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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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Li Z, Lai M, Zhao S, Zhou Y, Luo J, Hao Y, Xie L, Wang Y, Yan F. Ultrasound Molecular Imaging for Multiple Biomarkers by Serial Collapse of Targeting Microbubbles with Distinct Acoustic Pressures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2108040. [PMID: 35499188 DOI: 10.1002/smll.202108040] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 04/08/2022] [Indexed: 06/14/2023]
Abstract
Ultrasound molecular imaging (UMI) has shown promise for assessing the expression levels of biomarkers for the early detection of various diseases. However, it remains difficult to simultaneously image multiple biomarkers in a single systemic administration, which is important for the accurate diagnosis of diseases and for understanding the dynamic intermolecular mechanisms that drive their malignant progression. The authors develop an ultrasound molecular imaging method by serial collapse of targeting microbubbles with distinct acoustic pressures for the simultaneous detection of two biomarkers. To test this, αv β3 -targeting lipid microbubbles (L-MBα ) and VEGFR2-targeting lipid-PLGA microbubbles (LP-MBv ) are fabricated and simultaneously injected into tumor-bearing mice at 7 and 14 days, followed by the low-intensity acoustic collapse of L-MBα and high-intensity acoustic collapse of LP-MBv . The UMI signals of L-MBα and LP-MBv are obtained by subtracting the first post-burst signals from the first pre-burst signals, and subtracting the second post-burst signals from the first post-burst signals, respectively. Interestingly, the signal intensities from UMI agree with the immunohistochemical staining results for αv β3 and VEGFR2. Importantly, they find a better fit for the invasive behavior of MDA-MB-231 breast tumors by analyzing the ratio of αv β3 integrin to VEGFR2, but not the single αv β3 or VEGFR2 levels.
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Affiliation(s)
- Zhenzhou Li
- Department of Ultrasound, The Second People's Hospital of Shenzhen, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518061, P. R. China
- Shenzhen University Health Science Center, Shenzhen, 518000, P. R. China
| | - Manlin Lai
- Department of Ultrasound, The Second People's Hospital of Shenzhen, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518061, P. R. China
- Shenzhen University Health Science Center, Shenzhen, 518000, P. R. China
| | - Shuai Zhao
- Department of Ultrasound, Suzhou Hospital of Anhui Medical University (Suzhou Municipal Hospital of Anhui Province), Suzhou, 234000, P. R. China
| | - Yi Zhou
- Department of Ultrasound, The Second People's Hospital of Shenzhen, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518061, P. R. China
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, P. R. China
| | - Jingna Luo
- Department of Ultrasound, The Second People's Hospital of Shenzhen, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518061, P. R. China
- Shenzhen University Health Science Center, Shenzhen, 518000, P. R. China
| | - Yongsheng Hao
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
| | - Liting Xie
- Department of Ultrasound, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, P. R. China
| | - Yaru Wang
- Department of Radiology, Suzhou Hospital of Anhui Medical University (Suzhou Municipal Hospital of Anhui Province), Suzhou, 234000, P. R. China
| | - Fei Yan
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China
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Güvener N, Appold L, de Lorenzi F, Golombek SK, Rizzo LY, Lammers T, Kiessling F. Recent advances in ultrasound-based diagnosis and therapy with micro- and nanometer-sized formulations. Methods 2017; 130:4-13. [PMID: 28552267 DOI: 10.1016/j.ymeth.2017.05.018] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/11/2017] [Accepted: 05/21/2017] [Indexed: 01/15/2023] Open
Abstract
Ultrasound (US) is one of the most frequently used imaging methods in the clinic. The broad spectrum of its applications can be increased by the use of gas-filled microbubbles (MB) as ultrasound contrast agents (UCA). In recent years, also nanoscale UCA like nanobubbles (NB), echogenic liposomes (ELIP) and nanodroplets have been developed, which in contrast to MB, are able to extravasate from the vessels into the tissue. New disease-specific UCA have been designed for the assessment of tissue biomarkers and advanced US to a molecular imaging modality. For this purpose, specific binding moieties were coupled to the UCA surface. The vascular endothelial growth factor receptor-2 (VEGFR-2) and P-/E-selectin are prominent examples of molecular US targets to visualize tumor blood vessels and inflammatory diseases, respectively. Besides their application in contrast-enhanced imaging, MB can also be employed for drug delivery to tumors and across the blood-brain barrier (BBB). This review summarizes the development of micro- and nanoscaled UCA and highlights recent advances in diagnostic and therapeutic applications, which are ready for translation into the clinic.
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Affiliation(s)
- Nihan Güvener
- Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany
| | - Lia Appold
- Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany
| | - Federica de Lorenzi
- Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany
| | - Susanne K Golombek
- Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany
| | - Larissa Y Rizzo
- Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany
| | - Twan Lammers
- Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany
| | - Fabian Kiessling
- Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, 52074 Aachen, Germany.
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Hughes MS, McCarthy JE, Bruillard PJ, Marsh JN, Wickline SA. Entropy vs. Energy Waveform Processing: A Comparison Based on the Heat Equation. ENTROPY 2016; 17:3518-3551. [PMID: 27110093 PMCID: PMC4838411 DOI: 10.3390/e17063518] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Virtually all modern imaging devices collect electromagnetic or acoustic waves and use the energy carried by these waves to determine pixel values to create what is basically an “energy” picture. However, waves also carry “information”, as quantified by some form of entropy, and this may also be used to produce an “information” image. Numerous published studies have demonstrated the advantages of entropy, or “information imaging”, over conventional methods. The most sensitive information measure appears to be the joint entropy of the collected wave and a reference signal. The sensitivity of repeated experimental observations of a slowly-changing quantity may be defined as the mean variation (i.e., observed change) divided by mean variance (i.e., noise). Wiener integration permits computation of the required mean values and variances as solutions to the heat equation, permitting estimation of their relative magnitudes. There always exists a reference, such that joint entropy has larger variation and smaller variance than the corresponding quantities for signal energy, matching observations of several studies. Moreover, a general prescription for finding an “optimal” reference for the joint entropy emerges, which also has been validated in several studies.
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Affiliation(s)
- Michael S. Hughes
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA 99354, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-509-375-2507; Fax: +1-505-375-6497
| | - John E. McCarthy
- Department of Mathematics, Washington University in St. Louis, 1 Brookings Dr., St Louis, MO 63130, USA
| | - Paul J. Bruillard
- Pacific Northwest National Laboratory, 902 Battelle Blvd., Richland, WA 99354, USA
| | - Jon N. Marsh
- School of Medicine, Washington University in St. Louis, 660 S. Euclid Ave, St Louis, MO 63110, USA
| | - Samuel A. Wickline
- School of Medicine, Washington University in St. Louis, 660 S. Euclid Ave, St Louis, MO 63110, USA
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Zhang W, Guo J, Xiang B, Fan H, Xu F. Improving the detection sensitivity of chromatography by stochastic resonance. Analyst 2014; 139:2099-107. [DOI: 10.1039/c3an02192k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review aims to provide readers with an overview of various methodologies and approaches used to improve sensitivity through stochastic resonance (SR) methods, with special emphasis on applications to improve the detectability of analytes in chromatographic signals.
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Affiliation(s)
- Wei Zhang
- State Key Laboratory of Quality Research in Chinese Medicine
- Macau University of Science and Technology
- Macau, China
| | - Jianru Guo
- State Key Laboratory of Quality Research in Chinese Medicine
- Macau University of Science and Technology
- Macau, China
| | - Bingren Xiang
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of education)
- China Pharmaceutical University
- Nanjing, China
| | - Hongyan Fan
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of education)
- China Pharmaceutical University
- Nanjing, China
| | - Fengguo Xu
- Key Laboratory of Drug Quality Control and Pharmacovigilance (Ministry of education)
- China Pharmaceutical University
- Nanjing, China
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Hughes MS, McCarthy JE, Marsh JN, Wickline SA. Joint entropy of continuously differentiable ultrasonic waveforms. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 133:283-300. [PMID: 23297902 PMCID: PMC3548839 DOI: 10.1121/1.4770245] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 10/17/2012] [Accepted: 11/19/2012] [Indexed: 06/01/2023]
Abstract
This study is based on an extension of the concept of joint entropy of two random variables to continuous functions, such as backscattered ultrasound. For two continuous random variables, X and Y, the joint probability density p(x,y) is ordinarily a continuous function of x and y that takes on values in a two dimensional region of the real plane. However, in the case where X=f(t) and Y=g(t) are both continuously differentiable functions, X and Y are concentrated exclusively on a curve, γ(t)=(f(t),g(t)), in the x,y plane. This concentration can only be represented using a mathematically "singular" object such as a (Schwartz) distribution. Its use for imaging requires a coarse-graining operation, which is described in this study. Subsequently, removal of the coarse-graining parameter is accomplished using the ergodic theorem. The resulting expression for joint entropy is applied to several data sets, showing the utility of the concept for both materials characterization and detection of targeted liquid nanoparticle ultrasonic contrast agents. In all cases, the sensitivity of these techniques matches or exceeds, sometimes by a factor of two, that demonstrated in previous studies that employed signal energy or alternate entropic quantities.
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Affiliation(s)
- M S Hughes
- Department of Medicine/Cardiology Division, Campus Box 8215, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, Missouri 63110-1093, USA.
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Pan H, Myerson JW, Hu L, Marsh JN, Hou K, Scott MJ, Allen JS, Hu G, San Roman S, Lanza GM, Schreiber RD, Schlesinger PH, Wickline SA. Programmable nanoparticle functionalization for in vivo targeting. FASEB J 2012; 27:255-64. [PMID: 23047896 DOI: 10.1096/fj.12-218081] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The emerging demand for programmable functionalization of existing base nanocarriers necessitates development of an efficient approach for cargo loading that avoids nanoparticle redesign for each individual application. Herein, we demonstrate in vivo a postformulation strategy for lipidic nanocarrier functionalization with the use of a linker peptide, which rapidly and stably integrates cargos into lipidic membranes of nanocarriers after simple mixing through a self-assembling process. We exemplified this strategy by generating a VCAM-1-targeted perfluorocarbon nanoparticle for in vivo targeting in atherosclerosis (ApoE-deficient) and breast cancer (STAT-1-deficient) models. In the atherosclerotic model, a 4.1-fold augmentation in binding to affected aortas was observed for targeted vs. nontargeted nanoparticles (P<0.0298). Likewise, in the breast cancer model, a 4.9-fold increase in the nanoparticle signal from tumor vasculature was observed for targeted vs. nontargeted nanoparticles (P<0.0216). In each case, the nanoparticle was registered with fluorine ((19)F) magnetic resonance spectroscopy of the nanoparticle perfluorocarbon core, yielding a quantitative estimate of the number of tissue-bound nanoparticles. Because other common nanocarriers with lipid coatings (e.g., liposomes, micelles, etc.) can employ this strategy, this peptide linker postformulation approach is applicable to more than half of the available nanosystems currently in clinical trials or clinical uses.
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Affiliation(s)
- Hua Pan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63108, USA
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