affiliation(s)
- Sinan Li
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Po-Hsiang Tsui
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Institute for Radiological Research, Chang Gung University, Taoyuan, Taiwan; Division of Pediatric Gastroenterology, Department of Pediatrics, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Weiwei Wu
- College of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Shuicai Wu
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China.
| | - Zhuhuang Zhou
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China.
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Karbalaeisadegh Y, Yao S, Zhu Y, Grimal Q, Muller M. Ultrasound Characterization of Cortical Bone Using Shannon Entropy. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:1824-1829. [PMID: 37244812 DOI: 10.1016/j.ultrasmedbio.2023.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/13/2023] [Accepted: 04/19/2023] [Indexed: 05/29/2023]
Abstract
OBJECTIVE Ultrasound backscattered signals encompass information on the microstructure of heterogeneous media such as cortical bone, in which pores act as scatterers and result in the scattering and multiple scattering of ultrasound waves. The objective of this study was to investigate whether Shannon entropy can be exploited to characterize cortical porosity. METHODS In the study described here, to demonstrate proof of concept, Shannon entropy was used as a quantitative ultrasound parameter to experimentally evaluate microstructural changes in samples with controlled scatterer concentrations made of a highly absorbing polydimethylsiloxane matrix (PDMS). Similar assessment was then performed using numerical simulations on cortical bone structures with varying average pore diameter (Ct.Po.Dm.), density (Ct.Po.Dn.) and porosity (Ct.Po.). RESULTS The results suggest that an increase in pore diameter and porosity lead to an increase in entropy, indicating increased levels of randomness in the signals as a result of increased scattering. The entropy-versus-scatterer volume fraction in PDMS samples indicates an initial increasing trend that slows down as the scatterer concentration increases. High levels of attenuation cause the signal amplitudes and corresponding entropy values to decrease drastically. The same trend is observed when porosity of the bone samples is increased above 15%. CONCLUSION Sensitivity of entropy to microstructural changes in highly scattering and absorbing media can potentially be exploited to diagnose and monitor osteoporosis.
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Affiliation(s)
- Yasamin Karbalaeisadegh
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - Shanshan Yao
- Department of Mechanical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Yong Zhu
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - Quentin Grimal
- Laboratory of Biomedical Imaging, Sorbonne University, Paris, France
| | - Marie Muller
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA.
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Tsui PH. Information Entropy and Its Applications. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1403:153-167. [PMID: 37495918 DOI: 10.1007/978-3-031-21987-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Ultrasound is a first-line diagnostic tool for imaging many disease states. A number of statistical distributions have been proposed to describe ultrasound backscattering measured from tissues having different disease states. As an example, in this chapter we use nonalcoholic fatty liver disease (NAFLD), which is a critical health issue on a global scale, to demonstrate the capabilities of ultrasound to diagnose disease. Ultrasound interaction with the liver is typically characterized by scattering, which is quantified for the purpose of determining the degree of liver steatosis and fibrosis. Information entropy provides an insight into signal uncertainty. This concept allows for the analysis of backscattered statistics without considering the distribution of data or the statistical properties of ultrasound signals. In this chapter, we examined the background of NAFLD and the sources of scattering in the liver. The fundamentals of information entropy and an algorithmic scheme for ultrasound entropy imaging are then presented. Lastly, some examples of using ultrasound entropy imaging to grade hepatic steatosis and evaluate the risk of liver fibrosis in patients with significant hepatic steatosis are presented to illustrate future opportunities for clinical use.
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Affiliation(s)
- Po-Hsiang Tsui
- Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan City, Taiwan.
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Petrella L, Nunes S, Perdigão F, Gomes M, Santos M, Pinto C, Morgado M, Travassos A, Santos J, Caixinha M. Feasibility assessment of the Eye Scan Ultrasound System for cataract characterization and optimal phacoemulsification energy estimation: protocol for a pilot, nonblinded and monocentre study. Pilot Feasibility Stud 2022; 8:219. [PMID: 36175978 PMCID: PMC9520812 DOI: 10.1186/s40814-022-01173-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 09/15/2022] [Indexed: 11/17/2022] Open
Abstract
Background Cataracts are lens opacifications that are responsible for more than half of blindness cases worldwide, and the only treatment is surgical intervention. Phacoemulsification surgery, the most frequently performed cataract surgery in developed countries, has associated risks, some of which are related to excessive phacoemulsification energy levels and times. The protocol proposed in herein will be used to evaluate the feasibility of a new experimental medical device, the Eye Scan Ultrasound System (ESUS), for the automatic classification of cataract type and severity and quantitative estimation of the optimal phacoemulsification energy. Methods The pilot study protocol will be used to evaluate the feasibility and safety of the ESUS in clinical practice. The study will be conducted in subjects with age-related cataracts and on healthy subjects as controls. The procedures include data acquisition with the experimental ESUS, classification based on the Lens Opacity Classification System III (LOCS III, comparator) using a slit lamp, contrast sensitivity test, optical coherence tomography, specular microscopy and surgical parameters. ESUS works in A-scan pulse-echo mode, with a central frequency of 20 MHz. From the collected signals, acoustic parameters will be extracted and used for automatic cataract characterization and optimal phacoemulsification energy estimation. The study includes two phases. The data collected in the first phase (40 patients, 2 eyes per patient) will be used to train the ESUS algorithms, while the data collected in the second phase (10 patients, 2 eyes per patient) will be used to assess the classification performance. System safety will be monitored during the study. Discussion The present pilot study protocol will evaluate the feasibility and safety of the ESUS for use in clinical practice, and the results will support a larger clinical study for the efficacy assessment of the ESUS as a diagnostic tool. Ultimately, the ESUS is expected to represent a valuable tool for surgical planning by reducing complications associated with excessive levels of phacoemulsification energy and surgical times, which will have a positive impact on healthcare systems and society. The study is not yet recruiting. Trial registration ClinicalTrials.gov identifier NCT04461912, registered on July 8, 2020.
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Affiliation(s)
- Lorena Petrella
- Department of Electrical and Computer Engineering, Univ Coimbra, 3030-290, Coimbra, Portugal. .,Centre for Mechanical Engineering, Materials and Processes, Univ Coimbra, 3030-788, Coimbra, Portugal. .,Centre for Informatics and Systems of the University of Coimbra, Univ Coimbra, 3030-290, Coimbra, Portugal.
| | - Sandrina Nunes
- Coimbra Institute for Clinical and Biomedical Research, Univ Coimbra, 3000-548, Coimbra, Portugal
| | - Fernando Perdigão
- Department of Electrical and Computer Engineering, Univ Coimbra, 3030-290, Coimbra, Portugal.,Instituto de Telecomunicações, 3030-290, Coimbra, Portugal
| | - Marco Gomes
- Department of Electrical and Computer Engineering, Univ Coimbra, 3030-290, Coimbra, Portugal.,Instituto de Telecomunicações, 3030-290, Coimbra, Portugal
| | - Mário Santos
- Department of Electrical and Computer Engineering, Univ Coimbra, 3030-290, Coimbra, Portugal.,Centre for Mechanical Engineering, Materials and Processes, Univ Coimbra, 3030-788, Coimbra, Portugal
| | - Carlos Pinto
- Department of Electrical and Computer Engineering, Univ Coimbra, 3030-290, Coimbra, Portugal.,Instituto de Telecomunicações, 3030-290, Coimbra, Portugal
| | - Miguel Morgado
- Coimbra Institute for Biomedical Imaging and Translational Research, Univ Coimbra, 3004-516, Coimbra, Portugal.,Department of Physics, Univ Coimbra, 3004-516, Coimbra, Portugal
| | | | - Jaime Santos
- Department of Electrical and Computer Engineering, Univ Coimbra, 3030-290, Coimbra, Portugal.,Centre for Mechanical Engineering, Materials and Processes, Univ Coimbra, 3030-788, Coimbra, Portugal
| | - Miguel Caixinha
- Centre for Mechanical Engineering, Materials and Processes, Univ Coimbra, 3030-788, Coimbra, Portugal.,Department of Physics, Univ Beira Interior, 6291-001, Covilhã, Portugal
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Fang J, Ting YN, Chen YW. Quantitative Assessment of Lung Ultrasound Grayscale Images Based on Shannon Entropy for the Detection of Pulmonary Aeration: An Animal Study. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2022; 41:1699-1711. [PMID: 34698398 DOI: 10.1002/jum.15851] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 08/23/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
OBJECTIVE Lung ultrasound (LUS) is a radiation-free, affordable, and bedside monitoring method that can detect changes in pulmonary aeration before hypoxic damage. However, visual scoring methods of LUS only enable subjective diagnosis. Therefore, quantitative analysis of LUS is necessary for obtaining objective information on pulmonary aeration. Because raw data are not always available in conventional ultrasound systems, Shannon entropy (ShanEn) of information theory without the requirement of raw data is valuable. In this study, we explored the feasibility of ShanEn estimated through grayscale histogram (GSH) analysis of LUS images for the quantification of pulmonary aeration. METHODS Different degrees of pulmonary aeration caused by edema was induced in 32 male New Zealand rabbits intravenously injected with 0.1 mL/kg saline (the control group) and 0.025, 0.05, and 0.1 mL/kg oleic acid (mild, moderate, and severe groups, respectively). In vivo grayscale LUS images were acquired using a commercial point-of-care ultrasound system for estimation of GSH and corresponding ShanEn. Both lungs of each rabbit were dissected, weighed, and dried to determine the wet weight-to-dry weight ratio (W/D) through gravimetry. RESULTS The determination coefficients of linear correlations between ShanEn and W/D increased from 0.0487 to 0.7477 with gain and dynamic range (DR). In contrast to visual scoring methods of pulmonary aeration that use median gain and low DR, ShanEn for quantifying pulmonary aeration requires high gain and DR. CONCLUSION The current findings indicate that ShanEn estimated through GSH analysis of LUS images acquired using conventional ultrasonic imaging systems has great potential to provide objective information on pulmonary aeration.
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Affiliation(s)
- Jui Fang
- x-Dimension Center for Medical Research and Translation, China Medical University Hospital, Taichung City, Taiwan
| | - Yen-Nien Ting
- x-Dimension Center for Medical Research and Translation, China Medical University Hospital, Taichung City, Taiwan
| | - Yi-Wen Chen
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung City, Taiwan
- High Performance Materials Institute for xD Printing, Asia University, Taichung City, Taiwan
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Wang CY, Chu SY, Lin YC, Tsai YW, Tai CL, Yang KC, Tsui PH. Quantitative imaging of ultrasound backscattered signals with information entropy for bone microstructure characterization. Sci Rep 2022; 12:414. [PMID: 35013540 PMCID: PMC8748747 DOI: 10.1038/s41598-021-04425-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/08/2021] [Indexed: 12/19/2022] Open
Abstract
Osteoporosis is a critical problem during aging. Ultrasound signals backscattered from bone contain information associated with microstructures. This study proposed using entropy imaging to collect the information in bone microstructures as a possible solution for ultrasound bone tissue characterization. Bone phantoms with different pounds per cubic foot (PCF) were used for ultrasound scanning by using single-element transducers of 1 (nonfocused) and 3.5 MHz (nonfocused and focused). Clinical measurements were also performed on lumbar vertebrae (L3 spinal segment) in participants with different ages (n = 34) and postmenopausal women with low or moderate-to-high risk of osteoporosis (n = 50; identified using the Osteoporosis Self-Assessment Tool for Taiwan). The signals backscattered from the bone phantoms and subjects were acquired for ultrasound entropy imaging by using sliding window processing. The independent t-test, one-way analysis of variance, Spearman correlation coefficient rs, and the receiver operating characteristic (ROC) curve were used for statistical analysis. The results indicated that ultrasound entropy imaging revealed changes in bone microstructures. Using the 3.5-MHz focused ultrasound, small-window entropy imaging (side length: one pulse length of the transducer) was found to have high performance and sensitivity in detecting variation among the PCFs (rs = − 0.83; p < 0.05). Small-window entropy imaging also performed well in discriminating young and old participants (p < 0.05) and postmenopausal women with low versus moderate-to-high osteoporosis risk (the area under the ROC curve = 0.80; cut-off value = 2.65; accuracy = 86.00%; sensitivity = 71.43%; specificity = 88.37%). Ultrasound small-window entropy imaging has great potential in bone tissue characterization and osteoporosis assessment.
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Affiliation(s)
- Chiao-Yin Wang
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyüan, Taiwan
| | - Sung-Yu Chu
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Taoyüan, Taiwan
| | - Yu-Ching Lin
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Keelung and Chang Gung University, Taoyüan, Taiwan
| | - Yu-Wei Tsai
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyüan, Taiwan
| | - Ching-Lung Tai
- Graduate Institute of Biomedical Engineering, Chang Gung University, Taoyüan, Taiwan
| | - Kuen-Cheh Yang
- Department of Family Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Hsiang Tsui
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyüan, Taiwan. .,Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Taoyüan, Taiwan. .,Division of Pediatric Gastroenterology, Department of Pediatrics, Chang Gung Memorial Hospital at Linkou, Taoyüan, Taiwan.
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Hepatic Steatosis Assessment Using Quantitative Ultrasound Parametric Imaging Based on Backscatter Envelope Statistics. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9040661] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hepatic steatosis is a key manifestation of non-alcoholic fatty liver disease (NAFLD). Early detection of hepatic steatosis is of critical importance. Currently, liver biopsy is the clinical golden standard for hepatic steatosis assessment. However, liver biopsy is invasive and associated with sampling errors. Ultrasound has been recommended as a first-line diagnostic test for the management of NAFLD. However, B-mode ultrasound is qualitative and can be affected by factors including image post-processing parameters. Quantitative ultrasound (QUS) aims to extract quantified acoustic parameters from the ultrasound backscattered signals for ultrasound tissue characterization and can be a complement to conventional B-mode ultrasound. QUS envelope statistics techniques, both statistical model-based and non-model-based, have shown potential for hepatic steatosis characterization. However, a state-of-the-art review of hepatic steatosis assessment using envelope statistics techniques is still lacking. In this paper, envelope statistics-based QUS parametric imaging techniques for characterizing hepatic steatosis are reviewed and discussed. The reviewed ultrasound envelope statistics parametric imaging techniques include acoustic structure quantification imaging, ultrasound Nakagami imaging, homodyned-K imaging, kurtosis imaging, and entropy imaging. Future developments are suggested.
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Performance Evaluations on Using Entropy of Ultrasound Log-Compressed Envelope Images for Hepatic Steatosis Assessment: An In Vivo Animal Study. ENTROPY 2018; 20:e20020120. [PMID: 33265211 PMCID: PMC7512613 DOI: 10.3390/e20020120] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 02/05/2018] [Accepted: 02/09/2018] [Indexed: 12/11/2022]
Abstract
Ultrasound B-mode imaging based on log-compressed envelope data has been widely applied to examine hepatic steatosis. Modeling raw backscattered signals returned from the liver parenchyma by using statistical distributions can provide additional information to assist in hepatic steatosis diagnosis. Since raw data are not always available in modern ultrasound systems, information entropy, which is a widely known nonmodel-based approach, may allow ultrasound backscattering analysis using B-scan for assessing hepatic steatosis. In this study, we explored the feasibility of using ultrasound entropy imaging constructed using log-compressed backscattered envelopes for assessing hepatic steatosis. Different stages of hepatic steatosis were induced in male Wistar rats fed with a methionine- and choline-deficient diet for 0 (i.e., normal control) and 1, 1.5, and 2 weeks (n = 48; 12 rats in each group). In vivo scanning of rat livers was performed using a commercial ultrasound machine (Model 3000, Terason, Burlington, MA, USA) equipped with a 7-MHz linear array transducer (Model 10L5, Terason) for ultrasound B-mode and entropy imaging based on uncompressed (HE image) and log-compressed envelopes (HB image), which were subsequently compared with histopathological examinations. Receiver operating characteristic (ROC) curve analysis and areas under the ROC curves (AUC) were used to assess diagnostic performance levels. The results showed that ultrasound entropy imaging can be used to assess hepatic steatosis. The AUCs obtained from HE imaging for diagnosing different steatosis stages were 0.93 (≥mild), 0.89 (≥moderate), and 0.89 (≥severe), respectively. HB imaging produced AUCs ranging from 0.74 (≥mild) to 0.84 (≥severe) as long as a higher number of bins was used to reconstruct the signal histogram for estimating entropy. The results indicated that entropy use enables ultrasound parametric imaging based on log-compressed envelope signals with great potential for diagnosing hepatic steatosis.
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Kurtul N, Yurttutan N, Baykara M. Investigation of the radiotherapy-related changes in the eye lens using computed tomography entropy analysis. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2018; 26:747-755. [PMID: 29889097 DOI: 10.3233/xst-18373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
OBJECTIVE The aim of this study was to apply texture analysis to investigate whether there was a change in the lens following radiotherapy. PATIENTS AND METHOD Patients who received radiotherapy (RT) for head and neck cancer or brain tumor were enrolled. Computed tomography (CT) images taken in the last month before RT and the most recent images after RT were compared. Entropy values were calculated using lens attenuation values. The lens doses were obtained from the dose-volume histogram data. RESULTS A total of 55 lenses were evaluated. The mean Hounsfield Unit value of the lenses was 66.14±12.16 before RT and 72.02±9.12 after RT (p = 0.007). The mean entropy value was 1.87±0.31 before RT and this reduced to 1.31±0.34 after RT (p < 0.001), respectively. As time increased, the difference in entropy also increased (p = 0.007). A correlation close to statistical significance was determined between the entropy difference and minimum, maximum and mean lens radiation dose (p = 0.052, p = 0.052, p = 0.063, respectively). The entropy difference was significantly reduced in the >4 Gy group (p = 0.046). CONCLUSION Study results indicated that the entropy values in the lens were signifcantly changed after radiotherapy and the degree of the change associated with dose and time.
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Affiliation(s)
- Neslihan Kurtul
- Department of Radiation Oncology, Sutcu Imam University Faculty of Medicine, Kahramanmaras, Turkey
| | - Nursel Yurttutan
- Department of Radiology, Sutcu Imam University Faculty of Medicine, Kahramanmaras, Turkey
| | - Murat Baykara
- Department of Radiology, Sutcu Imam University Faculty of Medicine, Kahramanmaras, Turkey
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Patil KK, Gacche RN. Inhibition of glycation and aldose reductase activity using dietary flavonoids: A lens organ culture studies. Int J Biol Macromol 2017; 98:730-738. [DOI: 10.1016/j.ijbiomac.2017.01.129] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 01/16/2017] [Accepted: 01/30/2017] [Indexed: 12/01/2022]
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Small-window parametric imaging based on information entropy for ultrasound tissue characterization. Sci Rep 2017; 7:41004. [PMID: 28106118 PMCID: PMC5247684 DOI: 10.1038/srep41004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 11/15/2016] [Indexed: 12/26/2022] Open
Abstract
Constructing ultrasound statistical parametric images by using a sliding window is a widely adopted strategy for characterizing tissues. Deficiency in spatial resolution, the appearance of boundary artifacts, and the prerequisite data distribution limit the practicability of statistical parametric imaging. In this study, small-window entropy parametric imaging was proposed to overcome the above problems. Simulations and measurements of phantoms were executed to acquire backscattered radiofrequency (RF) signals, which were processed to explore the feasibility of small-window entropy imaging in detecting scatterer properties. To validate the ability of entropy imaging in tissue characterization, measurements of benign and malignant breast tumors were conducted (n = 63) to compare performances of conventional statistical parametric (based on Nakagami distribution) and entropy imaging by the receiver operating characteristic (ROC) curve analysis. The simulation and phantom results revealed that entropy images constructed using a small sliding window (side length = 1 pulse length) adequately describe changes in scatterer properties. The area under the ROC for using small-window entropy imaging to classify tumors was 0.89, which was higher than 0.79 obtained using statistical parametric imaging. In particular, boundary artifacts were largely suppressed in the proposed imaging technique. Entropy enables using a small window for implementing ultrasound parametric imaging.
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Effects of Fatty Infiltration of the Liver on the Shannon Entropy of Ultrasound Backscattered Signals. ENTROPY 2016. [DOI: 10.3390/e18090341] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Tsui PH. Current status and future prospects of scattering statistics in ultrasound imaging. J Med Ultrasound 2016. [DOI: 10.1016/j.jmu.2016.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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