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Zhuang B, Rohling R, Abolmaesumi P. Region-of-Interest-Based Closed-Loop Beamforming for Spinal Ultrasound Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2019; 66:1266-1280. [PMID: 31059437 DOI: 10.1109/tuffc.2019.2914957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Clear visualization of spine structures in ultrasound imaging is difficult due to factors such as specular reflection, off-axis energy, and reverberation artifacts. The received channel data from the spine are often tilted even after delay correction, resulting in signal cancellation during the beamforming process. Conventional beamformers are not designed to tackle this issue. This paper proposes a closed-loop beamforming method which feeds back the location of the spine to the beamforming process so that backscattered bone signals can be aligned prior to the beamforming. To suppress the weak soft tissue and reverberation artifacts and increase the contrast of bones, a tensor-based filtering is employed prior to the cross-correlation-based alignment. Directional filtering is also employed to improve the bone surface detection. Phantom studies show improvement on the sharpness of the spine without shape distortion. In vivo results confirm significant contrast improvement of spinal structures. Compared with the conventional delay-and-sum beamforming, the proposed method improves the contrast ratio (CR) of the spine from 0.56 to 0.96. The 6-dB width of bone surfaces is also reduced by 51%.
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Singla P, Dixon AJ, Sheeran JL, Scalzo D, Mauldin FW, Tiouririne M. Feasibility of Spinal Anesthesia Placement Using Automated Interpretation of Lumbar Ultrasound Images: A Prospective Randomized Controlled Trial. ACTA ACUST UNITED AC 2019; 10. [PMID: 31179158 PMCID: PMC6555430 DOI: 10.4172/2155-6148.1000878] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background: This study evaluated the efficacy of spinal anesthesia administration by resident physicians when using an ultrasound system with automated neuraxial landmark detection capabilities. Methods: 150 patients were enrolled in this trial. Anesthesiology residents placed spinals in subjects undergoing scheduled cesarean delivery using one of three techniques to identify neuraxial landmarks: palpation, ultrasound, or combined palpation and ultrasound. Ultrasound was performed using a handheld system that automatically identified neuraxial landmarks (e.g. midline, intervertebral spaces). All residents watched a 10-minute video and received 20 minutes of hands-on training prior to participating in the study. First insertion success rate was the primary end point. Results: Among all patients, use of ultrasound resulted in a 11% greater first-insertion success rate (RR: 1.11 [0.85–1.47], p=0.431), a 15% reduction in needle insertions (RR: 0.85, p=0.052), and a 26% decrease in needle passes (RR: 0.74, p=0.070). In obese patients of BMI ≥ 30 kg/m2, use of ultrasound resulted in 26% greater first-insertion success rates (RR: 1.26, p=0.187), a 21% decrease in needle insertions (RR: 0.79, p=0.025), a 38% decrease in needle passes (RR: 0.62, p=0.030), and a 75% decrease in patients reporting neutral or low patient satisfaction with anesthesia administration (RR: 0.25, p=0.004). Discussion: Resident anesthesiologists competently utilized the ultrasound system after receiving minimal training. Technical endpoints and patient satisfaction trended towards improvement when ultrasound was used prior to spinal placement, with stronger trends observed in obese patients. Additional study is required to fully characterize the impact of the ultrasound system on clinical efficacy.
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Affiliation(s)
- Priyanka Singla
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA 22908, Virginia, USA
| | - Adam J Dixon
- Rivanna Medical, LLC, 107 E Water St, Charlottesville, VA 22902, Virginia, USA.,Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, Virginia, USA
| | - Jessica L Sheeran
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA 22908, Virginia, USA
| | - David Scalzo
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA 22908, Virginia, USA
| | - Frank W Mauldin
- Rivanna Medical, LLC, 107 E Water St, Charlottesville, VA 22902, Virginia, USA.,Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, Virginia, USA
| | - Mohamed Tiouririne
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA 22908, Virginia, USA
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Imaging Performance of a Handheld Ultrasound System With Real-Time Computer-Aided Detection of Lumbar Spine Anatomy: A Feasibility Study. Invest Radiol 2018; 52:447-455. [PMID: 28230717 DOI: 10.1097/rli.0000000000000361] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the imaging performance of a handheld ultrasound system and the accuracy of an automated lumbar spine computer-aided detection (CAD) algorithm in the spines of human subjects. MATERIALS AND METHODS This study was approved by the institutional review board of the University of Virginia. The authors designed a handheld ultrasound system with enhanced bone image quality and fully automated CAD of lumbar spine anatomy. The imaging performance was evaluated by imaging the lumbar spines of 68 volunteers with body mass index between 18.5 and 48 kg/m. The accuracy, sensitivity, and specificity of the lumbar spine CAD algorithm were assessed by comparing the algorithm's results to ground-truth segmentations of neuraxial anatomy provided by radiologists. RESULTS The lumbar spine CAD algorithm detected the epidural space with a sensitivity of 94.2% (95% confidence interval [CI], 85.1%-98.1%) and a specificity of 85.5% (95% CI, 81.7%-88.6%) and measured its depth with an error of approximately ±0.5 cm compared with measurements obtained manually from the 2-dimensional ultrasound images. The spine midline was detected with a sensitivity of 93.9% (95% CI, 85.8%-97.7%) and specificity of 91.3% (95% CI, 83.6%-96.9%), and its lateral position within the ultrasound image was measured with an error of approximately ±0.3 cm. The bone enhancement imaging mode produced images with 5.1- to 10-fold enhanced bone contrast when compared with a comparable handheld ultrasound imaging system. CONCLUSIONS The results of this study demonstrate the feasibility of CAD for assisting with real-time interpretation of ultrasound images of the lumbar spine at the bedside.
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Zhuang B, Rohling R, Abolmaesumi P. Accumulated Angle Factor-Based Beamforming to Improve the Visualization of Spinal Structures in Ultrasound Images. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:210-222. [PMID: 29389653 DOI: 10.1109/tuffc.2017.2781726] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In recent years, ultrasound has been increasingly used to guide needle insertion procedures for spinal anesthesia. The primary anatomical targets are facet joints and epidural spaces. For these procedures, accurate visualization of the spine anatomy is of critical importance. Challenges arising from the interactions between the ultrasound beam and spinal structures including tilt caused by specular reflections, off-axis interference, and reverberations often result in weakened and blurred vertebra surfaces. Previously, adaptive beamforming methods have been proposed to improve the resolution and contrast. However, most of these methods are not specialized for improving the contrast of specular targets like bones. In this paper, we propose an accumulated angle factor (AAF)-based beamforming method customized for bone surface enhancement. This approach applies a Hilbert transform on delay compensated channel data across the receive aperture. The accumulated phase change across the receive aperture is then calculated and utilized as the weight in the beamforming output. We compared our method with classical delay and sum (DAS) beamforming method and adaptive beamforming methods such as Wiener, phase coherence factor (PCF), CF, and generalized CF (GCF) beamforming. In 12 volunteer data sets, the mean contrast ratio between the vertebrae surface and the surrounding tissue for DAS, Wiener, PCF, CF, GCF, and the proposed AAF methods are 0.49, 0.64, 0.82, 0.77, 0.76, and 0.91, respectively. The contrast is significantly improved in the proposed method.
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Robles G, Fresno JM, Giannetti R. Ultrasonic bone localization algorithm based on time-series cumulative kurtosis. ISA TRANSACTIONS 2017; 66:469-475. [PMID: 27665141 DOI: 10.1016/j.isatra.2016.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 04/08/2016] [Accepted: 09/06/2016] [Indexed: 06/06/2023]
Abstract
The design and optimization of protective equipment and devices such as exoskeletons and prosthetics have the potential to be enhanced by the ability of accurately measure the positions of the bones during movement. Existing technologies allow a quite precise measurement of motion-mainly by using coordinate video-cameras and skin-mounted markers-but fail in directly measuring the bone position. Alternative approaches, as fluoroscopy, are too invasive and not usable during extended lapses of time, either for cost or radiation exposure. An approach to solve the problem is to combine the skin-glued markers with ultrasound technology in order to obtain the bone position by measuring at the same time the marker coordinates in 3D space and the depth of the echo from the bone. Given the complex structure of the bones and the tissues, the echoes from the ultrasound transducer show a quite complex structure as well. To reach a good accuracy in determining the depth of the bones, it is of paramount importance the ability to measure the time-of-flight (TOF) of the pulse with a high level of confidence. In this paper, the performance of several methods for determining the TOF of the ultrasound pulse has been evaluated when they are applied to the problem of measuring the bone depth. Experiments have been made using both simple setups used for calibration purposes and in real human tissues to test the performance of the algorithms. The results show that the method used to process the data to evaluate the time-of-flight of the echo signal can significantly affect the value of the depth measurement, especially in the cases when the verticality of the sensor with respect to the surface causing the main echo cannot be guaranteed. Finally, after testing several methods and processing algorithms for both accuracy and repeatability, the proposed cumulative kurtosis algorithm was found to be the most appropriate in the case of measuring bone depths in vivo with ultrasound sensors at frequencies around 5MHz.
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Affiliation(s)
- Guillermo Robles
- Department of Electrical Engineering, Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain.
| | - José Manuel Fresno
- Department of Electrical Engineering, Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain.
| | - Romano Giannetti
- Department of Electronics and Automatization, Universidad Pontificia Comillas de Madrid, 28015 Madrid, Spain.
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Bandaru RS, Sornes AR, Hermans J, Samset E, D'hooge J. Delay and Standard Deviation Beamforming to Enhance Specular Reflections in Ultrasound Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2016; 63:2057-2068. [PMID: 27913326 DOI: 10.1109/tuffc.2016.2613963] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Although interventional devices, such as needles, guide wires, and catheters, are best visualized by X-ray, real-time volumetric echography could offer an attractive alternative as it avoids ionizing radiation; it provides good soft tissue contrast, and it is mobile and relatively cheap. Unfortunately, as echography is traditionally used to image soft tissue and blood flow, the appearance of interventional devices in conventional ultrasound images remains relatively poor, which is a major obstacle toward ultrasound-guided interventions. The objective of this paper was therefore to enhance the appearance of interventional devices in ultrasound images. Thereto, a modified ultrasound beamforming process using conventional-focused transmit beams is proposed that exploits the properties of received signals containing specular reflections (as arising from these devices). This new beamforming approach referred to as delay and standard deviation beamforming (DASD) was quantitatively tested using simulated as well as experimental data using a linear array transducer. Furthermore, the influence of different imaging settings (i.e., transmit focus, imaging depth, and scan angle) on the obtained image contrast was evaluated. The study showed that the image contrast of specular regions improved by 5-30 dB using DASD beamforming compared with traditional delay and sum (DAS) beamforming. The highest gain in contrast was observed when the interventional device was tilted away from being orthogonal to the transmit beam, which is a major limitation in standard DAS imaging. As such, the proposed beamforming methodology can offer an improved visualization of interventional devices in the ultrasound image with potential implications for ultrasound-guided interventions.
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Tiouririne M, Nguyen S, Hossack JA, Owen K, William Mauldin F. Handheld real-time volumetric imaging of the spine: technology development. J Med Eng Technol 2014; 38:100-3. [PMID: 24446802 DOI: 10.3109/03091902.2013.877989] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Technical difficulties, poor image quality and reliance on pattern identifications represent some of the drawbacks of two-dimensional ultrasound imaging of spinal bone anatomy. To overcome these limitations, this study sought to develop real-time volumetric imaging of the spine using a portable handheld device. The device measured 19.2 cm × 9.2 cm × 9.0 cm and imaged at 5 MHz centre frequency. 2D imaging under conventional ultrasound and volumetric (3D) imaging in real time was achieved and verified by inspection using a custom spine phantom. Further device performance was assessed and revealed a 75-min battery life and an average frame rate of 17.7 Hz in volumetric imaging mode. The results suggest that real-time volumetric imaging of the spine is a feasible technique for more intuitive visualization of the spine. These results may have important ramifications for a large array of neuraxial procedures.
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Affiliation(s)
- Mohamed Tiouririne
- Department of Anesthesiolgoy, Division of Obstetric Anesthesia , Univeristy of Virginia, Charlottesville, VA , USA
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Owen K, Mauldin FW, Nguyen S, Tiouririne M, Hossack JA. Improved elevational and azimuthal motion tracking using sector scans. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:671-684. [PMID: 23549528 DOI: 10.1109/tuffc.2013.2616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Ultrasound data motion tracking is widely used to estimate relative tissue/transducer motion, for example in freehand 3-D imaging, in which successive 2-D ultrasound scan planes are registered in a 3-D volume. Speckle-tracking and decorrelation-based methods are used to estimate motion in the azimuthal and elevational planes. However, the performance of speckle-tracking is significantly degraded in sectorscan systems because of point-spread function rotation with lateral motion. In this paper, we develop a new method for joint azimuthal¿elevational motion estimation based on the complex correlation of individual IQ-demodulated sector-scan A-lines arising from tissue motion in 3-D space. We show that our method has performance benefits over both speckle-tracking and decorrelation-based tracking for motion estimation in sector-scan systems, particularly when there is both elevational and azimuthal motion. Motion-tracking efficacy is further demonstrated by improved freehand imaging of a known target (anatomically accurate 3-D-printed lumbar spine model) in a tissue-mimicking phantom, with an rms surface distance error of 1.2 mm, compared with 2.43 mm for conventional methods. These data indicate that the new algorithm is capable of improved tracking performance for sector scan systems, enabling effective freehand 3-D scanning.
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Affiliation(s)
- Kevin Owen
- University of Virginia, Charlottesville, VA, USA.
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Tasinkevych Y, Klimonda Z, Lewandowski M, Nowicki A, Lewin PA. Modified multi-element synthetic transmit aperture method for ultrasound imaging: A tissue phantom study. ULTRASONICS 2013; 53:570-579. [PMID: 23131337 DOI: 10.1016/j.ultras.2012.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 10/03/2012] [Accepted: 10/03/2012] [Indexed: 06/01/2023]
Abstract
The paper presents the modified multi-element synthetic transmit aperture (MSTA) method for ultrasound imaging. It is based on coherent summation of RF echo signals with apodization weights taking into account the finite size of the transmit subaperture and of the receive element. The work presents extension of the previous study where the modified synthetic transmit aperture (STA) method was considered and verified [1]. In the case of MSTA algorithm the apodization weights were calculated for each imaging point and all combinations of the transmit subaperture and receive element using their angular directivity functions (ADFs). The ADFs were obtained from the exact solution of the corresponding mixed boundary-value problem for periodic baffle system modeling the transducer array. Performance of the developed method was tested using Field II simulated synthetic aperture data of point reflectors for 4MHz 128-element transducer array with 0.3mm pitch and 0.02mm kerf to estimate the visualization depth and lateral resolution. Also experimentally determined data of the tissue-mimicking phantom (Dansk Fantom Service, model 571) obtained using 128 elements, 4MHz, linear transducer array (model L14-5/38) and Ultrasonix SonixTOUCH Research platform were used for qualitative assessment of imaging contrast improvement. Comparison of the results obtained by the modified and conventional MSTA algorithms indicated 15dB improvement of the noise reduction in the vicinity of transducer's surface (1mm depth), and concurrent increase in the visualization depth (86% augment of the scattered amplitude at the depth of 90mm). However, this increase was achieved at the expense of minor degradation of the lateral resolution of approximately 8% at the depth of 50mm and 5% at the depth of 90mm.
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Affiliation(s)
- Y Tasinkevych
- Institute of Fundamental Technological Research of the Polish Academy of Sciences, Pawinskiego 5B, Warsaw 02-106, Poland.
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Michalek P, Donaldson W, McAleavey F, Johnston P, Kiska R. Ultrasound imaging of the infraorbital foramen and simulation of the ultrasound-guided infraorbital nerve block using a skull model. Surg Radiol Anat 2012; 35:319-22. [DOI: 10.1007/s00276-012-1039-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Accepted: 10/26/2012] [Indexed: 11/27/2022]
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