1
|
Hayashi T, Matsumoto N, Hatake S, Takeshi Y, Suzuki K, Nishiyama Y, Nagayama H, Kimura K. Nerve sonography to detect intraneural microvascularity in patients with peripheral neuropathy. Clin Neurophysiol 2024; 166:244-249. [PMID: 39226617 DOI: 10.1016/j.clinph.2024.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 08/05/2024] [Accepted: 08/13/2024] [Indexed: 09/05/2024]
Abstract
OBJECTIVE We assessed microvessel flow within peripheral nerves using nerve sonography in patients with peripheral neuropathy. METHODS This study included consecutive patients with peripheral neuropathy who were admitted to our hospital. The patients were divided into two groups: inflammatory neuropathies for immune-mediated neuropathies, such as Guillain - Barré syndrome and chronic inflammatory demyelinating polyneuropathy, and the rest were defined as non-inflammatory neuropathies. We assessed nerve size and intraneural blood flow at four sites on each median and ulnar nerve. Blood flow was evaluated using color Doppler imaging, advanced dynamic flow (ADF), and superb microvascular imaging (SMI) techniques. RESULTS Thirty-nine patients (median age, 60.0 years; 20 male) were enrolled in this study. An increase in intraneural blood flow was observed in five patients when evaluated by color Doppler, five patients by ADF, and 13 patients by SMI. An overall analysis of the three methods showed that intraneural blood flow was significantly higher in patients with inflammatory neuropathy than in those with non-inflammatory neuropathy (54.2% vs. 0%, p = 0.0005). CONCLUSIONS Intraneural hypervascularization is more frequent in patients with inflammatory neuropathy than in those with non-inflammatory neuropathy. SIGNIFICANCE Evaluation of microvessel flow within peripheral nerves may contribute to the diagnosis of peripheral neuropathy.
Collapse
Affiliation(s)
| | | | - Seira Hatake
- Department of Neurology, Nippon Medical School, Tokyo, Japan
| | - Yuho Takeshi
- Department of Neurology, Nippon Medical School, Tokyo, Japan
| | - Kentaro Suzuki
- Department of Neurology, Nippon Medical School, Tokyo, Japan
| | | | | | - Kazumi Kimura
- Department of Neurology, Nippon Medical School, Tokyo, Japan
| |
Collapse
|
2
|
Jung H, Shung KK, Lim HG. Ultrasonic High-Resolution Imaging and Acoustic Tweezers Using Ultrahigh Frequency Transducer: Integrative Single-Cell Analysis. SENSORS (BASEL, SWITZERLAND) 2023; 23:1916. [PMID: 36850513 PMCID: PMC9962640 DOI: 10.3390/s23041916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Ultrasound imaging is a highly valuable tool in imaging human tissues due to its non-invasive and easily accessible nature. Despite advances in the field of ultrasound research, conventional transducers with frequencies lower than 20 MHz face limitations in resolution for cellular applications. To address this challenge, we employed ultrahigh frequency (UHF) transducers and demonstrated their potential applications in the field of biomedical engineering, specifically for cell imaging and acoustic tweezers. The lateral resolution achieved with a 110 MHz UHF transducer was 20 μm, and 6.5 μm with a 410 MHz transducer, which is capable of imaging single cells. The results of our experiments demonstrated the successful imaging of a single PC-3 cell and a 15 μm bead using an acoustic scanning microscope equipped with UHF transducers. Additionally, the dual-mode multifunctional UHF transducer was used to trap and manipulate single cells and beads, highlighting its potential for single-cell studies in areas such as cell deformability and mechanotransduction.
Collapse
Affiliation(s)
- Hayong Jung
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - K. Kirk Shung
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Hae Gyun Lim
- Department of Biomedical Engineering, Pukyong National University, Busan 48513, Republic of Korea
| |
Collapse
|
3
|
Bilodeau M, Quaegebeur N, Berry A, Masson P. Correlation-based ultrasound imaging of strong reflectors with phase coherence filtering. ULTRASONICS 2022; 119:106631. [PMID: 34801835 DOI: 10.1016/j.ultras.2021.106631] [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: 10/06/2020] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Two main metrics are usually employed to assess the quality of medical ultrasound (US) images, namely the contrast and the spatial resolution. A number of imaging algorithms have been proposed to improve one of those metrics, often at the expense of the other one. This paper presents the application of a correlation-based ultrasound imaging method, called Excitelet, to medical US imaging applications and the inclusion of a new Phase Coherence (PC) metric within its formalism. The main idea behind this algorithm, originally developed and validated for Non-Destructive Testing (NDT) applications, is to correlate a reference signal database with the measured signals acquired from a transducer array. In this paper, it is shown that improved lateral resolutions and a reduction of imaging artifacts are obtained over the Synthetic Aperture Focusing Technique (SAFT) when using Excitelet in conjunction with a PC filter. This novel method shows potential for the imaging of specular reflectors, such as invasive surgical tools. Numerical and experimental results presented in this paper demonstrate the benefit, in terms of contrast and resolution, of using the Excitelet method combined with PC for the imaging of strong reflectors.
Collapse
Affiliation(s)
- M Bilodeau
- GAUS, Department of Mechanical Engineering, Université de Sherbrooke, QC, J1K, 2R1, Canada.
| | - N Quaegebeur
- GAUS, Department of Mechanical Engineering, Université de Sherbrooke, QC, J1K, 2R1, Canada; Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada
| | - A Berry
- GAUS, Department of Mechanical Engineering, Université de Sherbrooke, QC, J1K, 2R1, Canada
| | - P Masson
- GAUS, Department of Mechanical Engineering, Université de Sherbrooke, QC, J1K, 2R1, Canada; Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada
| |
Collapse
|
4
|
Qi Y, Guo Y, Wang Y. Image Quality Enhancement Using a Deep Neural Network for Plane Wave Medical Ultrasound Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:926-934. [PMID: 32915734 DOI: 10.1109/tuffc.2020.3023154] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Plane wave imaging (PWI), a typical ultrafast medical ultrasound imaging mode, adopts single plane wave emission without focusing to achieve a high frame rate. However, the imaging quality is severely degraded in comparison with the commonly used focused line scan mode. Conventional adaptive beamformers can improve imaging quality at the cost of additional computation. In this article, we propose to use a deep neural network (DNN) to enhance the performance of PWI while maintaining a high frame rate. In particular, the PWI response from a single point target is used as the network input, while the focused scan response from the same point serves as the desired output, which is the main contribution of this method. To evaluate the performance of the proposed method, simulations, phantom experiments and in vivo studies are conducted. The delay-and-sum (DAS), the coherence factor (CF), a previously proposed deep learning-based method and the DAS with focused scan are used for comparison. Numerical metrics, including the contrast ratio (CR), the contrast-to-noise ratio (CNR), and the speckle signal-to-noise ratio (sSNR), are used to quantify the performance. The results indicate that the proposed method can achieve superior resolution and contrast performance. Specifically, the proposed method performs better than the DAS in all metrics. Although the CF provides a higher CR, its CNR and sSNR are much lower than those of the proposed method. The overall performance is also better than that of the previous deep learning method and at the same level with focused scan performance. Additionally, in comparison with the DAS, the proposed method requires little additional computation, which ensures high temporal resolution. These results validate that the proposed method can achieve a high imaging quality while maintaining the high frame rate associated with PWI.
Collapse
|
5
|
Varnosfaderani MHH, Asl BM. Minimum variance based fusion of fundamental and second harmonic ultrasound imaging: Simulation and experimental study. ULTRASONICS 2019; 96:203-213. [PMID: 30876656 DOI: 10.1016/j.ultras.2019.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 11/12/2018] [Accepted: 01/17/2019] [Indexed: 06/09/2023]
Abstract
Harmonic imaging is widely used in clinical ultrasound due to its higher resolution in comparison with fundamental mode. However, the low amplitude of harmonic components in this imaging method is a crucial problem, resulting in a high sensitivity to noise, while the fundamental imaging is more robust against noise. To exploit the benefits of both the fundamental and harmonic imaging, we propose a minimum variance (MV)-based adaptive combination of fundamental and harmonic images. The performance of the proposed mixing-together MV (MTMV) beamformer is evaluated on simulated and experimental RF data. The results of the simulated point targets show that in the regions near of point targets, where the desire signals exist, the proposed MTMV beamformer mostly follows the MV-beamformed harmonic image to retain a better resolution. In the regions far from the point targets, where there is just noise, it follows the MV-beamformed fundamental image to benefit from more robustness. Also, the results of the simulated and experimental cyst phantoms indicate that MTMV reduces the background noise level and improves the contrast without compromising the high resolution of the MV-beamformed harmonic image. In the simulated cyst phantom, in comparison to DAS (fundamental), DAS (harmonic), MV (fundamental), MV (harmonic), and wavelet fusion, the image contrast ratio (CR) is increased, in average, about 5.2 dB, 3.5 dB, 1.5 dB, 3.6 dB, and 2.8 dB, respectively. The contrast-to-noise ratio (CNR) is significantly improved; about 59%, 53%, 41%, 37%, and 24%, respectively. In the experimental cyst phantom, these relative improvements are about 6.6 dB, 3.5 dB, 4.2 dB, 2.1 dB, and 3.8 dB for CR, and about 64%, 52%, 25%, 33%, and 33%, for CNR, respectively.
Collapse
|
6
|
Jeganathan S, Budziszewski E, Hernandez C, Wu H, Gilbert D, Tavri S, Exner AA. Tunable Polymer Embolic Implant for Vascular Occlusion. ACS Biomater Sci Eng 2019; 5:1849-1856. [DOI: 10.1021/acsbiomaterials.8b01530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
7
|
Khairalseed M, Brown K, Parker KJ, Hoyt K. Real-time H-scan ultrasound imaging using a Verasonics research scanner. ULTRASONICS 2019; 94:28-36. [PMID: 30606648 PMCID: PMC6467760 DOI: 10.1016/j.ultras.2018.12.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 11/29/2018] [Accepted: 12/19/2018] [Indexed: 05/10/2023]
Abstract
H-scan ultrasound (US) is a new imaging technique that relies on matching a model that describes US image formation to the mathematics of a class of Gaussian-weighted Hermite polynomials (GH). In short, H-scan US (where the 'H' denotes Hermite or hue) is a tissue classification technique that images the relative size of acoustic scatterers. Herein, we detail development of a real-time H-scan US imaging technology that was implemented on a programmable US research scanner (Vantage 256, Verasonics Inc, Kirkland, WA). This custom US imaging system has a dual display for real-time visualization of both the H-scan and B-scan US images. This MATLAB-based (Mathworks Inc, Natick, MA) system includes a graphical user interface (GUI) for controlling the entire US scan sequence including the raw radio frequency (RF) data acquisition parameters, image processing, variable control of a parallel set of convolution filters used to derive the H-scan US signal, and data (cine loop) save. The system-level structure used for software-based image reconstruction and display is detailed. Imaging studies were conducted using a series of homogeneous and heterogeneous tissue-mimicking phantom materials embedded with monodisperse spherical US scatterers of size 15-40 µm in diameter. Relative to H-scan US image measurements from a phantom with 15 µm-sized scatterers, data from phantoms with the 30 and 40 µm-sized scatterers exhibited mean intensity increases of 5.2% and 11.6%, respectively. Overall, real-time H-scan US imaging is a promising approach for visualizing the relative size and distribution of acoustic scattering objects.
Collapse
Affiliation(s)
- Mawia Khairalseed
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA; Department of Biomedical Engineering, Sudan University of Science and Technology and Africa City of Technology, Khartoum, Sudan
| | - Katherine Brown
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY 14611, USA
| | - Kenneth Hoyt
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA; Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| |
Collapse
|
8
|
Qi Y, Wang Y, Yu J, Guo Y. 2-D Minimum Variance Based Plane Wave Compounding with Generalized Coherence Factor in Ultrafast Ultrasound Imaging. SENSORS 2018; 18:s18124099. [PMID: 30477114 PMCID: PMC6308455 DOI: 10.3390/s18124099] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 11/16/2022]
Abstract
Plane wave compounding (PWC) is an effective modality for ultrafast ultrasound imaging. It can provide higher resolution and better noise reduction than plane wave imaging (PWI). In this paper, a novel beamformer integrating the two-dimensional (2-D) minimum variance (MV) with the generalized coherence factor (GCF) is proposed to maintain the high resolution and contrast along with a high frame rate for PWC. To specify, MV beamforming is adopted in both the transmitting aperture and the receiving one. The subarray technique is therefore upgraded into the sub-matrix division. Then, the output of each submatrix is used to adaptively compute the GCF using a 2-D fast Fourier transform (FFT). After the 2-D MV beamforming and the 2-D GCF weighting, the final output can be obtained. Results of simulations, phantom experiments, and in vivo studies confirm the advantages of the proposed method. Compared with the delay-and-sum (DAS) beamformer, the full width at half maximum (FWHM) is 90% smaller and the contrast ratio (CR) improvement is 154% in simulations. The over-suppression of desired signals, which is a typical drawback of the coherence factor (CF), can be effectively avoided. The robustness against sound velocity errors is also enhanced.
Collapse
Affiliation(s)
- Yanxing Qi
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
| | - Yuanyuan Wang
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai 200032, China.
| | - Jinhua Yu
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai 200032, China.
| | - Yi Guo
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai 200032, China.
| |
Collapse
|
9
|
Zhao J, Wang Y, Zeng X, Yu J, Yiu BYS, Yu ACH. Plane wave compounding based on a joint transmitting-receiving adaptive beamformer. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2015; 62:1440-1452. [PMID: 26276954 DOI: 10.1109/tuffc.2014.006934] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Plane wave compounding is a useful mode for ultrasound imaging because it can make a good compromise between imaging quality and frame rate. It is also useful for broad view ultrasound imaging. Traditional coherent plane wave compounding coherently sums the echo data of different steered transmitting waves as the output. The data correlation information of different emissions is not considered. Therefore, some adaptive techniques can be introduced into the compounding procedure. In this paper, we propose a Joint Transmitting-Receiving (JTR) adaptive beamforming scheme for plane wave compounding. Unlike traditional adaptive beamformers, the proposed beamforming scheme is designed for the 2-D data set obtained from multiple plane wave firings. It calculates both the transmitting aperture weights and the receiving aperture weights and then combines them into a 2-D adaptive weight function for compounding. Experiments are conducted on both simulated and phantom data. Results show that the proposed scheme has better performance on both point targets and cysts than the existing plane wave compounding approach. Because of the adaptive process in both apertures for compounding, an improved resolution is observed in both simulation and phantom studies. When the eigenanalysis is introduced, a contrast enhancement is achieved. For the simulated cyst, a contrast ratio (CR) improvement of 48% is achieved compared with the traditional plane wave compounding. For the phantom cyst, this improvement is 213.8%. The proposed scheme also has good robustness against sound velocity errors. Therefore, it is effective in enhancing the coherent plane wave compounding quality.
Collapse
|
10
|
Si-Mohamed S, Aïchoun I, Schuster I, Di Rienzo M, Dauzat M, Pérez-Martin A, Bouly S. [B-mode sonography visualizing microemboli flow in the main cerebral arteries]. JOURNAL DES MALADIES VASCULAIRES 2015; 40:187-191. [PMID: 25862592 DOI: 10.1016/j.jmv.2015.03.002] [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: 11/04/2014] [Accepted: 03/01/2015] [Indexed: 06/04/2023]
Abstract
In a patient with a mechanical prosthetic aortic valve admitted for transient amnesia, transcranial duplex Doppler and B-mode sonography visualized the transit of microemboli along the main cerebral arteries. Gaseous microemboli resulting from a cavitation phenomenon at valve closure were seen as high-intensity transient signals (HITS). To our knowledge, this is the first report of microemboli flow visualized in B-mode.
Collapse
Affiliation(s)
- S Si-Mohamed
- Service d'exploration et médecine vasculaire, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France.
| | - I Aïchoun
- Service d'exploration et médecine vasculaire, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France; Service d'exploration fonctionnelle du système nerveux, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France; Service d'imagerie médicale, centre hospitalier de Bagnols-sur-Cèze, 7, avenue Alphonse-Daudet, 30200 Bagnols-sur-Cèze, France
| | - I Schuster
- Service d'exploration et médecine vasculaire, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France; Service d'exploration fonctionnelle du système nerveux, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France
| | - M Di Rienzo
- Service d'exploration et médecine vasculaire, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France; Service d'exploration fonctionnelle du système nerveux, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France
| | - M Dauzat
- Service d'exploration et médecine vasculaire, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France; Service d'exploration fonctionnelle du système nerveux, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France
| | - A Pérez-Martin
- Service d'exploration et médecine vasculaire, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France; Service d'exploration fonctionnelle du système nerveux, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France
| | - S Bouly
- Service d'exploration fonctionnelle du système nerveux, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France; Service de neurologie, centre hospitalier universitaire de Nîmes, place du Professeur-Robert-Debré, 30029 Nîmes, France
| |
Collapse
|
11
|
Vascular 3D+T Freehand Ultrasound Using Correlation of Doppler and Pulse-Oximetry Data. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/978-3-319-07521-1_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
12
|
Etaix N, Dubois J, Fink M, Ing RK. Increasing the modal density in plates for mono-element focusing in air. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 134:1049-1054. [PMID: 23927104 DOI: 10.1121/1.4812260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Acoustic focusing experiments usually require large arrays of transducers. It has been shown by Etaix et al. [J. Acoust. Soc. Am. 131, 395-399 (2012)] that the use of a cavity allows reducing this number of transducers. This paper presents experiments with Duralumin plates (the cavities) containing scatterers to improve the contrast of focusing. The use of a scatterer array in the plate allows increasing the modal density at given frequencies. The scatterers used are membranes and buttons that are manufactured in Duralumin plates. Their resonances are studied both experimentally and numerically. Such scatterers present the advantage of having a tunable frequency resonance, which allows controlling the frequencies at which the modal density increases. The dispersion relations of plates with scatterer array show high modal density at given frequencies. Finally acoustic focusing experiments in air, using these plates, are compared to the ones of simple duralumin plates demonstrating the improvement of contrast. Acoustic source localization is also realized using these plates.
Collapse
Affiliation(s)
- Nicolas Etaix
- Institut Langevin, Ecole Superieure de Physique et de Chimie Industrielles, ParisTech, CNRS Unité Mixte de Recherche 7587, 1 Rue Jussieu, 75005 Paris, France
| | | | | | | |
Collapse
|
13
|
Etaix N, Fink M, Ing RK. Acoustic imaging device with one transducer. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2012; 131:EL395-EL399. [PMID: 22559458 DOI: 10.1121/1.3699533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper presents a low profile imaging device using only one piezoelectric transducer and a microphone. The transducer is glued to an aluminum plate of non-regular geometry that acts as an acoustic cavity. Beam steering is achieved, and the acoustic waves should be focused anywhere in front of the plate. Finally, using a single microphone receiver working in echographic mode, our imaging device is able to locate any object placed in front of it.
Collapse
Affiliation(s)
- Nicolas Etaix
- Institut Langevin, Université Paris 7, ESPCI, CNRS Unité Mixte de Recherche 7587, 10 rue Vauquelin, 75231 Paris Cédex 05, France.
| | | | | |
Collapse
|
14
|
Koolwal AB, Barbagli F, Carlson CR, Liang DH. A fast slam approach to freehand 3-d ultrasound reconstruction for catheter ablation guidance in the left atrium. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:2037-2054. [PMID: 22014856 DOI: 10.1016/j.ultrasmedbio.2011.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Revised: 07/31/2011] [Accepted: 08/09/2011] [Indexed: 05/31/2023]
Abstract
We present a method for real-time, freehand 3D ultrasound (3D-US) reconstruction of moving anatomy, with specific application towards guiding the catheter ablation procedure in the left atrium. Using an intracardiac echo (ICE) catheter with a pose (position/orientation) sensor mounted to its tip, we continually mosaic 2D-ICE images of a left atrium phantom model to form a 3D-US volume. Our mosaicing strategy employs a probabilistic framework based on simultaneous localization and mapping (SLAM), a technique commonly used in mobile robotics for creating maps of unexplored environments. The measured ICE catheter tip pose provides an initial estimate for compounding 2D-ICE image data into the 3D-US volume. However, we simultaneously consider the overlap-consistency shared between 2D-ICE images and the 3D-US volume, computing a "corrected" tip pose if need be to ensure spatially-consistent reconstruction. This allows us to compensate for anatomic movement and sensor drift that would otherwise cause motion artifacts in the 3D-US volume. Our approach incorporates 2D-ICE data immediately after acquisition, allowing us to continuously update the registration parameters linking sensor coordinates to 3D-US coordinates. This, in turn, enables real-time localization and display of sensorized therapeutic catheters within the 3D-US volume for facilitating procedural guidance.
Collapse
Affiliation(s)
- Aditya B Koolwal
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA.
| | | | | | | |
Collapse
|
15
|
Choi Y, Lee H, Hong H, Ohm WS. Two-dimensional virtual array for ultrasonic nondestructive evaluation using a time-reversal chaotic cavity. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 130:2720-2727. [PMID: 22087900 DOI: 10.1121/1.3643828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Despite its introduction more than a decade ago, a two-dimensional ultrasonic array remains a luxury in nondestructive evaluation because of the complexity and cost associated with its fabrication and operation. This paper describes the construction and performance of a two-dimensional virtual array that solves these problems. The virtual array consists of only two transducers (one each for transmit and receive) and an aluminum chaotic cavity, augmented by a 10 × 10 matrix array of rectangular rods. Each rod, serving as an elastic waveguide, is calibrated to emit a collimated pulsed sound beam centered at 2.5 MHz using the reciprocal time reversal. The resulting virtual array is capable of pulse-echo interrogation of a solid sample in direct contact along 10 × 10 scan lines. Three-dimensional imaging of an aluminum test piece, the nominal thickness of which is in the order of 1 cm, is successfully carried out using the virtual array.
Collapse
Affiliation(s)
- Youngsoo Choi
- School of Mechanical Engineering, Yonsei University, Seoul 120-749, Korea
| | | | | | | |
Collapse
|
16
|
Erchinger FG, Dimcevski G, Engjom T, Gilja OH. Transabdominal ultrasonography of the pancreas: basic and new aspects. ACTA ACUST UNITED AC 2011. [DOI: 10.2217/iim.11.36] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
17
|
|
18
|
Bozzato A, Loika A, Hornung J, Koch M, Zenk J, Uter W, Iro H. Comparison of conventional B-scan, tissue harmonic imaging, compound imaging and tissue harmonic compound imaging in neck lesion characterisation. Eur Arch Otorhinolaryngol 2010; 267:1593-8. [DOI: 10.1007/s00405-010-1255-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 04/09/2010] [Indexed: 10/19/2022]
|
19
|
Forsberg F, Berghella V, Merton DA, Rychlak K, Meiers J, Goldberg BB. Comparing image processing techniques for improved 3-dimensional ultrasound imaging. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2010; 29:615-619. [PMID: 20375380 DOI: 10.7863/jum.2010.29.4.615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
OBJECTIVE The purpose of this study was to compare volumetric image processing techniques for reducing noise and speckle while retaining tissue structures in 3-dimensional (3D) gray scale ultrasound imaging. METHODS Eighty subjects underwent a clinically indicated abdominal or obstetric 3D ultrasound examination (20 hepatic, 20 renal, and 40 obstetric cases). Volume data were processed on a pixel ("2-dimensional [2D] processing") or a voxel ("3D processing") basis using commercially available image enhancement software (ContextVision AB, Linköping, Sweden). Randomized, side-by-side comparisons of the image processing techniques were performed for each subject. An independent and blinded reader scored the volumes for image quality on a 3-point scale from 1 (worst) to 3 (best) and compared the results using a nonparametric Wilcoxson signed rank test. RESULTS The 40 subjects with abdominal 3D imaging received a mean score (+/- 1 SD) of 1.52 +/- 0.51, 2.45 +/- 0.60, and 2.75 +/- 0.44 for the original, the 2D processed, and the 3D processed volumes, respectively. The differences between the unprocessed and the processed volumes were highly statistically significant (P < .0001), as was the difference between the 2D and 3D processing methods (P = .002). Similar results were obtained for the obstetric data sets (n = 39 due to an acquisition problem) with a mean score of 1.03 +/- 0.16 for the original, 2.33 +/- 0.48 for the 2D processed, and 2.79 +/- 0.47 for the 3D processed volumes (P < .003). CONCLUSIONS A new volumetric ultrasound image enhancement technique has been assessed in abdominal and obstetric applications. Compared to unprocessed volumes and volumes processed with 2D image enhancement software, the new 3D processing technique performed best.
Collapse
Affiliation(s)
- Flemming Forsberg
- Department of Radiology, Division of Ultrasound, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | | | | | | | | | | |
Collapse
|
20
|
|
21
|
|
22
|
A probabilistic framework for freehand 3D ultrasound reconstruction applied to catheter ablation guidance in the left atrium. Int J Comput Assist Radiol Surg 2009; 4:425-37. [DOI: 10.1007/s11548-009-0354-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 04/26/2009] [Indexed: 10/20/2022]
|
23
|
Ahman H, Thompson L, Swarbrick A, Woodward J. Understanding the Advanced Signal Processing Technique of Real-Time Adaptive Filters. JOURNAL OF DIAGNOSTIC MEDICAL SONOGRAPHY 2009. [DOI: 10.1177/8756479309334354] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Diagnostic ultrasound manufacturers are advancing the technology of sonographic systems, providing superior image quality and improving the diagnostic confidence for both sonographers and radiologists. Real-time adaptive filters (RTAFs) are perhaps the least known among the advanced signal processing techniques available on most modern sonography machines, which is further complicated by the fact that RTAF appears under various trademark names. Despite the different proprietary names, RTAFs generally employ a postprocessing mathematical algorithm to real-time imaging that improves contrast resolution by reducing noise and artifacts while simultaneously enhancing the edges and smoothing the tissue texture of structures. This technique may be applied across a wide variety of clinical examinations and may not yet be completely understood and appreciated by sonographers. This review aims to educate readers on how RTAFs work, supported by examples of their benefit to image quality. In particular, the authors describe the effectiveness of using RTAF for superficial structures (thyroid, abdominal wall), deep structures (abdomen, pelvis), and dynamic examinations, including musculoskeletal and vascular applications.
Collapse
Affiliation(s)
- Hilary Ahman
- Mohawk-McMaster Institute for Applied Health Sciences, Hamilton, Ontario, Canada,
| | - Lindsay Thompson
- Mohawk-McMaster Institute for Applied Health Sciences, Hamilton, Ontario, Canada
| | - Amy Swarbrick
- Mohawk-McMaster Institute for Applied Health Sciences, Hamilton, Ontario, Canada
| | - Julie Woodward
- Mohawk-McMaster Institute for Applied Health Sciences, Hamilton, Ontario, Canada
| |
Collapse
|
24
|
Montaldo G, Tanter M, Bercoff J, Benech N, Fink M. Coherent plane-wave compounding for very high frame rate ultrasonography and transient elastography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2009; 56:489-506. [PMID: 19411209 DOI: 10.1109/tuffc.2009.1067] [Citation(s) in RCA: 792] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The emergence of ultrafast frame rates in ultrasonic imaging has been recently made possible by the development of new imaging modalities such as transient elastography. Data acquisition rates reaching more than thousands of images per second enable the real-time visualization of shear mechanical waves propagating in biological tissues, which convey information about local viscoelastic properties of tissues. The first proposed approach for reaching such ultrafast frame rates consists of transmitting plane waves into the medium. However, because the beamforming process is then restricted to the receive mode, the echographic images obtained in the ultrafast mode suffer from a low quality in terms of resolution and contrast and affect the robustness of the transient elastography mode. It is here proposed to improve the beamforming process by using a coherent recombination of compounded plane-wave transmissions to recover high-quality echographic images without degrading the high frame rate capabilities. A theoretical model is derived for the comparison between the proposed method and the conventional B-mode imaging in terms of contrast, signal-to-noise ratio, and resolution. Our model predicts that a significantly smaller number of insonifications, 10 times lower, is sufficient to reach an image quality comparable to conventional B-mode. Theoretical predictions are confirmed by in vitro experiments performed in tissue-mimicking phantoms. Such results raise the appeal of coherent compounds for use with standard imaging modes such as B-mode or color flow. Moreover, in the context of transient elastography, ultrafast frame rates can be preserved while increasing the image quality compared with flat insonifications. Improvements on the transient elastography mode are presented and discussed.
Collapse
Affiliation(s)
- Gabriel Montaldo
- Laboratoire Ondes et Acoustique, Ecole Supérieure de Physique et Chimie Industrielles (ESPCI), INSERM, Paris, France
| | | | | | | | | |
Collapse
|
25
|
John BS, Rowland D, Ratnam L, Walkden M, Nayak S, Patel U, Anson K, Nassiri D. Percutaneous renal intervention: comparison of 2-D and time-resolved 3-D (4-D) ultrasound for minimal calyceal dilation using an ultrasound phantom and fluoroscopic control. ULTRASOUND IN MEDICINE & BIOLOGY 2008; 34:1765-1769. [PMID: 18485569 DOI: 10.1016/j.ultrasmedbio.2008.03.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 03/03/2008] [Accepted: 03/14/2008] [Indexed: 05/26/2023]
Abstract
The rapid advances made by ultrasound in recent years have increasingly taken 3-D ultrasound (3DUS) and 4-D ultrasound (4DUS) from the research setting to the patient's bedside. There are still unexplored areas like renal percutaneous intervention, where 4DUS has yet to be proven an effective tool. Ultrasound-only guidance in renal percutaneous access is used in selected well-dilated pelvi-calyceal systems (PCS), and fluoroscopy is often utilized as an adjunct. Our aim was to compare 2-D and 4-D guidance for punctures, with fluoroscopy as control, using an in vitro ultrasound phantom. Agar and latex were the tissue-mimicking materials used for the construction of the phantom. The latex targets were designed to simulate multidirection-facing minimally dilated renal calyces. Two interventional fellows punctured the "calyces" using first 2DUS and then 4DUS guidance, making use of a different set of targets each time. The time to puncture, time to introduction of wire, quality of puncture (judged on fluoroscopy) and global rating of both modalities were documented. There was no significant difference between the times to puncture using 2DUS (1.8 min) and 4DUS (2 min). Nor was there a significant difference in the quality of puncture. 4DUS had a higher median difficulty rating. The multiplanar reformatted (MPR) longitudinal and transverse images were found to be the most useful for needle guidance. Cross hairs in all MPR images were not just useful in aligning the images on target but also as surrogate targets. The phantom was found to be robust, with only one instance of air introduction after 30 punctures. We have found that 4DUS is at least as good as 2DUS in terms of quality of punctures in vitro. The technology still has some way to go as frame rates, transducer size and resolution improve.
Collapse
Affiliation(s)
- Babbin S John
- Department of Urology, St. George's Hospital, London, UK.
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Lewandowski M, Nowicki A. High frequency coded imaging system with RF. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2008; 55:1878-1882. [PMID: 18986930 DOI: 10.1109/tuffc.2008.871] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Coded transmission is an approach to solve the inherent compromise between penetration and resolution required in ultrasound imaging. Our goal was to examine the applicability of the coded excitation to HF (20-35 MHz) ultrasound imaging. A novel real-time imaging system for research and evaluation of the coded transmission was developed. The digital programmable coder- digitizer module based on the field programmable gate array (FPGA) chip supports arbitrary waveform coded transmission and RF echo sampling up to 200 megasamples per second, as well as real-time streaming of digitized RF data via a high-speed USB interface to the PC. All RF and image data processing were implemented in the software. A novel balanced software architecture supports real-time processing and display at rates up to 30 frames/sec. The system was used to acquire quantitative data for sine burst and 16-bit Golay code excitation at 20 MHz fundamental frequency. SNR gain close to 14 dB was obtained. The example of the skin scan clearly shows the extended penetration and improved contrast when a 35-MHz Golay code is used. The system presented is a practical and low-cost implementation of a coded excitation technique in HF ultrasound imaging that can be used as a research tool as well as to be introduced into production.
Collapse
|
27
|
Whatmough C, Guitian J, Baines E, Benigni L, Mahoney PN, Mantis P, Lamb CR. ULTRASOUND IMAGE COMPOUNDING: EFFECT ON PERCEIVED IMAGE QUALITY. Vet Radiol Ultrasound 2007; 48:141-5. [PMID: 17385373 DOI: 10.1111/j.1740-8261.2007.00221.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In order to determine the effect of different image compounding functions on perceived image quality, 84 pairs of ultrasound images were collected, mixed, and reviewed by four independent observers who were asked to identify the highest quality image of each pair. Each image in a pair was made using the same orientation, transducer, frequency, and gain settings but different compounding settings. Outcomes were analyzed using logistic regression. Observers judged compound images to be better quality than noncompound images in 69% cases, the same quality in 24%, and poorer quality in 7%. Overall, compound images were considered significantly better quality than noncompound images (P < 0.001). Compound images were more likely to be considered better quality than the corresponding noncompound images when combined transmit/receive spatial compounding was used rather than receive-only spatial compounding or transmit compounding, and when the vector transducer or the curvilinear transducer were used rather than the linear transducer. Observers considered improved border definition and increased signal to noise ratio to be the properties that accounted most often for higher quality of compound images compared with noncompound images.
Collapse
Affiliation(s)
- Charlotte Whatmough
- Department of Veterinary Clinical Sciences, The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, UK
| | | | | | | | | | | | | |
Collapse
|
28
|
Taggart LR, Baddour RE, Giles A, Czarnota GJ, Kolios MC. Ultrasonic characterization of whole cells and isolated nuclei. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:389-401. [PMID: 17257739 DOI: 10.1016/j.ultrasmedbio.2006.07.037] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Revised: 07/22/2006] [Accepted: 07/27/2006] [Indexed: 05/13/2023]
Abstract
High frequency ultrasound imaging (20 to 60 MHz) is increasingly being used in small animal imaging, molecular imaging and for the detection of structural changes during cell and tissue death. Ultrasonic tissue characterization techniques were used to measure the speed of sound, attenuation coefficient and integrated backscatter coefficient for (a) acute myeloid leukemia cells and corresponding isolated nuclei, (b) human epithelial kidney cells and corresponding isolated nuclei, (c) multinucleated human epithelial kidney cells and d) human breast cancer cells. The speed of sound for cells varied from 1522 to 1535 m/s, while values for nuclei were lower, ranging from 1493 to 1514 m/s. The attenuation coefficient slopes ranged from 0.0798 to 0.1073 dB mm(-1) MHz(-1) for cells and 0.0408 to 0.0530 dB mm(-1) MHz(-1) for nuclei. Integrated backscatter coefficient values for cells and isolated nuclei showed much greater variation and increased from 1.71 x 10(-4) Sr(-1) mm(-1) for the smallest nuclei to 26.47 x 10(-4) Sr(-1) mm(-1) for the cells with the largest nuclei. The findings suggest that integrated backscatter coefficient values, but not attenuation or speed of sound, are correlated with the size of the nuclei.
Collapse
Affiliation(s)
- Linda R Taggart
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | | | | | | | | |
Collapse
|
29
|
Volpe A, Caramaschi P, Marchetta A, Biasi D, Bambara LM, Arcaro G. B-flow ultrasound in a case of giant cell arteritis. Clin Rheumatol 2007; 26:1955-7. [PMID: 17308856 DOI: 10.1007/s10067-007-0584-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 01/31/2007] [Accepted: 01/31/2007] [Indexed: 11/29/2022]
Abstract
We present the case of a 75-year-old woman with suspected giant cell arteritis. In the diagnostic procedure, we used B-flow ultrasound, a non-Doppler technology for blood flow imaging. The advantages of this technique and its possible role in the diagnosis of giant cell arteritis are discussed.
Collapse
Affiliation(s)
- Alessandro Volpe
- Dipartimento di Medicina Generale, Ospedale Sacro Cuore, Via Sempreboni 5, 37024, Negrar, Italy.
| | | | | | | | | | | |
Collapse
|
30
|
Evans KD. The Interface Between Sonographer and the Sonographic Machine. JOURNAL OF DIAGNOSTIC MEDICAL SONOGRAPHY 2007. [DOI: 10.1177/8756479306296950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kevin D. Evans
- The Ohio State University, School of Allied Medical Professions, Division of Radiologic Science and Therapy, 453 West 10th Avenue, 340 A. Atwell Hall, Columbus, OH 43210
| |
Collapse
|
31
|
Development of a Confocal Optical System Design for Molecular Imaging Applications of Biochip. Int J Biomed Imaging 2007; 2007:79710. [PMID: 18256735 PMCID: PMC2211516 DOI: 10.1155/2007/79710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 06/23/2007] [Accepted: 07/15/2007] [Indexed: 11/18/2022] Open
Abstract
A novel confocal optical system design and a dual laser confocal scanner have been developed to meet the requirements of highly sensitive detection of biomolecules on microarray chips, which is characterized by a long working distance (wd>3.0 mm), high numerical aperture (NA=0.72), and only 3 materials and 7 lenses used. This confocal optical system has a high scanning resolution, an excellent contrast and signal-to-noise ratio, and an efficiency of collected fluorescence of more than 2-fold better than that of other commercial confocal biochip scanners. The scanner is as equally good for the molecular imaging detection of enclosed biochips as for the detection of biological samples on a slide surface covered with a cover-slip glass. Some applications of gene and protein imagings using the dual laser confocal scanner are described.
Collapse
|
32
|
Poon TC, Rohling RN. Three-dimensional extended field-of-view ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2006; 32:357-69. [PMID: 16530094 DOI: 10.1016/j.ultrasmedbio.2005.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 10/24/2005] [Accepted: 11/03/2005] [Indexed: 05/07/2023]
Abstract
Three-dimensional (3-D) extended field-of-view ultrasound creates a mosaic view from a set of volumes acquired from a dedicated 3-D ultrasound machine combined with a position tracker. A simple compounding technique can be used to combine the volumes together using only the position measurements, but some misalignment remains. Two different registration methods were developed to correct these errors in the overlapping regions. The first method divides the overlap into smaller blocks and warps the blocks to best align the features. The second method is similar, but uses rigid body registration of the blocks. Experiments in vitro and in vivo showed that block-based registration with warping produced the most reproducible results and the greatest increase in similarity among the overlapping regions. It also produced the best reconstruction accuracy, with a mean distance error of 0.4 mm measured across 101.78 mm in a phantom, representing 0.4% error.
Collapse
Affiliation(s)
- Tony C Poon
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada
| | | |
Collapse
|
33
|
Abstract
New sonographic techniques in urology, together with their principles of operation, will be presented. Together with the utilization of broadband ultrasound scanners and digital beam formers, leading to better spatial resolution and increased line density in ultrasound imaging, panorama sonography enables the outline of wide lateral regions independent of the width of the scanner. Spatial compound sonography achieves a comparatively better visualization of details in the b-mode image than has yet been available. The continuously improved 3-D, now leading to 4-D, techniques, which means real time capabilities, make the visualization of unrestricted imaging planes, which are not seen in conventional 2-D techniques, possible. The second harmonic imaging technique, including the special applications tissue harmonic imaging (THI) and contrast harmonic imaging (CHI), uses special ultrasound signal processing procedures for capturing and evaluating tissue hemoperfusion-here in combination with ultrasound contrast agents (UCA). Furthermore, microvascular imaging (MVI) enables the visualization of perfusion in tissues reaching the microcirculation regions. This leads to new possibilities for the assessment of pathological perfusion patterns, e.g. in andrology (perfusion of testicles) and uro-oncology (hyperperfusion of malignant regions).
Collapse
Affiliation(s)
- H Heynemann
- Universitätsklinik und Poliklinik für Urologie, Martin-Luther-Universität Halle-Wittenberg.
| | | | | | | |
Collapse
|