1,001 results on '"Mechanical index"'
Search Results
52. In vivo study of enhanced chemotherapy combined with ultrasound image-guided focused ultrasound (USgFUS) treatment for pancreatic cancer in a xenograft mouse model.
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Park, Eun-Joo, Ahn, Yun Deok, and Lee, Jae Young
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PANCREATIC cancer diagnosis , *PANCREATIC cancer treatment , *CANCER chemotherapy , *XENOGRAFTS , *ULTRASONIC imaging , *LABORATORY mice , *ANIMAL experimentation , *ANIMALS , *BIOLOGICAL models , *COMBINED modality therapy , *MICE , *PANCREAS , *PANCREATIC tumors , *RESEARCH funding , *ULTRASONIC therapy , *PILOT projects , *TREATMENT effectiveness , *TUMOR treatment - Abstract
Objectives: This study was designed to investigate whether focused ultrasound (FUS) treatment with a higher mechanical index (MI) can enhance the effects of combined chemotherapy more than with a lower MI, and to evaluate the feasibility of the chemotherapy combined with FUS at a higher MI as an alternative treatment protocol.Methods: Mice in the first study were divided into six groups: control, chemotherapy only (GEM), two groups treated with FUS only at two different MIs, and two groups treated with chemotherapy and FUS (GEM + FUS). Mice were treated with a single-session treatment; one session consisted of three weekly treatments and 1 week of follow-up monitoring. In the second study, mice were assigned to two groups (GEM, GEM + FUS) and treated with four treatment sessions.Results: In the single-session treatment, tumor growth was most effectively suppressed in GEM + FUS group with a higher MI. Tumor growth rate was significantly lower in GEM + FUS group than in GEM group for multiple-session treatment. Specifically, three of ten mice in GEM + FUS group showed complete remission.Conclusions: This study demonstrated that FUS at a higher MI can enhance chemotherapy outcomes more than at a lower MI and demonstrated the potential of FUS in combination with chemotherapy as a new cancer treatment protocol.Key Points: • Combined treatment of chemotherapy and focused ultrasound can effectively suppress tumor growth. • For the focused ultrasound treatment conditions used in this study, focused ultrasound with relatively higher mechanical index shows more enhanced therapeutic outcomes than with the lower mechanical index. • Combination therapy shows the possibility as a new cancer treatment protocol. [ABSTRACT FROM AUTHOR]- Published
- 2018
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53. Pulmonary Capillary Hemorrhage Induced by Diagnostic Ultrasound in Ventilated Rats.
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Miller, Douglas L., Dong, Zhihong, Dou, Chunyan, and Raghavendran, Krishnan
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PULMONARY function tests , *ULTRASONIC imaging , *AUTOMATIC indexing , *COMET tails , *ARTIFICIAL respiration , *ANIMALS , *BIOLOGICAL models , *CAPILLARIES , *HEMORRHAGE , *LUNGS , *LUNG diseases , *RATS , *RESEARCH funding - Abstract
Pulmonary capillary hemorrhage (PCH) can be induced by diagnostic ultrasound-a potential safety issue. Anesthetized rats were intubated for intermittent positive-pressure ventilation (IPPV) with 0 end-expiratory pressure, +4 cm H2O end-expiratory pressure (PEEP) and -4 cm H2O end-expiratory pressure (NEEP). Rats were imaged at 7.6 MHz with a Philips HDI 5000 ultrasound machine. The output was low (mechanical index [MI] = 0.22) for aiming and then was raised for 5 min in 20 different exposure groups with n = 8. Peak rarefactional pressure amplitudes were measured in water and de-rated for chest attenuation. The PCH areas were measured on the lung surface. At 2.2 MPa, PCH was 9.3 ± 6.6 mm2 for IPPV, 1.6 ± 3.2 mm2 for PEEP (p <0.001) and 26.8 ± 6.4 mm2 for NEEP (p <0.001). Thresholds were 1.3 MPa for IPPV, 2.1 MPa for PEEP and 1.0 MPa for NEEP. The small ventilator pressures subtracted or added to trans-capillary stress generated by diagnostic ultrasound pulses, virtually eliminating PCH for PEEP but enhancing PCH for NEEP. [ABSTRACT FROM AUTHOR]
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- 2018
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54. Maritime environmental performance indicators for urban waterways in Amsterdam.
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Jacobs, F. A. G., Visser, K., and Stapersma, D.
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Owing to new regulations starting from 2025, all commercial canal boats have to comply to zero local emission standards in Amsterdam. It is therefore vital that a clear emission indicator is made available for vessels with a varying operational profile, such as canal boats. In this paper, it is argued that current indicators, such as the Energy Efficiency Design Index, are not suitable for these (passenger) vessels. This paper proposes environmental performance indicators that can quantify emissions, (non-dimensional) energy and fuel usage based on an operational profile set in the design phase. This profile includes part load operation and auxiliary consumers and it can compare new designed concepts with current baseline vessels based on the ‘benefit for society’ of different vessel types. In the proposed environmental performance indicators, several operational modes can be defined, in contrast with the currently proposed Energy Efficiency Design Index, which is a point index at 75% of installed power. To gauge not only local emissions but also global emissions, the environmental performance indicator methodology is used to determine a minimum efficiency from any power generation method. This minimum efficiency follows from a comparison between baseline vessels and concepts that are more energy efficient and emission friendly. The proposed environmental performance indicators were validated using measurements on typical propulsion configurations of canal boats in Amsterdam. Three full electric concepts were designed and compared with the measured baseline vessels. As full electric concepts do not have local emissions, the method of power generation must satisfy the requirement to have less global emissions than the mechanical baseline. Furthermore, an energy efficiency of at least 33% is calculated from a fossil-fuelled land-based power plant (including transport) to the boundary from quay to boat to be required for newly designed electric concepts to be more energy efficient than the mechanical baseline. [ABSTRACT FROM AUTHOR]
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- 2018
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55. Does Intravenous Infusion Influence Diagnostic Ultrasound‐Induced Pulmonary Capillary Hemorrhage?
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Miller, Douglas L., Dong, Zhihong, Dou, Chunyan, and Raghavendran, Krishnan
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INTRAVENOUS therapy ,LUNG disease diagnosis ,HEMORRHAGE diagnosis ,LABORATORY rats ,VETERINARY ultrasonography ,EMERGENCY medicine - Abstract
Objectives: Pulmonary diagnostic ultrasound (US) can induce pulmonary capillary hemorrhage (PCH) in mammals. This singular biological effect of diagnostic US imaging was discovered more than 25 years ago but remains poorly understood. Our objective here was to investigate rapid infusion of intravenous fluids as a possible stressor for capillaries, which might enhance pulmonary diagnostic US‐induced PCH. Methods: Rats were anesthetized with Telazol (Zoetis, Inc, Kalamazoo, MI), which yielded relatively low pulmonary diagnostic US‐induced PCH, or Telazol and xylazine, which yielded relatively high pulmonary diagnostic US‐induced PCH. Groups of rats were not infused or infused either with normal saline, 10% mannitol, or 5% albumin. Rats were scanned in a warmed water bath with B‐mode US for 5 minutes with a 7.6‐MHz linear array set to different mechanical index values to obtain exposure response information. Pulmonary capillary hemorrhage was observed as comet tail artifacts in the image and measured on the lung surface. Results: For Telazol anesthesia, all of the PCH results were very low, with no significant differences at the maximum output with an in situ peak rarefactional pressure amplitude of 2.1 MPa (on‐screen mechanical index, 0.9). The addition of xylazine to the Telazol anesthetic significantly enhanced the PCH (P < .001) without infusion and likewise for the mannitol and albumin infusion. Saline infusion eliminated this enhancement, with significantly reduced PCH for Telazol‐plus‐xylazine anesthesia (P < .001); however, both mannitol and albumin infusion resulted in significantly more PCH than saline infusion (P < .01). Conclusions: These results show PCH dependence on the specific intravenous infusion fluid and illustrate the complex importance of physiologic parameters for US‐induced PCH. [ABSTRACT FROM AUTHOR]
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- 2018
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56. Characterization of Thermal and Mechanical Indices from Serial Ultrasound Exams and Associations with Neonatal Anthropometry: The NICHD Fetal Growth Studies.
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Smarr, Melissa M., Buck Louis, Germaine M., Albert, Paul S., Sungduk Kim, Fuchs, Karin M., Grewal, Jagteshwar, D'Alton, Mary E., and Grantz, Katherine L.
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NAVEL , *THIGH , *ABDOMINAL physiology , *HEAD physiology , *TRICEPS physiology , *CHEST physiology , *ANTHROPOMETRY , *ARM , *BIRTH weight , *DELIVERY (Obstetrics) , *ETHNIC groups , *GESTATIONAL age , *LONGITUDINAL method , *MATERNAL age , *RACE , *ULTRASONIC imaging , *WEIGHT gain , *MULTIPLE regression analysis , *BODY mass index , *FETAL development , *PHYSIOLOGY - Abstract
Objective This article aims to determine if the number of maternal ultrasound scans where the highest thermal (TI) or mechanical (MI) indices recorded during obstetrical ultrasound exceed 1.0 were associated with neonatal anthropometric measurements. Study Design A prospective cohort of 2,334 nonobese low-risk pregnant women from 12 U.S. clinical sites underwent a total of six ultrasound scans, for which the highest TI and MI values were recorded. Neonatal anthropometric measurements were obtained within 12 to 24 hours of delivery. Multiple linear regression models adjusted for maternal race/ ethnicity, body mass index, weight gain, and gestational age were used to examine associations between the number of maternal ultrasounds during gestation with a TI or MI exceeding 1.0 and the mean change in neonatal anthropometry. Results Ultrasounds with TI or MI >1.0 were not associated with birth weight, neonatal length, nor head, chest, and abdominal circumferences. TI >1.0 was negatively associated with neonatal mid-upper arm and mid-upper thigh circumferences. MI >1.0 was negatively associated with neonatal skinfold measurements of the anterior thigh and triceps, and neonatal circumferences of the mid-upper thigh and umbilicus. Conclusion Prenatal ultrasound examinations in which TI or MI intermittently exceeded 1.0 did not identify a pattern of alterations of birth size. [ABSTRACT FROM AUTHOR]
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- 2018
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57. The Dependence of Glomerular Capillary Hemorrhage Induced by Contrast Enhanced Diagnostic Ultrasound on Microbubble Diameter.
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Miller, Douglas L., Lu, Xiaofang, Dou, Chunyan, Fabiilli, Mario L., and Church, Charles C.
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MICROBUBBLES , *HEMORRHAGE , *CAPILLARIES , *ULTRASONIC imaging , *HISTOLOGY - Abstract
A recently proposed two-criterion model for cavitational bioeffects in tissue with microbubbles (MBs) was tested. The glomerular capillary hemorrhage bioeffect was observed in rat kidney for contrast agent MB suspensions with mean diameters of 1.6, 3.1 and 5.5 µm. A diagnostic ultrasound machine was used at 3.6 MHz and 5.5 MHz for intermittent scans at power settings 2 dB apart. Petechial hemorrhage counts scored on the surface of the kidneys, and glomeruli were scored in histology. Thresholds for the petechial hemorrhage measurements were the same for the large and medium MB suspensions but substantially higher for the small MBs. For the histology, the medium MBs gave a higher threshold than the large MBs at 5.5 MHz. The pressure amplitude thresholds are in approximate agreement with theory, and the optimum MB size counterintuitively increased for increasing ultrasound frequency, as predicted. The two-criterion model of MB-associated capillary hemorrhage is supported. [ABSTRACT FROM AUTHOR]
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- 2018
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58. Evaluating the Benefit of Elevated Acoustic Output in Harmonic Motion Estimation in Ultrasonic Shear Wave Elasticity Imaging.
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Deng, Yufeng, Palmeri, Mark L., Rouze, Ned C., Haystead, Clare M., and Nightingale, Kathryn R.
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DIAGNOSTIC ultrasonic imaging , *HARMONIC motion , *SHEAR waves , *ELASTICITY , *LIVER radiography , *SIGNAL-to-noise ratio - Abstract
Harmonic imaging techniques have been applied in ultrasonic elasticity imaging to obtain higher-quality tissue motion tracking data. However, harmonic tracking can be signal-to-noise ratio and penetration depth limited during clinical imaging, resulting in decreased yield of successful shear wave speed measurements. A logical approach is to increase the source pressure, but the in situ pressures used in diagnostic ultrasound have been subject to a de facto upper limit based on the Food and Drug Administration guideline for the mechanical index (MI <1.9). A recent American Institute of Ultrasound in Medicine report concluded that an in situ MI up to 4.0 could be warranted without concern for increased risk of cavitation in non-fetal tissues without gas bodies if there were a concurrent clinical benefit. This work evaluates the impact of using an elevated MI in harmonic motion tracking for hepatic shear wave elasticity imaging. The studies indicate that high-MI harmonic tracking increased shear wave speed estimation yield by 27% at a focal depth of 5 cm, with larger yield increase in more difficult-to-image patients. High-MI tracking improved harmonic tracking data quality by increasing the signal-to-noise ratio and decreasing jitter in the tissue motion data. We conclude that there is clinical benefit to use of elevated acoustic output in shear wave tracking, particularly in difficult-to-image patients. [ABSTRACT FROM AUTHOR]
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- 2018
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59. Focal Liver Lesion: Nonlinear Contrast-Enhanced Ultrasound Imaging
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Migaleddu, Vincenzo, Virgilio, Giuseppe, and Hayat, M. A., editor
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- 2009
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60. Hepatocellular Carcinoma: Contrast-Enhanced Sonography
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Choi, Byung Ihn, Kim, Se Hyung, and Hayat, M. A., editor
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- 2009
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61. Improved Modelling of Ultrasound Contrast Agent Diminution for Blood Perfusion Analysis
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Kier, Christian, Meyer-Wiethe, Karsten, Seidel, Günter, Mertins, Alfred, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Yang, Guang-Zhong, editor, Hawkes, David, editor, Rueckert, Daniel, editor, Noble, Alison, editor, and Taylor, Chris, editor
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- 2009
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62. Safety of Ultrasonographic Agents
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Oyen, Raymond, Baert, A. L., editor, Knauth, M., editor, Thomsen, Henrik S., editor, and Webb, Judith A. W., editor
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- 2009
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63. Getting Ready for the Study
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Chenzbraun, Adrian and Chenzbraun, Adrian, editor
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- 2009
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64. Future Directions – New Developments in Ultrasound
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Schwartz, G.A., Averkiou, M.A., de la Rosette, Jean J.M.C.H., editor, Manyak, Michael J., editor, Harisinghani, Mukesh G., editor, and Wijkstra, Hessel, editor
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- 2009
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65. Effect of Intermittent High–Mechanical Index Impulses on Left Ventricular Strain
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Feng Xie, Joan Olson, Ahmed Aboeata, Lijun Qian, Thomas R. Porter, Arif Albulushi, and Daniel Mathers
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medicine.medical_specialty ,Heart Ventricles ,Myocardial Infarction ,Systolic function ,030204 cardiovascular system & hematology ,Ventricular Function, Left ,030218 nuclear medicine & medical imaging ,Ventricular Dysfunction, Left ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Humans ,Medicine ,Radiology, Nuclear Medicine and imaging ,Ejection fraction ,business.industry ,Ultrasound ,Therapeutic effect ,Stroke Volume ,Blood flow ,Cardiology ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,Mechanical index ,Left ventricular strain - Abstract
Intermittent high-mechanical index (MI) impulses from a transthoracic ultrasound transducer are recommended for regional wall motion analysis and assessment of myocardial perfusion following intravenous administration of ultrasound enhancing agents (UEAs). High-MI impulses (1.0) applied in this setting have also been shown to increase microvascular blood flow through a purinergic signaling pathway, but their effects on left ventricular (LV) myocardial function are unknown. Therefore, the aim of this study was to investigate the effect of transthoracic intermittent high-MI impulses during intravenous UEA infusion in patients with normal and abnormal resting systolic function.Fifty patients referred for echocardiography to evaluate LV systolic function during continuous infusion of UEAs (Definity 3% infusion) were prospectively assigned to low-MI (0.2) imaging alone (group 1) or low-MI (0.2) imaging with intermittent high-MI impulses (five frames, 1.8 MHz, MI = 1.0-1.2) applied at least two times in each apical window to clear myocardial contrast (group 2). Global longitudinal strain (GLS) measurements were obtained at baseline before UEA administration and at 5-min intervals up to 10-min after infusion completion.There were no differences between groups with respect to age, gender, resting GLS, biplane LV ejection fraction, or cardiac risk factors. Resting GLS in group 1 was -15.5 ± 5.2% before UEA infusion and -15.5 ± 5.4% at 10 min after UEA infusion. In comparison, GLS increased in group 2 (-15.3 ± 5.0 before infusion and -16.8 ± 4.8% at 10 min, P .00001). Improvements in GLS were seen in patients with normal and abnormal systolic function. Regional analysis demonstrated that the increase in strain in patients with abnormal LV ejection fractions was primarily in the apical segments (-12.0 ± 2.7% before infusion and -13.4 ± 3.4% at 10 min, P = .001).High-MI impulses during infusion of a commercially available contrast agent can improve LV systolic function and may have therapeutic effect in patients with LV dysfunction.
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- 2021
66. Piezoelectric Single Crystal Ultrasonic Transducer for Endoscopic Drug Release in Gastric Mucosa
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Hanmin Peng, Zhu Pancheng, Jun Tian, and Linli Mao
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Electromechanical coupling coefficient ,Materials science ,Acoustics and Ultrasonics ,Endoscope ,Transducers ,Equipment Design ,01 natural sciences ,Piezoelectricity ,Sonophoresis ,Drug Liberation ,Acoustic streaming ,Transducer ,Pharmaceutical Preparations ,Gastric Mucosa ,0103 physical sciences ,Humans ,Ultrasonics ,Ultrasonic sensor ,Electrical and Electronic Engineering ,010301 acoustics ,Instrumentation ,Mechanical index ,Biomedical engineering - Abstract
Modern advanced minimally invasive surgery has been implemented for most of the significant gastrointestinal diseases. However, patients with coagulopathy or unresectable tumors cannot be cured by current treatment methods. Moreover, other existing medical devices for targeted drug release are too large to be applied in gastric endoscope because the diameter of the biopsy channel is smaller than 3 mm. To address it, in this work, we developed a piezoelectric single crystal ultrasonic transducer (the diameter was only 2.2 mm and the mass was 0.076 g) to produce acoustic waves, which could promote the drug release in the designed position of the digestive tract through an endoscope. It exhibited the electromechanical coupling coefficient of 0.36 and the center frequency of 6.9 MHz with the −6-dB bandwidth of 23%. In in vitro sonophoresis experiment, the gastric mucosa permeability to Bovine Serum Albumin increased about 5.6 times when the ultrasonic transducer was activated at 40 $\text{V}_{{\text {pp}}}$ and 60% duty ratio, proving that employment of this transducer could facilitate drug penetration in the gastric mucosa. Meanwhile, the permeability could be adjusted by tuning the duty ratio of the ultrasonic transducer. The corresponding sonophoresis mechanism was related to the acoustic streaming and the thermal effect produced by the transducer. In addition, the measured maximum power density was 128 mW/cm2 and the mechanical index of the ultrasonic transducer was 0.02. The results held a great implication for applications of the transducer for targeted drug release in the gastrointestinal tract.
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- 2021
67. Pulsed ultrasound attenuates the hyperglycemic exacerbation of myocardial ischemia–reperfusion injury
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Joseph C. Gigliotti, Aimee Zhang, Di Wu, Yikui Tian, Zequan Yang, Eric J. Charles, Alexander L. Klibanov, J. Hunter Mehaffey, and Irving L. Kron
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Exacerbation ,Ultrasonic Therapy ,medicine.medical_treatment ,Intraperitoneal injection ,Myocardial Reperfusion Injury ,030204 cardiovascular system & hematology ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Animals ,Medicine ,Receptors, Cholinergic ,Myocardial infarction ,Cholinergic anti-inflammatory pathway ,Cardioprotection ,business.industry ,medicine.disease ,Vagotomy ,Acetylcholine ,Mice, Inbred C57BL ,Disease Models, Animal ,Ultrasonic Waves ,030228 respiratory system ,Hyperglycemia ,Cardiology ,Surgery ,Cardiology and Cardiovascular Medicine ,business ,Reperfusion injury ,Spleen ,Mechanical index ,Signal Transduction - Abstract
Objective Acute hyperglycemia during myocardial infarction worsens outcomes in part by inflammatory mechanisms. Pulsed ultrasound has anti-inflammatory potential in bone healing and neuromodulation. We hypothesized that pulsed ultrasound would attenuate the hyperglycemic exacerbation of myocardial ischemia–reperfusion injury via the cholinergic anti-inflammatory pathway. Methods Acute hyperglycemia was induced in wild-type C57BL6 or acetylcholine-receptor knockout (α7nAChR-/-) mice by intraperitoneal injection of glucose. Pulsed ultrasound (frequency 7 MHz, bursting mechanical index 1.2, duration 1 second, repeated every 6 seconds for 2 minutes, 20-second total exposure) was performed at the spleen or neck after glucose injection. Separate mice underwent vagotomy before treatment. The left coronary artery was occluded for 20 minutes, followed by 60 minutes of reperfusion. The primary end point was infarct size in explanted hearts. Results Splenic pulsed ultrasound significantly decreased infarct size in wild-type C57BL6 mice exposed to acute hyperglycemia and myocardial ischemia–reperfusion injury (5.2% ± 4.4% vs 16.9% ± 12.5% of risk region, P = .013). Knockout of α7nAChR abrogated the beneficial effect of splenic pulsed ultrasound (22.2% ± 12.1%, P = .79 vs control). Neck pulsed ultrasound attenuated the hyperglycemic exacerbation of myocardial infarct size (3.5% ± 4.8%, P = .004 vs control); however, the cardioprotective effect disappeared in mice that underwent vagotomy. Plasma acetylcholine, β2 adrenergic receptor, and phosphorylated Akt levels were increased after splenic pulsed ultrasound treatment. Conclusions Pulsed ultrasound treatment of the spleen or neck attenuated the hyperglycemic exacerbation of myocardial ischemia–reperfusion injury leading to a 3-fold decrease in infarct size. Pulsed ultrasound may provide cardioprotection via the cholinergic anti-inflammatory pathway and could be a promising new nonpharmacologic, noninvasive therapy to reduce infarct size during acute myocardial infarction and improve patient outcomes.
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- 2021
68. Echocardiographic Assessment of Ventricular Systolic Function
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Bulwer, Bernard E., Solomon, Scott D., Janardhanan, Rajesh, Cannon, Christopher P., editor, Armani, Annemarie M., editor, Solomon, Scott D., editor, and Bulwer, Bernard, editor
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- 2007
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69. ULTRASOUND CONTRAST AGENTS
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CACHARD, CHRISTIAN, BASSET, OLIVIER, Lemoigne, Yves, editor, Caner, Alessandra, editor, and Rahal, Ghita, editor
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- 2007
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70. Mutual Attraction of Oscillating Microbubbles
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Postema, Michiel, Mleczko, Michał, Schmitz, Georg, Buzug, Thorsten M., editor, Holz, Dietrich, editor, Bongartz, Jens, editor, Kohl-Bareis, Matthias, editor, Hartmann, Ulrich, editor, and Weber, Simone, editor
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- 2007
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71. Safety of Ultrasound Contrast Agents
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Oyen, R., Baert, A. L., editor, Sartor, K., editor, and Thomsen, Henrik S., editor
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- 2006
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72. Contrast-Enhanced Ultrasound in Low-Energy Blunt Abdominal Trauma
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Thorelius, Lars and Lencioni, Riccardo, editor
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- 2006
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73. Abdominal Vessels
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Martegani, Alberto, Aiani, Luca, Borghi, Claudia, and Lencioni, Riccardo, editor
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- 2006
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74. Contrast Ultrasound in Cerebrovascular Disease and Stroke Management
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Bartels, Eva and Lencioni, Riccardo, editor
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- 2006
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75. Contrast-Enhanced Ultrasound: Basic Physics and Technology Overview
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Cosgrove, David, Eckersley, Robert, and Lencioni, Riccardo, editor
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- 2006
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76. Follow-up of Oncology Patients Undergoing Chemotherapy
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Lassau, Nathalie, Leclère, Jérome, Péronneau, Pierre, and Lencioni, Riccardo, editor
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- 2006
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77. Detection and Characterisation of Liver Metastases
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Albrecht, Thomas and Lencioni, Riccardo, editor
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- 2006
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78. Sonography of Liver Metastases
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Albrecht, Thomas, Baert, A. L., editor, Sartor, K., editor, Lencioni, Riccardo, editor, Cioni, Dania, editor, and Bartolozzi, Carlo, editor
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- 2005
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79. Improved Characterization of Reactive and Malignant Lymph Nodes Using Contrast-Enhanced Ultrasound
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Solbiati, Luigi, Cova, Luca, Albrecht, Thomas, Thorelius, Lars, Solbiati, Luigi, Cova, Luca, and Frauscher, Ferdinand
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- 2005
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80. Biological Safety of Diagnostic Sonography
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Maulik, Dev and Maulik, Dev, editor
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- 2005
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81. Introduction
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Regine, Giovanni, Atzori, Maurizio, Fabbri, Romano, Regine, Giovanni, Atzori, Maurizio, and Fabbri, Romano
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- 2013
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82. Hydrophone Spatial Averaging Correction for Acoustic Exposure Measurements From Arrays—Part I: Theory and Impact on Diagnostic Safety Indexes
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Keith A. Wear
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Physics ,Acoustics and Ultrasonics ,Hydrophone ,Transducers ,Inverse filter ,Inverse ,Acoustics ,Impulse (physics) ,01 natural sciences ,Article ,Computational physics ,symbols.namesake ,0103 physical sciences ,symbols ,Electrical and Electronic Engineering ,Center frequency ,Acoustic radiation force ,010301 acoustics ,Instrumentation ,Doppler effect ,Mechanical index ,Ultrasonography - Abstract
This article reports underestimation of mechanical index (MI) and nonscanned thermal index for bone near focus (TIB) due to hydrophone spatial averaging effects that occur during acoustic output measurements for clinical linear and phased arrays. TIB is the appropriate version of thermal index (TI) for fetal imaging after ten weeks from the last menstrual period according to the American Institute of Ultrasound in Medicine (AIUM). Spatial averaging is particularly troublesome for highly focused beams and nonlinear, nonscanned modes such as acoustic radiation force impulse (ARFI) and pulsed Doppler. MI and variants of TI (e.g., TIB), which are displayed in real-time during imaging, are often not corrected for hydrophone spatial averaging because a standardized method for doing so does not exist for linear and phased arrays. A novel analytic inverse-filter method to correct for spatial averaging for pressure waves from linear and phased arrays is derived in this article (Part I) and experimentally validated in a companion article (Part II). A simulation was developed to estimate potential spatial-averaging errors for typical clinical ultrasound imaging systems based on the theoretical inverse filter and specifications for 124 scanner/transducer combinations from the U.S. Food and Drug Administration (FDA) 510(k) database from 2015 to 2019. Specifications included center frequency, aperture size, acoustic output parameters, hydrophone geometrical sensitive element diameter, etc. Correction for hydrophone spatial averaging using the inverse filter suggests that maximally achievable values for MI, TIB, thermal dose ( ${t} _{{43}}$ ), and spatial-peak-temporal-average intensity ( ${I} _{\text {spta}}$ ) for typical clinical systems are potentially higher than uncorrected values by (means ± standard deviations) 9% ± 4% (ARFI MI), 19% ± 15% (ARFI TIB), 50% ± 41% (ARFI ${t} _{{43}}$ ), 43% ± 39% (ARFI ${I} _{\text {spta}}$ ), 7% ± 5% (pulsed Doppler MI), 15% ± 11% (pulsed Doppler TIB), 42% ± 31% (pulsed Doppler ${t} _{{43}}$ ), and 33% ± 27% (pulsed Doppler ${I} _{\text {spta}}$ ). These values correspond to frequencies of 3.2 ± 1.3 (ARFI) and 4.1 ± 1.4 MHz (pulsed Doppler), and the model predicts that they would increase with frequency. Inverse filtering for hydrophone spatial averaging significantly improves the accuracy of estimates of MI, TIB, ${t} _{{43}}$ , and ${I} _{\text {spta}}$ for ARFI and pulsed Doppler signals.
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- 2021
83. The diagnostic value of contrast-enhanced ultrasound (CEUS) for assessing hepatocellular carcinoma compared to histopathology; a retrospective single-center analysis of 119 patients1
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Dirk A. Clevert, Vincent Schwarze, Johannes Rübenthaler, N. von Münchhausen, Matthias P. Fabritius, W. Völckers, Moritz L Schnitzer, Matthias F Froelich, Thomas Geyer, Constantin Marschner, and L Zhang
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Male ,medicine.medical_specialty ,Carcinoma, Hepatocellular ,Physiology ,Contrast Media ,Single Center ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,medicine ,Humans ,Retrospective Studies ,Ultrasonography ,medicine.diagnostic_test ,business.industry ,Liver Neoplasms ,Retrospective cohort study ,Hematology ,medicine.disease ,Contrast medium ,Hepatocellular carcinoma ,Liver biopsy ,Female ,030211 gastroenterology & hepatology ,Histopathology ,Radiology ,Cardiology and Cardiovascular Medicine ,business ,Mechanical index ,Contrast-enhanced ultrasound - Abstract
BACKGROUND: HCC as the 6th most common tumor entity with the fourth highest mortality and an increasing prevalence especially due to today’s lifestyle acquires a high attention in the clinical setting. Beside CECT and CEMRI, CEUS depicts a dynamic, low-risk and radiation free imaging method that finds its use mainly in screening and active surveillance programs. PURPOSE: The aim of the retrospective study was to evaluate the diagnostic value of CEUS in correlation to pathologic findings. MATERIALS AND METHODS: Between 2004 and 2018 a total number of 119 patients were included in this retrospective single-center study. Every patient underwent CEUS in addition to a native B-mode and Color-Doppler scan. After given informed consent SonoVue® (Bracco, Milan, Italy), a second-generation blood-pool agent, was used as contrast medium. Every examination was performed and interpreted by a single experienced radiologist (EFSUMB level 3). A low mechanical index (MI) of
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- 2021
84. Microbubbles: Basic Principles
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Serra, Viviana, Fernández, Miguel Angel García, Zamorano, José Luis, Zamorano, José Luis, and Fernández, Miguel Angel García
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- 2004
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85. Organization of the Contrast Echocardiography Laboratory: Tips and Tricks
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Fernández, Teresa López, David, Esther Pérez, Yangüela, Mar Moreno, Zamorano, José Luis, Fernández, Miguel Angel García, Zamorano, José Luis, and Fernández, Miguel Angel García
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- 2004
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86. Improvement of Detection Sensitivity of Microbubbles as Sensors to Detect Ambient Pressure
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Fei Li, Deyu Li, and Fei Yan
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microbubbles ,pressure sensors ,noninvasive blood pressure measurement ,mechanical index ,subharmonic amplitude ,Chemical technology ,TP1-1185 - Abstract
Microbubbles are considered a promising tool for noninvasive estimation of local blood pressure. It is reported that the subharmonic scattering amplitude of microbubbles decreases by 9 to 12 dB when immersed in the media under an ambient pressure variation from 0 to 180 mmHg. However, the pressure sensitivity still needs to be improved to satisfy clinical diagnostic requirements. Here, we investigated the effects of acoustic parameters on the pressure sensitivity of microbubbles through measuring the acoustic attenuation and scattering properties of commercially available SonoVue microbubbles. Our results showed that the first harmonic, subharmonic, and ultraharmonic amplitudes of microbubbles were reduced by 6.6 dB, 10.9 dB, and 9.3 dB at 0.225 mechanical index (MI), 4.6 dB, 19.8 dB, and 12.3 dB at 0.25 MI, and 18.5 dB, 17.6 dB, and 12.6 dB at 0.3 MI, respectively, when the ambient pressure increased from 0 to 180 mmHg. Our finding revealed that a moderate MI (0.25⁻0.4) exciting microbubbles could significantly improve their sensitivities to detect ambient pressure.
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- 2018
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87. Hands-on Contrast Ultrasound
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Correas, J. M., Hélénon, O., Solbiati, Luigi, Martegani, Alberto, Leen, Edward, Correas, Jean Michel, Burns, Peter N., and Becker, Dirk
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- 2003
- Full Text
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88. Pulse Inversion Harmonic Imaging (ATL HDI 5000)
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Kudo, Masatoshi and Kudo, Masatoshi
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- 2003
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89. Contrast Imaging (Toshiba PowerVision 8000 and Aplio)
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Kudo, Masatoshi and Kudo, Masatoshi
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- 2003
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90. Evaluation of the Scan Duration and Mechanical and Thermal Indices Applied for the Diagnostic Ultrasound Examinations
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Shadab Moradi Birgani, Zahra Farzanegan, Marziyeh Tahmasbi, Mehrnaz Malekzade, Hamid Yazdaninejad, and Jafar Fatahi Asl
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medicine.medical_specialty ,Pregnancy ,Radiological and Ultrasound Technology ,Diagnostic ultrasound ,business.industry ,Ultrasound ,Direct observation ,medicine.disease ,Ultrasonography, Prenatal ,Pregnancy Trimester, First ,Cross-Sectional Studies ,medicine ,Humans ,Female ,Radiology, Nuclear Medicine and imaging ,Sampling (medicine) ,Prospective Studies ,Radiology ,Human safety ,business ,Mechanical index ,Ultrasonography ,General ultrasound - Abstract
OBJECTIVE Although epidemiological studies have failed to show the harmful effects of ultrasound in humans, as a form of energy, ultrasound has the potential to cause bio-effects in tissues. Therefore, clinical guidelines have been established for ultrasound technology related to human safety, which include Thermal (TI) and mechanical (MI) indices. The appropriate TI and MI ranges for embryonic examinations are between 0-1.0 and 0-0.4, respectively. The accepted TI and MI ranges are 0-2.0 and 0-1.9, respectively, for general ultrasound examinations. In addition, the scan duration should be kept as low as possible. Therefore, the present study aimed at evaluating the scan duration, TI, and MI as measures of acoustic output during ultrasound studies. METHODS A cross-sectional descriptive study was conducted for patients undergoing pregnancy checkups, routine checkups, and initial diagnosis ultrasound examinations. Samples were selected from imaging departments of 4 educational hospitals based on convenience sampling and 321 checklists completed by direct observation of ultrasound examinations. RESULTS For pregnancy scans, the mean TI and MI were obtained as 0.32 ± 0.27 and 1.15 ± 0.13, respectively. For non-pregnancy examinations, the mean value of TI and MI were 0.30 ± 0.29 and 1.07 ± 0.35, respectively. Therefore, mean TI for pregnancy and non-pregnancy examinations and mean MI for non-pregnancy studies obtained lower than the permitted values, while the mean MI was higher than the permitted level for first trimester of pregnancy. Also, relatively suitable scan durations were seen in reviewed studies. CONCLUSION From this study, it may be concluded that the reported ultrasound scans were safe.
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- 2020
91. L’échographie de contraste pour analyse de la perfusion myocardique : une vieille technique pleine d’avenir ?
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P. Garçon
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medicine.medical_specialty ,Acute coronary syndrome ,business.industry ,030204 cardiovascular system & hematology ,medicine.disease ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Contrast echocardiography ,Cardiology ,Medicine ,Thrombus ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,Mechanical index - Abstract
Myocardial perfusion assessment with contrast echocardiography has been studied for more than 25 years. It is a feasible and safe technique. Rather it has an additional value in pharmacologic stress test remains unclear. However, with adequate settings (using both low and very low mechanical index), perfusion analysis can be very useful for the diagnosis of apical thrombus or tumor, viability assessment, and acute coronary syndrome with non-informative ECG.
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- 2020
92. Estimation of the distribution of low-intensity ultrasound mechanical index as a parameter affecting the proliferation of spermatogonia stem cells in vitro.
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Moghaddam, Zeinab Hormozi, Mokhtari-Dizaji, Manijhe, Movahedin, Mansoureh, and Ravari, Mohammad Ehsan
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- *
ULTRASONIC waves , *CELL proliferation , *SPERMATOGENESIS , *CELL differentiation , *SOUND pressure - Abstract
Considering the use of physical and mechanical stimulation, such as low-intensity ultrasound for proliferation and differentiation of stem cells, it is essential to understand the physical and acoustical mechanisms of acoustic waves in vitro. Mechanical index is used for quantifying acoustic cavitation and the relationship between acoustic pressure and the frequency. In this study, modeling of the mechanical index was applied to provide treatment protocol and to understand the effective physical processes on reproducibility of stem cells. Due to low intensity of ultrasound, Rayleigh integral model has been used for acoustic pressure computation. The acoustic pressure and mechanical index equations are modeled and solved to estimate optimal mechanical index for 28, 40, 150 kHz and 1 MHz frequencies. This model are solved in different intensities and distances from transducer in cylindrical coordinates. Based on the results of the mechanical index, regions with threshold mechanical index of 0.7 were identified for extracting of radiation arrangement to cell medium. Acoustic pressure distribution along the axial and radial was extracted. In order to validate the results of the modeling, the acoustic pressure in the water and near field depth was measured by a piston hydrophone. Results of modeling and experiments show that the model is consistent well to experimental results with 0.91 and 0.90 correlation of coefficient (p < 0.05) for 1 MHz and 40 kHz. Low-intensity ultrasound with 0.40 mechanical index is more effective on enhancing the proliferation rate of the spermatogonia stem cells during the seven days of culture. In contrast, higher mechanical index has a harmful effect on the spermatogonial stem cells. Thus, considering cavitation threshold of different materials is necessary to find effective mechanical index ranges on proliferation for the used frequencies. This acoustic propagation model and ultrasound mechanical index assessments can be used with acceptable accuracy, for the extraction special arrangement of acoustic exposure used in biological conditions in vitro. This model provides proper treatment planning in vitro and in vivo by estimating the cavitation phenomenon. [ABSTRACT FROM AUTHOR]
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- 2017
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93. Neonatal Cranial Ultrasound: Are Current Safety Guidelines Appropriate?
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Lalzad, Assema, Wong, Flora, and Schneider, Michal
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PREMATURE infants , *ULTRASONIC imaging , *FETAL brain abnormalities , *COGNITIVE ability , *NERVE tissue , *PHYSIOLOGY , *SAFETY , *BRAIN , *FETAL ultrasonic imaging , *MEDICAL protocols , *SKULL - Abstract
Ultrasound can lead to thermal and mechanical effects in interrogated tissues. We reviewed the literature to explore the evidence on ultrasound heating on fetal and neonatal neural tissue. The results of animal studies have suggested that ultrasound exposure of the fetal or neonatal brain may lead to a significant temperature elevation at the bone-brain interface above current recommended safety thresholds. Temperature increases between 4.3 and 5.6°C have been recorded. Such temperature elevations can potentially affect neuronal structure and function and may also affect behavioral and cognitive function, such as memory and learning. However, the majority of these studies were carried out more than 25 y ago using non-diagnostic equipment with power outputs much lower than those of modern machines. New studies to address the safety issues of cranial ultrasound are imperative to provide current clinical guidelines and safety recommendations. [ABSTRACT FROM AUTHOR]
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- 2017
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94. Assessment of Myocardial Perfusion by Contrast Echocardiography
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Burns, Peter N, Becher, Harald, Burns, Peter N, and Becher, Harald
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- 2000
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95. Contrast Agents for Echocardiography: Principles and Instrumentation
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Burns, Peter N, Becher, Harald, Burns, Peter N, and Becher, Harald
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- 2000
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96. Mechanisms for Induction of Pulmonary Capillary Hemorrhage by Diagnostic Ultrasound: Review and Consideration of Acoustical Radiation Surface Pressure.
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Miller, Douglas L.
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PLEURA , *ULTRASONIC imaging , *HEMORRHAGE , *ACOUSTIC radiation pressure , *PULMONARY circulation , *ANATOMY , *ANIMAL experimentation , *BIOLOGICAL models , *CAPILLARIES , *LUNGS , *LUNG diseases , *MICE , *PRESSURE , *RABBITS , *RATS , *RESEARCH funding , *SOUND - Abstract
Diagnostic ultrasound can induce pulmonary capillary hemorrhage (PCH) in rats and other mammals. This phenomenon represents the only clearly demonstrated biological effect of (non-contrast enhanced) diagnostic ultrasound and thus presents a uniquely important safety issue. However, the physical mechanism responsible for PCH remains uncertain more than 25 y after its discovery. Experimental research has indicated that neither heating nor acoustic cavitation, the predominant mechanisms for bioeffects of ultrasound, is responsible for PCH. Furthermore, proposed theoretical mechanisms based on gas-body activation, on alveolar resonance and on impulsive generation of liquid droplets all appear unlikely to be responsible for PCH, owing to unrealistic model assumptions. Here, a simple model based on the acoustical radiation surface pressure (ARSP) at a tissue-air interface is hypothesized as the mechanism for PCH. The ARSP model seems to explain some features of PCH, including the approximate frequency independence of PCH thresholds and the dependence of thresholds on biological factors. However, ARSP evaluated for experimental threshold conditions appear to be too weak to fully account for stress failure of pulmonary capillaries, gauging by known stresses for injurious physiologic conditions. Furthermore, consideration of bulk properties of lung tissue suggests substantial transmission of ultrasound through the pleura, with reduced ARSP and potential involvement of additional mechanisms within the pulmonary interior. Although these recent findings advance our knowledge, only a full understanding of PCH mechanisms will allow development of science-based safety assurance for pulmonary ultrasound. [ABSTRACT FROM AUTHOR]
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- 2016
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97. Examination of Effects of Low-Frequency Ultrasound on Scleral Permeability and Collagen Network.
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Suen, Wai-Leung Langston, Jiang, Jun, Wong, Hoi Sang, Qu, Jianan, and Chau, Ying
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MEDICAL ultrasonics , *COLLAGEN , *DRUG delivery systems , *ULTRASONICS in ophthalmology , *ANISOTROPY , *SCLERA , *ANIMAL experimentation , *BIOLOGICAL models , *MOLECULAR structure , *PERMEABILITY , *RABBITS , *ULTRASONIC imaging , *METABOLISM - Abstract
Delivery of therapeutics to the intraocular space or to targeted tissues in the posterior segment is challenging because of the structural and dynamic barriers surrounding the eye. Previously, we reported the feasibility of using ultrasound (US) irradiation to deliver macromolecules to the posterior segment of the eye via the transscleral route, which consists of sclera as the outermost anatomic barrier. In this study, we found that although ultrasound increases scleral permeability for macromolecules, the scleral collagen arrangement remains undisturbed. In an ex vivo experiment, protein permeation across the sclera was significantly enhanced by ultrasound in the stable cavitation regime. The scleral collagen network was further examined by second harmonic generation imaging. Quantitative image analysis techniques were adopted to examine the density, anisotropy and interlacing pattern of collagen fibers before and after ultrasound irradiation. Repeated ultrasound applications did not induce significant changes in the arrangement of collagen fibrils at 40 kHz with a spatial average temporal average intensity (ISATA) <1.8 W/cm2. These parameters correspond to a mechanical index (MI) below 0.8 in our setting. These data suggested that enhanced permeation of macromolecules across the sclera was achieved without disturbing the collagen network of the sclera. This evidence supports that low-frequency, low-intensity ultrasound is a tolerable approach to transscleral drug delivery. [ABSTRACT FROM AUTHOR]
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- 2016
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98. The dynamic enhanced characterization with low mechanical index gray-scale harmonic imaging inflammatory pseudotumor of liver compared with hepatic VX2 tumor and normal liver
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Ying Shi, Cheng-gong Lei, Xueping Bai, Qinxiu Wang, Ying-yan Qiao, and Xing-hua Wang
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Pathology ,medicine.medical_specialty ,Carcinoma, Hepatocellular ,Contrast Media ,Medicine (miscellaneous) ,Malignancy ,Granuloma, Plasma Cell ,General Biochemistry, Genetics and Molecular Biology ,Internal Medicine ,medicine ,Animals ,Pharmacology (medical) ,Vein ,Genetics (clinical) ,Ultrasonography ,business.industry ,Liver Neoplasms ,Ultrasound ,medicine.disease ,medicine.anatomical_structure ,Hepatocellular carcinoma ,Reviews and References (medical) ,Inflammatory pseudotumor ,Rabbits ,Differential diagnosis ,business ,Perfusion ,Mechanical index - Abstract
Background Inflammatory pseudotumor of the liver (IPTL) is misdiagnosed usually as a malignant tumor based on the imaging findings. Differential diagnosis should be established to avoid hepatic resection. At imaging, IPTL has been misdiagnosed usually as hepatocellular carcinoma (HCC). It is usually found firstly using conventional ultrasonic examination, which cannot give a definitive diagnosis. Because of its atypical clinical presentation and radiological appearance, a presumptive diagnosis of malignancy is frequently made. With the development of ultrasound systems and ultrasound contrast agents (UCA), contrast-enhanced ultrasound is widely used in diagnosing focal lesions of the liver. Objectives To delineate the hemodynamic features of IPTL compared with hepatic VX2 tumor and normal liver using contrast-enhanced ultrasound. Material and methods Freund's complete adjuvant (FCA) was injected using a modified method into the desirable portion of the liver in rabbits. Two weeks after the injection, solitary IPTLs were formed (which was proved with pathological examination). Ten rabbits with IPTL, 10 rabbits with VX2 carcinoma and 10 healthy rabbits were studied using contrast-enhanced ultrasound with bolus injection of SonoVueTM through the peripheral vein. Corresponding parameters such as time to enhancement (ET), time to peak intensity (PIT), time to ascent (AT), and time to lighten (LT) were measured with wash-in/wash-out curve. Results Contrast-enhanced imaging clearly delineated the dynamic enhancement of the lesions and liver parenchyma during the whole phase. Inflammatory pseudotumor of the liver showed the same enhanced features as the liver parenchyma. In VX2 tumors, hyperechoic enhancement in arterial phase and hypoechoic enhancement was observed in the portal and delayed phase compared with the surrounding hepatic parenchyma. The normal liver showed whole of liver parenchyma enhanced in portal phase. Conclusions The study showed that contrast-enhanced ultrasound provided useful information about perfusion in IPTL and VX2 carcinoma. Contrast-enhanced ultrasound is a useful technique in the differential diagnosis of focal liver lesions if combined with time-intensity curve.
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- 2020
99. Targeted Ultrasound Contrast Imaging of Tumor Vasculature With Positively Charged Microbubbles
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Galina Diakova, Alexander L. Klibanov, and Zhongmin Du
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Contrast Media ,Adenocarcinoma ,Polyethylene Glycols ,030218 nuclear medicine & medical imaging ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Phosphatidylcholine ,PEG ratio ,Animals ,Radiology, Nuclear Medicine and imaging ,Ultrasonography ,Microbubbles ,Pulse (signal processing) ,business.industry ,Ultrasound ,General Medicine ,Blood flow ,Mice, Inbred C57BL ,chemistry ,Colonic Neoplasms ,Phosphatidylcholines ,Contrast ratio ,business ,030217 neurology & neurosurgery ,Mechanical index ,Biomedical engineering - Abstract
PURPOSE Molecular ultrasound imaging of tumor vasculature is being actively investigated with microbubble contrast agents targeted to neovasculature biomarkers. Yet, a universal method of targeting tumor vasculature independent of specific biomarkers, or in their absence, would be desirable. We report the use of electrostatic interaction to achieve adherence of microbubbles to tumor vasculature and resulting tumor delineation by ultrasound imaging. METHODS AND MATERIALS Microbubbles were prepared from decafluorobutane gas by amalgamation of aqueous micellar medium. Distearoyl phosphatidylcholine (DSPC) and polyethylene glycol (PEG)-stearate were used as microbubble shell-forming lipids; cationic lipid distearoyl trimethylammoniumpropane (DSTAP) was included to introduce positive electrostatic charge. Microbubbles were subjected to flotation in normal gravity, to remove larger particles. Murine colon adenocarcinoma tumor (MC38, J. Schlom, National Institutes of Health) was inoculated in the hind leg of C57BL/6 mice. Contrast ultrasound imaging was performed under isoflurane anesthesia, using a clinical imaging system in low power mode, with tissue signal suppression (contrast pulse sequencing, 7 MHz, 1 Hz; Mechanical Index, 0.2). The ultrasound probe was positioned to monitor the tumor and contralateral leg muscle; microbubble contrast signal was monitored for 30 minutes or more, after intravenous bolus administration of 2.10 microbubbles. Individual time point frames were extracted from ultrasound video recording and analyzed with ImageJ. RESULTS Mean bubble diameter was ~1.6 to 2 μm; 99.9% were less than 5 μm, to prevent blocking blood flow in capillaries. For cationic DSTAP-carrying microbubbles, contrast signal was observed in the tumor beyond 30 minutes after injection. As the fraction of positively charged lipid in the bubble shell was increased, adherent contrast signal in the tumor also increased, but accumulation of DSTAP-microbubbles in the normal muscle increased as well. For bubbles with the highest positive charge tested, DSTAP-DSPC molar ratio 1:4, at 10 minutes after intravenous administration of microbubbles, the contrast signal difference between the tumor and normal muscle was 1.5 (P < 0.005). At 30 minutes, tumor/muscle contrast signal ratio improved and reached 2.1. For the DSTAP-DSPC 1:13 preparation, tumor/muscle signal ratio exceeded 3.6 at 10 minutes and reached 5.4 at 30 minutes. Microbubbles with DSTAP-DSPC ratio 1:22 were optimal for tumor targeting: at 10 minutes, tumor/muscle signal ratio was greater than 7 (P < 0.005); at 30 minutes, greater than 16 (P < 0.01), sufficient for tumor delineation. CONCLUSIONS Cationic microbubbles are easy to prepare. They selectively accumulate in the tumor vasculature after intravenous administration. These microbubbles provide target-to-control contrast ratio that can exceed an order of magnitude. Adherent microbubbles delineate the tumor mass at extended time points, at 30 minutes and beyond. This may allow for an extension of the contrast ultrasound examination time. Overall, positively charged microbubbles could become a universal ultrasound contrast agent for cancer imaging.
- Published
- 2020
100. Preliminary study on the electromagnetic field treatment of osteoporosis in rats
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Jiaqi Bi, Miao Yu, Xiaowei Sun, Ying Zhang, Shaoting Liu, Shengnan Liu, Qiushi Song, and Daofei Qu
- Subjects
medicine.medical_specialty ,Disuse osteoporosis ,Magnetic Field Therapy ,0206 medical engineering ,Osteoporosis ,Biomedical Engineering ,Biophysics ,osteocalcin ,Health Informatics ,Bioengineering ,02 engineering and technology ,Pulsed electromagnetic field ,Bone remodeling ,Rats, Sprague-Dawley ,bone biomechanics ,Biomaterials ,03 medical and health sciences ,0302 clinical medicine ,Bone Density ,Internal medicine ,Animals ,Medicine ,Alendronate ,Bone Density Conservation Agents ,biology ,business.industry ,Significant difference ,bone morphogenetic protein-2 (BMP-2) ,medicine.disease ,osteoporosis ,020601 biomedical engineering ,Skeleton (computer programming) ,Rats ,Disease Models, Animal ,Endocrinology ,Mechanical stability ,Osteocalcin ,biology.protein ,Female ,business ,030217 neurology & neurosurgery ,Mechanical index ,Research Article ,Information Systems - Abstract
OBJECTIVE: In our study, the influence of PEMF on skeleton morphology and bone metabolism on rats with disuse osteoporosis was investigated, and the possibility of using it for the treatment of disuse osteoporosis was explored. METHODS: The rats in the ALN group were treated with alendronate, and the rats in the PEMF group were exposed to pulsed electromagnetic fields (3.82 mT, 10 Hz) for 40 mind-1. Rats were sacrificed by the end of 2, 4, 8 and 12 weeks, and serum and right leg bones were collected. Serum BMP-2, BGP concentrations and bone metabolism and biomechanical parameters were measured. RESULTS: The bone structural mechanical indices and material mechanical indices of the right femur in all groups of mice during weeks 2 and 4 were decreased. At week 8 the bone structural mechanical index and maximum stress of the right femur in the ALN group were markedly raised compared with the CON group (P< 0.01). Only maximum stress and strain were improved in the ALN group and had a significant difference (P< 0.05) at week 12. The serum BGP and BMP-2 concentration in the PEMF and ALN groups was increased (P< 0.05) at week 2, but this increase was not synchronized. After 8 weeks, BGP and BMP-2 level in the PEMF group was observably elevated (P
- Published
- 2020
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