Effects of Neuromuscular Electrical Stimulation and Therapeutic Ultrasound on Quadriceps Contracture of Immobilized Rats

Quadriceps contracture is a condition where the muscle-tendon unit is abnormally shortened. The treatment prognosis is guarded to poor depending on the progress of the disease. To improve the prognosis, we investigated the effectiveness of therapeutic ultrasound and NMES in treating quadriceps contracture in an immobilized rat model. Thirty-six Wistar rats were randomized into control, immobilization alone, immobilization and spontaneous recovery, immobilization and therapeutic ultrasound, immobilization and NMES, and immobilization and therapeutic ultrasound and NMES combination groups. The continuous therapeutic ultrasound (frequency, 3 MHz, intensity 1 W/cm2) and NMES (TENS mode, frequency 50 Hz; intensity 5.0 ± 0.8 mA) were performed on the quadriceps muscle. On Day 15, immobilization-induced quadriceps contracture resulted in a decreased ROM of the stifle joint, reduction in the sarcomere length, muscle atrophy, and muscle fibrosis. On Day 43, therapeutic ultrasound, NMES, and combining both methods improved muscle atrophy and shortening and decreased collagen type I and III and α-SMA protein. The combination of therapeutic ultrasound and NMES significantly reduced the mRNA expression of IL-1β, TGF-β1, and HIF-1α and increased TGF-β3. Therefore, the combination of therapeutic ultrasound and NMES is the most potent rehabilitation program for treating quadriceps contracture.

Analyzing Gene Expression After Administration of Low-Intensity Therapeutic Ultrasound in Human Islet Cells

OBJECTIVES

Diabetes mellitus is a complex heterogenous metabolic disease that significantly affects the world population. Although many treatments exist, including medications such as metformin, sulfonylureas, and glucagon-like peptide-1 (GLP) receptor agonist, there is growing interest in finding alternative methods to noninvasively treat this disease. It has been previously shown that low-intensity ultrasound stimulation of pancreatic β-cells in mice can elicit insulin secretion as a potential treatment for this disease. This is desirable as therapeutic ultrasound has the ability to induce bioeffects while selectively focusing deep within tissues, allowing for modulation of hormone secretion in the pancreas to mitigate insufficient levels of insulin.

METHODS

Exactly 800 kHz ultrasound with intensity 0.5 W/cm2 was administered 5 minutes continuously, that is, 100% duty cycle, to donor pancreatic human islets, followed by 1 hour incubation and RT-qPCR to assess the effect of ultrasound stimulation on gene expression. The genes were insulin (INS), glucagon (Glu), amylin (Amy), and binding immunoglobulin protein (BiP). Nine donor pancreatic human islets were used to assess insulin and glucagon secretion, while eight samples were used for amylin and BiP. Fold change (FC) was calculated to analyze the effect of ultrasound stimulation on the gene expression of the donor islet cells. High-glucose and thapsigargin-treated islets were utilized as positive controls. Cell viability testing was done using a Trypan Blue Exclusion Test.

RESULTS

Ultrasound stimulation did not cause a statistically significant upregulation in any of the tested genes (INS FC = 1.15, P-value = .5692; Glu FC = 1.60, P-value = .2231; Amy FC, P-value = .2863; BiP FC = 2.68, P-value = .3907).

CONCLUSIONS

The results of this study show that the proposed ultrasound treatment parameters do not appear to significantly affect gene expression of any gene tested.

In vivo high-speed microscopy of microbubbles in the chorioallantoic membrane model

Rationale: The acoustic stimulation of microbubbles within microvessels can elicit a spectrum of therapeutically relevant bioeffects from permeabilization to perfusion shutdown. These bioeffects ultimately arise from complex interactions between microbubbles and microvascular walls, though such interactions are poorly understood particularly at high pressure, due to a paucity of direct in vivo observations. The continued development of focused ultrasound methods hinges in large part on establishing links between microbubble-microvessel interactions, cavitation signals, and bioeffects. Methods: Here, a system was developed to enable simultaneous high-speed intravital imaging and cavitation monitoring of microbubbles in vivo in a chorioallantoic membrane model. Exposures were conducted using the clinical agent DefinityTM under conditions previously associated with microvascular damage (1 MHz, 0.5-3.5 MPa, 5 ms pulse length). Results: Ultrasound-activated microbubbles could be observed and were found to induce localized wall deformations that were more pronounced in smaller microvessels and increased with pressure. A central finding was that microbubbles could extravasate from microvessels (from 34% of vessels at 1 MPa to 79% at 3 MPa) during insonation (94% within 0.5 ms) and that this occurred more frequently and in progressively larger microvessels (up to 180 µm) as pressure was increased. Following microbubble extravasation, transient or sustained red blood cell leakage ensued at the extravasation site in 96% of cases for pressures ≥1 MPa. Conclusions: The results here represent the first high-speed in vivo investigation of high-pressure focused ultrasound-induced microbubble-microvessel interactions. This data provides direct evidence that the process of activated microbubble extravasation can occur in vivo and that it is linked to producing microvessel wall perforations of sufficient size to permit red blood cell leakage. The association of red blood cell leakage with microbubble extravasation provides mechanistic insight into the process of microvessel rupture, which has been widely observed in histology.

Ultrasound-mediated nano-sized drug delivery systems for cancer treatment: Multi-scale and multi-physics computational modeling

Computational modeling enables researchers to study and understand various complex biological phenomena in anticancer drug delivery systems (DDSs), especially nano-sized DDSs (NSDDSs). The combination of NSDDSs and therapeutic ultrasound (TUS), that is, focused ultrasound and low-intensity pulsed ultrasound, has made significant progress in recent years, opening many opportunities for cancer treatment. Multiple parameters require tuning and optimization to develop effective DDSs, such as NSDDSs, in which mathematical modeling can prove advantageous. In silico computational modeling of ultrasound-responsive DDS typically involves a complex framework of acoustic interactions, heat transfer, drug release from nanoparticles, fluid flow, mass transport, and pharmacodynamic governing equations. Owing to the rapid development of computational tools, modeling the different phenomena in multi-scale complex problems involved in drug delivery to tumors has become possible. In the present study, we present an in-depth review of recent advances in the mathematical modeling of TUS-mediated DDSs for cancer treatment. A detailed discussion is also provided on applying these computational models to improve the clinical translation for applications in cancer treatment. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Ultrasonic therapies for seizures and drug-resistant epilepsy

Ultrasonic therapy is an increasingly promising approach for the treatment of seizures and drug-resistant epilepsy (DRE). Therapeutic focused ultrasound (FUS) uses thermal or nonthermal energy to either ablate neural tissue or modulate neural activity through high- or low-intensity FUS (HIFU, LIFU), respectively. Both HIFU and LIFU approaches have been investigated for reducing seizure activity in DRE, and additional FUS applications include disrupting the blood-brain barrier in the presence of microbubbles for targeted-drug delivery to the seizure foci. Here, we review the preclinical and clinical studies that have used FUS to treat seizures. Additionally, we review effective FUS parameters and consider limitations and future directions of FUS with respect to the treatment of DRE. While detailed studies to optimize FUS applications are ongoing, FUS has established itself as a potential noninvasive alternative for the treatment of DRE and other neurological disorders.

Non-thermal Acoustic Enhancement of Chemotherapeutic Effects of Cisplatin on Xenografted Cervical Cancer in Mice

BACKGROUND/AIM

We examined the effect of low-intensity focused ultrasound (FUS) on unbinding cisplatin from plasma proteins and enhancing its chemotherapeutic efficacy using a mouse model of xenograft human cervical cancer.

MATERIALS AND METHODS

FUS, operating in a pulsed mode, was applied to a dialysis cassette immersed in a normal saline bath containing both bovine serum albumin (BSA) and cisplatin, and the unbound level of cisplatin diffused into the cassette was measured. To assess the in vivo efficacy of the technique, athymic nu/nu mice were inoculated with human cervical cancer cells under four different combinatory conditions, with and without the administration of cisplatin and FUS. FUS was delivered to the tumor mass for 1 h across four separate sessions spanning a period of 10 days, following the intraperitoneal injection of cisplatin.

RESULTS

In vitro equilibrium dialysis revealed that non-thermal application of FUS increased the concentration of unbound cisplatin compared to cassettes that were not exposed to sonication, suggesting successful unbinding. Assessment of tumor growth in vivo showed that FUS following cisplatin administration resulted in a significant reduction in tumor growth, whereas the administration of cisplatin alone exhibited plateau growth. Without administration of cisplatin, equivalent rates of aggressive tumor growth were observed regardless of the application of FUS.

CONCLUSION

Pulsed application of FUS can unbind cisplatin from albumin and enhance its tumoricidal effects in cervical cancer. Further assessment of intratumoral/systemic cisplatin concentration is required to quantify its selective delivery to the tumor.

Efficient PD-L1 imaging of murine glioblastoma with FUS-aided immunoPET by leveraging FcRn-antibody interaction

Rationale: The passage of antibodies through the blood-brain barrier (BBB) and the blood-tumoral barrier (BTB) is determinant not only to increase the immune checkpoint inhibitors efficacy but also to monitor prognostic and predictive biomarkers such as the programmed death ligand 1 (PD-L1) via immunoPET. Although the involvement of neonatal Fc receptor (FcRn) in antibody distribution has been demonstrated, its function at the BBB remains controversial, while it is unknown at the BTB. In this context, we assessed FcRn's role by pharmacokinetic immunoPET imaging combined with focused ultrasounds (FUS) using unmodified and FcRn low-affinity IgGs targeting PD-L1 in a preclinical orthotopic glioblastoma model. Methods: Transcranial FUS were applied over the whole brain in mice shortly before injecting the anti-PD-L1 IgG 89Zr-DFO-C4 or its FcRn low-affinity mutant 89Zr-DFO-C4Fc-MUT in a syngeneic glioblastoma murine model (GL261-GFP). Brain uptake was measured from PET scans acquired up to 7 days post-injection. Kinetic modeling was performed to compare the brain kinetics of both C4 formats. Results: FUS efficiently enhanced the delivery of both C4 radioligands in the brain with high reproducibility. 89Zr-DFO-C4Fc-MUT mean concentrations in the brain reached a significant uptake of 3.75±0.41%ID/cc with FUS against 1.92±0.45%ID/cc without, at 1h post-injection. A substantial and similar entry of both C4 radioligands was observed at a rate of 0.163±0.071 mL/h/g of tissue during 10.4±4.6min. The impaired interaction with FcRn of 89Zr-DFO-C4Fc-MUT significantly decreased the efflux constant from the healthy brain tissue to plasma compared with non-mutated IgG. Abolishing FcRn interaction allows determining the target engagement related to the specific binding as soon as 12h post-injection. Conclusion: Abolishing Fc-FcRn interaction confers improved kinetic properties to 89Zr-DFO-C4Fc-MUT for immunoPET imaging. FUS-aided BBB/BTB disruption enables quantitative imaging of PD-L1 expression by glioblastoma tumors within the brain.

Quantitative Thermal Stimulation Using Therapeutic Ultrasound to Improve Cerebral Blood Flow and Reduce Vascular Stiffness

It is important to improve cerebrovascular health before the occurrence of cerebrovascular disease, as it has various aftereffects and a high recurrence rate, even with appropriate treatment. Various medical recommendations for preventing cerebrovascular diseases have been introduced, including smoking cessation, exercise, and diet. However, the effectiveness of these methods varies greatly from person to person, and their effects cannot be confirmed unless they are practiced over a long period. Therefore, there is a growing need to develop more quantitative methods that are applicable to the public to promote cerebrovascular health. Thus, in this study, we aimed to develop noninvasive and quantitative thermal stimulation techniques using ultrasound to improve cerebrovascular health and prevent cerebrovascular diseases. This study included 27 healthy adults in their 20s (14 males, 13 females). Thermal stimulation using therapeutic ultrasound at a frequency of 3 MHz was applied to the right sternocleidomastoid muscle in the supine posture for 2 min at four intensities (2.4, 5.1, 7.2, and 10.2 W/cm2). Diagnostic ultrasound was used to measure the peak systolic velocity (PSV), heart rate (HR), and pulse wave velocity (PWV) in the right common carotid artery (CCA), and the physiological changes were compared between intervention intensities. Compared to pre-intervention (preI), the PSV showed a significant increase during intervention (durI) at intensities of 7.2 W/cm2 and 10.2 W/cm2 (p = 0.010 and p = 0.021, respectively). Additionally, PWV showed a significant decrease for post-intervention (postI) at 7.2 W/cm2 and 10.2 W/cm2 (p = 0.036 and p = 0.035, respectively). However, the HR showed no significant differences at any of the intensities. The results demonstrate that an intervention at 3 MHz with an intensity of 7.2 W/cm2 or more can substantially increase cerebral blood flow and reduce arterial stiffness. Therefore, the use of therapeutic ultrasound of appropriate intensity is expected to improve the cerebral blood flow and reduce vascular stiffness to maintain cerebral blood flow at a certain level, which is closely related to the prevention and treatment of cerebrovascular diseases, thereby improving cerebrovascular health.

Aberration correction in abdominal histotripsy

In transabdominal histotripsy, ultrasound pulses are focused on the body to noninvasively destroy soft tissues via cavitation. However, the ability to focus is limited by phase aberration, or decorrelation of the ultrasound pulses due to spatial variation in the speed of sound throughout heterogeneous tissue. Phase aberration shifts, broadens, and weakens the focus, thereby reducing the safety and efficacy of histotripsy therapy. This paper reviews and discusses aberration effects in histotripsy and in related therapeutic ultrasound techniques (e.g., high intensity focused ultrasound), with an emphasis on aberration by soft tissues. Methods for aberration correction are reviewed and can be classified into two groups: model-based methods, which use segmented images of the tissue as input to an acoustic propagation model to predict and compensate phase differences, and signal-based methods, which use a receive-capable therapy array to detect phase differences by sensing acoustic signals backpropagating from the focus. The relative advantages and disadvantages of both groups of methods are discussed. Importantly, model-based methods can correct focal shift, while signal-based methods can restore substantial focal pressure, suggesting that both methods should be combined in a 2-step approach. Aberration correction will be critical to improving histotripsy treatments and expanding the histotripsy treatment envelope to enable non-invasive, non-thermal histotripsy therapy for more patients.

Color-Changing Reflection Hologram for Quality Assurance of Therapeutic Ultrasound Systems

The acoustic output of clinical therapeutic ultrasound equipment requires regular quality assurance (QA) testing to ensure the safety and efficacy of the treatment and that any potentially harmful deviations from the expected output power density are detected as soon as possible. A hologram, consisting of a reflection grating fabricated in an acrylate photopolymer film, has been developed to produce an immediate, visible, and permanent change in the color of the reconstructed hologram from red to green in response to incident ultrasound energy. The influence of the therapeutic ultrasound insonation parameters (exposure time, ultrasound power density, and proximity to the point of maximum acoustic pressure) on the hologram's response has been investigated for two types of therapeutic ultrasound systems: a sonoporation system and an ultrasound physiotherapy system. Findings show that, above a switching temperature of 45 °C, the ultrasound-induced temperature rise produces a structural change in the hologram, which manifests as a visible color change. The area of the color change region correlates with the ultrasound exposure conditions. The suitability of the hologram as a simple and quick QA test tool for therapeutic ultrasound systems has been demonstrated. A prototype ultrasound testing unit which facilitates user-friendly, reproducible testing of the holograms in a clinical setting is also reported.

Exploring the Potential of Ultrasound Therapy to Reduce Skin Scars: An In Vitro Study Using a Multi-Well Device Based on Printable Piezoelectric Transducers

Excessive skin scarring affects over 100 million patients worldwide, with effects ranging from cosmetic to systemic problems, and an effective treatment is yet to be found. Ultrasound-based therapies have been used to treat a variety of skin disorders, but the exact mechanisms behind the observed effects are still unclear. The aim of this work was to demonstrate the potential of ultrasound for the treatment of abnormal scarring by developing a multi-well device based on printable piezoelectric material (PiezoPaint™). First, compatibility with cell cultures was evaluated using measurements of heat shock response and cell viability. Second, the multi-well device was used to treat human fibroblasts with ultrasound and quantify their proliferation, focal adhesions, and extracellular matrix (ECM) production. Ultrasound caused a significant reduction in fibroblast growth and ECM deposition without changes in cell viability or adhesion. The data suggest that these effects were mediated by nonthermal mechanisms. Interestingly, the overall results suggest that ultrasound treatment would a be beneficial therapy for scar reduction. In addition, it is expected that this device will be a useful tool for mapping the effects of ultrasound treatment on cultured cells.

Cytotoxicity, Dermal Toxicity, and In Vivo Antifungal Effect of Griseofulvin-Loaded Vaterite Carriers Administered via Sonophoresis

The search for novel therapeutic strategies to treat fungal diseases is of special importance nowadays given the emerging threat of drug resistance. Various particulate delivery systems are extensively being developing to enhance bioavailability, site-specific penetration, and therapeutic efficacy of antimycotics. Recently, we have designed a novel topical formulation for griseofulvin (Gf) drug, which is currently commercially available in oral dosage forms due to its limited skin permeation. The proposed formulation is based on vaterite carriers that enabled effective incorporation and ultrasonically assisted delivery of Gf to hair follicles improving its dermal bioavailability. Here, we evaluated the effect of ultrasound on the viability of murine fibroblasts co-incubated with either Gf-loaded carriers or a free form of Gf and investigated the influence of both forms on different subpopulations of murine blood cells. The study revealed no sufficient cyto- and hemotoxicity of the carriers, even at the highest investigated concentrations. We also conducted a series of in vivo experiments to assess their multi-dose dermal toxicity and antifungal efficiency. Visual and histological examinations of the skin in healthy rabbits showed no obvious adverse effects after US-assisted application of the Gf-loaded carriers. At the same time, investigation of therapeutic efficiency for the designed formulation in comparison with free Gf and isoconazole drugs in a guinea pig model of trichophytosis revealed that the vaterite-based form of Gf provided the most rapid and effective cure of infected animals together with the reduction in therapeutic procedure number. These findings pave the way to improving antifungal therapy of superficial mycoses and justifying further preclinical studies.

Combination of Focused Ultrasound, Immunotherapy, and Chemotherapy: New Perspectives in Breast Cancer Therapy

Focused ultrasound is a treatment modality increasingly used for diverse therapeutic applications, and currently approved for several indications, including prostate cancers and uterine fibroids. But what about breast cancer? Breast cancer is the most common and deadliest cancer in women worldwide. While there are different treatment strategies available, there is a need for development of more effective and personalized modalities, with fewer side effects. Therapeutic ultrasound is such an option, and this review summarizes the state of the art in their use for the treatment of breast cancer and evaluate potentials of novel treatment approaches combining therapeutic ultrasound, immuno- and chemo-therapies.

Modeling of Ultrasound Stimulation of Adolescent Pancreas for Insulin Release Therapy

OBJECTIVES

Our previous published studies have focused on safety and effectiveness of using therapeutic ultrasound (TUS) for treatment of type 2 diabetes mellitus (T2DM) in preclinical models. Here we present a set of simulation studies to explore potential ultrasound application schemes that would be feasible in a clinical setting.

METHODS

Using the multiphysics modeling tool OnScale, we created two-dimensional (2D) models of the human abdomen from CT images captured from one normal weight adolescent patient, and one obese adolescent patient. Based on our previous studies, the frequency of our TUS was 1 MHz delivered from a planar unfocused transducer. We tested five different insonation angles, as well as four ultrasound intensities combined with four different duty factors and five durations of application to explore how these variables effect the peak pressure and temperature delivered to the pancreas as well as surrounding tissue in the model.

RESULTS

We determined that ultrasound applied directly from the anterior of the patient abdomen at 5 W/cm² delivered consistent acoustic pressures to the pancreas at the levels which we have previously found to be effective at inducing an insulin release from preclinical models.

CONCLUSIONS

Our modeling work indicates that it may be feasible to non-invasively apply TUS in clinical treatment of T2DM.

A novel method for conformity assessment testing of therapeutic ultrasounds for post-market surveillance purposes

BACKGROUND

Therapeutic ultrasounds are medical devices used for treatment of conditions such muscle spasms, joint contractures or general muscle pain. Their function relies in the delivery of ultrasonic pulses that generate heat in tissue thus relieving the symptoms of aforementioned conditions. Accuracy of the delivered pulses directly affects the quality and effectiveness of the treatment and has to be ensured throughout the utilization of the therapeutic ultrasound in practice. The new Medical Device Regulation (MDR) defines medical device post-market surveillance (PMS) as performed by independent, third-party, notified bodies more strategically in hope to improve traceability of device performance. However, there is still an apparent gap in terms of standardised conformity assessment testing methods.

OBJECTIVE

This paper proposes a novel method for conformity assessment testing of therapeutic ultrasounds for post-market surveillance purposes.

METHOD

The method was developed based on metrology characteristics of therapeutic ultrasounds and includes visual, electrical safety and performance inspections of therapeutic ultrasounds to ensure that both safety and treatment reliability are achieved.

RESULTS

The developed method was validated between 2018 and 2021 in healthcare institutions of all levels. The results obtained during validation suggest that conformity assessment testing of therapeutic ultrasounds as a method used during PMS contributes to significant improvement in devices' accuracy and reliability.

CONCLUSION

A standardized approach in conformity assessment testing of therapeutic ultrasounds during PMS, besides increasing reliability of the devices, is the first step in digital transformation of management of these devices in healthcare institutions opening possibility for use of artificial intelligence.

High intensity focused ultrasound atomization and erosion in healthy and tendinopathic tendons

Objective.High-intensity focused ultrasound (HIFU) can induce thermal and mechanical mechanisms in a well-defined focal volume of tissues. Histotripsy is a form of mechanical HIFU that can initiate and interact with bubble(s) to cause shock scattering and perhaps atomization within the bubble(s) to fractionate most soft tissues. Ultrasonic atomization, or the ejection of fine droplets from an acoustically-excited liquid exposed to air, has been shown to erode planar soft tissue surfaces, which has led to theories that atomization is a mechanism in histotripsy. However, healthy tendons show resistance to conventional histotripsy; pre-treatment of tendons with heat increases susceptibility to histotripsy fractionation. This study investigates ultrasonic atomization and erosion from planar healthy and tendinopathic tendon surfaces as we evaluate HIFU parameters for histotripsy in tendons.Approach.Forty-sixex vivobovine tendon-air interfaces were pre-conditioned to surface wetting, heat baths of 20 °C (unaltered), 37 °C (body temperature), and 58 °C (collagen degradation), collagenase soaks for 1, 3, 5, and 24 h (mimicking tendinopathic tendons), and phosphate buffered saline soaks for 24 h. Ejected fragments, histology, and gross analysis determined erosion success. Tissue displacement from the HIFU radiation force was monitored with high-speed photography, and tissue relaxation was pixel-tracked and fit to a Kelvin-Voigt model to evaluate changes in viscoelastic properties.Main results.Results showed that atomization produced holes in 24 h collagenase tendons and surface pitting in 58 °C, 3 h, and 5 h collagenase tendons. Increased mound heights and viscoelastic constants in pre-heated (to 58 °C) and collagenase-soaking (3+ hours) tendinopathic models caused a decrease in elasticity and/or increase in viscosity, increasing susceptibility to erosion by HIFU atomization.Significance.Therefore, tendons with chronic tendinopathies may be more susceptible than healthy tendons to histotripsy fractionation.

Integrating Therapeutic Ultrasound With Nanosized Drug Delivery Systems in the Battle Against Cancer

Controlled, localized, and timely activation of nanosized drug delivery systems (NSDDSs), using an external stimulus such as therapeutic ultrasound (TUS), can improve the efficacy of cancer treatments compared to either conventional chemotherapy methods or passive NSDDSs alone. Specifically, TUS induces thermal and mechanical effects that trigger drug release from NSDDSs and overcomes drug delivery barriers in tumor microenvironments to allow nanoparticle drug carriers to penetrate more deeply into tumor tissue while minimizing side effects. This review highlights recent advancements, contemplates future prospects, and addresses challenges in using TUS-mediated NSDDSs for cancer treatment, encompassing preclinical and clinical applications.

Acoustic and Thermal Characterization of Therapeutic Ultrasonic Langevin Transducers under Continuous- and Pulsed Wave Excitations

We previously conducted an empirical study on Langevin type transducers in medical use by examining the heat effect on porcine tissue. For maximum acoustic output, the transducer was activated by a continuous sinusoidal wave. In this work, pulsed waves with various duty factors were applied to our transducer model in order to examine their effect on functionality. Acoustic power, electro-acoustic conversion efficiency, acoustic pressure, thermal effect on porcine tissue and bovine muscle, and heat generation in the transducer were investigated under various input conditions. For example, the results of applying a continuous wave of 200 V_PP and a pulse wave of 70% duty factor with the same amplitude to the transducer were compared. It was found that continuous waves generated 9.79 W of acoustic power, 6.40% energy efficiency, and 24.84 kPa acoustic pressure. In pulsed excitation, the corresponding values were 9.04 W, 8.44%, and 24.7 kPa, respectively. The maximum temperature increases in bovine muscle are reported to be 83.0 °C and 89.5 °C for each waveform, whereas these values were 102.5 °C and 84.5 °C in fatty porcine tissue. Moreover, the heat generation around the transducer was monitored under continuous and pulsed modes and was found to be 51.3 °C and 50.4 °C. This shows that pulsed excitation gives rise to less thermal influence on the transducer. As a result, it is demonstrated that a transducer triggered by pulsed waves improves the energy efficiency and provides sufficient thermal impact on biological tissues by selecting proper electrical excitation types.

Systematic Review of Complementary and Alternative Veterinary Medicine in Sport and Companion Animals: Therapeutic Ultrasound

BACKGROUND

To explore the scientific evidence for therapeutic ultrasound (TU), we conducted a systematic review of the literature on TU in dogs, horses, donkeys, and cats.

METHODS

In three major databases, relevant articles published in 1980-2020 were identified. The risk of bias in each article was evaluated.

RESULTS

Twenty-four relevant articles on the effects of TU in dogs, nine in horses, two in donkeys, and one in cats were identified. TU usually involved 2-6 treatments weekly for up to 4 weeks. Articles on tendon, ligament, and bone healing, acute aseptic arthritis, osteoarthritis, paraparesis, hindquarter weakness, and back muscle pain were identified. In experimental bone lesions in dogs, there is moderate scientific evidence for enhanced healing. For the treatment of other musculoskeletal conditions, the scientific evidence is insufficient due to the high risk of bias. There is substantial evidence that continuous TU increases tissue temperature in muscles and tendons by up to 5 °C in healthy animals. For disorders in tendons, ligaments, muscles, and joints in sport and companion animals, there is insufficient evidence for the clinical effects of TU.

Therapeutic Ultrasound Halts Progression of Chronic Kidney Disease In Vivo via the Regulation of Markers Associated with Renal Epithelial-Mesenchymal Transition and Senescence

Low-intensity pulsed ultrasound (LIPUS), a therapeutic type of ultrasound, is known to enhance bone fracture repair processes and help some tissues to heal. Here, we investigated the therapeutic potential of LIPUS for the treatment of chronic kidney disease (CKD) in two CKD mouse models. CKD mice were induced using both unilateral renal ischemia/reperfusion injury (IRI) with nephrectomy and adenine administration. The left kidneys of the CKD mice were treated using LIPUS with the parameters of 3 MHz, 100 mW/cm2, and 20 min/day, based on the preliminary experiments. The mice were euthanized 14 days after IRI or 28 days after the end of adenine administration. LIPUS treatment effectively alleviated the decreases in the body weight and albumin/globulin ratio and the increases in the serum renal functional markers, fibroblast growth factor-23, renal pathological changes, and renal fibrosis in the CKD mice. The parameters for epithelial-mesenchymal transition (EMT), senescence-related signal induction, and the inhibition of α-Klotho and endogenous antioxidant enzyme protein expression in the kidneys of the CKD mice were also significantly alleviated by LIPUS. These results suggest that LIPUS treatment reduces CKD progression through the inhibition of EMT and senescence-related signals. The application of LIPUS may be an alternative non-invasive therapeutic intervention for CKD therapy.

Inhibition of Walker-256 Tumor Growth by Combining Microbubble-Enhanced Ultrasound and Endostar

OBJECTIVES

This research is to investigate the anti-tumor effects by combining anti-vascular effect of microbubble enhanced ultrasound (MEUS) mechanical destruction and anti-angiogenic effect of Endostar.

METHODS

Rats bearing Walker-256 tumor were randomly divided into 4 groups treated by Endostar + MEUS combination, Endostar, MEUS or Sham ultrasound (US), respectively. MEUS was induced by Sonazoid microbubble and a focused therapeutic US device. Contrast-enhanced ultrasound (CEUS) was used to assess tumor perfusion before and after treatment. Microvessel density (MVD) was evaluated with immunohistochemical staining of CD31, CD34, and VEGFA. TUNEL assay was used to determine the apoptosis rate of tumor cells.

RESULTS

Endostar + MEUS combined group induced the most reduced blood perfusion and most retarded tumor growth compared with other 3 groups. Decreased MVD was shown in Endostar + MEUS, Endostar and MEUS group, but the lowest MVD value was presented in the combined treatment group. Significant increase was observed in the combined therapy group and MEUS group.

CONCLUSIONS

This study showed an improved anti-vascular and anti-angiogenic effect achieved by combining Endostar and MEUS, and may provide a new method potential for anti-tumor therapy.

Prospective Assessment of Clinical Tests Used to Evaluate Tibial Stress Fracture

Background:

Tibial stress fracture (SFx) is the most common SFx of the lower extremity. Presently, diagnostic accuracy of clinical examination techniques for tibial SFx remains suboptimal.

Purpose:

To assess the diagnostic effectiveness of 5 clinical tests for tibial SFx individually versus a test item cluster.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

A total of 50 patients with tibial pain (17 with bilateral symptoms) were assessed with 5 clinical examination tests (tibial fulcrum test, focal tenderness to palpation, heel percussion test, therapeutic ultrasound test, and 128-Hz tuning fork test) before they underwent diagnostic imaging (radionuclide bone scan). The application of the clinical tests was counterbalanced to minimize the likelihood of carryover effects. Patients provided a pain rating immediately before and after the application of each clinical test.

Results:

The prevalence of tibial SFx among the study participants was 52.2%. High levels of specificity were produced by the therapeutic ultrasound test (93.8%), tuning fork test (90.6%), and percussion test (90.6%). The fulcrum test had moderate to high specificity (84.4%). All tests demonstrated low levels of sensitivity, with the highest levels found for focal tenderness to palpation (48.6%) and fulcrum (45.7%). The fulcrum test provided the highest positive likelihood ratio (2.93), followed by the therapeutic ultrasound test (2.30). The fulcrum test had the lowest negative likelihood ratio (0.64), with the focal tenderness to palpation and tuning fork tests having negative likelihood ratios >1.0. Combinations of these clinical tests did not improve the prediction of tibial SFx above that observed among the individual tests.

Conclusion:

The clinical tests evaluated were generally highly specific, but all had low sensitivity. The fulcrum test provided the highest level of diagnostic accuracy; however, it was inadequate for definitive clinical management. Combining tests did not improve the diagnostic accuracy of tibial SFx.

First-in-man histotripsy of hepatic tumors: the THERESA trial, a feasibility study

Rationale Current hepatic locoregional therapies are limited in terms of effectiveness and toxicities. Given promising pre-clinical results, a first in-human trial was designed to assess the technical effectiveness and safety profile of histotripsy, a noninvasive, non-thermal, non-ionizing focused ultrasound therapy that creates precise, predictable tissue destruction, in patients with primary and secondary liver tumors.Methods A multicenter phase I trial (Theresa Study) was performed in a single country with 8 weeks of planned follow-up. Eight of fourteen recruited patients were deemed eligible and enrolled in the study. Hepatic histotripsy, was performed with a prototype system (HistoSonics, Inc., Ann Arbor, MI). Eleven tumors were targeted in the 8 patients who all had unresectable end-stage multifocal liver tumors: colorectal liver metastases (CRLM) in 5 patients (7 tumors), breast cancer metastases in 1 (1 tumor), cholangiocarcinoma metastases in 1 (2 tumors), and hepatocellular carcinoma (HCC) in 1 (1 tumor). The primary endpoint was acute technical success, defined as creating a zone of tissue destruction per planned volume assessed by MRI 1-day post-procedure. Safety (device-related adverse events) through 2 months was a secondary endpoint.Results The 8 patients had a median age of 60.4 years with an average targeted tumor diameter of 1.4 cm. The primary endpoint was achieved in all procedures. The secondary safety profile endpoint identified no device-related adverse events. Two patients experienced a continuous decline in tumor markers during the eight weeks following the procedure.Conclusions This first-in-human trial demonstrates that hepatic histotripsy effectively destroys liver tissue in a predictable manner, correlating very well with the planned histotripsy volume, and has a high safety profile without any device-related adverse events. Based on these results, the need for more definitive clinical trials is warranted. Trial Registration: Study to Evaluate VORTX Rx (Theresa). NCT03741088. https://clinicaltrials.gov/ct2/show/NCT03741088 KEY POINTSHistotripsy, a new noninvasive, non-thermal, non-ionizing focused ultrasound therapy, safely created a zone of tissue destruction in the liver that correlated very well with the pre-defined planned tissue destruction volume.In this first human trial histotripsy was well tolerated with no histotripsy device-related adverse events and its primary endpoint of acute technical success was achieved in all 8 enrolled patients with primary or secondary liver tumors.This new locoregional therapy for patients with liver tumors is safe and effective, warranting further trials.

Therapeutic Ultrasound and Shockwave Therapy for Tendinopathy: A Narrative Review

ABSTRACT

Tendon injury is prevalent and costly in the United States, comprising 45% of the 66 million musculoskeletal injuries and costing $114 billion annually. Surgical and therapeutic methods, such as arthroscopic surgery, dry needling, and physical therapy, produce mixed success in reintroducing a healing response in tendinopathy due in part to inconsistent dosing and monitoring. Ultrasound is one therapeutic modality that has been shown to noninvasively induce bioeffects in tendon that may help promote healing. However, results from this modality have also been mixed. This review compares the current state of the field in therapeutic ultrasound and shockwave therapy, including low-intensity therapeutic ultrasound, extracorporeal shockwave therapy, and radial shockwave therapy, and evaluates the efficacy in treating tendinopathies with ultrasound. We found that the mixed successes may be attributed to the wide variety of achievable parameters within each broader treatment type and the lack of standardization in measurements and reporting. Despite mixed outcomes, all three therapies show potential as an alternative therapy with lower-risk adverse effects than more invasive methods like surgery. There is currently insufficient evidence to conclude which ultrasound modality or settings are most effective. More research is needed to understand the healing effects of these different therapeutic ultrasound and shockwave modalities.

Therapeutic Ultrasound for Topical Corneal Delivery of Macromolecules

Purpose

The objective of this study was to utilize therapeutic ultrasound in enhancing delivery of topical macromolecules into the cornea.

Methods

Rabbit corneas were dissected and placed in a diffusion cell with a small ultra-red fluorescent protein (smURFP; molecular weight of 32,000 Da) as a macromolecule solution. The corneas were treated with continuous ultrasound application at frequencies of 400 or 600 kHz and intensities of 0.8 to 1.0 W/cm2 for 5 minutes, or sham-treated. Fluorescence imaging of the cornea sections was used to observe the delivery of macromolecules into individual epithelial cells. Spectrophotometric analysis at smURFP maximal absorbance of 640 nm was done to determine the presence of macromolecules in the receiver compartment. Safety of ultrasound application was studied through histology analysis.

Results

Ultrasound-treated corneas showed smURFP delivery into epithelial cells by fluorescence in the cytoplasm, whereas sham-treated corneas lacked any appreciable fluorescence in the individual cells. The sham group showed 0% of subcellular penetration, whereas the 400 kHz ultrasound-treated group and 600 kHz ultrasound-treated group showed 31% and 57% of subcellular penetration, respectively. Spectrophotometry measurements indicated negligible presence of smURFP macromolecules in the receiver compartment solution in both the sham and ultrasound treatment groups, and these macromolecules did not cross the entire depth of the cornea. Histological studies showed no significant corneal damage due to ultrasound application.

Conclusions

Therapeutic ultrasound application was shown to increase the delivery of smURFP macromolecules into the cornea.

Translational Relevance

Our study offers a clinical potential for a minimally invasive macromolecular treatment of corneal diseases.

Effects of phase aberration on transabdominal focusing for a large aperture, lowf-number histotripsy transducer

Objective. Soft tissue phase aberration may be particularly severe for histotripsy due to large aperture and lowf-number transducer geometries. This study investigated how phase aberration from human abdominal tissue affects focusing of a large, strongly curved histotripsy transducer.Approach.A computational model (k-Wave) was experimentally validated withex vivoporcine abdominal tissue and used to simulate focusing a histotripsy transducer (radius: 14.2 cm,f-number: 0.62, central frequencyfc: 750 kHz) through the human abdomen. Abdominal computed tomography images from 10 human subjects were segmented to create three-dimensional acoustic property maps. Simulations were performed focusing at 3 target locations in the liver of each subject with ideal phase correction, without phase correction, and after separately matching the sound speed of water and fat to non-fat soft tissue.Main results.Experimental validation in porcine abdominal tissue showed that simulated and measured arrival time differences agreed well (average error, ∼0.10 acoustic cycles atfc). In simulations with human tissue, aberration created arrival time differences of 0.65μs (∼0.5 cycles) at the target and shifted the focus from the target by 6.8 mm (6.4 mm pre-focally along depth direction), on average. Ideal phase correction increased maximum pressure amplitude by 95%, on average. Matching the sound speed of water and fat to non-fat soft tissue decreased the average pre-focal shift by 3.6 and 0.5 mm and increased pressure amplitude by 2% and 69%, respectively.Significance.Soft tissue phase aberration of large aperture, lowf-number histotripsy transducers is substantial despite low therapeutic frequencies. Phase correction could potentially recover substantial pressure amplitude for transabdominal histotripsy. Additionally, different heterogeneity sources distinctly affect focusing quality. The water path strongly affects the focal shift, while irregular tissue boundaries (e.g. fat) dominate pressure loss.

Effect of Therapeutic Ultrasound on the Release of Insulin, Glucagon, and Alpha-Amylase from Ex Vivo Pancreatic Models

OBJECTIVES

Our previously published studies showed the potential of therapeutic ultrasound (US) as a novel non-pharmacological alternative for the treatment of secretory deficiencies in type 2 diabetes. Despite showing enhanced insulin release from beta cells, these studies did not explore the potential effects of US treatment on other cells in the islets of Langerhans such as glucagon-secreting alpha cells or acinar cells of the exocrine pancreas.

METHODS

We applied US parameters found capable of safely stimulating insulin secretion from pancreatic beta cells (f = 800 kHz, ISPTA  = 0.5-1 W/cm2 , 5 minutes) to a diced rabbit pancreas model in culture plates (n = 6 per group). Released quantities of insulin and glucagon in response to US treatment were measured by collecting aliquots of the extracellular medium prior to the start of the treatment (t = 0 minute), immediately after treatment (t = 5 minutes) and 30 minutes after the end of treatment (t = 35 minutes). Potential release of digestive enzyme alpha-amylase as a result of US treatment was evaluated in rabbit pancreas experiments. Preliminary studies were also performed in a small number of human pancreatic islets in culture plates (n = 3 per group). The general integrity of the US-treated rabbit pancreatic tissue and human pancreatic islets was evaluated through histological analysis.

RESULTS

While sham-treated rabbit pancreas samples showed decreased extracellular insulin content, there was an increase in insulin release at t = 5 minutes from samples treated with US at 800 kHz and 1 W/cm2 (P <.005). Furthermore, no further insulin release was detected at t = 35 minutes. No statistically significant difference in extracellular glucagon and alpha-amylase concentrations was observed between US-treated and sham rabbit pancreas groups. Preliminary studies in human islets appeared to follow trends observed in rabbit pancreas studies. Islet and other pancreatic tissue integrity did not appear to be affected by the US treatment.

CONCLUSION

A potential US-based strategy for enhanced insulin release would require optimization of insulin secretion from pancreatic beta cells while minimizing glucagon and pancreatic enzyme secretions.

Therapeutic Ultrasound-Enhanced Transcorneal PHMB Delivery In Vitro

OBJECTIVE

Delivery of therapeutic agents to the cornea is a difficult task in the treatment of parasitic keratitis. In this study, we looked at using different combinations of ultrasound parameters to enhance corneal permeability to polyhexamethylene biguanide (PHMB), a clinically available ophthalmic antiparasitic formulation.

METHODS

Permeability of PHMB was investigated in vitro using a standard diffusion cell setup. Continuous or 25% duty-cycle ultrasound was used at frequencies of 400 or 600 kHz, intensities of 0.5 or 0.8 W/cm² , and exposure times ranging from 1 to 5 minutes. Structural changes in the cornea were examined using light microscopy.

RESULTS

Ultrasound exposure produced increases in transcorneal delivery in every treatment parameter combination when compared to the sham treatment. The highest increase was 2.36 times for 5 minutes of continuous ultrasound at a frequency of 600 kHz and an intensity of 0.5 W/cm² with statistical significance (p <.001). Histological analysis showed that ultrasound application only caused structural changes in the corneal epithelium, with most damage being at the surface layers.

CONCLUSIONS

This study suggests the possibility of therapeutic ultrasound as a novel drug delivery technique for the treatment of parasitic keratitis. Further studies are needed to examine the thermal effects of these proposed ultrasound applications and the long-term viability of this treatment.

Synergic effects of ultrasound and laser therapies on mesentery for management of obesity and diabetes in rats

Nowadays, the mesentery as a new organ was discovered. Mesenteric events may play an important role in the pathophysiology of several diseases. The aim of our study was investigate the synergic effects of ultrasound (US) and laser therapies on mesentery in obese-hyperglycemic rats. The 25 male Wistar rats were randomized into five groups. Obese nondiabetic (OND) group: obese rats without diabetes and no treatment conditions; SHAM group: obese-hyperglycemic rats treated with placebo; US group: obese-hyperglycemic rats treated with US; LASER group: obese-hyperglycemic rats treated with laser and; US+LASER group: obese-hyperglycemic rats treated with US plus laser. An animal model of type 2 diabetes based on a hyperlipidemic diet combined with a low dose of streptozotocin was used in this study. Body mass and biochemical measurements were performed. GOT and GPT level showed a significant reduction in the treated groups than SHAM. The total cholesterol, triglycerides and very low-density lipoprotein (VLDL) levels showed significantly lower values for the US+LASER group. There was also reduced risk of cardiovascular diseases evidenced by Castelli index in the treated groups than SHAM. This study showed that the US and laser treatment on mesentery resulted to an improvement in biochemical measurements of the obese-hyperglycemic rats, especially the total cholesterol, triglycerides and VLDL levels.

Effects of 1 MHz Therapeutic Ultrasound on Limb Blood Flow and Microvascular Reactivity: A Randomized Pilot Trial

A randomized, double-blind, placebo-controlled, cross-over study where continuous therapeutic ultrasound (CUS; at 0.4 W/cm²), pulsed therapeutic ultrasound (PUS; at 20% duty cycle, 0.08 W/cm²), both at 1 MHz, and placebo (equipment on, no energy provided) were randomized and applied over the forearm of the non-dominant arm for 5 min in 10 young, healthy individuals. Absolute and peak forearm blood flow (FBF) were measured via Venous Occlusion Plethysmography. FBF was measured before, halfway, and after (immediately and 5 min after) the therapeutic ultrasound (TUS) intervention. Post-ischemic peak FBF was measured 10 min before and 10 min after the TUS intervention. A two-way repeated measures ANOVA (group × time) was selected to assess differences in FBF before, during, and after TUS treatment, and for peak FBF before and after TUS treatment. FBF increased 5 min after TUS in CUS compared to placebo (2.96 ± 1.04 vs. 2.09 ± 0.63 mL/min/100 mL of tissue, p < 0.05). PUS resulted in the greatest increase in Peak FBF at 10 min after US (Δ = 3.96 ± 2.02 mL/min/100 mL of tissue, p = 0.06). CUS at 1 MHz was an effective treatment modality for increasing FBF up to 5 min after intervention, but PUS resulted in the greatest increase in peak FBF at 10 min after intervention.

Antibacterial Sonodynamic Therapy: Current Status and Future Perspectives

Multidrug-resistant bacteria have emerged in both community and hospital settings, partly due to the misuse of antibiotics. The inventory of viable antibiotics is rapidly declining, and efforts toward discovering newer antibiotics are not yielding the desired outcomes. Therefore, alternate antibacterial therapies based on physical mechanisms such as light and ultrasound are being explored. Sonodynamic therapy (SDT) is an emerging therapeutic approach that involves exposing target tissues to a nontoxic sensitizing chemical and low-intensity ultrasound. SDT can enable site-specific cytotoxicity by producing reactive oxygen species (ROS) in response to ultrasound, which can be harnessed for treating bacterial infections. This approach can potentially be used for both superficial and deep-seated microbial infections. The majority of the sonosensitizers reported are nonpolar, exhibiting limited bioavailability and a high clearance rate in the body. Therefore, targeted delivery agents such as nanoparticle composites, liposomes, and microbubbles are being investigated. This article reviews recent developments in antibacterial sonodynamic therapy, emphasizing biophysical and chemical mechanisms, novel delivery agents, ultrasound exposure and image guidance strategies, and the challenges in the pathway to clinical translation.

Functional intersections between extracellular vesicles and oncolytic therapies

Minimally invasive focal therapies for nonviral oncolysis are a cornerstone of cancer therapeutics. Our ability to optimally deploy oncolytic therapies and identify synergistic combination approaches requires a deeper understanding of elicited biological responses. Extracellular vesicles (EV), which orchestrate a variety of pathophysiological processes and have a critical role in the evolution of primary and disseminated tumors, are now known to be potently modulated by oncolytic focal therapies, such as radiotherapy, photodynamic therapy (PDT), and therapeutic ultrasound (TUS). In this review, we summarize the diverse impacts of the aforementioned therapeutic modalities on EV biology, and highlight the most recent advances in EV-based drug delivery systems leveraging these modalities.

Ultrasound-Enabled Therapeutic Delivery and Regenerative Medicine: Physical and Biological Perspectives

The role of ultrasound in medicine and biological sciences is expanding rapidly beyond its use in conventional diagnostic imaging. Numerous studies have reported the effects of ultrasound on cellular and tissue physiology. Advances in instrumentation and electronics have enabled successful in vivo applications of therapeutic ultrasound. Despite path breaking advances in understanding the biophysical and biological mechanisms at both microscopic and macroscopic scales, there remain substantial gaps. With the progression of research in this area, it is important to take stock of the current understanding of the field and to highlight important areas for future work. We present herein key developments in the biological applications of ultrasound especially in the context of nanoparticle delivery, drug delivery, and regenerative medicine. We conclude with a brief perspective on the current promise, limitations, and future directions for interfacing ultrasound technology with biological systems, which could provide guidance for future investigations in this interdisciplinary area.

Transcranial MR-Guided Histotripsy System

Histotripsy has been previously shown to treat a wide range of locations through excised human skulls in vitro. In this article, a transcranial magnetic resonance (MR)-guided histotripsy (tcMRgHt) system was developed, characterized, and tested in the in vivo pig brain through an excised human skull. A 700-kHz, 128-element MR-compatible phased-array ultrasound transducer with a focal depth of 15 cm was designed and fabricated in-house. Support structures were also constructed to facilitate transcranial treatment. The tcMRgHt array was acoustically characterized with a peak negative pressure up to 137 MPa in free field, 72 MPa through an excised human skull with aberration correction, and 48.4 MPa without aberration correction. The electronic focal steering range through the skull was 33.5 mm laterally and 50 mm axially, where a peak negative pressure above the 26-MPa cavitation intrinsic threshold can be achieved. The MR compatibility of the tcMRgHt system was assessed quantitatively using SNR, B0 field map, and B1 field map in a clinical 3T magnetic resonance imaging (MRI) scanner. Transcranial treatment using electronic focal steering was validated in red blood cell phantoms and in vivo pig brain through an excised human skull. In two pigs, targeted cerebral tissue was successfully treated through the human skull as confirmed by MRI. Excessive bleeding or edema was not observed in the peri-target zones by the time of pig euthanasia. These results demonstrated the feasibility of using this preclinical tcMRgHt system for in vivo transcranial treatment in a swine model.

Preliminary effects of low-intensity focused ultrasound treatment program for cancer-related neuropathic pain

Aim: To evaluate the effectiveness of low-intensity focused ultrasound (LIFU) therapy in the management of cancer-related neuropathic pain (CNP). Methods: A retrospective review with 22 patients with CNP treated with LIFU therapy (frequency 3 Hz, 3 W/cm², pulse mode duty cycle 50%) was conducted. Results: Out of the 22 patients, 15 had CNP secondary to chemotherapy-induced peripheral neuropathy. Compared with baseline, there was a significant reduction in numeric pain rating scale (p < 0.001). Additionally, 76.5% of patients (n = 13) were considered to be responders to LIFU therapy. Conclusion: LIFU therapy may be a viable treatment modality in the management of CNP, specifically chemotherapy-induced peripheral neuropathy, with a minimal side effect profile. Larger, prospective studies with a structured protocol are necessary.

Therapeutic Ultrasound Triggered Silk Fibroin Scaffold Degradation

A patient's capacity for tissue regeneration varies based on age, nutritional status, disease state, lifestyle, and gender. Because regeneration cannot be predicted prior to biomaterial implantation, there is a need for responsive biomaterials with adaptive, personalized degradation profiles to improve regenerative outcomes. This study reports a new approach to use therapeutic ultrasound as a means of altering the degradation profile of silk fibroin biomaterials noninvasively postimplantation. By evaluating changes in weight, porosity, surface morphology, compressive modulus, and chemical structure, it is concluded that therapeutic ultrasound can trigger enhanced degradation of silk fibroin scaffolds noninvasively. By removing microbubbles on the scaffold surface, it is found that acoustic cavitation is the mechanism responsible for changing the degradation profile. This method is proved to be safe for human cells with no negative effects on cell viability or metabolism. Sonication through human skin also effectively triggers scaffold degradation, increasing the clinical relevance of these results. These findings suggest that silk is an ultrasound-responsive biomaterial, where the degradation profile can be adjusted noninvasively to improve regenerative outcomes.

Comparing the efficacy of continuous and pulsed ultrasound therapies in patients with lateral epicondylitis: A double-blind, randomized, placebo-controlled study

Objectives

The aim of this study was to investigate the efficacy of continuous and pulsed ultrasound therapies in lateral epicondylitis.

Patients and methods

A total of 51 patients (18 males, 33 females; mean age: 46.52±6.16 years; range, 27 to 64 years) who were diagnosed with lateral epicondylitis between February 2013 and October 2014 were included. The patients were randomized to either continuous ultrasound (n=17), pulsed ultrasound (n=17), or placebo (n=17) groups. First group received 10 sessions of continuous ultrasound therapy. The second group received 10 sessions of pulsed ultrasound therapy in a ratio of 1:4. The third group received 10 sessions of placebo treatment. The pain levels of the patients were evaluated using Visual Analog Scale (VAS). The muscle strength was evaluated using a dynamometer. For functional evaluation, Duruöz’s Hand Index (DHI) and Patient-Rated Tennis Elbow Evaluation (PRTEE) scales were used. Assessments were made at baseline, at the end of therapy, and one month after therapy. The thickness of the common extensor tendon was also measured using ultrasonic imaging at baseline and at the end of therapy.

Results

At the end of the study, there was a statistically significant improvement in the rest and activation VAS scores, and DHI and PRTEE scores in both continuous and pulsed ultrasound therapy groups, compared to placebo (p<0.05). However, no superiority was found between the continuous and pulsed ultrasound therapy groups (p>0.05). A statistically significant reduction in the common extensor tendon thickness was found only in the pulsed ultrasound therapy group (p<0.05).

Conclusion

Our study results show that both continuous and pulsed ultrasound applications are effective in the treatment of lateral epicondylitis.

Relief of Lower Urinary Tract Symptoms After MRI-Guided Transurethral Ultrasound Ablation for Localized Prostate Cancer: Subgroup Analyses in Patients with Concurrent Cancer and Benign Prostatic Hyperplasia

Background: MRI-guided transurethral ultrasound ablation (TULSA) offers minimally invasive thermal ablation of benign and malignant prostate tissue, using directional high-intensity ultrasound and real-time, magnetic resonance thermometry feedback control. Feasibility of TULSA for alleviating lower urinary tract symptoms (LUTSs) associated with benign prostatic hyperplasia (BPH) is retrospectively assessed in a subgroup of men from a localized prostate cancer study who also had LUTSs. Patients and Methods: TULSA was used to ablate 90% of the prostate gland in 30 men with localized prostate cancer, without plans to spare ejaculatory ducts. Mean ± standard deviation treatment time was 37 ± 10 minutes. Retrospective analysis was conducted on a subpopulation of nine patients who also suffered from LUTSs (International Prostate Symptom Score [IPSS] ≥ 12 at baseline) as well as a smaller subgroup of five patients with IPSS >12 and peak urinary flow (Q_max) <15 mL/second. Urinary symptom relief, continence, and erectile function were assessed using IPSS, International Index of Erectile Function (IIEF), and uroflowmetry. Results: At 12 months post-TULSA, IPSS improved significantly by 58% to 6.3 ± 5.0 (p = 0.003), with at least a moderate (≥6 points) reduction in eight of nine patients. IPSS quality of life improved in eight of nine patients. Erectile function (IIEF-EF) remained stable from 14.6 ± 9.3 at baseline to 15.7 ± 9.0 at 12 months. The proportion of patients with erections sufficient for penetration (IIEF Q2 ≥2) was unchanged. Full urinary continence (pad free and leak free) was achieved at 12 months in all patients. In five men who suffered from more severe symptoms, Q_max increased from 11.6 ± 2.6 mL/second to 22.5 ± 14.2 mL/second at 12 months (p = 0.126). Perfused prostate volume, measured on MRI, decreased 70% to 13.6 ± 4.6 mL (p = 0.003) at 12 months. All adverse events were mild to moderate (Common Terminology Criteria for Adverse Events [CTCAE] Grade 1-2) with no serious events reported. Conclusions: This retrospective analysis demonstrates promising safety and feasibility of TULSA to relieve LUTSs, with improvement in IPSS comparable with modern, minimally invasive surgical therapies. Larger controlled studies with BPH-specific ablation plans in men seeking treatment for LUTSs are warranted.

Multimodal therapy for treatment of equine back pain: a report of 15 cases

Back pain and diseases of the spine are considered significant problems in equine sports and veterinary medicine. This article reports a multimodal approach to the treatment of equine back pain using ozonized platelet rich plasma (PRP), dynamic mobilization exercises, and therapeutic shoeing in 15 horses involved in the vaquejada discipline. Fifteen American Quarter Horses of both sexes engaged in vaquejada in the state of Rio Grande do Norte, Brazil, with a mean age of 8.61 ? 1.73 years were examined at a training center for lower performance diagnostics or back pain. A complete clinical examination was performed on all horses at rest to determine the general conformation and alterations in posture, symmetry, and curvature of the spine. The horses were examined while walking and trotting in straight lines and circles to determine the presence of lameness and/or gait asymmetry. Spinal abnormalities on clinical examination were classified on a scale of 0 to 5 based on the following parameters: degree of response to pain from back palpation, hypertonicity of the back muscles, stiffness of the thoracolumbar joint, and physical dysfunction. After physical examination, ultrasound was performed to identify the cause of the thoracolumbar pain. The therapeutic protocol consisted of the intralesional application of ozonized PRP combined with therapeutic ultrasound, dynamic mobilization exercises, and therapeutic shoeing. All treated animals returned to sports activities at a higher level of performance than at the beginning of the treatment. Six months after treatment, telephone contact was made with the owner or trainer to determine if the back pain had relapsed. None of the animals relapsed during this period, and they participated in vaquejada normally.

Review on experimental study and clinical application of low-intensity pulsed ultrasound in inflammation

Low-intensity pulsed ultrasound (LIPUS), as physical therapy, is widely used in both research and clinical settings. It induces multiple bioeffects, such as alleviating pain, promoting tissue repair, and shortening disease duration. LIPUS can also mediate inflammation. This paper reviews the application of LIPUS in inflammation and discusses the underlying mechanism. In basic experiments, LIPUS can regulate inflammatory responses at the cellular level by affecting some signaling pathways. In a clinical trial, LIPUS has been shown to alleviate inflammatory responses efficiently. As a cheap, safe, and convenient physical method, LIPUS is promising as anti-inflammatory therapy.

The additive efficacy of therapeutic low-intensity pulsed ultrasound in the treatment of vitiligo: A randomized, left-right comparison clinical trial

Repigmentation of vitiligo relies on the proliferation and migration of melanoblasts from hair follicles to the epidermis to replenish epidermal melanin. Our previous study has demonstrated low-intensity pulsed ultrasound (LIPUS) can stimulate melanoblast migration in vitro. We sought to evaluate the potential additive efficacy and safety of LIPUS for repigmentation of vitiligo. Twenty-seven adult patients with stable generalized vitiligo on the face or trunk were recruited in this randomized, open, left-right comparison study. In each patient, two symmetric lesional sites were randomly selected; one was assigned as the target lesion, which was treated with add-on LIPUS twice weekly for 24 weeks, and the other as the control lesion, which was administrated with sham sonification. The primary outcome was the difference of repigmentation degree between the target and control lesions at week 24, based on the 7-point physician global assessment score. At the end of study, 23 patients with vitiligo on the face (n = 10) or trunk (n = 13) completed the 24-week treatment course. Enhanced repigmentation for vitiligo receiving LIPUS as compared to sham sonification was observed in 38.5% (5/13) of the patients with truncal vitiligo, but none of those with facial vitiligo. Truncal vitiligo (P = .046) and higher intensity of LIPUS administered (P = .01) were statistically significantly associated with the effectiveness of additive LIPUS treatment. The LIPUS treatment was well-tolerated without remarkable adverse effects. This pilot study showed that LIPUS could provide therapeutic benefits and could be considered as a treatment adjunct for truncal vitiligo.

High-Intensity Focused Ultrasound in the Treatment of Breast Cancer

High-intensity focused ultrasound (HIFU) is a non-invasive method of ablating malignant tumors. This paper will review the current clinical application of HIFU specially in the treatment of breast cancer. In addition to clinical studies, this review will also look into some basic studies that could address the technical issues related to this modality. In general, HIFU is considered to be safe being non-invasive and non-ionizing. The complication occurrence rate is low and repeated treatment is possible, making it an attractive option for some patients. However, for more than two decades since it was first used to treat breast cancer, clinical studies on HIFU still remain at the investigative stage and are only available in several centers. Reasons contributing to such few studies on HIFU include lack of specialized medical team and bioengineering technical staff, and breast cancer-dedicated imaging-HIFU platform to attain positive outcomes. Despite these circumstances, we believe that HIFU will eventually become the treatment of choice for most breast cancer patients in the near future.

Non-invasive recanalization of deep venous thrombosis by high frequency ultrasound in a swine model with follow-up

AIMS

Pulsed cavitational ultrasound therapy (thombotripsy) allows the accurate fractionation of a distant thrombus. We aimed to evaluate the efficacy and safety of non-invasive thrombotripsy using a robotic assisted and high frequency ultrasound approach to recanalize proximal deep venous thrombosis (DVT) in a swine model.

METHODS

Occlusive thrombosis was obtained with a dual jugular and femoral endoveinous approach. The therapeutic device was composed of a 2.25 MHz focused transducer centered by a linear ultrasound probe, and a robotic arm. The feasibility, security, and efficacy (venous channel patency) assessment after thrombotripsy was performed on 13 pigs with acute occluded DVT. To assess the mid-term efficacy of this technique, 8 pigs were followed up for 14 days after thrombotripsy and compared with 8 control pigs. The primary efficacy endpoint was the venous patency. Safety was assessed by the search for local vessel wall injury and pulmonary embolism.

RESULTS

We succeeded in treating all pigs except two with no accessible femoral vein. After median treatment duration of 23 minutes of cavitation, all treated DVT were fully recanalized acutely. At 14 days, in the treated group, six of the eight pigs had a persistent patent vein and two pigs had a venous reocclusion. In the control group all pigs had a persistent venous occlusion. At sacrifice, no local vein nor arterial wall damage were observed as well as no evidence of pulmonary embolism in all pigs.

CONCLUSION

High frequency thrombotripsy seems to be effective and safe for non-invasive venous recanalization of DVT.

An Integrated Robotic System for MRI-Guided Neuroablation: Preclinical Evaluation

OBJECTIVE

Treatment of brain tumors requires high precision in order to ensure sufficient treatment while minimizing damage to surrounding healthy tissue. Ablation of such tumors using needle-based therapeutic ultrasound (NBTU) under real-time magnetic resonance imaging (MRI) can fulfill this need. However, the constrained space and strong magnetic field in the MRI bore restricts patient access limiting precise placement of the NBTU ablation tool. A surgical robot compatible with use inside the bore of an MRI scanner can alleviate these challenges.

METHODS

We present preclinical trials of a robotic system for NBTU ablation of brain tumors under real-time MRI guidance. The system comprises of an updated robotic manipulator and corresponding control electronics, the NBTU ablation system and applications for planning, navigation and monitoring of the system.

RESULTS

The robotic system had a mean translational and rotational accuracy of 1.39  ± 0.64 mm and 1.27 [Formula: see text] in gelatin phantoms and 3.13  ± 1.41 mm and 5.58 [Formula: see text] in 10 porcine trials while causing a maximum reduction in signal to noise ratio (SNR) of 10.3%.

CONCLUSION

The integrated robotic system can place NBTU ablator at a desired target location in porcine brain and monitor the ablation in realtime via magnetic resonance thermal imaging (MRTI).

SIGNIFICANCE

Further optimization of this system could result in a clinically viable system for use in human trials for various diagnostic or therapeutic neurosurgical interventions.

Therapeutic Ultrasound in Cardiovascular Medicine

An advantage of therapeutic ultrasound (US) is the ability to cause controlled biological effects noninvasively. Depending on the magnitude and frequency of exposure parameters, US can interact in different ways with a variety of biological tissues. The development and clinical utility of therapeutic US techniques are now rapidly growing, especially with regard to the application of US pulses for cardiac pacing and the potential treatment of cardiovascular diseases. This review outlines the basic principles of US-based therapy in cardiology, including the acoustic properties of the cardiovascular tissue, and the use of US in therapeutic cardiovascular medicine.

Palliative MRI-guided transurethral ultrasound ablation for symptomatic locally advanced prostate cancer

PURPOSE

Locally advanced prostate cancer can cause bladder outlet obstruction, gross hematuria and frequent hospitalization. While these complications are commonly treated by palliative transurethral resection of the prostate, the improvement is often insufficient. The purpose of this study was to evaluate the safety and feasibility of MRI-guided transurethral ultrasound ablation as an alternative palliative treatment option (pTULSA) for men suffering from symptomatic locally advanced prostate cancer.

METHODS

This prospective, phase one study included 10 men in need of palliative surgical intervention due to urinary retention and gross hematuria caused by locally advanced prostate cancer. Patients were followed for 1 year at 3-month intervals. Time without catheter, time without hematuria, reduction in hospitalization time, and adverse events were measured.

RESULTS

Ten patients with locally advanced prostate cancer were enrolled, all having continuous catheterization due to urinary retention and nine had gross hematuria before treatment. At 1 week post-pTULSA five patients were catheter-free. At last follow-up catheter-free and gross hematuria-free rates were 70% and 100%, respectively. Average hospitalization time from local complications reduced from 7.3 to 1.4 days in the 6 months before and after pTULSA. No > Grade 2 treatment related adverse events were reported, with all five being urinary tract infections.

CONCLUSIONS

pTULSA appears safe and feasible for palliative ablation of locally advanced prostate cancer. The therapy seems to accomplish long-term hematuria control, can relieve bladder outlet obstruction in selected patients, and seems to reduce the burden of hospitalization due to local complications. Trial Registration Number: NCT03350529.

Dose-dependent effects of ultrasound therapy on hepatocellular carcinoma

Non-invasive ischemic cancer therapy requires reduced blood flow whereas drug delivery and radiation therapy require increased tumor perfusion for a better response. In this study we investigate the hypothesis that different dose models of antivascular ultrasound therapy (AVUS) can have opposite effects on hepatocellular carcinoma (HCC) tumor blood flow. HCC was induced in 22 Wistar rats by ingestion of diethylnitrosamine (DEN) for 12 weeks. Rats received AVUS treatment at low and high doses. Low dose group received 1 watt/cm2 ultrasound for 1 min with 0.2 mL microbubbles injected IV. High dose group received 2 watts/cm2 for 2 min with 0.7 mL microbubbles IV. A sham group did not receive any treatment. Tumor perfusion was measured before and after AVUS with contrast-enhanced ultrasound. Quantitative perfusion measures: perfusion index (PI) and peak enhancement (PE) were obtained from each AVUS dose. After high-dose AVUS, PE and PI decreased by an average of 58.1 ± 4.9% and 49.1 ± 6.5 % respectively. Conversely, following low dose AVUS, PE and PI increased from baseline by an average of 47.8 ± 4.5% % and 20.3 ± 2.4 %, respectively. The high-dose AVUS therapy decreased tumoral perfusion, an effect that could be used for noninvasive ischemic therapy. Conversely, low-dose therapy increased tumor perfusion, which may improve drug delivery or radiation therapy. These opposite therapy effects can support multiple roles for AVUS in cancer therapy by tunable modulation of blood flow in tumors.

Ultrasound neuromodulation: mechanisms and the potential of multimodal stimulation for neuronal function assessment

Focused ultrasound (FUS) neuromodulation has shown that mechanical waves can interact with cell membranes and mechanosensitive ion channels, causing changes in neuronal activity. However, the thorough understanding of the mechanisms involved in these interactions are hindered by different experimental conditions for a variety of animal scales and models. While the lack of complete understanding of FUS neuromodulation mechanisms does not impede benefiting from the current known advantages and potential of this technique, a precise characterization of its mechanisms of action and their dependence on experimental setup (e.g., tuning acoustic parameters and characterizing safety ranges) has the potential to exponentially improve its efficacy as well as spatial and functional selectivity. This could potentially reach the cell type specificity typical of other, more invasive techniques e.g., opto- and chemogenetics or at least orientation-specific selectivity afforded by transcranial magnetic stimulation. Here, the mechanisms and their potential overlap are reviewed along with discussions on the potential insights into mechanisms that magnetic resonance imaging sequences along with a multimodal stimulation approach involving electrical, magnetic, chemical, light, and mechanical stimuli can provide.

Therapeutic ultrasound combined with microbubbles improves atherosclerotic plaque stability by selectively destroying the intraplaque neovasculature

Objective: The current antiangiogenic therapy for atherosclerotic plaques was mainly achieved by the use of antiangiogenic drugs, but serious side effects have limited the clinical application. The present study investigated whether therapeutic ultrasound (TUS) treatment with appropriate pressure could selectively deplete the neovasculature in vulnerable plaques to improve its stability with no side effects on the body; the underlying mechanisms were also explored.

Methods and Results: A mouse model of advanced atherosclerosis was generated by maintaining apolipoprotein E-deficient (ApoE-/-) mice on a hypercholesterolemic diet (HCD). Plaque, skeletal muscle, mesentery and skin tissue from 114 atheroma-bearing mice were subjected to sham therapy, an ultrasound application combined with microbubbles at four different ultrasound pressures (1.0, 2.0, 3.0, 5.0 MPa), or ultrasound at 5.0 MPa alone. Microvessel density (MVD) was assessed by immunofluorescence and immunohistochemical methods. The plaque necrotic center/fiber cap (NC/FC) ratio and vulnerability index were calculated to evaluate plaque vulnerability. Twenty-four hours after TUS treatment at 3.0 MPa, the MVD in the plaque was substantially decreased by 84% (p < 0.05), while there was almost no change in MVD and neovessel density (NVD) in normal tissues, including skeletal muscle, mesentery and skin. Additionally, a marked reduction in the number of immature vessels was observed in the plaques (reduced by 90%, p < 0.05), whereas the number of mature vessels was not significantly decreased. Furthermore, TUS treatment at 3.0 MPa significantly improved plaque stability, as reflected by the NC/FC ratio and vulnerability index, which may be due to the selective destruction of intraplaque neovascularization by TUS treatment, thereby decreasing the extravasation of erythrocytes and leading to vascular inflammation alleviation and thin-cap fibroatheroma reduction.

Conclusions: TUS treatment at 3.0 MPa selectively depleted plaque neovessels and improved the stability of vulnerable plaques through a reduction in erythrocyte extravasation and inflammatory mediator influx, with no significant effect on normal tissue.

Comparative efficacy of analgesic gel phonophoresis and ultrasound in the treatment of temporomandibular joint disorders

Aim

The aim of this study is to determine the efficacy of phonophoresis in patients with temporomandibular disorders.

Objective

To prove that phonophoresis could be an effective treatment modality in in patients with temporomandibular disorders.

Procedure

Fifty patients diagnosed clinically and radiographically as temporomandibular disorder were randomly assigned into either of the two groups, namely, (Group A) plain ultrasound and (Group B) phonophoresis. Acoustic gel containing no pharmacological agent was applied in the ultrasound group, whereas a gel containing aceclofenac was applied in the phonophoresis group. Each group was treated three times a week for 2 weeks. The assessment of pain and inflammation both before and after treatment were done using the visual analog scale (VAS) and Creactive protein (CRP).

Results

Intergroup comparison was done and analyzed statistically using independent ttest. Intragroup comparison was done using paired ttest. A significant difference in VAS scores and CRP levels before and after treatment were seen within both ultrasound phonophoresis PH groups. No significant difference was noted statistically between ultrasound and phonophoresis group.

Conclusion

The results of this study suggests that though plain ultrasound as well as phonophoresis with aceclofenac gel are effective in the management of temporomandibular disorders. Phonophoresis was found be slightly superior as evident in VAS scores and CRP levels though not statistically significant.