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Sojahrood AJ, Yang C, Counil C, Nittayacharn P, Goertz DE, Exner AA, Kolios MC. Influence of the liquid ionic strength on the resonance frequency and shell parameters of lipid-coated microbubbles. J Colloid Interface Sci 2024; 664:533-538. [PMID: 38484521 DOI: 10.1016/j.jcis.2024.01.185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 01/13/2024] [Accepted: 01/26/2024] [Indexed: 04/07/2024]
Abstract
The correct measurement of the resonance frequency and shell properties of coated microbubbles (MBs) is essential in understanding and optimizing their response to ultrasound (US) exposure parameters. In diagnostic and therapeutic ultrasound, MBs are typically surrounded by blood; however, the influence of the medium charges on the MB resonance frequency has not been systematically studied using controlled measurements. This study aims to measure the medium charge interactions on MB behavior by measuring the frequency-dependent attenuation of the same size MBs in mediums with different charge densities. In-house lipid-coated MBs with C3F8 gas core were formulated. The MBs were isolated to a mean size of 2.35 μm using differential centrifugation. MBs were diluted to ≈8×105 MBs/mL in distilled water (DW), Phosphate-Buffered Saline solution (PBS1x) and PBS10x. The frequency-dependent attenuation of the MBs solutions was measured using an aligned pair of PVDF transducers with a center frequency of 10MHz and 100% bandwidth in the linear oscillation regime (7 kPa pressure amplitude). The MB shell properties were estimated by fitting the linear equation to experiments. Using a pendant drop tension meter, the surface tension at the equilibrium of ≈6 mm diameter size drops of the same MB shell was measured inside DW, PBS1x and PBS10x. The surface tension at the C3F8/solution interface was estimated by fitting the Young-Laplace equation from the recorded images. The frequency of the peak attenuation at different salinity levels was 13, 7.5 and 6.25 MHz in DW, PBS1x and PBS-10x, respectively. The attenuation peak increased by ≈140% with increasing ion density. MBs' estimated shell elasticity decreased by 64% between DW and PBS-1x and 36% between PBS-1x and PBS-10x. The drop surface tension reduced by 10.5% between DW and PBS-1x and by 5% between PBS-1x and PBS-10x, respectively. Reduction in the shell stiffness is consistent with the drop surface tension measurements. The shell viscosity was reduced by ≈40% between DW and PBS-1x and 42% between PBS-1x and PBS-10x. The reduction in the fitted stiffness and viscosity is possibly due to the formation of a densely charged layer around the shell, further reducing the effective surface tension on the MBs. The changes in the resonance frequency and estimated shell parameters were significant and may potentially help to better understand and explain bubble behavior in applications.
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Affiliation(s)
- A J Sojahrood
- Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Physics, Toronto Metropolitan University, Toronto, Canada; Institute for Biomedical Engineering, Science and Technology (IBEST), a partnership between Toronto Metropolitan University and St. Michael's Hospital, Toronto, Ontario, Canada.
| | - C Yang
- Department of Physics, Toronto Metropolitan University, Toronto, Canada; Institute for Biomedical Engineering, Science and Technology (IBEST), a partnership between Toronto Metropolitan University and St. Michael's Hospital, Toronto, Ontario, Canada
| | - C Counil
- Department of Biomedical Engineering, Case Western University, Cleveland, OH, USA
| | - P Nittayacharn
- Department of Biomedical Engineering, Case Western University, Cleveland, OH, USA; Department of Biomedical Engineering, Faculty of Engineering, Mahidol University, Puttamonthon, Nakorn Pathom, Thailand
| | - D E Goertz
- Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Ontario, Canada
| | - A A Exner
- Department of Biomedical Engineering, Case Western University, Cleveland, OH, USA
| | - M C Kolios
- Department of Physics, Toronto Metropolitan University, Toronto, Canada; Institute for Biomedical Engineering, Science and Technology (IBEST), a partnership between Toronto Metropolitan University and St. Michael's Hospital, Toronto, Ontario, Canada
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Polydorou AE, May JP, Makris K, Ferri S, Wu Q, Stride E, Carugo D, Evans ND. An investigation into the cytotoxic effects of microbubbles and their constituents on osteosarcoma and bone marrow stromal cells. Biochim Biophys Acta Gen Subj 2023; 1867:130481. [PMID: 37802372 DOI: 10.1016/j.bbagen.2023.130481] [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: 07/19/2023] [Revised: 09/26/2023] [Accepted: 10/02/2023] [Indexed: 10/10/2023]
Abstract
BACKGROUND Ultrasound-responsive microbubbles offer a means of achieving minimally invasive, localised drug delivery in applications including regenerative medicine. To facilitate their use, however, it is important to determine any cytotoxic effects they or their constituents may have. The aim of this study was to test the hypothesis that phospholipid-shelled microbubbles are non-toxic to human bone-derived cells at biologically-relevant concentrations. METHODS Microbubbles were fabricated using combinations of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC), polyoxyethylene(40) stearate (PEG40S) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene-glycol)-2000] (DSPE-PEG2000). Microbubble size and concentration were measured as a function of time and temperature by optical microscopy. Effects on MG63 osteosarcoma and human bone marrow stromal cells (BMSCs) were measured for up to 72 h by assay for viability, metabolic activity and proliferation. RESULTS DBPC:DSPE-PEG2000 microbubbles were significantly more stable than DSPC:PEG40S microbubbles under all conditions tested. Serum-containing medium had no detrimental effect on microbubble stability, but storage at 37 °C compared to at 4 °C reduced stability for both preparations, with almost complete dissolution of microbubbles at times ≥24 h. DSPC:PEG40S microbubbles had greater inhibitory effects on cell metabolism and growth than DBPC:DSPE-PEG2000 microbubbles, with PEG40S found to be the principle inhibitory component. These effects were only evident at high microbubble concentrations (≥20% (v/v)) or with prolonged culture (≥24 h). Increasing cell-microbubble contact by inversion culture in a custom-built device had no inhibitory effect on metabolism. CONCLUSIONS These data indicate that, over a broad range of concentrations and incubation times, DBPC:DSPE-PEG2000 and DSPC:PEG40S microbubbles have little effect on osteoblastic cell viability and growth, and that PEG40S is the principle inhibitory component in the formulations investigated.
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Affiliation(s)
- A E Polydorou
- Centre for Human Development, Stem Cells and Regenerative Medicine, Bone and Joint Research group, University of Southampton, United Kingdom; Bioengineering Sciences Group, Institute for Life Sciences, University of Southampton, United Kingdom
| | - J P May
- Centre for Human Development, Stem Cells and Regenerative Medicine, Bone and Joint Research group, University of Southampton, United Kingdom; Bioengineering Sciences Group, Institute for Life Sciences, University of Southampton, United Kingdom
| | - K Makris
- Bioengineering Sciences Group, Institute for Life Sciences, University of Southampton, United Kingdom
| | - S Ferri
- Centre for Human Development, Stem Cells and Regenerative Medicine, Bone and Joint Research group, University of Southampton, United Kingdom; Bioengineering Sciences Group, Institute for Life Sciences, University of Southampton, United Kingdom
| | - Q Wu
- Institute of Biomedical Engineering, University of Oxford, United Kingdom
| | - E Stride
- Institute of Biomedical Engineering, University of Oxford, United Kingdom; Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, United Kingdom
| | - D Carugo
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, United Kingdom
| | - N D Evans
- Centre for Human Development, Stem Cells and Regenerative Medicine, Bone and Joint Research group, University of Southampton, United Kingdom; Bioengineering Sciences Group, Institute for Life Sciences, University of Southampton, United Kingdom.
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Jiang Y, Hou X, Zhao X, Jing J, Sun L. Tracking adoptive natural killer cells via ultrasound imaging assisted with nanobubbles. Acta Biomater 2023; 169:542-555. [PMID: 37536495 DOI: 10.1016/j.actbio.2023.07.058] [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: 05/04/2023] [Revised: 07/06/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023]
Abstract
The recent years has witnessed an exponential growth in the field of natural killer (NK) cell-based immunotherapy for cancer treatment. As a prerequisite to precise evaluations and on-demand interventions, the noninvasive tracking of adoptive NK cells plays a crucial role not only in post-treatment monitoring, but also in offering opportunities for preclinical studies on therapy optimizations. Here, we describe an NK cell tracking strategy for cancer immunotherapy based on ultrasound imaging modality. Nanosized ultrasound contrast agents, gas vesicles (GVs), were surface-functionalized to label NK cells. Unlike traditional microbubble contrast agents, nanosized GVs with their unique thermodynamical stability enable the detection of labeled NK cells under nonlinear contrast-enhanced ultrasound (nCEUS), without a noticeable impact on cellular viability or migration. By such labeling, we were able to monitor the trafficking of systematically infused NK cells to a subcutaneous tumor model. Upon co-treatment with interleukin (IL)-2, we observed a rapid enhancement in NK cell trafficking at the tumor site as early as 3 h post-infusion. Altogether, we show that the proposed ultrasound-based tracking strategy is able to capture the dynamical changes of cell trafficking in NK cell-based immunotherapy, providing referencing information for early-phase monotherapy evaluation, as well as understanding the effects of modulatory co-treatment. STATEMENT OF SIGNIFICANCE: In cellular immunotherapies, the post-infusion monitoring of the living therapeutics has been challenging. Several popular imaging modalities have been explored the monitoring of the adoptive immune cells, evaluating their trafficking and accumulation in the tumor. Here we demonstrated, for the first time, the ultrasound imaging-based immune cell tracking strategy. We showed that the acoustic labeling of adoptive immune cells was feasible with nanosized ultrasound contrast agents, overcoming the size and stability limitations of traditional microbubbles, enabling dynamical tracking of adoptive natural killer cells in both monotherapy and synergic treatment with cytokines. This article introduced the cost-effective and ubiquitous ultrasound imaging modality into the field of cellular immunotherapies, with broad prospectives in early assessment and on-demand image-guided interventions.
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Affiliation(s)
- Yizhou Jiang
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Room ST409 Hung Hom, Hong Kong SAR 999077, PR China
| | - Xuandi Hou
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Room ST409 Hung Hom, Hong Kong SAR 999077, PR China
| | - Xinyi Zhao
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Room ST409 Hung Hom, Hong Kong SAR 999077, PR China
| | - Jianing Jing
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Room ST409 Hung Hom, Hong Kong SAR 999077, PR China
| | - Lei Sun
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Room ST409 Hung Hom, Hong Kong SAR 999077, PR China.
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Liu X, Wu Z, Manzoli M, Jicsinszky L, Cavalli R, Battaglia L, Cravotto G. Medium-high frequency sonication dominates spherical-SiO 2 nanoparticle size. ULTRASONICS SONOCHEMISTRY 2022; 90:106181. [PMID: 36182836 PMCID: PMC9526221 DOI: 10.1016/j.ultsonch.2022.106181] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Spherical SiO2 nanoparticles (SSNs) have been inventively synthesized using the Stöber method with sonication at medium-high frequencies (80, 120, and 500 kHz), aiming to control SSN size and shorten reaction time. Compared to the conventional method, such sonication allowed the Stöber reaction complete in 20-60 min with a low molar ratio of NH4OH/tetraethyl orthosilicate (0.84). The hydrodynamic diameters of 63-117 nm of SSNs were obtained under sonication with 80, 120, and 500 kHz of ultrasonic frequencies. Moreover, the SSNs obtained were smaller at 120 kHz than at 80 kHz in a multi-frequencies ultrasonic reactor, and the SSN size decreased with increasing ultrasonic power at 20 °C, designating the sonochemical unique character, namely, the SSN-size control is associated with the number of microbubbles originated by sonication. With another 500 kHz ultrasonic bath, the optimal system temperature for producing smaller SSNs was proven to be 20 °C. Also, the SSN size decreased with increasing ultrasonic power. The smallest SSNs (63 nm, hydrodynamic diameter by QELS, or 21 nm by FESEM) were obtained by sonication at 207 W for 20 min at 20 °C. Furthermore, the SSN size increased slightly with increasing sonication time and volume, favoring the scale-up of SSNs preparation. The mechanisms of controlling the SSN size were further discussed by the radical's role and effects of ammonia and ethanol concentration.
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Affiliation(s)
- Xiaolin Liu
- Department of Drug Science and Technology and NIS-Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy
| | - Zhilin Wu
- Department of Drug Science and Technology and NIS-Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy.
| | - Maela Manzoli
- Department of Drug Science and Technology and NIS-Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy
| | - László Jicsinszky
- Department of Drug Science and Technology and NIS-Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy
| | - Roberta Cavalli
- Department of Drug Science and Technology and NIS-Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy
| | - Luigi Battaglia
- Department of Drug Science and Technology and NIS-Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy
| | - Giancarlo Cravotto
- Department of Drug Science and Technology and NIS-Centre for Nanostructured Interfaces and Surfaces, University of Turin, Via Pietro Giuria 9, 10125 Turin, Italy.
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5
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Yusefi H, Helfield B. The influence of inter-bubble spacing on the resonance response of ultrasound contrast agent microbubbles. ULTRASONICS SONOCHEMISTRY 2022; 90:106191. [PMID: 36223708 PMCID: PMC9563339 DOI: 10.1016/j.ultsonch.2022.106191] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/29/2022] [Accepted: 10/05/2022] [Indexed: 06/06/2023]
Abstract
Ultrasound-driven microbubbles, typically between 1 and 8 µm in diameter, are resonant scatterers that are employed as diagnostic contrast agents and emerging as potentiators of targeted therapies. Microbubbles are administered in populations whereby their radial dynamics - key to their effectiveness - are greatly affected by intrinsic (e.g. bubble size) and extrinsic (e.g. boundaries) factors. In this work, we aim to understand how two neighbouring microbubbles influence each other. We developed a finite element model of a system of two individual phospholipid-encapsulated microbubbles vibrating in proximity to each other to study the effect of inter-bubble distance on microbubble radial resonance response. For the case of two equal-sized and identical bubbles, each bubble exhibits a decrease between 7 and 10% in the frequency of maximum response (fMR) and an increase in amplitude of maximum response (AMR) by 9-11% as compared to its isolated response in free-space, depending on the bubble size examined. For a system of two unequal-sized microbubbles, the large bubble shows no significant change, however the smaller microbubble shows an increase in fMR by 7-11% and a significant decrease in AMR by 38-52%. Furthermore, in very close proximity the small bubble shows a secondary off-resonance peak at the corresponding fMR of its larger companion microbubble. Our work suggests that frequency-dependent microbubble response is greatly affected by the presence of another bubble, which has implications in both imaging and therapy applications. Furthermore, our work suggests a mechanism by which nanobubbles show significant off-resonance vibrations in the clinical frequency range, a behaviour that has been observed experimentally but heretofore unexplained.
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Affiliation(s)
- Hossein Yusefi
- Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Brandon Helfield
- Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada; Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada.
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6
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An Open Access Chamber Designed for the Acoustic Characterisation of Microbubbles. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12041818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Microbubbles are used as contrast agents in clinical ultrasound for Left Ventricular Opacification (LVO) and perfusion imaging. They are also the subject of promising research in therapeutics as a drug delivery mechanism or for sonoporation and co-administration. For maximum efficacy in these applications, it is important to understand the acoustic characteristics of the administered microbubbles. Despite this, there is significant variation in the experimental procedures and equipment used to measure the acoustic properties of microbubble populations. A chamber was designed to facilitate acoustic characterisation experiments and was manufactured using additive manufacturing techniques. The design has been released to allow wider uptake in the research community. The efficacy of the chamber for acoustic characterisation has been explored with an experiment to measure the scattering of SonoVue® microbubbles at the fundamental frequency and second harmonic under interrogation from emissions in the frequency range of 1.6 to 6.4 MHz. The highest overall scattering values were measured at 1.6 MHz and decreased as the frequency increased, a result which is in agreement with previously published measurements. Statistical analysis of the acoustic scattering measurements have been performed and a significant difference, at the 5% significance level, was found between the samples containing contrast agent and the control sample containing only deionised water. These findings validate the proposed design for measuring the acoustic scattering characteristics of ultrasound contrast agents.
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7
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Langeveld SAG, Meijlink B, Beekers I, Olthof M, van der Steen AFW, de Jong N, Kooiman K. Theranostic Microbubbles with Homogeneous Ligand Distribution for Higher Binding Efficacy. Pharmaceutics 2022; 14:pharmaceutics14020311. [PMID: 35214044 PMCID: PMC8878664 DOI: 10.3390/pharmaceutics14020311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/14/2022] [Accepted: 01/16/2022] [Indexed: 02/05/2023] Open
Abstract
Phospholipid-coated targeted microbubbles are used for ultrasound molecular imaging and locally enhanced drug delivery, with the binding efficacy being an important trait. The use of organic solvent in microbubble production makes the difference between a heterogeneous or homogeneous ligand distribution. This study demonstrates the effect of ligand distribution on the binding efficacy of phospholipid-coated ανβ3-targeted microbubbles in vitro using a monolayer of human umbilical-vein endothelial cells and in vivo using chicken embryos. Microbubbles with a homogeneous ligand distribution had a higher binding efficacy than those with a heterogeneous ligand distribution both in vitro and in vivo. In vitro, 1.55× more microbubbles with a homogeneous ligand distribution bound under static conditions, while this was 1.49× more under flow with 1.25 dyn/cm2, 1.56× more under flow with 2.22 dyn/cm2, and 1.25× more in vivo. The in vitro dissociation rate of bound microbubbles with homogeneous ligand distribution was lower at low shear stresses (1–5 dyn/cm2). The internalized depth of bound microbubbles was influenced by microbubble size, not by ligand distribution. In conclusion, for optimal binding the use of organic solvent in targeted microbubble production is preferable over directly dispersing phospholipids in aqueous medium.
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Affiliation(s)
- Simone A. G. Langeveld
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
- Correspondence:
| | - Bram Meijlink
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
| | - Inés Beekers
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
- Department of Health, ORTEC B.V., 2719 EA Zoetermeer, The Netherlands
| | - Mark Olthof
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
| | - Antonius F. W. van der Steen
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
| | - Nico de Jong
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
- Imaging Physics, Delft University of Technology, 2628 CJ Delft, The Netherlands
| | - Klazina Kooiman
- Thorax Center, Biomedical Engineering, Erasmus University Medical Center Rotterdam, 3000 CA Rotterdam, The Netherlands; (B.M.); (I.B.); (M.O.); (A.F.W.v.d.S.); (N.d.J.); (K.K.)
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Ntoulia A, Aguirre Pascual E, Back SJ, Bellah RD, Beltrán Salazar VP, Chan PKJ, Chow JS, Coca Robinot D, Darge K, Duran C, Epelman M, Ključevšek D, Kwon JK, Sandhu PK, Woźniak MM, Papadopoulou F. Contrast-enhanced voiding urosonography, part 1: vesicoureteral reflux evaluation. Pediatr Radiol 2021; 51:2351-2367. [PMID: 33787945 DOI: 10.1007/s00247-020-04906-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/11/2020] [Accepted: 11/09/2020] [Indexed: 12/17/2022]
Abstract
Contrast-enhanced voiding urosonography (ceVUS) is a well-established, sensitive and safe ultrasound (US) modality for detecting and grading vesicoureteral reflux (VUR) and urethral imaging in children. Nearly three decades of remarkable advances in US technology and US contrast agents have refined ceVUS's diagnostic potential. The recent approval of Lumason/SonoVue in the United States, Europe and China for pediatric intravesical applications marked the beginning of a new era for this type of contrast US imaging. Consequently, the use of ceVUS in children has expanded to multiple places around the globe. In the first part of this review article, we describe the current experience in the use of ceVUS for VUR evaluation, with an emphasis on historical background, examination technique, image interpretation and diagnostic accuracy. In the second part, we will present the role of ceVUS for urethral imaging in children.
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Affiliation(s)
- Aikaterini Ntoulia
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA.
| | | | - Susan J Back
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Richard D Bellah
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Viviana P Beltrán Salazar
- Department of Radiology, Hospital Universitari Parc Tauli - Universitat Autónoma de Barcelona, Sabadell, Barcelona, Spain
| | - Pui Kwan Joyce Chan
- Department of Radiology, Hong Kong Children's Hospital, Hong Kong (SAR), People's Republic of China
| | - Jeanne S Chow
- Department of Radiology, Boston Children's Hospital, Harvard University, Boston, MA, USA
| | - David Coca Robinot
- Department of Radiology, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Kassa Darge
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Carmina Duran
- Department of Radiology, Hospital Universitari Parc Tauli - Universitat Autónoma de Barcelona, Sabadell, Barcelona, Spain
| | - Monica Epelman
- Department of Radiology, Nemours Children's Health System/Nemours Children's Hospital, Orlando, FL, USA
| | - Damjana Ključevšek
- Department of Radiology, University Children's Hospital Ljubljana, Ljubljana, Slovenia
| | - Jeannie K Kwon
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Preet Kiran Sandhu
- Department of Radiology, Le Bonheur Children's Hospital, Memphis, TN, USA
| | - Magdalena M Woźniak
- Department of Pediatric Radiology, Medical University of Lublin, Lublin, Poland
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9
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LuTheryn G, Glynne-Jones P, Webb JS, Carugo D. Ultrasound-mediated therapies for the treatment of biofilms in chronic wounds: a review of present knowledge. Microb Biotechnol 2020; 13:613-628. [PMID: 32237219 PMCID: PMC7111087 DOI: 10.1111/1751-7915.13471] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 07/21/2019] [Indexed: 12/11/2022] Open
Abstract
Bacterial biofilms are an ever-growing concern for public health, featuring both inherited genetic resistance and a conferred innate tolerance to traditional antibiotic therapies. Consequently, there is a growing interest in novel methods of drug delivery, in order to increase the efficacy of antimicrobial agents. One such method is the use of acoustically activated microbubbles, which undergo volumetric oscillations and collapse upon exposure to an ultrasound field. This facilitates physical perturbation of the biofilm and provides the means to control drug delivery both temporally and spatially. In line with current literature in this area, this review offers a rounded argument for why ultrasound-responsive agents could be an integral part of advancing wound care. To achieve this, we will outline the development and clinical significance of biofilms in the context of chronic infections. We will then discuss current practices used in combating biofilms in chronic wounds and then critically evaluate the use of acoustically activated gas microbubbles as an emerging treatment modality. Moreover, we will introduce the novel concept of microbubbles carrying biologically active gases that may facilitate biofilm dispersal.
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Affiliation(s)
- Gareth LuTheryn
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK
- National Biofilms Innovation Centre, University of Southampton, Southampton, UK
| | - Peter Glynne-Jones
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Jeremy S Webb
- National Biofilms Innovation Centre, University of Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
- Centre for Biological Sciences, University of Southampton, Southampton, UK
| | - Dario Carugo
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK
- National Biofilms Innovation Centre, University of Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
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10
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Nio AQX, Faraci A, Christensen-Jeffries K, Raymond JL, Monaghan MJ, Fuster D, Forsberg F, Eckersley RJ, Lamata P. Optimal Control of SonoVue Microbubbles to Estimate Hydrostatic Pressure. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:557-567. [PMID: 31634833 PMCID: PMC7053253 DOI: 10.1109/tuffc.2019.2948759] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The measurement of cardiac and aortic pressures enables diagnostic insight into cardiac contractility and stiffness. However, these pressures are currently assessed invasively using pressure catheters. It may be possible to estimate these pressures less invasively by applying microbubble ultrasound contrast agents as pressure sensors. The aim of this study was to investigate the subharmonic response of the microbubble ultrasound contrast agent SonoVue (Bracco Spa, Milan, Italy) at physiological pressures using a static pressure phantom. A commercially available cell culture cassette with Luer connections was used as a static pressure chamber. SonoVue was added to the phantom, and radio frequency data were recorded on the ULtrasound Advanced Open Platform (ULA-OP). The mean subharmonic amplitude over a 40% bandwidth was extracted at 0-200-mmHg hydrostatic pressures, across 1.7-7.0-MHz transmit frequencies and 3.5%-100% maximum scanner acoustic output. The Rayleigh-Plesset equation for single-bubble oscillations and additional hysteresis experiments were used to provide insight into the mechanisms underlying the subharmonic pressure response of SonoVue. The subharmonic amplitude of SonoVue increased with hydrostatic pressure up to 50 mmHg across all transmit frequencies and decreased thereafter. A decreasing microbubble surface tension may drive the initial increase in the subharmonic amplitude of SonoVue with hydrostatic pressure, while shell buckling and microbubble destruction may contribute to the subsequent decrease above 125-mmHg pressure. In conclusion, a practical operating regime that may be applied to estimate cardiac and aortic blood pressures from the subharmonic signal of SonoVue has been identified.
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11
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Chen W, Cai H, Zhang X, Huang D, Yang J, Chen C, Qian Q, He Y, Chen Z. Physiologic Factors Affecting the Circulatory Persistence of Copolymer Microbubbles and Comparison of Contrast-Enhanced Effects between Copolymer Microbubbles and Sonovue. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:721-734. [PMID: 31899039 DOI: 10.1016/j.ultrasmedbio.2019.11.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 11/21/2019] [Accepted: 11/30/2019] [Indexed: 06/10/2023]
Abstract
Ultrasound contrast agents have been widely used in clinical diagnosis. Knowledge of the physiologic factors affecting circulatory persistence is helpful in preparing long-lasting microbubbles (MBs) for blood perfusion and drug delivery research. In the study described here, we prepared copolymer MBs, compared their characteristics and contrast-enhanced effects with those of SonoVue and investigated the influence of external pressure, temperature, plasma components, renal microcirculation and cardiac motion on their circulatory persistence. The mean size of the copolymer MBs was 3.57 μm, larger than that of SonoVue. The copolymer MBs had longer circulatory persistence than SonoVue. At external pressures of 110 and 150 mm Hg, neither the quantity nor the morphology of the copolymer MBs changed. Further, their quantity and size were similar after incubation at 4°C and 39.4°C and when rabbit plasma and saline were compared. In vivo contrast-enhanced ultrasonography revealed a slightly larger area under the curve for the renal artery than for the renal vein. Thus, copolymer MBs exhibited good stability. However, the quantity of copolymer MBs decreased significantly after 180 s of circulation in an isolated toad heart perfusion model, indicating that cardiac motion was the main factor affecting their circulatory persistence.
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Affiliation(s)
- Wanping Chen
- Department of Ultrasound, Affiliated Union Hospital of Fujian Medical University, Fuzhou, China
| | - Hongjiao Cai
- Fisheries College of Jimei University, Xiamen, China
| | - Xiujuan Zhang
- Department of Ultrasound, Affiliated Union Hospital of Fujian Medical University, Fuzhou, China
| | - Danfeng Huang
- Department of Ultrasound, Affiliated Union Hospital of Fujian Medical University, Fuzhou, China
| | - Jing Yang
- Department of Pharmacy, Affiliated Union Hospital of Fujian Medical University, Fuzhou, China
| | - Cong Chen
- Department of Ultrasound, Affiliated Union Hospital of Fujian Medical University, Fuzhou, China
| | - Qingfu Qian
- Department of Ultrasound, Affiliated Union Hospital of Fujian Medical University, Fuzhou, China
| | - Yimi He
- Department of Ultrasound, Affiliated Union Hospital of Fujian Medical University, Fuzhou, China
| | - Zhikui Chen
- Department of Ultrasound, Affiliated Union Hospital of Fujian Medical University, Fuzhou, China.
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12
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Kilic S. Effect of Temperature on Stability of Lipid Microbubbles. JOURNAL OF THE TURKISH CHEMICAL SOCIETY, SECTION A: CHEMISTRY 2019. [DOI: 10.18596/jotcsa.594219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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13
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Shelf-Life Evaluation and Lyophilization of PBCA-Based Polymeric Microbubbles. Pharmaceutics 2019; 11:pharmaceutics11090433. [PMID: 31454967 PMCID: PMC6781551 DOI: 10.3390/pharmaceutics11090433] [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] [Received: 06/30/2019] [Revised: 08/12/2019] [Accepted: 08/22/2019] [Indexed: 12/28/2022] Open
Abstract
Poly(n-butyl cyanoacrylate) microbubbles (PBCA-MB) are extensively employed for functional and molecular ultrasound (US) imaging, as well as for US-mediated drug delivery. To facilitate the use of PBCA-MB as a commercial platform for biomedical applications, it is important to systematically study and improve their stability and shelf-life. In this context, lyophilization (freeze drying) is widely used to increase shelf-life and promote product development. Here, we set out to analyze the stability of standard and rhodamine-B loaded PBCA-MB at three different temperatures (4 °C, 25 °C, and 37 °C), for a period of time of up to 20 weeks. In addition, using sucrose, glucose, polyvinylpyrrolidone (PVP), and polyethylene glycol (PEG) as cryoprotectants, we investigated if PBCA-MB can be lyophilized without affecting their size, concentration, US signal generation properties, and dye retention. Stability assessment showed that PBCA-MB remain largely intact for three and four weeks at 4 °C and 25 °C, respectively, while they disintegrate within one to two weeks at 37 °C, thereby compromising their acoustic properties. Lyophilization analyses demonstrated that PBCA-MB can be efficiently freeze-dried with 5% sucrose and 5% PVP, without changing their size, concentration, and US signal generation properties. Experiments involving rhodamine-B loaded MB indicated that significant dye leakage from the polymeric shell takes place within two to four weeks in case of non-lyophilized PBCA-MB. Lyophilization of rhodamine-loaded PBCA-MB with sucrose and PVP showed that the presence of the dye does not affect the efficiency of freeze-drying, and that the dye is efficiently retained upon MB lyophilization. These findings contribute to the development of PBCA-MB as pharmaceutical products for preclinical and clinical applications.
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14
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Helfield B. A Review of Phospholipid Encapsulated Ultrasound Contrast Agent Microbubble Physics. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:282-300. [PMID: 30413335 DOI: 10.1016/j.ultrasmedbio.2018.09.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/11/2018] [Accepted: 09/20/2018] [Indexed: 06/08/2023]
Abstract
Ultrasound contrast agent microbubbles have expanded the utility of biomedical ultrasound from anatomic imaging to the assessment of microvascular blood flow characteristics and ultrasound-assisted therapeutic applications. Central to their effectiveness in these applications is their resonant and non-linear oscillation behaviour. This article reviews the salient physics of an oscillating microbubble in an ultrasound field, with particular emphasis on phospholipid-coated agents. Both the theoretical underpinnings of bubble vibration and the experimental evidence of non-linear encapsulated bubble dynamics and scattering are discussed and placed within the context of current and emerging applications.
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Affiliation(s)
- Brandon Helfield
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
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15
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Rojas JD, Dayton PA. Vaporization Detection Imaging: A Technique for Imaging Low-Boiling-Point Phase-Change Contrast Agents with a High Depth of Penetration and Contrast-to-Tissue Ratio. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:192-207. [PMID: 30482709 DOI: 10.1016/j.ultrasmedbio.2018.08.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 08/17/2018] [Accepted: 08/22/2018] [Indexed: 06/09/2023]
Abstract
Phase-change contrast agents (PCCAs) possess advantages over microbubble contrast agents, such as the ability to extravasate and circulate longer in the vasculature that could enhance the diagnostic capabilities of contrast-enhanced ultrasound. PCCAs typically have a liquid perfluorocarbon (PFC) core that can be vaporized into echogenic microbubbles. Vaporization of submicron agents filled with liquid PFCs at body temperature usually requires therapeutic pressures higher than typically used for diagnostic imaging, but low-boiling-point PCCAs using decafluorobutane or octafluoropropane can be vaporized using pressures in the diagnostic imaging regime. Low-boiling-point PCCAs produce a unique acoustic signature that can be separated from tissue and bubble signals to make images with high contrast-to-tissue ratios. In this work, we explore the effect of pulse length and concentration on the vaporization signal of PCCAs and a new technique to capture and use the signals to make high contrast-to-tissue ratio images in vivo. The results indicate that using a short pulse may be ideal for imaging because it does not interact with created bubbles but still produces strong signals for making images. Furthermore, it was found that capturing PCCA vaporization signals produced higher contrast-to-tissue ratio values and better depth of penetration than imaging the bubbles generated by droplet activation using conventional contrast imaging techniques. The resolution of the vaporization signal images is poor because of the low frequency of the signals, but their high sensitivity may be used for applications such as molecular imaging, where the detection of small numbers of contrast agents is important.
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Affiliation(s)
- Juan D Rojas
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA
| | - Paul A Dayton
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, North Carolina, USA.
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16
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Ključevšek D, Pečanac O, Tomažič M, Glušič M. Potential causes of insufficient bladder contrast opacification and premature microbubble destruction during contrast-enhanced voiding urosonography in children. JOURNAL OF CLINICAL ULTRASOUND : JCU 2019; 47:36-41. [PMID: 30393874 DOI: 10.1002/jcu.22656] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 09/14/2018] [Accepted: 09/27/2018] [Indexed: 06/08/2023]
Abstract
Contrast-enhanced voiding urosonography (ceVUS) has been recognized as a child-friendly examination with high diagnostic accuracy for vesicoureteric reflux detection. A single bolus and the infusion techniques of ceVUS are described. Insufficient bladder contrast opacification during the filling phase and premature destruction of SonoVue microbubbles might occur. Data regarding SonoVue's features, doses, bladder contrast opacification, US bladder parameters, urine catheter, antibiotic prophylaxis, and childrens behaviors were collected to discover the possible causes of the contrast vanishing observed during bladder filling in 10% of examinations and in the later phase of ceVUS in 5% of examinations. An updated ceVUS examination protocol is suggested.
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Affiliation(s)
- Damjana Ključevšek
- Department of Radiology, University Children's Hospital Ljubljana, Slovenia
| | - Olivera Pečanac
- Department of Radiology, University Children's Hospital Ljubljana, Slovenia
| | - Mojca Tomažič
- Department of Radiology, University Children's Hospital Ljubljana, Slovenia
| | - Mojca Glušič
- Department of Radiology, University Children's Hospital Ljubljana, Slovenia
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17
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Segers T, Lassus A, Bussat P, Gaud E, Frinking P. Improved coalescence stability of monodisperse phospholipid-coated microbubbles formed by flow-focusing at elevated temperatures. LAB ON A CHIP 2018; 19:158-167. [PMID: 30511070 DOI: 10.1039/c8lc00886h] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Monodisperse phospholipid-coated ultrasound contrast agent (UCA) microbubbles can be directly synthesized in a lab-on-a-chip flow-focusing device. However, high total lipid concentrations are required to minimize on-chip bubble coalescence. Here, we characterize the coalescence probability and the long-term size stability of microbubbles formed using DPPC and DSPC based lipid mixtures as a function of temperature. We show that the coalescence probability can be dramatically reduced by increasing the temperature during bubble formation. Moreover, it is shown that the increased coalescence stability can be explained from an exponential increase of the relative viscosity in the thin liquid film between the colliding bubbles. Furthermore, it was found that the relative viscosity of a DPPC lipid mixture is 7.6 times higher than that of a DSPC mixture and that it can be explained solely from the higher DPPC liposome concentration. Regarding long-term bubble stability, the ratio of the initial on-chip bubble size to the final stable bubble size was always found to be 2.2 for DPPC and DSPC coated bubbles with 10 mol% DPPE-PEG5000, independent of the temperature. Moreover, it was demonstrated that the microbubble suspensions formed at elevated temperatures are highly stable over a time window of 2 to 4 days when collected in a vial. All in all, this work shows that, by increasing the temperature during bubble formation from room temperature to 70 °C, the efficiency of the use of phospholipids in microbubble formation by flow-focusing can be increased by 5 times.
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Affiliation(s)
- Tim Segers
- Bracco Suisse S.A., Route de la Galaise 31, 1228 Geneva, Switzerland.
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18
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Voorneveld J, Engelhard S, Vos HJ, Reijnen MMPJ, Gijsen F, Versluis M, Jebbink EG, de Jong N, Bosch JG. High-Frame-Rate Contrast-Enhanced Ultrasound for Velocimetry in the Human Abdominal Aorta. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:2245-2254. [PMID: 29994206 DOI: 10.1109/tuffc.2018.2846416] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Treatment of abdominal aortic (AA) aneurysms and stenotic lesions may be improved by analyzing their associated blood-flow patterns. Angle-independent blood-flow patterns in the AA can be obtained by combining echo-particle image velocimetry (ePIV) with high-frame-rate (HFR) contrast-enhanced ultrasonography. However, ePIV performance is affected by ultrasound contrast agent (UCA) concentration, microbubble stability, and tissue clutter. In this study, we assessed the influence of acoustic pressure and UCA concentration on image quality for ePIV analysis. We also compared amplitude modulation (AM) and singular value decomposition (SVD) as tissue suppression strategies for ePIV. Fourteen healthy volunteers were imaged in the region of the distal AA. We tested four different UCA bolus volumes (0.25, 0.5, 0.75, and 1.5 mL) and four different acoustic output pressures (mechanical indices: 0.01, 0.03, 0.06, and 0.09). As image quality metrics, we measured contrast-to-background ratio, bubble disruption ratio, and maximum normalized cross-correlation value during ePIV. At mechanical indices ≥ 0.06, we detected severe bubble destruction, suggesting that very low acoustic pressures should be used for ePIV. SVD was able to suppress tissue clutter better than AM. The maximum tracking correlation was affected by both UCA concentration and flow rate, where at high flow rates, lower UCA concentrations resulted in slightly higher correlation values but more signal drop-outs during late diastole. HFR ePIV was successfully performed in the AA of healthy volunteers and shows promise for future studies in patients.
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Voorneveld J, Muralidharan A, Hope T, Vos HJ, Kruizinga P, van der Steen AFW, Gijsen FJH, Kenjeres S, de Jong N, Bosch JG. High Frame Rate Ultrasound Particle Image Velocimetry for Estimating High Velocity Flow Patterns in the Left Ventricle. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:2222-2232. [PMID: 29990263 DOI: 10.1109/tuffc.2017.2786340] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Echocardiographic determination of multicomponent blood flow dynamics in the left ventricle remains a challenge. In this paper, we compare contrast enhanced, high frame rate (HFR) (1000 frames/s) echo-particle image velocimetry (ePIV) against optical particle image velocimetry (oPIV, gold standard), in a realistic left ventricular (LV) phantom. We find that ePIV compares well to oPIV, even for the high velocity inflow jet (normalized RMSE = 9% ± 1%). In addition, we perform the method of proper orthogonal decomposition, to better qualify and quantify the differences between the two modalities. We show that ePIV and oPIV resolve very similar flow structures, especially for the lowest order mode with a cosine similarity index of 86%. The coarser resolution of ePIV does result in increased variance and blurring of smaller flow structures when compared to oPIV. However, both modalities are in good agreement with each other for the modes that constitute the bulk of the kinetic energy. We conclude that HFR ePIV can accurately estimate the high velocity diastolic inflow jet and the high energy flow structures in an LV setting.
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20
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Kilic S, Bolukcu ES. Phase behavior of DSPC/PEG40St mixtures at higher emulsifier contents. Colloids Surf B Biointerfaces 2018; 171:368-376. [DOI: 10.1016/j.colsurfb.2018.07.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/23/2018] [Accepted: 07/23/2018] [Indexed: 12/23/2022]
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21
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Kilic S. Quantification of PEG40St squeeze out from DSPC/PEG40St monolayers at higher molar ratios. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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22
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Engelhard S, Voorneveld J, Vos HJ, Westenberg JJM, Gijsen FJH, Taimr P, Versluis M, de Jong N, Bosch JG, Reijnen MMPJ, Groot Jebbink E. High-Frame-Rate Contrast-enhanced US Particle Image Velocimetry in the Abdominal Aorta: First Human Results. Radiology 2018; 289:119-125. [PMID: 30015586 DOI: 10.1148/radiol.2018172979] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To study the feasibility of high-frame-rate (HFR) contrast material-enhanced (CE) ultrasound particle image velocimetry (PIV), or echo PIV, in the abdominal aorta. Materials and Methods Fifteen healthy participants (six men; median age, 23 years [age range, 18-34 years]; median body mass index, 20.3 kg/m2 [range, 17.3-24.9 kg/m2]) underwent HFR CE US. US microbubbles were injected at incremental doses (0.25, 0.5, 0.75, and 1.5 mL), with each dose followed by US measurement to determine the optimal dosage. Different US mechanical index values were evaluated (0.09, 0.06, 0.03, and 0.01) in a diverging wave acquisition scheme. PIV analysis was performed via pairwise cross-correlation of all captured images. Participants also underwent phase-contrast MRI. The echo PIV and phase-contrast MRI velocity profiles were compared via calculation of similarity index and relative difference in peak velocity. Results Visualization of the aortic bifurcation with HFR CE US was successful in all participants. Optimal echo PIV results were achieved with the lowest contrast agent dose of 0.25 mL in combination with the lowest mechanical indexes (0.01 or 0.03). Substantial bubble destruction occurred at higher mechanical indexes (≥0.06). Flow patterns were qualitatively similar in the echo PIV and MR images. The echo PIV and MRI velocity profiles showed good agreement (similarity index, 0.98 and 0.99; difference in peak velocity, 8.5% and 17.0% in temporal and spatial profiles, respectively). Conclusion Quantification of blood flow in the human abdominal aorta with US particle image velocimetry (echo PIV) is feasible. Use of echo PIV has potential in the clinical evaluation of aortic disease. © RSNA, 2018 Online supplemental material is available for this article.
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Affiliation(s)
- Stefan Engelhard
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Jason Voorneveld
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Hendrik J Vos
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Jos J M Westenberg
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Frank J H Gijsen
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Pavel Taimr
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Michel Versluis
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Nico de Jong
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Johan G Bosch
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Michel M P J Reijnen
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
| | - Erik Groot Jebbink
- From the Department of Vascular Surgery, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, the Netherlands (S.E., M.M.P.J.R., E.G.J.); Department of Biomedical Engineering, Thorax Center ( J.V., H.J.V., F.J.H.G., N.d.J., J.G.B.), and Department of Gastroenterology and Hepatology (P.T.), Erasmus Medical Center, Rotterdam, the Netherlands; Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands ( J.J.M.W.); Physics of Fluids Group, Technical Medical ( TechMed ) Centre, University of Twente, Enschede, the Netherlands (M.V., E.G.J.); and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands (N.d.J.)
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Lum JS, Stobbe DM, Borden MA, Murray TW. Photoacoustic technique to measure temperature effects on microbubble viscoelastic properties. APPLIED PHYSICS LETTERS 2018; 112:111905. [PMID: 29576628 PMCID: PMC5851782 DOI: 10.1063/1.5005548] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 02/27/2018] [Indexed: 06/08/2023]
Abstract
Phospholipid-coated microbubbles are being developed for several biomedical applications, but little is known about the effect of temperature on the viscoelastic properties of the shell. Here, we report on the use of a photoacoustic technique to study the shell properties of individual microbubbles as a function of temperature. The microbubbles were driven into small-amplitude oscillations by ultrasound waves generated from the absorption of an intensity-modulated infrared laser, and these oscillations were detected by forward-light scattering of a second blue laser. The drive laser modulation frequency was swept to determine the resonant response of 2-4 μm radius microbubbles. Lipid shell elasticity and viscosity were determined by modeling the microbubble response as a linear harmonic oscillator. The results from slow heating showed a linear decrease in elasticity and viscosity between 21 and 53 °C and a corresponding increase in the maximum oscillation amplitude. Rapid heating to 38 °C, on the other hand, showed a transient response in the viscoelastic properties, suggesting shell rupture and reformation during microbubble growth and subsequent dissolution. These effects are important for biomedical applications, which require warming of the microbubbles to body temperature.
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Affiliation(s)
- Jordan S. Lum
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - David M. Stobbe
- Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, USA
| | - Mark A. Borden
- Authors to whom correspondence should be addressed: . Telephone: 303.492.7236 and . Telephone: 303.492.7750
| | - Todd W. Murray
- Authors to whom correspondence should be addressed: . Telephone: 303.492.7236 and . Telephone: 303.492.7750
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24
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Shekhar H, Smith NJ, Raymond JL, Holland CK. Effect of Temperature on the Size Distribution, Shell Properties, and Stability of Definity ®. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:434-446. [PMID: 29174045 PMCID: PMC5759968 DOI: 10.1016/j.ultrasmedbio.2017.09.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 05/08/2023]
Abstract
Physical characterization of an ultrasound contrast agent (UCA) aids in its safe and effective use in diagnostic and therapeutic applications. The goal of this study was to investigate the impact of temperature on the size distribution, shell properties, and stability of Definity®, a U.S. Food and Drug Administration-approved UCA used for left ventricular opacification. A Coulter counter was modified to enable particle size measurements at physiologic temperatures. The broadband acoustic attenuation spectrum and size distribution of Definity® were measured at room temperature (25 °C) and physiologic temperature (37 °C) and were used to estimate the viscoelastic shell properties of the agent at both temperatures. Attenuation and size distribution was measured over time to assess the effect of temperature on the temporal stability of Definity®. The attenuation coefficient of Definity® at 37 °C was as much as 5 dB higher than the attenuation coefficient measured at 25 °C. However, the size distributions of Definity® at 25 °C and 37 °C were similar. The estimated shell stiffness and viscosity decreased from 1.76 ± 0.18 N/m and 0.21 × 10-6 ± 0.07 × 10-6 kg/s at 25 °C to 1.01 ± 0.07 N/m and 0.04 × 10-6 ± 0.04 × 10-6 kg/s at 37 °C, respectively. Size-dependent differences in dissolution rates were observed within the UCA population at both 25 °C and 37 °C. Additionally, cooling the diluted UCA suspension from 37 °C to 25 °C accelerated the dissolution rate. These results indicate that although temperature affects the shell properties of Definity® and can influence the stability of Definity®, the size distribution of this agent is not affected by a temperature increase from 25 °C to 37 °C.
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Affiliation(s)
- Himanshu Shekhar
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA.
| | - Nathaniel J Smith
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Jason L Raymond
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Christy K Holland
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA; Department of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio, USA
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25
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Stock E, Duchateau L, Saunders JH, Volckaert V, Polis I, Vanderperren K. Repeatability of Contrast-Enhanced Ultrasonography of the Kidneys in Healthy Cats. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:426-433. [PMID: 29174044 DOI: 10.1016/j.ultrasmedbio.2017.09.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 09/20/2017] [Accepted: 09/25/2017] [Indexed: 06/07/2023]
Abstract
Contrast-enhanced ultrasound can be used to image and quantify tissue perfusion. It holds great potential for the use in the diagnosis of various diffuse renal diseases in both human and veterinary medicine. Nevertheless, the technique is known to have an inherent relatively high variability, related to various factors associated with the patient, the contrast agent and machine settings. Therefore, the aim of this study was to assess week-to-week intra- and inter-cat variation of several perfusion parameters obtained with CEUS of both kidneys of 12 healthy cats. Repeatability was determined by calculating the coefficient of variation (CV). The contrast-enhanced ultrasound parameters with the lowest variation for the renal cortex were time-to-peak (CV 6.0%), rise time (CV 13%), fall time (CV 19%) and mean transit time (24%). Intensity-related parameters and parameters related to the slope of the time-intensity curve had a CV of >35%. Lower repeatability was present for perfusion parameters derived from the renal medulla compared with the renal cortex. Normalization to the inter-lobar artery does not cause a reduction in variation. In conclusion, time-related parameters for the cortex show a reasonable repeatability; whereas poor repeatability is present for intensity-related parameters and parameters related to in- and outflow of contrast agent. Poor repeatability is also present for all perfusion parameters for the renal medulla, except for time to peak, which has a good repeatability.
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Affiliation(s)
- Emmelie Stock
- Department of Veterinary Medical Imaging and Small Animal Orthopedics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
| | - Luc Duchateau
- Department of Comparative Physiology and Biometrics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Jimmy H Saunders
- Department of Veterinary Medical Imaging and Small Animal Orthopedics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Veerle Volckaert
- Department of Veterinary Medical Imaging and Small Animal Orthopedics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Ingeborgh Polis
- Department of Medicine and Clinical Biology of Small Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Katrien Vanderperren
- Department of Veterinary Medical Imaging and Small Animal Orthopedics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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26
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Verkaik M, van Poelgeest EM, Kwekkeboom RFJ, Ter Wee PM, van den Brom CE, Vervloet MG, Eringa EC. Myocardial contrast echocardiography in mice: technical and physiological aspects. Am J Physiol Heart Circ Physiol 2017; 314:H381-H391. [PMID: 29101165 DOI: 10.1152/ajpheart.00242.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Myocardial contrast echocardiography (MCE) offers the opportunity to study myocardial perfusion defects in mice in detail. The value of MCE compared with single-photon emission computed tomography, positron emission tomography, and computed tomography consists of high spatial resolution, the possibility of quantification of blood volume, and relatively low costs. Nevertheless, a number of technical and physiological aspects should be considered to ensure reproducibility among research groups. The aim of this overview is to describe technical aspects of MCE and the physiological parameters that influence myocardial perfusion data obtained with this technique. First, technical aspects of MCE discussed in this technical review are logarithmic compression of ultrasound data by ultrasound systems, saturation of the contrast signal, and acquisition of images during different phases of the cardiac cycle. Second, physiological aspects of myocardial perfusion that are affected by the experimental design are discussed, including the anesthesia regimen, systemic cardiovascular effects of vasoactive agents used, and fluctuations in body temperature that alter myocardial perfusion. When these technical and physiological aspects of MCE are taken into account and adequately standardized, MCE is an easily accessible technique for mice that can be used to study the control of myocardial perfusion by a wide range of factors.
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Affiliation(s)
- Melissa Verkaik
- Department of Nephrology, Institute Cardiovascular Research VU, VU University Medical Centre , Amsterdam , The Netherlands.,Department of Physiology, Institute Cardiovascular Research VU, VU University Medical Centre , Amsterdam , The Netherlands
| | - Erik M van Poelgeest
- Department of Physiology, Institute Cardiovascular Research VU, VU University Medical Centre , Amsterdam , The Netherlands
| | - Rick F J Kwekkeboom
- Department of Physiology, Institute Cardiovascular Research VU, VU University Medical Centre , Amsterdam , The Netherlands
| | - Piet M Ter Wee
- Department of Nephrology, Institute Cardiovascular Research VU, VU University Medical Centre , Amsterdam , The Netherlands
| | - Charissa E van den Brom
- Department of Anaesthesiology, Institute Cardiovascular Research VU, VU University Medical Centre , Amsterdam , The Netherlands
| | - Marc G Vervloet
- Department of Nephrology, Institute Cardiovascular Research VU, VU University Medical Centre , Amsterdam , The Netherlands
| | - Etto C Eringa
- Department of Physiology, Institute Cardiovascular Research VU, VU University Medical Centre , Amsterdam , The Netherlands
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27
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Platts DG, Bartnikowski N, Gregory SD, Scalia GM, Fraser JF. Contrast Microsphere Destruction by a Continuous Flow Ventricular Assist Device: An In Vitro Evaluation Using a Mock Circulation Loop. BIOMED RESEARCH INTERNATIONAL 2017; 2017:4907898. [PMID: 28884121 PMCID: PMC5572588 DOI: 10.1155/2017/4907898] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/22/2017] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Transthoracic echocardiography (TTE) is fundamental in managing patients supported with ventricular assist devices (VAD). However imaging can be difficult in these patients. Contrast improves image quality but they are hydrodynamically fragile agents. The aim was to assess contrast concentration following passage through a VAD utilising a mock circulation loop (MCL). METHODS Heartware continuous flow (CF) VAD was incorporated into a MCL. Definity® contrast was infused into the MCL with imaging before and after CF-VAD. 5 mm2 regions of interest were used to obtain signal intensity (decibels), as a surrogate of contrast concentration. RESULTS Four pump speeds revealed significant reduction in contrast signal intensity after CF-VAD compared to before CF-VAD (all p < 0.0001). Combined pre- and postpump data at all speeds showed a 22.2% absolute reduction in contrast signal intensity across the CF-VAD (14.8 ± 0.8 dB prepump versus 11.6 ± 1.4 dB postpump; p < 0.0001). Mean signal intensity reduction at each speed showed an inverse relationship between speed and relative reduction in signal intensity. CONCLUSION Contrast microsphere transit through a CF-VAD within a MCL resulted in significant reduction in signal intensity, consistent with destruction within the pump. This was evident at all CF-VAD pump speeds but relative signal drop was inversely proportional to pump speed.
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Affiliation(s)
- David G. Platts
- Department of Echocardiography, The Prince Charles Hospital, Brisbane, QLD, Australia
- School of Medicine, University of Queensland, Brisbane, QLD, Australia
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
| | - Nicole Bartnikowski
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Shaun D. Gregory
- School of Medicine, University of Queensland, Brisbane, QLD, Australia
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
- School of Engineering, Griffith University, Brisbane, QLD, Australia
| | - Gregory M. Scalia
- Department of Echocardiography, The Prince Charles Hospital, Brisbane, QLD, Australia
- School of Medicine, University of Queensland, Brisbane, QLD, Australia
- Heart Care Partners, Wesley Hospital, Brisbane, QLD, Australia
| | - John F. Fraser
- School of Medicine, University of Queensland, Brisbane, QLD, Australia
- Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, The Prince Charles Hospital, Brisbane, QLD, Australia
- Adult Intensive Care Service, The Prince Charles Hospital, Brisbane, QLD, Australia
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28
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Mulvana H, Browning RJ, Luan Y, de Jong N, Tang MX, Eckersley RJ, Stride E. Characterization of Contrast Agent Microbubbles for Ultrasound Imaging and Therapy Research. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:232-251. [PMID: 27810805 DOI: 10.1109/tuffc.2016.2613991] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The high efficiency with which gas microbubbles can scatter ultrasound compared with the surrounding blood pool or tissues has led to their widespread employment as contrast agents in ultrasound imaging. In recent years, their applications have been extended to include super-resolution imaging and the stimulation of localized bio-effects for therapy. The growing exploitation of contrast agents in ultrasound and in particular these recent developments have amplified the need to characterize and fully understand microbubble behavior. The aim in doing so is to more fully exploit their utility for both diagnostic imaging and potential future therapeutic applications. This paper presents the key characteristics of microbubbles that determine their efficacy in diagnostic and therapeutic applications and the corresponding techniques for their measurement. In each case, we have presented information regarding the methods available and their respective strengths and limitations, with the aim of presenting information relevant to the selection of appropriate characterization methods. First, we examine methods for determining the physical properties of microbubble suspensions and then techniques for acoustic characterization of both suspensions and single microbubbles. The next section covers characterization of microbubbles as therapeutic agents, including as drug carriers for which detailed understanding of their surface characteristics and drug loading capacity is required. Finally, we discuss the attempts that have been made to allow comparison across the methods employed by various groups to characterize and describe their microbubble suspensions and promote wider discussion and comparison of microbubble behavior.
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29
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Sun C, Panagakou I, Sboros V, Butler MB, Kenwright D, Thomson AJW, Moran CM. Influence of temperature, needle gauge and injection rate on the size distribution, concentration and acoustic responses of ultrasound contrast agents at high frequency. ULTRASONICS 2016; 70:84-91. [PMID: 27140502 DOI: 10.1016/j.ultras.2016.04.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 02/16/2016] [Accepted: 04/16/2016] [Indexed: 06/05/2023]
Abstract
This paper investigated the influence of needle gauge (19G and 27G), injection rate (0.85ml·min(-1), 3ml·min(-1)) and temperature (room temperature (RT) and body temperature (BT)) on the mean diameter, concentration, acoustic attenuation, contrast to tissue ratio (CTR) and normalised subharmonic intensity (NSI) of three ultrasound contrast agents (UCAs): Definity, SonoVue and MicroMarker (untargeted). A broadband substitution technique was used to acquire the acoustic properties over the frequency range 17-31MHz with a preclinical ultrasound scanner Vevo770 (Visualsonics, Canada). Significant differences (P<0.001-P<0.05) between typical in vitro setting (19G needle, 3ml·min(-1) at RT) and typical in vivo setting (27G needle, 0.85ml·min(-1) at BT) were found for SonoVue and MicroMarker. Moreover we found that the mean volume-based diameter and concentration of both SonoVue and Definity reduced significantly when changing from typical in vitro to in vivo experimental set-ups, while those for MicroMarker did not significantly change. From our limited measurements of Definity, we found no significant change in attenuation, CTR and NSI with needle gauge. For SonoVue, all the measured acoustic properties (attenuation, CTR and NSI) reduced significantly when changing from typical in vitro to in vivo experimental conditions, while for MicroMarker, only the NSI reduced, with attenuation and CTR increasing significantly. These differences suggest that changes in physical compression and temperature are likely to alter the shell structure of the UCAs resulting in measureable and significant changes in the physical and high frequency acoustical properties of the contrast agents under typical in vitro and preclinical in vivo experimental conditions.
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Affiliation(s)
- Chao Sun
- Medical Physics, Centre for Cardiovascular Research, University of Edinburgh, Edinburgh, UK; Ultrasound Department, Xijing Hospital, Xi'an, China
| | - Ioanna Panagakou
- Medical Physics, Centre for Cardiovascular Research, University of Edinburgh, Edinburgh, UK
| | - Vassilis Sboros
- Medical Physics, Centre for Cardiovascular Research, University of Edinburgh, Edinburgh, UK; Institute of Biochemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, UK
| | - Mairead B Butler
- Medical Physics, Centre for Cardiovascular Research, University of Edinburgh, Edinburgh, UK; Institute of Biochemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, UK
| | - David Kenwright
- Medical Physics, Centre for Cardiovascular Research, University of Edinburgh, Edinburgh, UK
| | - Adrian J W Thomson
- Medical Physics, Centre for Cardiovascular Research, University of Edinburgh, Edinburgh, UK
| | - Carmel M Moran
- Medical Physics, Centre for Cardiovascular Research, University of Edinburgh, Edinburgh, UK.
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30
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Kivinen J, Togtema M, Mulzer G, Choi J, Zehbe I, Curiel L, Pichardo S. Sonoporation efficacy on SiHa cells in vitro at raised bath temperatures-experimental validation of a prototype sonoporation device. J Ther Ultrasound 2015; 3:19. [PMID: 26550479 PMCID: PMC4636885 DOI: 10.1186/s40349-015-0040-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 10/26/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A device was devised which aimed to reduce the time and expertise required to perform sonoporation on adherent cell cultures. This prototype device was used to examine the superficial effect of bath temperature on sonoporation efficacy. METHODS The prototype device consisted of six ultrasound transducers affixed beneath an Opticell stage. Six transducers with nominal diameters of 20 mm were constructed and the acoustic field of each was characterized using hydrophone scanning. A near field treatment plane was chosen for each transducer to minimize field heterogeneity in the near field. Cervical cancer-derived SiHa cells were exposed to nine different treatments in the presence of plasmid DNA-expressing green fluorescent protein (GFP). Ultrasound treatment with Definity ultrasound contrast agent (US+UCA) present, ultrasound treatment without contrast agent present (US), and a sham ultrasound treatment in the presence of ultrasound contrast agent (CA) were each performed at bath temperatures of 37, 39.5, and 42 °C. Each treatment was performed in biological triplicate. GFP expression and PARP expression following treatment were measured using fluorescent microscopy and digital image processing. Cell detachment was measured using phase contrast microscopy before and after treatment. RESULTS Mean (± s.d.) transfection rates for the US+UCA treatment were 5.4(±0.92), 5.8(±1.3), and 5.3(±1.1) % at 37, 39.5, and 42 °C, respectively. GFP expression and cell detachment were both significantly affected by the presence of ultrasound contrast agent (p < 0.001, p < 0.001). Neither GFP expression, PARP expression, or detachment differed significantly between bath temperatures. CONCLUSIONS Bath temperature did not impact the efficacy of sonoporation treatment on SiHa cells in vitro. The prototype device was found to be suitable for performing sonoporation on adherent cell cultures and will reduce the time and expertise required for conducting sonoporation experiments on adherent cell cultures in the future.
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Affiliation(s)
- Jonathan Kivinen
- Department of Electrical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1 Canada.,Image-Guided Interventions, Thunder Bay Regional Research Institute, 980 Oliver Road, Thunder Bay, Ontario, P7B 6V4 Canada
| | - Melissa Togtema
- Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1 Canada.,Probe Development and Biomarker Exploration, Thunder Bay Regional Research Institute, 980 Oliver Road, Thunder Bay, Ontario, P7B 6V4 Canada
| | - Gregor Mulzer
- Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1 Canada.,Probe Development and Biomarker Exploration, Thunder Bay Regional Research Institute, 980 Oliver Road, Thunder Bay, Ontario, P7B 6V4 Canada
| | - Joshua Choi
- Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1 Canada
| | - Ingeborg Zehbe
- Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1 Canada.,Probe Development and Biomarker Exploration, Thunder Bay Regional Research Institute, 980 Oliver Road, Thunder Bay, Ontario, P7B 6V4 Canada
| | - Laura Curiel
- Department of Electrical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1 Canada.,Image-Guided Interventions, Thunder Bay Regional Research Institute, 980 Oliver Road, Thunder Bay, Ontario, P7B 6V4 Canada
| | - Samuel Pichardo
- Department of Electrical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1 Canada.,Image-Guided Interventions, Thunder Bay Regional Research Institute, 980 Oliver Road, Thunder Bay, Ontario, P7B 6V4 Canada
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31
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Gourevich D, Volovick A, Dogadkin O, Wang L, Mulvana H, Medan Y, Melzer A, Cochran S. In Vitro Investigation of the Individual Contributions of Ultrasound-Induced Stable and Inertial Cavitation in Targeted Drug Delivery. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:1853-64. [PMID: 25887690 DOI: 10.1016/j.ultrasmedbio.2015.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 03/01/2015] [Accepted: 03/11/2015] [Indexed: 05/23/2023]
Abstract
Ultrasound-mediated targeted drug delivery is a therapeutic modality under development with the potential to treat cancer. Its ability to produce local hyperthermia and cell poration through cavitation non-invasively makes it a candidate to trigger drug delivery. Hyperthermia offers greater potential for control, particularly with magnetic resonance imaging temperature measurement. However, cavitation may offer reduced treatment times, with real-time measurement of ultrasonic spectra indicating drug dose and treatment success. Here, a clinical magnetic resonance imaging-guided focused ultrasound surgery system was used to study ultrasound-mediated targeted drug delivery in vitro. Drug uptake into breast cancer cells in the vicinity of ultrasound contrast agent was correlated with occurrence and quantity of stable and inertial cavitation, classified according to subharmonic spectra. During stable cavitation, intracellular drug uptake increased by a factor up to 3.2 compared with the control. Reported here are the value of cavitation monitoring with a clinical system and its subsequent employment for dose optimization.
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Affiliation(s)
- Dana Gourevich
- Institute for Medical Science and Technology, School of Medicine, University of Dundee, Dundee, United Kingdom; Capsutech Ltd., Nazareth, Israel
| | - Alexander Volovick
- Institute for Medical Science and Technology, School of Medicine, University of Dundee, Dundee, United Kingdom; InSightec Ltd., Haifa, Israel
| | - Osnat Dogadkin
- Institute for Medical Science and Technology, School of Medicine, University of Dundee, Dundee, United Kingdom; InSightec Ltd., Haifa, Israel
| | - Lijun Wang
- Institute for Medical Science and Technology, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Helen Mulvana
- School of Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Yoav Medan
- Department of Biomedical Engineering, Technion, Haifa, Israel
| | - Andreas Melzer
- Institute for Medical Science and Technology, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Sandy Cochran
- Institute for Medical Science and Technology, School of Medicine, University of Dundee, Dundee, United Kingdom.
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32
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Zhou Z, Wu W, Wu S, Xia J, Wang CY, Yang C, Lin CC, Tsui PH. A survey of ultrasound elastography approaches to percutaneous ablation monitoring. Proc Inst Mech Eng H 2014; 228:1069-82. [DOI: 10.1177/0954411914554438] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Percutaneous thermal ablation has been widely used as a minimally invasive treatment for tumors. Treatment monitoring is essential for preventing complications while ensuring treatment efficacy. Mechanical testing measurements on tissue reveal that tissue stiffness increases with temperature and ablation duration. Different types of imaging methods can be used to monitor ablation procedures, including temperature or thermal strain imaging, strain imaging, modulus imaging, and shear modulus imaging. Ultrasound elastography demonstrates the potential to become the primary imaging modality for monitoring percutaneous ablation. This review briefly presented the state-of-the-art ultrasound elastography approaches for monitoring radiofrequency ablation and microwave ablation. These techniques were divided into four groups: quasi-static elastography, acoustic radiation force elastography, sonoelastography, and applicator motion elastography. Their advantages and limitations were compared and discussed. Future developments were proposed with respect to heat-induced bubbles, tissue inhomogeneities, respiratory motion, three-dimensional monitoring, multi-parametric monitoring, real-time monitoring, experimental data center for percutaneous ablation, and microwave ablation monitoring.
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Affiliation(s)
- Zhuhuang Zhou
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Weiwei Wu
- College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing, China
| | - Shuicai Wu
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Jingjing Xia
- School of Electronic Information Engineering, Tianjin University, Tianjin, China
| | - Chiao-Yin Wang
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chunlan Yang
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Chung-Chih Lin
- Department of Computer Science and Information Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Po-Hsiang Tsui
- Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Medical Image Research Center, Institute for Radiological Research, Chang Gung University, Taoyuan, Taiwan
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Shekhar H, Rychak JJ, Doyley MM. Modifying the size distribution of microbubble contrast agents for high-frequency subharmonic imaging. Med Phys 2014; 40:082903. [PMID: 23927358 DOI: 10.1118/1.4813017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Subharmonic imaging is of interest for high frequency (>10 MHz) nonlinear imaging, because it can specifically detect the response of ultrasound contrast agents (UCA). However, conventional UCA produce a weak subharmonic response at high frequencies, which limits the sensitivity of subharmonic imaging. We hypothesized that modifying the size distribution of the agent can enhance its high-frequency subharmonic response. The overall goal of this study was to investigate size-manipulated populations of the agent to determine the range of sizes that produce the strongest subharmonic response at high frequencies (in this case, 20 MHz). A secondary goal was to assess whether the number or the volume-weighted size distribution better represents the efficacy of the agent for high-frequency subharmonic imaging. METHODS The authors created six distinct agent size distributions from the native distribution of a commercially available UCA (Targestar-P®). The median (number-weighted) diameter of the native agent was 1.63 μm, while the median diameters of the size-manipulated populations ranged from 1.35 to 2.99 μm. The authors conducted acoustic measurements with native and size-manipulated agent populations to assess their subharmonic response to 20 MHz excitation (pulse duration 1.5 μs, pressure amplitudes 100-398 kPa). RESULTS The results showed a considerable difference between the subharmonic response of the agent populations that were investigated. The subharmonic response peaked for the agent population with a median diameter of 2.15 μm, which demonstrated a subharmonic signal that was 8 dB higher than the native agent. Comparing the subharmonic response of different UCA populations indicated that microbubbles with diameters between 1.3 and 3 μm are the dominant contributors to the subharmonic response at 20 MHz. Additionally, a better correlation was observed between the subharmonic response of the agent and the number-weighted size-distribution (R2=0.98) than with the volume-weighted size distribution (R2=0.53). CONCLUSIONS Modifying the size distribution of the agent appears to be a viable strategy to improve the sensitivity of high-frequency subharmonic imaging. In addition, when the size distribution of the UCA has not been suitably modified, the number-weighted size distribution is a useful parameter to accurately describe the efficacy of the agent for high-frequency subharmonic imaging.
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Affiliation(s)
- Himanshu Shekhar
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627, USA
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Gupta I. Investigating the Influence of the Physiological Environment on Quantitative Contrast-enhanced Ultrasound Imaging. J Med Ultrasound 2014. [DOI: 10.1016/j.jmu.2013.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Raymond JL, Haworth KJ, Bader KB, Radhakrishnan K, Griffin JK, Huang SL, McPherson DD, Holland CK. Broadband attenuation measurements of phospholipid-shelled ultrasound contrast agents. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:410-21. [PMID: 24262056 PMCID: PMC4026002 DOI: 10.1016/j.ultrasmedbio.2013.09.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 09/03/2013] [Accepted: 09/13/2013] [Indexed: 05/04/2023]
Abstract
The aim of this study was to characterize the frequency-dependent acoustic attenuation of three phospholipid-shelled ultrasound contrast agents (UCAs): Definity, MicroMarker and echogenic liposomes. A broadband through-transmission technique allowed for measurement over 2 to 25 MHz with a single pair of transducers. Viscoelastic shell parameters of the UCAs were estimated using a linearized model developed by N. de Jong, L. Hoff, T. Skotland and N. Bom (Ultrasonics 1992; 30:95-103). The effect of diluent on the attenuation of these UCA suspensions was evaluated by performing attenuation measurements in 0.5% (w/v) bovine serum albumin and whole blood. Changes in attenuation and shell parameters of the UCAs were investigated at room temperature (25°C) and physiologic temperature (37°C). The attenuation of the UCAs diluted in 0.5% (w/v) bovine serum albumin was found to be identical to the attenuation of UCAs in whole blood. For each UCA, attenuation was higher at 37°C than at 25°C, underscoring the importance of conducting characterization studies at physiologic temperature. Echogenic liposomes exhibited a larger increase in attenuation at 37°C versus 25°C than either Definity or MicroMarker.
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Affiliation(s)
- Jason L Raymond
- Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA.
| | - Kevin J Haworth
- Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA; Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Kenneth B Bader
- Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | | | - Joseph K Griffin
- Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA
| | - Shao-Ling Huang
- Division of Cardiology, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - David D McPherson
- Division of Cardiology, Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Christy K Holland
- Biomedical Engineering Program, University of Cincinnati, Cincinnati, Ohio, USA; Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA
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36
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Ultrasound assisted particle and cell manipulation on-chip. Adv Drug Deliv Rev 2013; 65:1600-10. [PMID: 23906935 DOI: 10.1016/j.addr.2013.07.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 07/15/2013] [Accepted: 07/18/2013] [Indexed: 11/21/2022]
Abstract
Ultrasonic fields are able to exert forces on cells and other micron-scale particles, including microbubbles. The technology is compatible with existing lab-on-chip techniques and is complementary to many alternative manipulation approaches due to its ability to handle many cells simultaneously over extended length scales. This paper provides an overview of the physical principles underlying ultrasonic manipulation, discusses the biological effects relevant to its use with cells, and describes emerging applications that are of interest in the field of drug development and delivery on-chip.
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Herold IHF, Russo G, Mischi M, Houthuizen P, Saidov T, van het Veer M, van Assen HC, Korsten HHM. Volume quantification by contrast-enhanced ultrasound: an in-vitro comparison with true volumes and thermodilution. Cardiovasc Ultrasound 2013; 11:36. [PMID: 24134671 PMCID: PMC4015786 DOI: 10.1186/1476-7120-11-36] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 10/14/2013] [Indexed: 12/02/2022] Open
Abstract
Background Contrast-enhanced ultrasound (CEUS) has recently been proposed as a minimally- invasive, alternative method for blood volume measurement. This study aims at comparing the accuracy of CEUS and the classical thermodilution techniques for volume assessment in an in-vitro set-up. Methods The in-vitro set-up consisted of a variable network between an inflow and outflow tube and a roller pump. The inflow and outflow tubes were insonified with an ultrasound array transducer and a thermistor was placed in each tube. Indicator dilution curves were made by injecting indicator which consisted of an ultrasound-contrast-agent diluted in ice-cold saline. Both acoustic intensity- and thermo-dilution curves were used to calculate the indicator mean transit time between the inflow and outflow tube. The volumes were derived by multiplying the estimated mean transit time by the flow rate. We compared the volumes measured by CEUS with the true volumes of the variable network and those measured by thermodilution by Bland-Altman and intraclass-correlation analysis. Results The measurements by CEUS and thermodilution showed a very strong correlation (rs = 0.94) with a modest volume underestimation by CEUS of −40 ± 28 mL and an overestimation of 84 ± 62 mL by thermodilution compared with the true volumes. Both CEUS and thermodilution showed a high statistically significant correlation with the true volume (rs = 0.97 (95% CI, 0.95 - 0.98; P<0.0001) and rs = 0.96 (95% CI, 0.94 - 0.98; P<0.0001, respectively). Conclusions CEUS volume estimation provides a strong correlation with both the true volumes in-vitro and volume estimation by thermodilution. It may therefore represent an interesting alternative to the standard, invasive thermodilution technique.
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Affiliation(s)
- Ingeborg H F Herold
- Department of Anesthesia and Intensive Care, Catharina hospital Eindhoven, Michelangelolaan 2, Eindhoven 5623 EJ, The Netherlands.
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O'Brien JP, Stride E, Ovenden N. Surfactant shedding and gas diffusion during pulsed ultrasound through a microbubble contrast agent suspension. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 134:1416-27. [PMID: 23927137 DOI: 10.1121/1.4812860] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Interest in coated microbubbles as agents for therapeutic and quantitative imaging applications in biomedical ultrasound has increased the need for their accurate theoretical characterization. Effects such as gas diffusion, variation in the properties of the coating and the resulting changes in bubble behavior under repeated exposure to ultrasound pulses are, however, still not well understood. In this study, a revised equation for microbubble motion is proposed that includes the effects of gas diffusion, as well as adsorption, desorption and shedding of a surfactant from the bubble surface. This is incorporated into a nonlinear wave propagation model to account for these additional time dependent effects in the response of microbubble populations. The results from the model indicate there can be significant changes in both bubble behavior and the propagated pulse over time. This is in agreement with existing experimental data but is not predicted by existing propagation models. The analysis indicates that changes in bubble dynamics are dominated by surfactant shedding on the timescale of a diagnostic ultrasound pulse and gas diffusion over the timescale of the pulse repetition frequency. The implications of these results for the development of more accurate algorithms for quantitative imaging and for therapeutic applications are discussed.
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Affiliation(s)
- Jean-Pierre O'Brien
- Department of Mathematics, University College London, Gower Street, London WC1E 6BT, United Kingdom
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Tokarczyk A, Rivens I, van Bavel E, Symonds-Tayler R, ter Haar G. An experimental system for the study of ultrasound exposure of isolated blood vessels. Phys Med Biol 2013; 58:2281-304. [PMID: 23478592 DOI: 10.1088/0031-9155/58/7/2281] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
An experimental system designed for the study of the effects of diagnostic or therapeutic ultrasound exposure on isolated blood vessels in the presence or absence of intraluminal contrast agent is described. The system comprised several components. A microscope was used to monitor vessel size (and thus vessel functionality), and potential leakage of intraluminal 70 kDa FITC-dextran fluorescence marker. A vessel chamber allowed the mounting of an isolated vessel whilst maintaining its viability, with pressure regulation for the control of intraluminal pressure and induction of flow for the infusion of contrast microbubbles. A fibre-optic hydrophone sensor mounted on the vessel chamber using a micromanipulator allowed pre-exposure targeting of the vessel to within 150 µm, and monitoring of acoustic cavitation emissions during exposures. Acoustic cavitation was also detected using changes in the ultrasound drive voltage and by detection of audible emissions using a submerged microphone. The suitability of this system for studying effects in the isolated vessel model has been demonstrated using a pilot study of 6 sham exposed and 18 high intensity focused ultrasound exposed vessels, with or without intraluminal contrast agent (SonoVue) within the vessels.
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Affiliation(s)
- Anna Tokarczyk
- Therapeutic Ultrasound, Joint Department of Physics, Royal Marsden NHS Foundation Trust: Institute of Cancer Research, Downs Road, Sutton, Surrey, SM2 5PT, UK
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Radhakrishnan K, Haworth KJ, Huang SL, Klegerman ME, McPherson DD, Holland CK. Stability of echogenic liposomes as a blood pool ultrasound contrast agent in a physiologic flow phantom. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:1970-81. [PMID: 22929652 PMCID: PMC4919816 DOI: 10.1016/j.ultrasmedbio.2012.06.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 06/19/2012] [Accepted: 06/28/2012] [Indexed: 05/09/2023]
Abstract
Echogenic liposomes (ELIP) are multifunctional ultrasound contrast agents (UCAs) with a lipid shell encapsulating both air and an aqueous core. ELIP are being developed for molecular imaging and image-guided therapeutic delivery. Stability of the echogenicity of ELIP in physiologic conditions is crucial to their successful translation to clinical use. In this study, we determined the effects of the surrounding media's dissolved air concentration, temperature transition and hydrodynamic pressure on the echogenicity of a chemically modified formulation of ELIP to promote stability and echogenicity. ELIP samples were diluted in porcine plasma or whole blood and pumped through a pulsatile flow system with adjustable hydrodynamic pressures and temperature. B-mode images were acquired using a clinical diagnostic scanner every 5 s for a total duration of 75 s. Echogenicity in porcine plasma was assessed as a function of total dissolved gas saturation. ELIP were added to plasma at room temperature (22 °C) or body temperature (37 °C) and pumped through a system maintained at 22 °C or 37 °C to study the effect of temperature transitions on ELIP echogenicity. Echogenicity at normotensive (120/80 mmHg) and hypertensive pressures (145/90 mmHg) was measured. ELIP were echogenic in plasma and whole blood at body temperature under normotensive to hypertensive pressures. Warming of samples from room temperature to body temperature did not alter echogenicity. However, in plasma cooled rapidly from body temperature to room temperature or in degassed plasma, ELIP lost echogenicity within 20 s at 120/80 mmHg. The stability of echogenicity of a modified ELIP formulation was determined in vitro at body temperature, physiologic gas concentration and throughout the physiologic pressure range. However, proper care should be taken to ensure that ELIP are not cooled rapidly from body temperature to room temperature as they will lose their echogenic properties. Further in vivo investigations will be needed to evaluate the optimal usage of ELIP as blood pool contrast agents.
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Affiliation(s)
- Kirthi Radhakrishnan
- Department of Internal Medicine, Division of Cardiovascular Diseases, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0586, USA.
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Mulvana H, Browning RJ, Tang MX, Hajnal JV, Eckersley RJ. Albumin coated microbubble optimization: custom fabrication and comprehensive characterization. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:1599-1607. [PMID: 22763010 DOI: 10.1016/j.ultrasmedbio.2012.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 04/26/2012] [Accepted: 05/07/2012] [Indexed: 06/01/2023]
Abstract
Gas microbubbles are used routinely to improve contrast in medical diagnostic imaging. The emerging fields of microbubble-enhanced quantitative imaging and microbubble-enhanced drug delivery have further enhanced the drive toward microbubble characterization and design techniques. The quest to improve efficiency, particularly in the field of drug delivery, presents a requirement to develop methods to manipulate microbubble properties to improve utility. This article presents an investigation in to the feasibility of influencing albumin shelled microbubble properties through the variation of albumin availability during fabrication. Microbubbles were fabricated from albumin suspensions of varying concentration before thorough physical and acoustic characterization. Microbubbles with shells fabricated from a 2% albumin suspension had a greater scattering to attenuation ratio (STAR) than 10% albumin preparations (4.4% and 2.2%, respectively) and approximately double the nonlinear STAR (from 0.7% to 1.5%). The 2% microbubbles also exhibited greater (up to 40%), more violent radial oscillations during high speed imaging than 5% and 10% preparations. The results show that microbubble characteristics can be simply manipulated in the lab and indicate that for a given application this may provide the opportunity to further enhance favorable characteristics.
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Affiliation(s)
- Helen Mulvana
- Department of Imaging Sciences, Imperial College London, United Kingdom
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Browning RJ, Mulvana H, Tang MX, Hajnal JV, Wells DJ, Eckersley RJ. Effect of albumin and dextrose concentration on ultrasound and microbubble mediated gene transfection in vivo. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:1067-1077. [PMID: 22502878 DOI: 10.1016/j.ultrasmedbio.2012.02.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 02/20/2012] [Accepted: 02/20/2012] [Indexed: 05/31/2023]
Abstract
Ultrasound and microbubble mediated gene transfection has great potential for site-selective, safe gene delivery. Albumin-based microbubbles have shown the greatest transfection efficiency but have not been optimised specifically for this purpose. Additionally, few studies have highlighted desirable properties for transfection specific microbubbles. In this article, microbubbles were made with 2% or 5% (w/v) albumin and 20% or 40% (w/v) dextrose solutions, yielding four distinct bubble types. These were acoustically characterised and their efficiency in transfecting a luciferase plasmid (pGL4.13) into female, CD1 mice myocardia was measured. For either albumin concentration, increasing the dextrose concentration increased scattering, attenuation and resistance to ultrasound, resulting in significantly increased transfection. A significant interaction was noted between albumin and dextrose; 2% albumin bubbles made with 20% dextrose showed the least transfection but the most transfection with 40% dextrose. This trend was seen for both nonlinear scattering and attenuation behaviour but not for resistance to ultrasound or total scatter. We have determined that the attenuation behaviour is an important microbubble characteristic for effective gene transfection using ultrasound. Microbubble behaviour can also be simply controlled by altering the initial ingredients used during manufacture.
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Affiliation(s)
- Richard J Browning
- Imaging Sciences Department, Imperial College London, Hammersmith Hospital, London, UK.
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Mulvana H, Stride E, Tang MX, Hajnal JV, Eckersley RJ. The influence of gas saturation on microbubble stability. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:1097-1100. [PMID: 22475697 DOI: 10.1016/j.ultrasmedbio.2012.02.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 02/08/2012] [Accepted: 02/09/2012] [Indexed: 05/31/2023]
Abstract
Accurate acoustic characterisation is an essential component of any experimental investigation concerning the use and development of microbubble contrast agents. It is of increasing importance as applications such as therapy and molecular and quantitative imaging are investigated. Such characterisation is generally conducted in the laboratory in the form of bulk acoustic studies or optical observation of single bubbles using high speed photography in a water tank containing "out-gassed" water. The approach is widely used in acoustics to prevent inaccurate measurements being made due to the presence of gas bubbles settling on instrumentation, however, the term is often used to cover a range of water preparation techniques and the final gas content of the water is not usually stated. This technical note demonstrates the influence of gas content on the stability of microbubble contrast agents and concludes that characterisation should always be conducted in equilibrated, gas-saturated water to ensure accurate and repeatable measurements are made.
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Affiliation(s)
- Helen Mulvana
- Imaging Sciences, Imperial College London, London, United Kingdom
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Mulvana H, Eckersley RJ, Tang MX, Pankhurst Q, Stride E. Theoretical and experimental characterisation of magnetic microbubbles. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:864-875. [PMID: 22480944 DOI: 10.1016/j.ultrasmedbio.2012.01.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 01/26/2012] [Accepted: 01/27/2012] [Indexed: 05/31/2023]
Abstract
In addition to improving image contrast, microbubbles have shown great potential in molecular imaging and drug/gene delivery. Previous work by the authors showed that considerable improvements in gene transfection efficiency were obtained using microbubbles loaded with magnetic nanoparticles under simultaneous exposure to ultrasound and magnetic fields. The aim of this study was to characterise the effect of nanoparticles on the dynamic and acoustic response of the microbubbles. High-speed video microscopy indicated that the amplitude of oscillation was very similar for magnetic and nonmagnetic microbubbles of the same size for the same ultrasound exposure (0.5 MHz, 100 kPa, 12-cycle pulse) and that this was minimally affected by an imposed magnetic field. The linear scattering to attenuation ratio (STAR) was also similar for suspensions of both bubble types although the nonlinear STAR was ~50% lower for the magnetic microbubbles. Both the video and acoustic data were supported by the results from theoretical modelling.
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Affiliation(s)
- Helen Mulvana
- Department of Imaging Sciences, Imperial College London, London, United Kingdom
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Sennoga CA, Yeh JSM, Alter J, Stride E, Nihoyannopoulos P, Seddon JM, Haskard DO, Hajnal JV, Tang MX, Eckersley RJ. Evaluation of methods for sizing and counting of ultrasound contrast agents. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:834-45. [PMID: 22402020 PMCID: PMC3657178 DOI: 10.1016/j.ultrasmedbio.2012.01.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 12/31/2011] [Accepted: 01/13/2012] [Indexed: 05/15/2023]
Abstract
A precise, accurate and well documented method for the sizing and counting of microbubbles is essential for all aspects of quantitative microbubble-enhanced ultrasound imaging. The efficacy of (a) electro-impedance volumetric zone sensing (ES) also called a Coulter counter/multisizer; (b) optical microscopy (OM); and (c) laser diffraction (LD), for the sizing and counting of microbubbles was assessed. Microspheres with certified mean diameter and number concentration were used to assess sizing and counting reproducibility (precision) and reliability (accuracy) of ES, OM and LD. SonoVue™ was repeatedly (n = 3) sized and counted to validate ES, OM and LD sizing and counting efficacy. Statistical analyses of intra-method variability for the SonoVue™ mean diameter showed that the best microbubble sizing reproducibility was obtained using OM with a mean diameter sizing variability of 1.1%, compared with a variability of 4.3% for ES and 7.1% for LD. The best microbubble counting reproducibility was obtained using ES with a number concentration variability of 8.3%, compared with a variability of 22.4% for OM and 32% for LD. This study showed that no method is fully suited to both sizing and counting of microbubbles.
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Affiliation(s)
- Charles A Sennoga
- Imaging Sciences Department, Imperial College London, Hammersmith Campus, London, United Kingdom.
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Mulvana H, Stride E, Tang M, Hajnal JV, Eckersley R. Temperature-dependent differences in the nonlinear acoustic behavior of ultrasound contrast agents revealed by high-speed imaging and bulk acoustics. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:1509-17. [PMID: 21741759 DOI: 10.1016/j.ultrasmedbio.2011.05.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 05/16/2011] [Accepted: 05/16/2011] [Indexed: 05/21/2023]
Abstract
Previous work by the authors has established that increasing the temperature of the suspending liquid from 20°C to body temperature has a significant impact on the bulk acoustic properties and stability of an ultrasound contrast agent suspension (SonoVue, Bracco Suisse SA, Manno, Lugano, Switzerland). In this paper the influence of temperature on the nonlinear behavior of microbubbles is investigated, because this is one of the most important parameters in the context of diagnostic imaging. High-speed imaging showed that raising the temperature significantly influences the dynamic behavior of individual microbubbles. At body temperature, microbubbles exhibit greater radial excursion and oscillate less spherically, with a greater incidence of jetting and gas expulsion, and therefore collapse, than they do at room temperature. Bulk acoustics revealed an associated increase in the harmonic content of the scattered signals. These findings emphasize the importance of conducting laboratory studies at body temperature if the results are to be interpreted for in vivo applications.
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Affiliation(s)
- Helen Mulvana
- Imaging Sciences Department, Imperial College Hammersmith Hospital, London, UK.
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Tang MX, Mulvana H, Gauthier T, Lim AKP, Cosgrove DO, Eckersley RJ, Stride E. Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability. Interface Focus 2011; 1:520-39. [PMID: 22866229 PMCID: PMC3262271 DOI: 10.1098/rsfs.2011.0026] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 04/26/2011] [Indexed: 12/14/2022] Open
Abstract
Ultrasound provides a valuable tool for medical diagnosis offering real-time imaging with excellent spatial resolution and low cost. The advent of microbubble contrast agents has provided the additional ability to obtain essential quantitative information relating to tissue vascularity, tissue perfusion and even endothelial wall function. This technique has shown great promise for diagnosis and monitoring in a wide range of clinical conditions such as cardiovascular diseases and cancer, with considerable potential benefits in terms of patient care. A key challenge of this technique, however, is the existence of significant variations in the imaging results, and the lack of understanding regarding their origin. The aim of this paper is to review the potential sources of variability in the quantification of tissue perfusion based on microbubble contrast-enhanced ultrasound images. These are divided into the following three categories: (i) factors relating to the scanner setting, which include transmission power, transmission focal depth, dynamic range, signal gain and transmission frequency, (ii) factors relating to the patient, which include body physical differences, physiological interaction of body with bubbles, propagation and attenuation through tissue, and tissue motion, and (iii) factors relating to the microbubbles, which include the type of bubbles and their stability, preparation and injection and dosage. It has been shown that the factors in all the three categories can significantly affect the imaging results and contribute to the variations observed. How these factors influence quantitative imaging is explained and possible methods for reducing such variations are discussed.
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Affiliation(s)
- M.-X. Tang
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
| | - H. Mulvana
- Imaging Sciences Department, Faculty of Medicine, Imperial College London, London W12 0HS, UK
| | - T. Gauthier
- Department of Experimental Medicine and Toxicology, Hammersmith Hospital, Imperial College London, London W12 0NN, UK
| | - A. K. P. Lim
- Hammersmith Hospital, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - D. O. Cosgrove
- Imaging Sciences Department, Faculty of Medicine, Imperial College London, London W12 0HS, UK
| | - R. J. Eckersley
- Imaging Sciences Department, Faculty of Medicine, Imperial College London, London W12 0HS, UK
| | - E. Stride
- Department Mechanical Engineering, University College London, London WC1E 7JE, UK
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