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Nagaoka R, Omura M, Hasegawa H. Investigation of a method to estimate the average speed of sound using phase variances of element signals for ultrasound compound imaging. J Med Ultrason (2001) 2024; 51:17-28. [PMID: 37947986 PMCID: PMC10954954 DOI: 10.1007/s10396-023-01378-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 09/06/2023] [Indexed: 11/12/2023]
Abstract
PURPOSE In the receive beamforming of an ultrasonography system, a B-mode image is reconstructed by assuming an average speed of sound (SoS) as a constant value. In our previous studies, we proposed a method for estimating the average SoS based on the coherence factor (CF) and the reciprocal of phase variances of element signals in delay-and-sum (DAS) beamforming. In this paper, we investigate the accuracy of estimation of the average SoS for compound imaging. METHODS For this purpose, two numerical simulations were performed with k-Wave software. Also, the estimation methods based on the CF and the reciprocal were applied to in vivo data from the common carotid artery, and B-mode images were reconstructed using the estimated average SoS. RESULTS In the first numerical simulation using an inhomogeneous phantom, the relationship between the accuracy and the transmission angles for the estimation was investigated, and the root mean squared errors (RMSEs) of estimates obtained based on the CF and the reciprocal of the phase variance were 1.25 ± 0.09, and 0.765 ± 0.17% at the transmission sequence of steering angles of (- 10°, - 5°, 0°, 5°, 10°), respectively. In the second numerical simulation using a cyst phantom, lateral resolutions were improved by reconstructing the image using the estimates obtained using the proposed strategy (reciprocal). By the proposed strategy, improvement of the continuity of the lumen-intima interface in the lateral direction was observed in the in vivo experiment. CONCLUSION Consequently, the results indicated that the proposed strategy was beneficial for estimation of the average SoS and image reconstruction.
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Affiliation(s)
- Ryo Nagaoka
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan.
| | - Masaaki Omura
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
| | - Hideyuki Hasegawa
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan
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2
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Ali R, Brevett T, Zhuang L, Bendjador H, Podkowa AS, Hsieh SS, Simson W, Sanabria SJ, Herickhoff CD, Dahl JJ. Aberration correction in diagnostic ultrasound: A review of the prior field and current directions. Z Med Phys 2023; 33:267-291. [PMID: 36849295 PMCID: PMC10517407 DOI: 10.1016/j.zemedi.2023.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/17/2022] [Accepted: 01/09/2023] [Indexed: 02/27/2023]
Abstract
Medical ultrasound images are reconstructed with simplifying assumptions on wave propagation, with one of the most prominent assumptions being that the imaging medium is composed of a constant sound speed. When the assumption of a constant sound speed are violated, which is true in most in vivoor clinical imaging scenarios, distortion of the transmitted and received ultrasound wavefronts appear and degrade the image quality. This distortion is known as aberration, and the techniques used to correct for the distortion are known as aberration correction techniques. Several models have been proposed to understand and correct for aberration. In this review paper, aberration and aberration correction are explored from the early models and correction techniques, including the near-field phase screen model and its associated correction techniques such as nearest-neighbor cross-correlation, to more recent models and correction techniques that incorporate spatially varying aberration and diffractive effects, such as models and techniques that rely on the estimation of the sound speed distribution in the imaging medium. In addition to historical models, future directions of ultrasound aberration correction are proposed.
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Affiliation(s)
- Rehman Ali
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY, USA
| | - Thurston Brevett
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Louise Zhuang
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Hanna Bendjador
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Anthony S Podkowa
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Scott S Hsieh
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Walter Simson
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Sergio J Sanabria
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA; University of Deusto/ Ikerbasque Basque Foundation for Science, Bilbao, Spain
| | - Carl D Herickhoff
- Department of Biomedical Engineering, University of Memphis, TN, USA
| | - Jeremy J Dahl
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA.
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3
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Mori S, Kanai H, Arakawa M. Speed-of-sound estimation in ultrasound propagation medium by considering size of target scatterer. J Med Ultrason (2001) 2023; 50:151-165. [PMID: 36905494 DOI: 10.1007/s10396-023-01282-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 12/05/2022] [Indexed: 03/12/2023]
Abstract
PURPOSE Accurate speed-of-sound (SoS) estimation in an ultrasound propagation medium improves imaging quality and contributes to better diagnosis of diseases. In conventional time-delay-based SoS estimation approaches studied by several groups, a received wave is assumed to be scattered from an ideal point scatterer. In these approaches, the SoS is overestimated when the target scatterer has a non-negligible size. In this paper, we propose the SoS estimation method that considers target size. METHODS In the proposed method, the error ratio of the estimated SoS using the conventional time-delay-based approach is determined from measurable parameters using the geometric relationship between the received elements and target. Subsequently, the SoS erroneously estimated using conventional estimation, assuming the ideal point scatterer as a target, is corrected by the determined estimation error ratio. To validate the proposed method, the SoS in water was estimated for several wire sizes. RESULTS The SoS in the water was overestimated using the conventional SoS estimation method, with a maximum positive error of 38 m/s. The proposed method corrected the SoS estimates, and the errors were suppressed to within 6 m/s, irrespective of the wire diameter. CONCLUSION The present results demonstrate that the proposed method can estimate the SoS by considering the target size without using information on the true SoS, true target depth, and true target size, which is applicable to in vivo measurements.
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Affiliation(s)
- Shohei Mori
- Graduate School of Engineering, Tohoku University, Sendai, Miyagi, 980-8579, Japan.
| | - Hiroshi Kanai
- Graduate School of Engineering, Tohoku University, Sendai, Miyagi, 980-8579, Japan.,Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, 980-8579, Japan
| | - Mototaka Arakawa
- Graduate School of Engineering, Tohoku University, Sendai, Miyagi, 980-8579, Japan.,Graduate School of Biomedical Engineering, Tohoku University, Sendai, Miyagi, 980-8579, Japan
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4
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Fetzer DT, Rosado-Mendez IM, Wang M, Robbin ML, Ozturk A, Wear KA, Ormachea J, Stiles TA, Fowlkes JB, Hall TJ, Samir AE. Pulse-Echo Quantitative US Biomarkers for Liver Steatosis: Toward Technical Standardization. Radiology 2022; 305:265-276. [PMID: 36098640 PMCID: PMC9613608 DOI: 10.1148/radiol.212808] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/07/2022] [Accepted: 04/14/2022] [Indexed: 11/11/2022]
Abstract
Excessive liver fat (steatosis) is now the most common cause of chronic liver disease worldwide and is an independent risk factor for cirrhosis and associated complications. Accurate and clinically useful diagnosis, risk stratification, prognostication, and therapy monitoring require accurate and reliable biomarker measurement at acceptable cost. This article describes a joint effort by the American Institute of Ultrasound in Medicine (AIUM) and the RSNA Quantitative Imaging Biomarkers Alliance (QIBA) to develop standards for clinical and technical validation of quantitative biomarkers for liver steatosis. The AIUM Liver Fat Quantification Task Force provides clinical guidance, while the RSNA QIBA Pulse-Echo Quantitative Ultrasound Biomarker Committee develops methods to measure biomarkers and reduce biomarker variability. In this article, the authors present the clinical need for quantitative imaging biomarkers of liver steatosis, review the current state of various imaging modalities, and describe the technical state of the art for three key liver steatosis pulse-echo quantitative US biomarkers: attenuation coefficient, backscatter coefficient, and speed of sound. Lastly, a perspective on current challenges and recommendations for clinical translation for each biomarker is offered.
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Affiliation(s)
| | | | - Michael Wang
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Michelle L. Robbin
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Arinc Ozturk
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Keith A. Wear
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Juvenal Ormachea
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Timothy A. Stiles
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - J. Brian Fowlkes
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Timothy J. Hall
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
| | - Anthony E. Samir
- From the Department of Radiology, University of Texas Southwestern
Medical Center, Dallas, Tex (D.T.F.); Departments of Medical Physics (I.M.R.M.,
T.J.H.) and Radiology (I.M.R.M.), University of Wisconsin, Institutes for
Medical Research, 1111 Highland Ave, Room 1005, Madison, WI 53705; General
Electric Healthcare, Milwaukee, Wis (M.W.); Department of Radiology, University
of Alabama at Birmingham, Birmingham, Ala (M.L.R.); Department of Radiology,
Massachusetts General Hospital, Boston, Mass (A.O.); U.S. Food and Drug
Administration, Silver Spring, Md (K.A.W.); Department of Electrical and
Computer Engineering, University of Rochester, Rochester, NY (J.O.); Department
of Natural Sciences, Kettering University, Flint, Mich (T.A.S.); Departments of
Biomedical Engineering and Radiology, University of Michigan, Ann Arbor, Mich
(J.B.F.); RSNA Quantitative Imaging Biomarkers Alliance (T.J.H.); and Center for
Ultrasound Research & Translation, Department of Radiology, Massachusetts
General Hospital, Harvard Medical School, Boston, Mass (A.E.S.)
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5
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Ormachea J, Parker KJ. A Preliminary Study of Liver Fat Quantification Using Reported Ultrasound Speed of Sound and Attenuation Parameters. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:675-684. [PMID: 35039191 DOI: 10.1016/j.ultrasmedbio.2021.12.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
The quantification of liver fat as a diagnostic assessment of steatosis remains an important priority for non-invasive imaging systems. We derive a framework in which the unknown fat volume percentage can be estimated from a pair of ultrasound measurements. The precise estimation of ultrasound speed of sound and attenuation within the liver is found to be sufficient for estimating fat volume assuming a classic model of the properties of a composite elastic material. In this model, steatosis is represented as a random dispersion of spherical fat vacuoles with acoustic properties similar to those of edible oils. Using values of speed of sound and attenuation from the literature in which normal and steatotic livers were studied near 3.5 MHz, we describe agreement of the new estimation method with independent measures of fat. This framework holds the potential for translation to clinical scanners with which the two ultrasound measurements can be made and used for improved quantitative assessment of steatosis.
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Affiliation(s)
- Juvenal Ormachea
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA.
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6
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Advances in ultrasonography: image formation and quality assessment. J Med Ultrason (2001) 2021; 48:377-389. [PMID: 34669073 PMCID: PMC8578163 DOI: 10.1007/s10396-021-01140-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/17/2021] [Indexed: 01/01/2023]
Abstract
Delay-and-sum (DAS) beamforming is widely used for generation of B-mode images from echo signals obtained with an array probe composed of transducer elements. However, the resolution and contrast achieved with DAS beamforming are determined by the physical specifications of the array, e.g., size and pitch of elements. To overcome this limitation, adaptive imaging methods have recently been explored extensively thanks to the dissemination of digital and programmable ultrasound systems. On the other hand, it is also important to evaluate the performance of such adaptive imaging methods quantitatively to validate whether the modification of the image characteristics resulting from the developed method is appropriate. Since many adaptive imaging methods have been developed and they often alter image characteristics, attempts have also been made to update the methods for quantitative assessment of image quality. This article provides a review of recent developments in adaptive imaging and image quality assessment.
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7
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Pirmoazen AM, Khurana A, El Kaffas A, Kamaya A. Quantitative ultrasound approaches for diagnosis and monitoring hepatic steatosis in nonalcoholic fatty liver disease. Theranostics 2020; 10:4277-4289. [PMID: 32226553 PMCID: PMC7086372 DOI: 10.7150/thno.40249] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 02/14/2020] [Indexed: 12/13/2022] Open
Abstract
Nonalcoholic fatty liver disease is a major global health concern with increasing prevalence, associated with obesity and metabolic syndrome. Recently, quantitative ultrasound-based imaging techniques have dramatically improved the ability of ultrasound to detect and quantify hepatic steatosis. These newer ultrasound techniques possess many inherent advantages similar to conventional ultrasound such as universal availability, real-time capability, and relatively low cost along with quantitative rather than a qualitative assessment of liver fat. In addition, quantitative ultrasound-based imaging techniques are less operator dependent than traditional ultrasound. Here we review several different emerging quantitative ultrasound-based approaches used for detection and quantification of hepatic steatosis in patients at risk for nonalcoholic fatty liver disease. We also briefly summarize other clinically available imaging modalities for evaluating hepatic steatosis such as MRI, CT, and serum analysis.
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Affiliation(s)
- Amir M. Pirmoazen
- Department of Radiology, School of Medicine, Stanford University, Stanford, California
| | - Aman Khurana
- Department of Radiology, University of Kentucky, Lexington, Kentucky
| | - Ahmed El Kaffas
- Department of Radiology, Molecular Imaging Program at Stanford, School of Medicine, Stanford University, Stanford, California
| | - Aya Kamaya
- Department of Radiology, School of Medicine, Stanford University, Stanford, California
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8
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Bulletti A, Mazzoni M, Prasanna S, Massari L, Menciassi A, Oddo CM, Capineri L. An Improved Strategy for Detection and Localization of Nodules in Liver Tissues by a 16 MHz Needle Ultrasonic Probe Mounted on a Robotic Platform. SENSORS (BASEL, SWITZERLAND) 2020; 20:E1183. [PMID: 32098102 PMCID: PMC7070588 DOI: 10.3390/s20041183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/10/2020] [Accepted: 02/20/2020] [Indexed: 12/02/2022]
Abstract
This study presents an improved strategy for the detection and localization of small size nodules (down to few mm) of agar in excised pork liver tissues via pulse-echo ultrasound measurements performed with a 16 MHz needle probe. This work contributes to the development of a new generation of medical instruments to support robotic surgery decision processes that need information about cancerous tissues in a short time (minutes). The developed ultrasonic probe is part of a scanning platform designed for the automation of surgery-associated histological analyses. It was coupled with a force sensor to control the indentation of tissue samples placed on a steel plate. For the detection of nodules, we took advantage of the property of nodules of altering not only the acoustical properties of tissues producing ultrasound attenuation, but also of developing patterns at their boundary that can modify the shape and the amplitude of the received echo signals from the steel plate supporting the tissues. Besides the Correlation Index Amplitude (CIA), which is linked to the overall amplitude changes of the ultrasonic signals, we introduced the Correlation Index Shape (CIS) linked to their shape changes. Furthermore, we applied AND-OR logical operators to these correlation indices. The results were found particularly helpful in the localization of the irregular masses of agar we inserted into some excised liver tissues, and in the individuation of the regions of major interest over which perform the vertical dissections of tissues in an automated analysis finalized to histopathology. We correctly identified up to 89% of inclusions, with an improvement of about 14% with respect to the result obtained (78%) from the analysis performed with the CIA parameter only.
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Affiliation(s)
- Andrea Bulletti
- Department of Information Engineering, Università degli Studi di Firenze, 50139 Florence, Italy; (A.B.); (M.M.)
| | - Marina Mazzoni
- Department of Information Engineering, Università degli Studi di Firenze, 50139 Florence, Italy; (A.B.); (M.M.)
- Consiglio Nazionale delle Ricerche of Italy, Istituto di Fisica Applicata “Nello Carrara”, 50121 Florence, Italy
| | - Sahana Prasanna
- Sant’Anna School of Advanced Studies, The BioRobotics Institute, 56025 Pisa, Italy; (S.P.); (L.M.); (A.M.); (C.M.O.)
| | - Luca Massari
- Sant’Anna School of Advanced Studies, The BioRobotics Institute, 56025 Pisa, Italy; (S.P.); (L.M.); (A.M.); (C.M.O.)
| | - Arianna Menciassi
- Sant’Anna School of Advanced Studies, The BioRobotics Institute, 56025 Pisa, Italy; (S.P.); (L.M.); (A.M.); (C.M.O.)
| | - Calogero Maria Oddo
- Sant’Anna School of Advanced Studies, The BioRobotics Institute, 56025 Pisa, Italy; (S.P.); (L.M.); (A.M.); (C.M.O.)
| | - Lorenzo Capineri
- Department of Information Engineering, Università degli Studi di Firenze, 50139 Florence, Italy; (A.B.); (M.M.)
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9
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Jakovljevic M, Hsieh S, Ali R, Chau Loo Kung G, Hyun D, Dahl JJ. Local speed of sound estimation in tissue using pulse-echo ultrasound: Model-based approach. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:254. [PMID: 30075660 PMCID: PMC6045494 DOI: 10.1121/1.5043402] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A model and method to accurately estimate the local speed of sound in tissue from pulse-echo ultrasound data is presented. The model relates the local speeds of sound along a wave propagation path to the average speed of sound over the path, and allows one to avoid bias in the sound-speed estimates that can result from overlying layers of subcutaneous fat and muscle tissue. Herein, the average speed of sound using the approach by Anderson and Trahey is measured, and then the authors solve the proposed model for the local sound-speed via gradient descent. The sound-speed estimator was tested in a series of simulation and ex vivo phantom experiments using two-layer media as a simple model of abdominal tissue. The bias of the local sound-speed estimates from the bottom layers is less than 6.2 m/s, while the bias of the matched Anderson's estimates is as high as 66 m/s. The local speed-of-sound estimates have higher standard deviation than the Anderson's estimates. When the mean local estimate is computed over a 5-by-5 mm region of interest, its standard deviation is reduced to less than 7 m/s.
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Affiliation(s)
- Marko Jakovljevic
- Department of Radiology, Stanford School of Medicine, Stanford, California 94305, USA
| | - Scott Hsieh
- Department of Radiology, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Rehman Ali
- Department of Radiology, Stanford School of Medicine, Stanford, California 94305, USA
| | | | - Dongwoon Hyun
- Department of Radiology, Stanford School of Medicine, Stanford, California 94305, USA
| | - Jeremy J Dahl
- Department of Radiology, Stanford School of Medicine, Stanford, California 94305, USA
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10
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Influence of ultrasound speckle tracking strategies for motion and strain estimation. Med Image Anal 2016; 32:184-200. [PMID: 27132112 DOI: 10.1016/j.media.2016.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 01/29/2016] [Accepted: 04/15/2016] [Indexed: 11/20/2022]
Abstract
Speckle Tracking is one of the most prominent techniques used to estimate the regional movement of the heart based on ultrasound acquisitions. Many different approaches have been proposed, proving their suitability to obtain quantitative and qualitative information regarding myocardial deformation, motion and function assessment. New proposals to improve the basic algorithm usually focus on one of these three steps: (1) the similarity measure between images and the speckle model; (2) the transformation model, i.e. the type of motion considered between images; (3) the optimization strategies, such as the use of different optimization techniques in the transformation step or the inclusion of structural information. While many contributions have shown their good performance independently, it is not always clear how they perform when integrated in a whole pipeline. Every step will have a degree of influence over the following and hence over the final result. Thus, a Speckle Tracking pipeline must be analyzed as a whole when developing novel methods, since improvements in a particular step might be undermined by the choices taken in further steps. This work presents two main contributions: (1) We provide a complete analysis of the influence of the different steps in a Speckle Tracking pipeline over the motion and strain estimation accuracy. (2) The study proposes a methodology for the analysis of Speckle Tracking systems specifically designed to provide an easy and systematic way to include other strategies. We close the analysis with some conclusions and recommendations that can be used as an orientation of the degree of influence of the models for speckle, the transformation models, interpolation schemes and optimization strategies over the estimation of motion features. They can be further use to evaluate and design new strategy into a Speckle Tracking system.
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11
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Huang BK, Choma MA. Microscale imaging of cilia-driven fluid flow. Cell Mol Life Sci 2015; 72:1095-113. [PMID: 25417211 PMCID: PMC4605231 DOI: 10.1007/s00018-014-1784-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/12/2014] [Accepted: 11/13/2014] [Indexed: 10/24/2022]
Abstract
Cilia-driven fluid flow is important for multiple processes in the body, including respiratory mucus clearance, gamete transport in the oviduct, right-left patterning in the embryonic node, and cerebrospinal fluid circulation. Multiple imaging techniques have been applied toward quantifying ciliary flow. Here, we review common velocimetry methods of quantifying fluid flow. We then discuss four important optical modalities, including light microscopy, epifluorescence, confocal microscopy, and optical coherence tomography, that have been used to investigate cilia-driven flow.
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Affiliation(s)
- Brendan K Huang
- Department of Biomedical Engineering, Yale University, New Haven, USA,
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12
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Jaeger M, Held G, Peeters S, Preisser S, Grünig M, Frenz M. Computed ultrasound tomography in echo mode for imaging speed of sound using pulse-echo sonography: proof of principle. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:235-50. [PMID: 25220274 DOI: 10.1016/j.ultrasmedbio.2014.05.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 05/21/2014] [Accepted: 05/23/2014] [Indexed: 05/15/2023]
Abstract
The limitations of diagnostic echo ultrasound have motivated research into novel modalities that complement ultrasound in a multimodal device. One promising candidate is speed of sound imaging, which has been found to reveal structural changes in diseased tissue. Transmission ultrasound tomography shows speed of sound spatially resolved, but is limited to the acoustically transparent breast. We present a novel method by which speed-of-sound imaging is possible using classic pulse-echo equipment, facilitating new clinical applications and the combination with state-of-the art diagnostic ultrasound. Pulse-echo images are reconstructed while scanning the tissue under various angles using transmit beam steering. Differences in average sound speed along different transmit directions are reflected in the local echo phase, which allows a 2-D reconstruction of the sound speed. In the present proof-of-principle study, we describe a contrast resolution of 0.6% of average sound speed and a spatial resolution of 1 mm (laterally) × 3 mm (axially), suitable for diagnostic applications.
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Affiliation(s)
- Michael Jaeger
- Institute of Applied Physics, University of Bern, Bern, Switzerland.
| | - Gerrit Held
- Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Sara Peeters
- Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Stefan Preisser
- Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Michael Grünig
- Institute of Applied Physics, University of Bern, Bern, Switzerland
| | - Martin Frenz
- Institute of Applied Physics, University of Bern, Bern, Switzerland
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13
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Kumagai H, Yokoyama K, Katsuyama K, Hara S, Yamamoto H, Yamagata T, Taniguchi N, Hirota N, Itoh K. A new method for measuring the speed of sound in rat liver ex vivo using an ultrasound system: correlation of sound speed with fat deposition. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:2499-2507. [PMID: 25130448 DOI: 10.1016/j.ultrasmedbio.2014.03.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Revised: 02/04/2014] [Accepted: 03/15/2014] [Indexed: 06/03/2023]
Abstract
The speed of sound correlates well with the fat content of the liver. Therefore, non-invasive quantification of sound speed in the liver might be of diagnostic value. Here we describe a new non-invasive method that would be clinically applicable for measurement of sound speed in the liver. Sprague-Dawley rats were divided into two groups: a control group and a fatty liver group prepared by keeping the rats on a choline-deficient diet for 6 wk. The livers were subjected to pathologic and biochemical analysis; the speed of sound through the liver tissue was measured using our proposed method and a pulser-receiver as standard. Our results indicated that use of the proposed method makes it feasible to diagnose fatty liver with good accuracy on the basis of sound speed. This approach would have considerable potential for non-invasive diagnosis of fatty liver and would be a valuable adjunct to conventional liver diagnostic procedures.
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Affiliation(s)
- Hideki Kumagai
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan.
| | - Koji Yokoyama
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan
| | - Kimito Katsuyama
- Imaging Technology Center, R&D Management Headquarters, Fujifilm Corporation, Tokyo, Japan
| | - Shoji Hara
- Imaging Technology Center, R&D Management Headquarters, Fujifilm Corporation, Tokyo, Japan
| | - Hiroaki Yamamoto
- Imaging Technology Center, R&D Management Headquarters, Fujifilm Corporation, Tokyo, Japan
| | | | - Nobuyuki Taniguchi
- Department of Clinical Laboratory Medicine, Jichi Medical University, Tochigi, Japan
| | - Norio Hirota
- Hirota Surgical Pathology Institute, Tochigi, Japan
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14
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Zhao Y, Cachard C, Liebgott H. Automatic needle detection and tracking in 3D ultrasound using an ROI-based RANSAC and Kalman method. ULTRASONIC IMAGING 2013; 35:283-306. [PMID: 24081726 DOI: 10.1177/0161734613502004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This article proposes a robust technique for needle detection and tracking using three-dimensional ultrasound (3D US). It is difficult for radiologists to detect and follow the position of micro tools, such as biopsy needles, that are inserted in human tissues under 3D US guidance. To overcome this difficulty, we propose a method that automatically reduces the processed volume to a limited region of interest (ROI), increasing at the same time the calculation speed and the robustness of the proposed technique. First, a line filter method that enhances the contrast of the needle against the background is used to facilitate the initialization of ROI using the tubularness information of the complete US volume. Then, the random sample consensus (RANSAC) and Kalman filter (RK) algorithm is used in the ROI to detect and track the precise position of the needle. A series of numerical inhomogeneous phantoms with a needle simulated from real 3D US volumes are used to evaluate our method. The results show that the proposed method is much more robust than the RANSAC algorithm when detecting the needle, regardless of whether or not the insertion axis corresponds to an acquisition plane in the 3D US volume. The possibility of failure is also discussed in this article.
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Affiliation(s)
- Yue Zhao
- 1Creatis, Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, France
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15
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Qu X, Azuma T, Liang JT, Nakajima Y. Average sound speed estimation using speckle analysis of medical ultrasound data. Int J Comput Assist Radiol Surg 2012; 7:891-9. [PMID: 22544670 DOI: 10.1007/s11548-012-0690-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 04/10/2012] [Indexed: 11/24/2022]
Abstract
PURPOSE Most ultrasound imaging systems assume a pre-determined sound propagation speed for imaging. However, a mismatch between assumed and real sound speeds can lead to spatial shift and defocus of ultrasound image, which may limit the applicability of ultrasound imaging. The estimation of real sound speed is important for improving positioning accuracy and focus quality of ultrasound image. METHOD A novel method using speckle analysis of ultrasound image is proposed for average sound speed estimation. Firstly, dynamic receive beam forming technology is employed to form ultrasound images. These ultrasound images are formed by same pre-beam formed radio frequency data but using different assumed sound speeds. Secondly, an improved speckle analysis method is proposed to evaluate focus quality of these ultrasound images. Thirdly, an iteration strategy is employed to locate the desired sound speed that corresponds to the best focus quality image. RESULTS For quantitative evaluation, a group of ultrasound data with 20 different structure patterns is simulated. The comparison of estimated and simulated sound speeds shows speed estimation errors to be -0.7 ± 2.54 m/s and -1.30 ± 5.15 m/s for ultrasound data obtained by 128- and 64-active individual elements linear arrays, respectively. Furthermore, we validate our method via phantom experiments. The sound speed estimation error is -1.52 ± 8.81 m/s. CONCLUSION Quantitative evaluation proves that proposed method can estimate average sound speed accurately using single transducer with single scan.
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Affiliation(s)
- Xiaolei Qu
- Department of Bioengineering, The University of Tokyo, Yayoi 2-11-16, Bunkyo, Tokyo, 113-8656, Japan.
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16
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Lindberg F, Öhberg F, Granåsen G, Brodin LÅ, Grönlund C. Pennation angle dependency in skeletal muscle tissue doppler strain in dynamic contractions. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:1151-1160. [PMID: 21640478 DOI: 10.1016/j.ultrasmedbio.2011.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 03/28/2011] [Accepted: 04/17/2011] [Indexed: 05/30/2023]
Abstract
Tissue velocity imaging (TVI) is a Doppler based ultrasound technique that can be used to study regional deformation in skeletal muscle tissue. The aim of this study was to develop a biomechanical model to describe the TVI strain's dependency on the pennation angle. We demonstrate its impact as the subsequent strain measurement error using dynamic elbow contractions from the medial and the lateral part of biceps brachii at two different loadings; 5% and 25% of maximum voluntary contraction (MVC). The estimated pennation angles were on average about 4° in extended position and increased to a maximal of 13° in flexed elbow position. The corresponding relative angular error spread from around 7% up to around 40%. To accurately apply TVI on skeletal muscles, the error due to angle changes should be compensated for. As a suggestion, this could be done according to the presented model.
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Affiliation(s)
- Frida Lindberg
- School of Technology and Health, Royal Institute of Technology (KTH), Huddinge, Sweden.
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17
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Bohris C, Bayer T, Gumpinger R. Ultrasound monitoring of kidney stone extracorporeal shockwave lithotripsy with an external transducer: does fatty tissue cause image distortions that affect stone comminution? J Endourol 2010; 24:81-8. [PMID: 19961334 DOI: 10.1089/end.2009.0158] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Ultrasound imaging, using either an inline or an external transducer, is a standard method for extracorporeal shockwave lithotripsy (SWL) monitoring. This study investigates whether image distortions caused by the low sound speed of fatty tissue could lead to incorrect stone positioning such that disintegration is affected. MATERIALS AND METHODS To define the accuracy needed for SWL monitoring, the dependency of fragmentation efficiency on the distance between stone center and SWL focus was examined by in vitro model stone tests. In a clinical study, 15 patients with kidney stones were treated with a Dornier Sigma FarSight. This lithotripter was equipped with both an inline and an external transducer. They were operated alternately to check for inconsistencies, which would indicate ultrasound image distortions. In addition, the ultrasound paths from the transducer to the SWL focus were analyzed for error estimation. RESULTS AND DISCUSSION In the model stone tests, the number of shock waves required for complete fragmentation doubled if the stone was about 7.5 to 10 mm off focus in lateral direction. In the clinical trial, the stone positions obtained from an inline and an external transducer coincided within a 5 mm range of tolerance, but that approach suffered from some practical difficulties, resulting in measurement imprecision. The sound path analysis showed that the lengths through fatty tissue were too short to result in significant image distortion. The body mass index (20-31 kg/m(2)) was representative, except for very obese patients. Additional confirmation of correct stone positioning could be achieved quite easily by looking for pixel movement in the B-mode image or employing Doppler hit/miss monitoring. CONCLUSION Within the study group, no image distortion caused by fatty tissue that could be clinically relevant for SWL was observed.
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18
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Nanayakkara ND, Chiu B, Samani A, Spence JD, Samarabandu J, Fenster A. A "twisting and bending" model-based nonrigid image registration technique for 3-D ultrasound carotid images. IEEE TRANSACTIONS ON MEDICAL IMAGING 2008; 27:1378-1388. [PMID: 18815090 DOI: 10.1109/tmi.2008.918326] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Atherosclerosis at the carotid bifurcation resulting in cerebral emboli is a major cause of ischemic stroke. Most strokes associated with carotid atherosclerosis can be prevented by lifestyle/dietary changes and pharmacological treatments if identified early by monitoring carotid plaque changes. Registration of 3-D ultrasound (US) images of carotid plaque obtained at different time points is essential for sensitive monitoring of plaque changes in volume and surface morphology. This registration technique should be nonrigid, since different head positions during image acquisition sessions cause relative bending and torsion in the neck, producing nonlinear deformations between the images. We modeled the movement of the neck using a "twisting and bending" model with only six parameters for nonrigid registration. We evaluated the algorithm using 3-D US carotid images acquired at two different head positions to simulate images acquired at different times. We calculated the mean registration error (MRE) between the segmented vessel surfaces in the target image and the registered image using a distance-based error metric after applying our "twisting and bending" model-based nonrigid registration algorithm. We achieved an average registration error of 0.80 +/-0.26 mm using our nonrigid registration technique, which was a significant improvement in registration accuracy over rigid registration, even with reduced degrees-of-freedom compared to the other nonrigid registration algorithms.
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Affiliation(s)
- Nuwan D Nanayakkara
- Imaging Research Laboratories, Robarts Research Institute and Graduate Program in Biomedical Engineering, The University of Western Ontario, London, ON N6A5K8, Canada.
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19
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Krücker JF, Fowlkes JB, Carson PL. Sound speed estimation using automatic ultrasound image registration. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2004; 51:1095-106. [PMID: 15478971 DOI: 10.1109/tuffc.2004.1334842] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A mismatch between the sound speed assumed for beamforming and scan conversion and the true sound speed in the tissue to be imaged can lead to significant defocusing and some geometric distortions in ultrasound images. A method is presented for estimating the average sound speed based on detection of these distortions using automatic registration of overlapping, electronically steered images. An acrylamide gel phantom containing vaporized dodecafluoropentane droplets as point targets was constructed to evaluate the technique. Good agreement (rms deviation <0.4%) was found between the sound speeds measured in the phantom using a reference pulse-echo technique and the image-based sound speed estimates. A significant improvement in accuracy (rms deviation <0.1%) was achieved by including the simulated sound field of the probe rather than assuming straight acoustic beams and propagation according to ray acoustics.
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Affiliation(s)
- Jochen F Krücker
- University of Michigan Health Systems, Department of Radiology, Ann Arbor, MI 48109-0553, USA.
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20
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Krücker JF, LeCarpentier GL, Fowlkes JB, Carson PL. Rapid elastic image registration for 3-D ultrasound. IEEE TRANSACTIONS ON MEDICAL IMAGING 2002; 21:1384-1394. [PMID: 12575875 DOI: 10.1109/tmi.2002.806424] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A Subvolume-based algorithm for elastic Ultrasound REgistration (SURE) was developed and evaluated. Designed primarily to improve spatial resolution in three-dimensional compound imaging, the algorithm registers individual image volumes nonlinearly before combination into compound volumes. SURE works in one or two stages, optionally using MIAMI Fuse software first to determine a global affine registration before iteratively dividing the volume into subvolumes and computing local rigid registrations in the second stage. Connectivity of the entire volume is ensured by global interpolation using thin-plate splines after each iteration. The performance of SURE was quantified in 20 synthetically deformed in vivo ultrasound volumes, and in two phantom scans, one of which was distorted at acquisition by placing an aberrating layer in the sound path. The aberrating layer was designed to induce beam aberrations reported for the female breast. Synthetic deformations of 1.5-2.5 mm were reduced by over 85% when SURE was applied to register the distorted image volumes with the original ones. Registration times were below 5 min on a 500-MHz CPU for an average data set size of 13 MB. In the aberrated phantom scans, SURE reduced the average deformation between the two volumes from 1.01 to 0.30 mm. This was a statistically significant (P = 0.01) improvement over rigid and affine registration transformations, which produced reductions to 0.59 and 0.50 mm, respectively.
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Affiliation(s)
- Jochen F Krücker
- Department of Radiology, University of Michigan, 200 Zina Pitcher Place, Kresge III. Rm. 3315, Ann Arbor, MI 48109-0553, USA.
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21
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Abstract
Myocardial motion exhibits frequency components of up to 100 Hz, as found by a phased tracking method. To simultaneously measure the rapid and minute velocity signals at multiple points along the surface of the left ventricle (LV), in this study, conventional ultrasonic diagnosis equipment was modified to allow 10 scan lines from a sector scanner to be arbitrarily selected in real-time for analysis. By considering the maximum value of the velocity in the heart wall and the maximum depth from the chest surface, the number of transmission directions of the ultrasonic pulses should be carefully confirmed to be 10 to avoid aliasing, which is much less than the number employed in conventional tissue Doppler imaging (TDI). By applying the system, the velocity signals at about 240 points in the heart walls were simultaneously measured for three healthy volunteers. During a short period of 35 ms around end-diastole, the velocity signals varied spatially in the heart wall. At the end of systole, in the wavelets near the base of the interventricular septum (IVS), the slow pulse continued for about 30 ms, just before the radiation timing of the second heart sound. Then, a steep pulse occurred just at the timing of the closure of the aortic valve. The steep pulse at the base preceded that at the apex by several ms. By Fourier transforming each wavelet, the spatial distribution of the phase of the steep pulse components were clearly displayed. By applying the measurement method to two patients with aortic stenosis (AS), irregular vibration signals, which correspond to the murmur of the heart sound, could be directly detected during the ejection period. In conventional TDI, only the large slow movements due to the heartbeat are displayed, but these rapid and minute velocity components cannot be displayed. In this study, moreover, the phase components were detected for the first time from each of the velocity signals simultaneously measured at multiple points along the 10 scan lines. This measurement and method of analysis offer potential for new diagnostic techniques in cardiac dysfunction.
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Affiliation(s)
- H Kanai
- Department of Electronic Engineering, Graduate School of Engineering, Tohoku University, Sendai, Japan.
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22
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Krücker JF, Meyer CR, LeCarpentier GL, Fowlkes JB, Carson PL. 3D spatial compounding of ultrasound images using image-based nonrigid registration. ULTRASOUND IN MEDICINE & BIOLOGY 2000; 26:1475-1488. [PMID: 11179622 DOI: 10.1016/s0301-5629(00)00286-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Medical ultrasound images are often distorted enough to significantly limit resolution during compounding (i.e., summation of images from multiple views). A new, volumetric image registration technique has been used successfully to enable high spatial resolution in three-dimensional (3D) spatial compounding of ultrasound images. Volumetric ultrasound data were acquired by scanning a linear matrix array probe in the elevational direction in a focal lesion phantom and in a breast in vivo. To obtain partly uncorrelated views, the volume of interest was scanned at five different transducer tilt angles separated by 4 degrees to 6 degrees. Pairs of separate views were registered by an automatic procedure based on a mutual information metric, using global full affine and thin-plate spline warping transformations. Registration accuracy was analyzed automatically in the phantom data, and manually in vivo, yielding average registration errors of 0.31 mm and 0.65 mm, respectively. In the vicinity of the warping control points, registrations obtained with warping transformations were significantly more accurate than full affine registrations. Compounded images displayed the expected reduction in speckle noise and increase in contrast-to-noise ratio (CNR), as well as better delineation of connective tissues and reduced shadowing. Compounding also revealed some apparent low contrast lobulations that were not visible in the single-sweep images. Given expected algorithmic and hardware enhancements, nonrigid, image-based registration shows great promise for reducing tissue motion and refraction artifacts in 3D spatial compounding.
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Affiliation(s)
- J F Krücker
- Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109-0553, USA.
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23
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Bohs LN, Geiman BJ, Anderson ME, Gebhart SC, Trahey GE. Speckle tracking for multi-dimensional flow estimation. ULTRASONICS 2000; 38:369-375. [PMID: 10829690 DOI: 10.1016/s0041-624x(99)00182-1] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Speckle tracking methods overcome the major limitations of current Doppler methods for flow imaging and quantification: angle dependence and aliasing. In this paper, we review the development of speckle tracking, with particular attention to the advantages and limitations of two-dimensional algorithms that use a single transducer aperture. Ensemble tracking, a recent speckle tracking method based upon parallel receive processing, is described. Experimental results with ensemble tracking indicate the ability to measure laminar flow in a phantom at a beam-vessel angle of 60 degrees, which had not been possible with previous 2D speckle tracking methods. Finally, important areas for future research in speckle tracking are briefly summarized.
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Affiliation(s)
- L N Bohs
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
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24
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Jiang P, Apfel RE. Method for determining the reliable prediction(s) of compositions of tissue phantoms. ULTRASOUND IN MEDICINE & BIOLOGY 1994; 20:791-802. [PMID: 7863568 DOI: 10.1016/0301-5629(94)90036-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In a previous paper, we showed that mixture laws can be used to predict the compositions of tissue phantoms. Due to the variation in the performance of the mixture laws when they are applied to phantoms, however, it is difficult to determine which predictions of the composition are most reliable. In this paper, we study the causes of the variation in the performances of different sets of mixture laws, and propose a criterion for choosing a reliable predictor. The predictions selected with the proposed criterion agree very well with the known compositions of phantoms. The potential uses of the mixture methodology and the criterion to tissue characterization are discussed.
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Affiliation(s)
- P Jiang
- Department of Mechanical Engineering, Yale University, New Haven, CT 06520
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25
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Hein IA, O'Brien WR. Current time-domain methods for assessing tissue motion by analysis from reflected ultrasound echoes-a review. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 1993; 40:84-102. [PMID: 18263161 DOI: 10.1109/58.212556] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The Doppler technique has traditionally been the method used to extract motion information from ultrasonic echoes reflected by moving tissues. The Doppler technique has been around for a long time, and has been extensively reviewed and analyzed in the literature. Recently, time-domain methodologies for estimating tissue motion have gained in popularity. Time-domain methods have advantages over Doppler methods in many applications, and as of yet have not been comprehensively reviewed. An overview of time-domain techniques that have appeared in the literature over the past few years is presented. Their potential advantages over Doppler are examined, and the individual techniques are compared.
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Affiliation(s)
- I A Hein
- Dept. of Electr. and Comput. Eng., Illinois Univ., Urbana, IL
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26
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Céspedes I, Ophir J, Huang Y. On the feasibility of pulse-echo speed of sound estimation in small regions: simulation studies. ULTRASOUND IN MEDICINE & BIOLOGY 1992; 18:283-91. [PMID: 1595134 DOI: 10.1016/0301-5629(92)90097-t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Computer simulations are used to study the feasibility of the estimation of sound speed in small regions with precision better than 1% using the Beam Tracking method. The speed of sound is estimated in a 10-mm by 10-mm region by considering a number of parallel tracks confined to the small region. The transducer focusing and the step sizes for the tracking and tracked transducers required to extract the maximum amount of uncorrelated data from the 10-mm by 10-mm region is evaluated. The results show that the speed of sound can be estimated with error less than 1% in a small region using a typical medical transducer. The statistical comparison of estimates in small areas with different speed of sound is also considered.
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Affiliation(s)
- I Céspedes
- Department of Radiology, University of Texas Medical School, Houston 77030
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27
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Ophir J, Moriya T, Yazdi Y. A single transducer transaxial compression technique for the estimation of sound speed in biological tissues. ULTRASONIC IMAGING 1991; 13:269-79. [PMID: 1957424 DOI: 10.1177/016173469101300304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
In this paper we report an extension to the TACT method for the estimation of sound speed with a single transducer to any depth. This method is based on the hypothesis that the displacement of the tissue caused by transaxial compression follows a theoretical function which we derive analytically. In this method, as in the original TACT, a transducer imparts an accurate transaxial compression to the tissue, and the corresponding change in the arrival time of an echo at a range of interest is measured. This procedure results in a biased speed estimate whose value is range dependent. The theoretical function is fitted to the experimental estimates, from which the unbiased sound speed is then computed.
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Affiliation(s)
- J Ophir
- Department of Radiology, University of Texas Medical School, Houston 77030
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28
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Robinson DE, Ophir J, Wilson LS, Chen CF. Pulse-echo ultrasound speed measurements: progress and prospects. ULTRASOUND IN MEDICINE & BIOLOGY 1991; 17:633-646. [PMID: 1962366 DOI: 10.1016/0301-5629(91)90034-t] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The data on the relationship of sound speed to tissue condition, and the development of methods for measurement of sound speed in vivo, are outlined. The methods developed by the authors are discussed. These include methods which use the spatial shift in images of targets viewed from different directions, time-of-flight measurements along incrementally tracked beams and echo tracking during transaxial compression of tissue. The reported sound-speed values are discussed, discrepancies noted and suggestions made on the potential clinical applications of in vivo sound-speed estimation.
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Affiliation(s)
- D E Robinson
- Division of Radiophysics, Commonwealth Scientific and Industrial Research Organisation, Sydney, Australia
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29
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Kondo M, Takamizawa K, Hirama M, Okazaki K, Iinuma K, Takehara Y. An evaluation of an in vivo local sound speed estimation technique by the crossed beam method. ULTRASOUND IN MEDICINE & BIOLOGY 1990; 16:65-72. [PMID: 2181764 DOI: 10.1016/0301-5629(90)90087-s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
An in vivo local sound speed estimation technique, using the crossed beam method, has been proposed and its applicability was evaluated. At first, the potential of this technique was studied by a mapping simulation using the ray tracing technique followed by an experiment with a cylindrical agar phantom. The simulation result showed that an exact measurement of local sound speed values was difficult, but the sound speed information for the local region (its relative magnitude to the surrounding medium) was emphasized as a refraction mapping pattern. The experimental results agreed well with the calculation results. Furthermore, a clinical application was performed, using the clinical system (modified electronic linear scanner), on two liver tumor patients.
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Affiliation(s)
- M Kondo
- Toshiba Research and Development Center, Kawasaki, Japan
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30
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Hill CR, Bamber JC, Cosgrove DO. Performance criteria for quantitative ultrasonography and image parameterisation. CLINICAL PHYSICS AND PHYSIOLOGICAL MEASUREMENT : AN OFFICIAL JOURNAL OF THE HOSPITAL PHYSICISTS' ASSOCIATION, DEUTSCHE GESELLSCHAFT FUR MEDIZINISCHE PHYSIK AND THE EUROPEAN FEDERATION OF ORGANISATIONS FOR MEDICAL PHYSICS 1990; 11 Suppl A:57-73. [PMID: 2286049 DOI: 10.1088/0143-0815/11/4a/307] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
For the purpose of assessing and comparing the practical performance of various specific approaches to quantitative tissue characterisation, three sets of performance criteria are proposed, relating respectively to contrast resolution, spatial resolution, and speed of presentation. In each case numerical performance targets are suggested: in particular that spatial resolution should preferably be within a linear factor of three of the best achievable anatomical resolution of the associated imaging techniques and that presentation speed should be 'real time' (i.e. about 10 Hz). In the light of these criteria and performance targets the main existing approaches to ultrasonic tissue characterisation are then considered. These are classified in two groups: first those approaches based on measurements of bulk properties of tissues and secondly those related to parameters of the structural organisation of tissues. Examination of available evidence suggests that the latter group are more promising than the former. Finally it is argued that ultrasonic methods of tissue characterisation have substantial practical potential but that the realisation of such potential is contingent on achieving consensus on choice of a single, optimised and generally applicable approach that would carry with it the linked benefits of industrial standardisation and broad sharing of clinical experience.
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Affiliation(s)
- C R Hill
- Department of Physics, Institute of Cancer Research, Sutton, Surrey, UK
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31
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Ophir J, Yazdi Y, Lin TS, Shattuck DP. Optimization of speed-of-sound estimation from noisy ultrasonic signals. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 1989; 36:16-24. [PMID: 18284945 DOI: 10.1109/58.16964] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The effects of prefiltering and the choice of time-delay estimators and statistical data reduction techniques on the precision of speed-of-sound estimation were investigated using the beam-tracking technique. It was found that prefiltering the data with an ideal 50-kHz low-pass filter improved the precision of the estimation in all cases. Echo cross-correlation had an advantage over peak detection for low signal-to-noise ratio (SNR) levels, but its advantage diminished as the signal-to-noise level improved due to filtering. The linear regression method was superior to the paired-point analysis technique under all conditions. Using the optimal set of parameters, precision on the order of 0.1% was achieved in a tissue-mimicking phantom when one beam was tracking along 75 mm in 1-mm increments.
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Affiliation(s)
- J Ophir
- Dept. of Radiol., Texas Univ. Med. Sch., Houston, TX
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32
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Abstract
Modern ultrasonic transducers mainly employ lead zirconate titanate (PZT) but vinylidene fluoride trifluoroethylene copolymer (P (VDF-TrPE)) is becoming more competitive. The static scanner is now largely replaced by mechanical or electronically controlled array real time systems; the speed of scanning is limited by the speed of sound and the resolution depends on the wavelength and so, ultimately, on the attenuation in tissue. Tissue inhomogeneities degrade the resolution. Intraoperative and intracavitary scanners have advantages in some anatomical situations and ultrasonic imaging can guide extracorporeal shock wave lithotripsy. Inexpensive battery powered scanners will soon become available. Duplex scanners are used to localize the acquisition of Doppler signals; blood flow volume rate can be estimated from measurements of blood velocity and vessel cross-sectional area, or by the attenuation-compensated technique which avoids the main sources of error. Colour flow mapping combines real time imaging with Doppler information, but has limited scanning speed. Computed tomography and acoustical microscopy are feasible. Speckle arises from the coherent nature of ultrasound and can be suppressed by summing uncorrelated images or by filtering. Image manipulation and display techniques are being developed to cope with three dimensional scan data and the approach is compatible with picture archiving and communication systems (PACS). Tissue characterization based on the measurement of properties has been disappointing but blood flow analysis and contrast agents are promising. Quality assurance programmes are crucial; ultrasonic diagnosis appears to be free from hazard and prudent use is determined by cost-benefit considerations.
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Affiliation(s)
- P N Wells
- Department of Medical Physics, Bristol General Hospital, UK
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33
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CHANDRARATNA PAN, JONES JOIEPIERCE, LEEMAN SIDNEY, TAK TAHIR, RAHIMTOOLA SHAHBUDINH. Ultrasonic Tissue Characterization of the Heart. Echocardiography 1988. [DOI: 10.1111/j.1540-8175.1988.tb00252.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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34
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Hayashi N, Tamaki N, Senda M, Yamamoto K, Yonekura Y, Torizuka K, Ogawa T, Katakura K, Umemura C, Kodama M. A new method of measuring in vivo sound speed in the reflection mode. JOURNAL OF CLINICAL ULTRASOUND : JCU 1988; 16:87-93. [PMID: 3130409 DOI: 10.1002/jcu.1870160204] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
This paper describes a new method for in vivo sound measurement in the reflection mode. The mean sound speed between the reflector and linear array transducer is measured using the following three parameters: time of flight, time of flight difference, and distance between two receiver elements. To detect time of flight, the system delay-line time compensator is adjusted to obtain the sharpest reflector image. This method was evaluated in vivo in human livers, specifically 26 normal, 27 cirrhotic, and 15 fatty livers. The mean sound speed between diaphragm and the transducer was obtained. The measured sound speed was significantly higher in cirrhotic livers and lower in fatty livers.
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Affiliation(s)
- N Hayashi
- Department of Radiology and Nuclear Medicine, Kyoto University School of Medicine, Japan
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35
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Manoharan A, Chen CF, Wilson LS, Griffiths KA, Robinson DE. Ultrasonic characterization of splenic tissue in myelofibrosis: further evidence for reversal of fibrosis with chemotherapy. Eur J Haematol 1988; 40:149-54. [PMID: 3278929 DOI: 10.1111/j.1600-0609.1988.tb00812.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Fibrosis in patients with myelofibrosis (MF) is seen not only in the bone marrow but also around the metaplastic foci in the spleen and liver. Following our observation of reversal of bone marrow fibrosis in MF patients treated with chemotherapy, we undertook ultrasonic splenic tissue characterization studies using sound speed measurements to assess the effect of such therapy on the splenic fibrosis. Single studies in 19 patients showed overlapping ranges among the three sub-groups classified according to the grade of bone marrow fibrosis, but the mean values in these sub-groups showed a trend towards decreasing sound speed with increasing marrow fibrosis. Sequential studies in 9 of these patients showed increased splenic sound speed with decreasing marrow fibrosis in 8 patients following treatment, with a reversal of this pattern seen in 1 patient 1-2 years post-treatment. These results suggest simultaneous reversal of fibrosis in the bone marrow and the spleen in MF patients receiving effective chemotherapy.
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Affiliation(s)
- A Manoharan
- Department of Clinical Haematology, St. George Hospital, University of New South Wales, Australia
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36
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Chen CF, Robinson DE, Wilson LS, Griffiths KA, Manoharan A, Doust BD. Clinical sound speed measurement in liver and spleen in vivo. ULTRASONIC IMAGING 1987; 9:221-35. [PMID: 3330336 DOI: 10.1177/016173468700900401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The paper describes an implementation of clinical sound speed measurement using either a commercial water path scanner or a specially developed dual transducer real time scanner, each interfaced to a general purpose minicomputer for off-line analysis. It describes the examination technique to obtain suitable in vivo clinical data from the liver and the spleen. It develops signal processing methods to achieve clinical confidence in individual measurements. Forty-five liver patients and 46 spleen patients were examined. Sound speed was found to correlate closely with fibrosis content in both the liver and the spleen with an increase in fibrosis resulting in a decrease in sound speed. Sound speed in various pathological conditions are discussed. Clinical results of sequential examinations on patients under treatment are presented and successful monitoring of the disease status is demonstrated. The potential clinical role of sound speed measurement is suggested.
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Affiliation(s)
- C F Chen
- Ultrasonics Institute, Chatswood, NSW, Australia
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37
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Kontonassios T, Ophir J. Variance reduction of speed of sound estimation in tissues using the beam tracking method. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 1987; 34:524-530. [PMID: 18291879 DOI: 10.1109/t-uffc.1987.26978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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38
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Sehgal CM, Brown GM, Bahn RC, Greenleaf JF. Measurement and use of acoustic nonlinearity and sound speed to estimate composition of excised livers. ULTRASOUND IN MEDICINE & BIOLOGY 1986; 12:865-74. [PMID: 3810981 DOI: 10.1016/0301-5629(86)90004-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The acoustic nonlinearity parameter B/A and sound speed c have been determined for excised normal and abnormal human livers at 20-37 degrees C. These values are compared with analytic measurements of fat and water content of tissues. The results show that normal liver containing 71.0% water and 2.9% fat by weight has a B/A value of 6.75 and sound speed of 1592 m/s at 37 degrees C. Both these parameters increase at an average rate of 0.026 degrees C and 1.5 m/s/degrees C, respectively, as the temperature is raised from 20 to 37 degrees C. Fatty liver (24% fat by weight) exhibits highest B/A (9.12) and lowest c (1522 m/s) of all the livers studied. In contrast to normal livers sound speed in such a liver was found to decrease with temperature. Based on the acoustic and composition measurements, quantitative correlations of B/A and c with fat-water composition have been developed. Inversion of these relationships provide a simple method to determine composition of a tissue sample from B/A and c measurements.
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39
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Ophir J. Estimation of the speed of ultrasound propagation in biological tissues: a beam-tracking method. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 1986; 33:359-68. [PMID: 18291797 DOI: 10.1109/t-uffc.1986.26843] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
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40
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Proceedings of the British Medical Ultrasound Society. Sixteenth annual meeting. Harrogate, December 11-13, 1984. Abstracts. Br J Radiol 1985; 58:687-99. [PMID: 3893616 DOI: 10.1259/0007-1285-58-691-687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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41
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Robinson D. Digital Reconstruction and Display of Compound Scan Ultrasound Images. ACTA ACUST UNITED AC 1984. [DOI: 10.1109/t-su.1984.31520] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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42
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Program and abstracts: Ninth International Symposium on Ultrasonic Imaging and Tissue Characterization. June 3-6, 1984, Washington, D.C. ULTRASONIC IMAGING 1984; 6:201-241. [PMID: 6539982 DOI: 10.1177/016173468400600209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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43
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Robinson DE, Knight PC. Interpolation scan conversion in pulse-echo ultrasound. ULTRASONIC IMAGING 1982; 4:297-310. [PMID: 6891128 DOI: 10.1177/016173468200400401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Some disadvantages of current digital scan conversion techniques are reviewed. An improved system is described which uses linear interpolation between available sampled data points to provide an estimate of the echo reflectivity at each grid point in the image. This approach avoids the problems of “missed pixels” inherent in the current approach, and the need to provide some smoothing or blurring function to remove them. The interpolated scan conversion allows data line spacing to be increased, leading to a reduced scan time for static scans and increased frame-rate for real-time, while retaining all the resolution available from the ultrasound system.
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