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Harriet Lea-Banks, Boon Teo, Eleanor Stride, Constantin C Coussios
A significant barrier to successful drug delivery is the limited penetration of nanoscale therapeutics beyond the vasculature. Building on recent in vivo findings in the context of cancer drug delivery, the current study investigates whether modification of nanoparticle drug-carriers to increase their density can be used to enhance their penetration into viscoelastic materials under ultrasound exposure. A computational model is first presented to predict the transport of identically sized nanoparticles of different densities in an ultrasonic field in the presence of an oscillating microbubble, by a combination of primary and secondary acoustic radiation forces, acoustic streaming and microstreaming...
November 21, 2016: Physics in Medicine and Biology
Yi Zhang, Chao Yang, Jian-Zhong Zou, Fei Chen, Xia Ou, Hai-Rong Zou, Yan Wang
OBJECTIVE: To compare the effect of low-dose focused ultrasound pre-irradiation and microbubbles for enhancing the ablation effect of high intensity focused ultrasound (HIFU) on VX2 hepatic tumor in rabbits. METHODS: Fifty-five rabbits bearing VX2 hepatic tumor were randomly divided into low-dose pre-irradiation + HIFU ablation group, microbubbles+HIFU ablation group, and HIFU ablation group for corresponding treatments. The pathological changes in the tumors after low-dose irradiation, time for HIFU ablation, tumor volume with coagulative necrosis, energy efficiency factor (EEF), pathological changes in the ablated tumor, and sound channel of HIFU ablation were observed...
October 20, 2016: Nan Fang Yi Ke da Xue Xue Bao, Journal of Southern Medical University
Ting Zhang, Zhong-Zhen Su, Ping Wang, Tao Wu, Wen Tang, Er-Jiao Xu, Jin-Xiu Ju, Xian-Yue Quan, Rong-Qin Zheng
PURPOSE: To investigate the value of double contrast-enhanced ultrasonography (DCEUS) in the detection of periampullary cancer. MATERIALS AND METHODS: Ninety-nine patients with surgery or biopsy-proven periampullary cancer who underwent both DCEUS and magnetic resonance imaging (MRI) examinations before operation were enrolled in our study. DCEUS in which intravenous microbubbles were used in combination with oral contrast agent and MRI were performed preoperatively to make a detection diagnosis of periampullary cancer...
November 2016: European Journal of Radiology
Zhuochen Wang, Karl Heath Martin, Wenbin Huang, Paul A Dayton, Xiaoning Jiang
Techniques to image the microvasculature may play an important role in imaging tumor-related angiogenesis and vasa vasorum associated with vulnerable atherosclerotic plaques. However, the microvasculature associated with these pathologies is difficult to detect using traditional B-mode ultrasound or even harmonic imaging due to small vessel size and poor differentiation from surrounding tissue. Acoustic angiography, a microvascular imaging technique which utilizes superharmonic imaging (detection of higher order harmonics of microbubble response), can yield a much higher contrast to tissue ratio (CTR) than second harmonic imaging methods...
October 20, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Paul S Sheeran, Naomi Matsuura, Mark A Borden, Ross Williams, Terry O Matsunaga, Peter N Burns, Paul A Dayton
Continued advances in the field of ultrasound and ultrasound contrast agents have created new approaches to imaging and medical intervention. Phase-shift perfluorocarbon droplets, which can be vaporized by ultrasound energy to transition from the liquid to the vapor state, are one of the most highly researched alternatives to clinical ultrasound contrast agents (i.e. microbubbles). In this review, part of a special issue on methods in biomedical ultrasonics, we survey current techniques to prepare ultrasound-activated nanoscale phase-shift perfluorocarbon droplets, including sonication, extrusion, homogenization, microfluidics, and microbubble condensation...
October 20, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Dongxiao Wang, Wanxian Luo, Ge Wen, Li Yang, Shaofu Hong, Shiyu Zhang, Jianxin Diao, Jianguo Wang, Hongqin Wei, Yingjia Li, Ying Wang
We have fabricated a negative-charged nanoparticle (Heparin-Folate-Tat-Taxol NP, H-F-Tat-T NP) with dual ligands, tumor targeting ligand folate and cell-penetrating peptide Tat, to deliver taxol presenting great anticancer activity for sensitive cancer cells, while it fails to overcome multidrug resistance (MDR) in MCF-7/T cells (taxol-resistant breast cancer cells). Ultrasound (US) can increase the sensitivity of positive-charged NPs thereby making it possible to reverse MDR through inducing NPs' drug release...
January 2017: Ultrasonics Sonochemistry
Siyuan Zhang, Zhiwei Cui, Tianqi Xu, Pan Liu, Dapeng Li, Shaoqiang Shang, Ranxiang Xu, Yujin Zong, Gang Niu, Supin Wang, Xijing He, Mingxi Wan
This paper compared the effects of flowing phase-shift nanodroplets (NDs) and lipid-shelled microbubbles (MBs) on subsequent cavitation during focused ultrasound (FUS) exposures. The cavitation activity was monitored using a passive cavitation detection method as solutions of either phase-shift NDs or lipid-shelled MBs flowed at varying velocities through a 5-mm diameter wall-less vessel in a transparent tissue-mimicking phantom when exposed to FUS. The intensity of cavitation for the phase-shift NDs showed an upward trend with time and cavitation for the lipid-shelled MBs grew to a maximum at the outset of the FUS exposure followed by a trend of decreases when they were static in the vessel...
January 2017: Ultrasonics Sonochemistry
N Platz Batista da Silva, M Schauer, M Hornung, S Lang, L P Beyer, I Wiesinger, C Stroszczynski, E M Jung
OBJECTIVE: To evaluate the efficacy of strain elastography (SE) using semi-quantitative measurement methods compared to constrast enhanced ultrasound during liver tumor surgery (Io-CEUS) for dignity assessment of focal liver lesions(FLL). MATERIAL AND METHODS: Prospective data acquisition and retrospective analysis of US data of 100 patients (116 lesions) who underwent liver tumor surgery between 10/2010 and 03/2016. Retrospective reading of SE color patterns was performed establishing groups depending on dominant color (>50% blue = stiff, inhomogenous, >50% yellow/red/green = soft tissue)...
October 20, 2016: Clinical Hemorheology and Microcirculation
Jinshun Xu, Yang Cao, Chunyan Xu, Xueqing Cheng, Yufeng You, Yuanzhi Yao, Jianxin Liu, Zhigang Wang, Pan Li, Min Lu
OBJECTIVES: To determine whether combining microbubbles (MBs) with diagnostic ultrasound (US) at a high mechanical index (MI) could enhance the microwave (MW) ablation of tumours. MATERIALS AND METHODS: Five therapeutic MW adjuvant protocols were studied: MW, MW + US, MW + US + MB, MW + US + NS (saline), and MW + MB. In 30 normal rabbit livers, the synergistic effects were evaluated via temperature, necrosis volume and histology. In 90 VX2 rabbit hepatic tumours, residual cells in the peripheral ablated tumours were examined via immunohistochemical assay and tumour growth...
October 20, 2016: International Journal of Hyperthermia
Emmelie Stock, Katrien Vanderperren, Hendrik Haers, Luc Duchateau, Myriam Hesta, Jimmy H Saunders
Contrast-enhanced ultrasound is a valuable and safe technique for the evaluation of organ perfusion. Repeated injections of ultrasound contrast agent are often administered during the same imaging session. However, it remains unclear if quantitative differences are present between the consecutive microbubble injections. Therefore, the first and second injection of contrast agent for the left renal cortex, renal medulla and the splenic parenchyma in healthy cats were compared. A lower peak intensity and area under the curve were observed for the first injection of contrast agent in the feline kidney, both for the renal cortex and medulla, and spleen...
October 13, 2016: Ultrasound in Medicine & Biology
Georg Dimcevski, Spiros Kotopoulis, Tormod Bjånes, Dag Hoem, Jan Schjøt, Bjørn Tore Gjertsen, Martin Biermann, Anders Molven, Halfdan Sorbye, Emmet McCormack, Michiel Postema, Odd Helge Gilja
BACKGROUND: The primary aim of our study was to evaluate the safety and potential toxicity of gemcitabine combined with microbubbles under sonication in inoperable pancreatic cancer patients. The secondary aim was to evaluate a novel image-guided microbubble-based therapy, based on commercially available technology, towards improving chemotherapeutic efficacy, preserving patient performance status, and prolonging survival. METHODS: Ten patients were enrolled and treated in this Phase I clinical trial...
October 12, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Juyoung Park, Muna Aryal, Natalia Vykhodtseva, Yong-Zhi Zhang, Nathan McDannold
Drug delivery in brain tumors is challenging because of the presence of blood-brain barrier (BBB) and the blood-tumor barrier (BTB). Focused ultrasound (FUS) combined with microbubbles can enhance the permeability of the BTB in brain tumors, as well as disrupting the BBB in the surrounding tissue. In this study, dynamic contrast-enhanced Magnetic Resonance Imaging (DCE-MRI) was used to characterize FUS-induced permeability changes in a rat glioma model and in the normal brain and to investigate the relationship between these changes and the resulting concentration of the chemotherapy agent doxorubicin (DOX)...
October 11, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Wolfgang Wiedemair, Zeljko Tukovic, Hrvoje Jasak, Dimos Poulikakos, Vartan Kurtcuoglu
Encapsulated microbubbles (MBs) serve as endovascular agents in a wide range of medical ultrasound applications. The oscillatory response of these agents to ultrasonic excitation is determined by MB size, gas content, viscoelastic shell properties and geometrical constraints. The viscoelastic parameters of the MB capsule vary during an oscillation cycle and change irreversibly upon shell rupture. The latter results in marked stress changes on the endothelium of capillary blood vessels due to altered MB dynamics...
October 12, 2016: Biomechanics and Modeling in Mechanobiology
Xiao-Qing Wang, Zhou-Na Li, Qi-Ming Wang, Zhonggao Gao, Zhe-Hu Jin
Keloids were characterized by excessive growth of fibrous tissues, and shared several pathological characteristics with cancer. They did put physical and emotional stress on patients in that keloids could badly change appearance of patients. N-(4-hydroxyphenyl) retinamide (4HPR) showed cytotoxic activity on a wide variety of invasive-growth cells. Our work was aim to prepare N-(4-hydroxyphenyl) retinamide-loaded lipid microbubbles (4HPR-LM) combined with ultrasound for anti-keloid therapy. 4HPR-loaded liposomes (4HPR-L) were first prepared by film evaporation method, and then 4HPR-LM were manufactured by mixing 4HPR-L and perfluoropentane (PFP) with ultrasonic cavitation method...
October 13, 2016: Journal of Liposome Research
Daniel P Herbst
The process of microbubble filtration from blood is complex and highly dependent on the forces of flow and buoyancy. To protect the patient from air emboli, arterial-line filters commonly use a micropore screen, a large volume housing with purpose-built shape, and a purge port to trap, separate, and remove circulating microbubbles. Although it has been proposed that an insufficient buoyancy force renders the purge port ineffective at removing microbubbles smaller than 500 μm, this research attempts to investigate the purge flow of an arterial-line filter to better understand the microbubble removal function in a typical radial filter design...
September 2016: Journal of Extra-corporeal Technology
Paul S Sheeran, Kimoon Yoo, Ross Williams, Melissa Yin, F Stuart Foster, Peter N Burns
Phase-shift perfluorocarbon droplets have been investigated for over 20 years as pre-clinical ultrasound contrast agents with distinctive advantages in imaging and therapy. A number of formulation strategies exist, each with inherent advantages and limitations. In this note, we demonstrate a unique opportunity: that phase-shift droplets can be generated directly from commercially available microbubbles. This may facilitate pre-clinical and translational development by reducing the in-house synthesis expertise and resources required to generate high concentration droplet emulsions...
October 7, 2016: Ultrasound in Medicine & Biology
Ruud Jg van Sloun, Libertario Demi, Arnoud W Postema, Jean Jmch de la Rosette, Hessel Wijkstra, Massimo Mischi
Prostate cancer (PCa) is the second-leading cause of cancer death in men; however, reliable tools for detection and localization are still lacking. Dynamic Contrast Enhanced UltraSound (DCE-US) is a diagnostic tool that is suitable for analysis of vascularization, by imaging an intravenously injected microbubble bolus. The localization of angiogenic vascularization associated with the development of tumors is of particular interest. Recently, methods for the analysis of the bolus convective dispersion process have shown promise to localize angiogenesis...
October 1, 2016: Medical Image Analysis
Siyu Liu, Jun Wu, Yuyang Gu, Xiasheng Guo, Juan Tu, Di Xu, Dong Zhang
The sub-harmonic response generated by oscillating ultrasound contrast microbubbles has been proven to be a potentially efficient and effective measure for non-invasive blood pressure evaluation. In this work, an improved approach to ambient pressure measurement is proposed, and the general principle underlying this approach is the combination of sub-harmonic responses of microbubbles with a chirp excitation technique. Agreement between theoretical and experimental studies indicates that compared with sinusoidal excitation, the chirp technique is beneficial in that it produces bubble sub-harmonics with higher amplitudes and lower generation thresholds and thus offers better sensitivity for ambient pressure evaluations...
October 4, 2016: Ultrasound in Medicine & Biology
Ajay Yadlapati, Mark Gajjar, Daniel R Schimmel, Mark J Ricciardi, James D Flaherty
ST-elevation myocardial infarction (STEMI), which constitutes nearly 25-40 % of current acute myocardial infarction (AMI) cases, is a medical emergency that requires prompt recognition and treatment. Since the 2013 STEMI practice guidelines, a wealth of additional data that may further advance optimal STEMI practices has emerged. These data highlight the importance of improving patient treatment and transport algorithms for STEMI from non-primary percutaneous coronary intervention (PCI) centers. In addition, a focus on the reduction of total pain-to-balloon (P2B) times rather than simply door-to-balloon (D2B) times may further improve outcomes after primary PCI for STEMI...
October 6, 2016: Internal and Emergency Medicine
Yutong Lin, Lizhou Lin, Mouwen Cheng, Lifang Jin, Lianfang Du, Tao Han, Lin Xu, Alfred C H Yu, Peng Qin
SonoVue microbubbles could serve as artificial nuclei for ultrasound-triggered stable and inertial cavitation, resulting in beneficial biological effects for future therapeutic applications. To optimize and control the use of the cavitation of SonoVue bubbles in therapy while ensuring safety, it is important to comprehensively understand the relationship between the acoustic parameters and the cavitation behavior of the SonoVue bubbles. An agarose-gel tissue phantom was fabricated to hold the SonoVue bubble suspension...
September 20, 2016: Ultrasonics Sonochemistry
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