Optimal Treatment Conditions of the Low-intensity Pulsed Ultrasound Therapy for the Treatment of Alzheimer’s Disease -Applications from Mice to Humans-

doi:10.21203/rs.3.rs-3142375/v1

Download PDF

Article

Optimal Treatment Conditions of the Low-intensity Pulsed Ultrasound Therapy for the Treatment of Alzheimer’s Disease -Applications from Mice to Humans-

https://doi.org/10.21203/rs.3.rs-3142375/v1

This work is licensed under a CC BY 4.0 License

Journal Publication

published 02 May, 2024

Read the published version in Journal of Medical Ultrasonics →

Version 1

posted

You are reading this latest preprint version

Background and Purpose

We have previously developed a novel therapy with low-intensity pulsed ultrasound (LIPUS) that ameliorates cognitive decline through upregulation of endothelial nitric oxide synthase in mouse models of Alzheimer's disease (AD) and vascular dementia. We then conducted a randomized, double-blind, placebo-controlled (RCT) pilot trial for efficacy and safety of the whole-brain LIPUS therapy in patients with early AD. We demonstrated that the LIPUS therapy is safe and tends to suppress the cognitive decline in AD patients. We here report the findings of our basic experiments that we performed for the pilot trial in order to apply the whole-brain LIPUS therapy from mice to humans.

Methods

We performed basic experiments of the LIPUS therapy to identify the optimal treatment condition. First, by using human temporal bone, we examined the relationship between bone density/thickness and ultrasound transmittance. Next, based on the results of ultrasound transmittance, we further examined mRNA expression of vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), and endothelial nitric oxide synthase (eNOS) in response to variable frequencies, duty cycles, and sound pressures.

Results

There was a significant correlation between bone thickness and transmittance (1.0 MHz, P < 0.001), while there was no significant correlation between bone density and transmittance (1.0 MHz, P = 0.421). At a frequency of 0.5 MHz, the optimum duty cycle was considered to be ~ 20%. When the tissue amplitude was in the range of 0.05–0.5 MPa, VEGF, FGF2 and eNOS were significantly upregulated by LIPUS. Thus, the conditions necessary for the LIPUS therapy for human brain were identified as sound pressure just below the probe 1.3 MPa (tissue amplitude 0.15 MPa), duty cycle 5%, and frequency 0.5 MHz.

Conclusions

We successfully found the optimal treatment conditions of the LIPUS therapy for the treatment of patients with AD.

Physical sciences/Engineering/Biomedical engineering

Health sciences/Neurology/Neurological disorders

Although the prevalence of Alzheimer’s disease (AD) has been rapidly increasing worldwide, effective and safe disease-modifying therapy remains to be developed. Recently, endothelial dysfunction with reduced nitric oxide (NO) availability has been suggested to play an important role in the pathogenesis of AD¹. For a novel therapeutic option of ischemic heart disease, we developed a low-intensity pulsed ultrasound (LIPUS) therapy that upregulates endogenous endothelial nitric oxide synthase (eNOS) with resultant angiogenesis and suppression of chronic inflammation^2–3. Moreover, in animal experiments, we demonstrated its efficacy and safety of the LIPUS therapy for several types of heart failure and cerebral infarction^4–8. Furthermore, we demonstrated in a mouse model of AD that the LIPUS therapy suppresses cognitive decline and reduced amyloid-beta (Aβ) accumulation through eNOS upregulation⁹. We then conducted a randomized, double-blind, placebo-controlled (RCT) pilot trial for the efficacy and safety of the LIPUS therapy in patients with early AD (mild cognitive impairment due to AD and mild AD)¹⁰. In this pilot trial, the LIPUS therapy was performed for the whole brain through the bilateral temporal bones alternatively for one hour 3 times a week as one session under the special conditions that we identified¹⁰. The LIPUS therapy was performed for a total of 6 sessions¹⁰. Among the 22 patients divided into 2 group in a 1:1 fashion, cognitive functions remained unchanged in the LIPUS group, while they progressively worsened at 24, 48, and 72 weeks in the placebo group¹⁰. Furthermore, no adverse effects were noted¹⁰.

For this trial, we needed to solve some issues in order to apply the basic experimental data in mice to humans. First, we needed to set ultrasonic frequency and sound pressure high enough to penetrate the thick human skull, which seemed to be 5–6 mm, while the previous evaluation was based on the thin mouse skull, which was less than 1mm. Second, we needed to establish an ultrasonic sound field that can sufficiently cover the distribution of Aβ that accumulates not only in the human hippocampus but also in the entire brain. Third, we needed a specific ultrasonic probe for the thick human skull.

We here report the findings of our basic experiments that we performed for the pilot trial in order to apply the whole-brain LIPUS therapy from mice to humans.

Relationships between Bone Density/Thickness and Ultrasound Transmittance

By using human temporal bone, we examined the relationship between bone density/thickness and ultrasound transmittance. Figure 1 shows the reference measurement values of ultrasonic waves, where the energy just below the probe is the highest. There was a significant correlation between bone thickness and transmittance (1.0 MHz, P < 0.001) (Fig. 2). Also, the transmittance was higher at lower frequencies (0.5 MHz: y = -0.098x + 0.78, expected transmittance at 2 cm under skull 58.4%; 1.0 MHz: y = -0.098x + 0.59, expected transmittance at 2 cm under skull 39.4%) (Fig. 3). Based on these results, the frequency of 1.875 MHz, which is the therapeutic condition used in the basic experiments, was modified to 0.5 MHz for human use.

In Vitro Experiments to Determine Optimal Irradiation Conditions

In the in vitro experiments, by using human umbilical vein endothelial cells, the frequency was first fixed at 0.5 MHz, and the duty cycle was changed to 1, 20, and 40% to examine changes in VEGF mRNA expression after the irradiation of LIPUS. When the duty cycle was fixed at 20%, significant mRNA expression of VEGF by LIPUS was observed at 0.5 and 1.875MHz (P < 0. 05), whereas the expression did not increase at 1% duty cycle (Fig. 4). Thus, when the frequency was fixed at 0.5MHz, VEGF mRNA expression significantly increased at duty cycle 20% (P < 0. 05) (Fig. 5). These results indicated that optimal frequency is 0.5 MHz and optimum duty cycle is ~ 20% (10% from the right and left probes). We used the frequency of 1.875 MHz in our previous experiment in mice with thin skell⁹. Next, we fixed the irradiation condition at frequency 0.5 MHz, duty cycle 20%, and the range of sound pressure (amplitude) was changed to 0.05–2.2 MPa, which is a sound pressure that can be set with a convex transducer. Under these conditions, we examined mRNA expressions of VEGF, FGF2, and eNOS. As shown in Fig. 6, VEGF and eNOS expressions were significantly upregulated in the range of 0.05–0.5 MPa and FGF expression at 0.5MPa without any effects at sound pressure greater than 1.08MPa. Thus, it was suggested that the optimal tissue amplitude is 0.05–0.5 MPa. In order to achieve this sound pressure in the human brain, it was estimated that the sound pressure just under the probe needed to be in the range of 0.5–1.5 MPa. Finally, considering the temperature rise at the patient bilateral temporal bones, the following two treatment conditions were compared for VEGF mRNA expression using cerebrovascular endothelial cells; condition 1, sound pressure just below the probe 1.3 MPa (tissue amplitude 0.15 MPa), each duty cycle 5%, and condition 2, sound pressure just below the probe 0.9 MPa (tissue amplitude 0.1 MPa), each duty cycle 10%. In the final verification experiment, cerebrovascular endothelial cells were used in order to confirm actual reactivity in the irradiated brain. In this comparative experiment, VEGF mRNA expression was significantly upregulated under the condition 1 as compared with condition 2 (Fig. 7).

In the present study, we aimed to determine the optimal treatment conditions of the LIPUS therapy from a mouse model of AD to humans. As a result, we were able to identify the treatment conditions for human brain, including sound pressure just below the probe 1.3 MPa (tissue amplitude 0.15 MPa), each duty cycle 5%, and frequency 0.5 MHz.

In our previous basic experiments using animal models of heart disease, we performed the LIPUS therapy under the following conditions; center frequency 1.875 MHz, pulse repetition frequency 2.74 kHz, number of cycles 32 (17 ${\mu }\text{s}$ burst length, that is, the duty cycle = 4.7%), ${I}_{\text{s}\text{p}\text{t}\text{a}}$ (spatial peak temporal average intensity) 117–162 mW/cm², and sound pressure 0.25 MPa^2–9. We demonstrated that this treatment condition physically stimulates the caveolae on vascular endothelial cell membranes and induces a series of intracellular signals that promote cell proliferation and tissue repair via eNOS¹¹. In the previous animal experiments with mice, the thickness of the mouse skull was less than 1 mm, so the attenuation of ultrasound transmission was negligible. However, it was difficult to ignore the attenuation when the same condition applied to human skull. From the present study, the thinnest temporal bone in the human skull is ~ 3–5 mm, and at 0.5 MHz, it was possible to deliver ultrasonic waves to the cranium with an attenuation rate of 30–40%. In addition, since the accumulation of Aβ in AD spreads to the entire brain as it progresses, we designed a diffusion-type therapeutic beam that ensures safety in compliance with Japanese Industrial Standards. We confirmed this ultrasonic sound field as shown in Fig. 1. In the clinical trial, we designed to produce sound pressure of 0.15 to 0.19 MPa in the deepest part of the hippocampus (approximately 8 cm deep), and sound pressure just below the skull needed to be 1.0 to 1.5 MPa or less to ensure safety¹⁰. The cone angle of the diffusive probe was set according to the size of the average elderly Japanese skull.

The next issue was the effect of bone properties such as thickness and density on sound pressure transmittance. Especially in the elderly patients, we thought that bone density could not be ignored, but as a result of this study, no significant correlation was found between bone density and transmittance. Interestingly, the scatterplot linear functions of bone thickness and transmittance coincidentally showed a negative correlation with exactly the same slope (-0.098) at 0.5 MHz and 1.0 MHz. The originally developed LIPUS therapy for heart disease was set at a frequency of 1.875 MHz, based on the standard for diagnostic ultrasound device for the heart. However, we needed to modify the frequency lower than 10 MHz, so that the LIPUS could sufficiently penetrate the human skull. As a result of examination using vascular endothelial cells, it was shown that the LIPUS-induced VEGF mRNA expression could be reproduced even at 0.5 MHz. However, we were unable to clarify the reason why VEGF upregulation was not observed under the conditions of frequency 1.0 MHz, duty cycle 20% or frequency 0.5 MHz, duty cycle 1%. We then found that when fixing the frequency at 0.5MHz, optimal duty cycle is ~ 20%. Furthermore, by evaluating mRNA expression of VEGF, FGF2, and eNOS, we found that optimal sound pressure is 0.05 to 0.5 MPa. Based on these results, the optimal treatment conditions were finally narrowed down to two conditions from the upper limit of the safety criteria, and the expression effect of VEGF was retested.

Other laboratories have also reported intracranial application of the LIPUS, albeit as a different concept from our whole-brain irradiation strategy. Jeong et al. examined the acute effect of combining microbubble intravenous injection and low-intensity transcranial focused ultrasound to the right hippocampus in 4 patients with AD, and reported the improvement in cognitive function within 24 hours¹². Popescu et al. also examined the efficacy of 2–4 weeks of transcranial ultrasound pulse stimulation (shock waves) for cortical atrophic lesions seen on MRI and reported a reduction in brain atrophy that could be associated with improved cognitive function¹³. However, these reports were based on the concept of local treatment targeting hippocampus by using focused ultrasound, and the irradiation conditions were quite different from our whole-brain irradiation strategy.

The present results were applied to the pilot trial to address the efficacy and safety of the LIPUS therapy for patients with early AD with promising results¹⁰. In this pilot trial, eligibility criteria included patients with a Clinical Dementia Rating (CDR) global score of 0.5–1.0 and a Japanese Mini Mental State Examination (MMSE-J) score more than 20¹⁰. Either the LIPUS treatment or the placebo procedure was performed to outpatients for 18 months at 3-month intervals for a total of 6 sessions (18 treatments). In the placebo group, changes in ADAS-J cog, the primary endpoint, worsened over time at 24, 48, and 72 weeks, whereas no changes were noted in the LIPUS-treated group¹⁰.

Several limitations should be mentioned for the present study. First, in the present study, although we used a human skull, irregular reflection was difficult to simulate completely. Thus, it was difficult to reliably verify the safety of intracranial ultrasound diffuse reflection. Second, we used cultured vascular endothelial cells to determine therapeutic ultrasound conditions, but it may have been necessary to examine its efficacy in vivo using large animals. Third, although the present study was performed on the premise of output below the safety standards of the Japanese Industrial Standards, it may have been necessary to verify more effective output conditions than the present standard.

In summary, we performed basic experiments for the "whole-brain irradiation" concept of human intracranial LIPUS therapy, and we successfully identified the optimal treatment conditions in humans. We plan to employ the same treatment conditions of the LIPUS therapy in the next coming pivotal clinical trial as well.

The present study was performed according to the protocols approved by the Ethics Committee of Tohoku University Graduate School of Medicine (2016-1-071 and 2017-1-581) and was conducted with the ethical principles under the Declaration of Helsinki. All the patients included in this study were given informed consent and they were obtained by written form.

Optimal Sound Field Setting of LIPUS for Intracranial Therapy

It was reported that Aβ accumulates throughout the brain beyond the hippocampus as the disease progresses in AD¹⁴. Thus, we aimed to apply the LIPUS to the whole brain from bilateral temporal bones with the thinnest thickness in the human skull, and designed the special probe that could achieve a sufficient sound field. For the LIPUS therapy, we used a multifunction generator (WF1974; NF Corporation Yokohama, Japan) with a bipolar amplifier (BA4825; NF Corporation Yokohama, Japan), and a planer ultrasound probe (Honda Electronics Co., Aichi, Japan). As the estimation of human skull volume, the radius of curvature of the probe was set based on the Japanese skull size database (Agency of Industrial Science and Technology, Tokyo, Japan). In addition, the distance from the temporal bone to the hippocampus was determined as 75–85 mm in adult patients who underwent head MRI at the Tohoku University Hospital. Thus, we designed the probe so that the sound pressure at the depth of 8 mm passed after the temporal bone from the surface to be within the therapeutic range (amplitude 0.1–0.5 MPa) (Fig. 1). In addition, for safety reason, we set the sound pressure not to exceed ${I}_{\text{s}\text{p}\text{t}\text{a}}$ (spatial peak temporal average intensity) 240 mW/cm² in the cranium based on the Japanese Industrial Standards.

Relationships between Bone Density/Thickness and Ultrasound Transmittance

Next, since the backbone data of the LIPUS therapy was based on the previous evaluation from the thin mouse skull, we needed to modify the therapeutic condition of LIPUS so that it could penetrate the human skull and exert a sufficient therapeutic effect to the brain. In this study, we used the skulls of 20 patients who underwent an autopsy at the Tohoku University Hospital Anatomy Department in 2016. Written consent was obtained from the families of all autopsy patients who donated skulls. Since brain tissue has steady blood perfusion, sound field distribution of LIPUS was thought to be stabilized in a few minutes. Thus, by submerging the human skull in a water tank, we used a hydrophone sensor to examine how much LIPUS penetrated the skull when irradiated from the temporal bone. In addition, the temporal bone thickness $(\varDelta {h}_{\text{b}})$ and bone density $\left({\rho }\right)$were treated as variables that could affect the transmittance, and the correlation with the transmittance was obtained.

The acoustic impedance of bone ${Z}_{\text{b}}$is given by ${Z}_{\text{b}}={\rho }_{\text{b}}{c}_{\text{b}}$, and the acoustic impedance of skin and brain soft tissue (almost same as water) ${Z}_{\text{w}}$is given by ${Z}_{\text{w}}={\rho }_{\text{w}}{c}_{\text{w}}$. Where the sound velocity in the bone is ${c}_{\text{b}}$, and its density is ${\rho }_{\text{b}}$, the sound velocity of water in the skin and brain soft tissue is ${c}_{\text{w}}$, and its density is ${\rho }_{\text{w}}$. Transmittance of incident sound pressure from skin to bone ${T}_{12}$ and transmittance of incident sound pressure from the bone to brain soft tissue ${T}_{23}$ was given as below;

$${T}_{12}=2{Z}_{\text{b}}/({Z}_{\text{b}}+{Z}_{\text{w}})$$

$${T}_{23}=2{Z}_{\text{w}}/({Z}_{\text{b}}+{Z}_{\text{w}})$$

On the other hand, when the propagation attenuation coefficient in the bone $\text{i}\text{s} \text{e}\text{x}\text{p}\text{r}\text{e}\text{s}\text{s}\text{e}\text{d} \text{a}\text{s} {{\alpha }}_{\text{b}}$, the propagation attenuation coefficient in soft tissue (water) ${{\alpha }}_{\text{w}}$, skin thickness $\varDelta {h}_{\text{w}1}$, bone thickness $\varDelta {h}_{\text{b}}$, brain soft tissue distance $\varDelta {h}_{\text{w}3}=80 \text{m}\text{m}$, the sound pressure ${P}_{1}$ at a depth of 80 mm in the brain can be obtained as shown below;

$${P}_{1}={P}_{0}\bullet \text{e}\text{x}\text{p}(-{{\alpha }}_{\text{w}}\varDelta {h}_{\text{w}1})\bullet {T}_{12}\bullet \text{e}\text{x}\text{p}(-{{\alpha }}_{\text{b}}\varDelta {h}_{\text{b}})\bullet {T}_{23}\bullet \text{e}\text{x}\text{p}(-{{\alpha }}_{\text{w}}\varDelta {h}_{\text{w}3})$$

where the sound pressure just below the probe is ${P}_{1}$.

Transmittance corresponds to ${P}_{1}/{P}_{0}$.

In Vitro Experiments to Determine Optimal Irradiation Conditions

In order to modify the treatment conditions for mice to those for humans, it seemed to be necessary to adjust not only the frequency but also the duty cycle and sound pressure. Thus, we next performed LIPUS irradiation experiments using cultured vascular endothelial cells and examined mRNA expression of vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), and endothelial nitric oxide synthase (eNOS). We irradiated endothelial cells with the LIPUS through an agar phantom gel as previously reported^2–3. The attenuation coefficient ${{\alpha }}_{\text{w}}$ of the phantom gel was almost comparable to that of living cells (e.g. muscles, fat, and blood). Human umbilical vein endothelial cells (HUVEC) from a single donor (Lonza, Basel, Switzerland) were cultured in a complete endothelial medium (EGM-2 BulletKit, Lonza). The cells were used at passages 3 to 5 and were maintained in EGM-2. Twenty-four hours before the LIPUS treatment, the cells (1×10⁵) were re-suspended in a 2-ml tube with EGM (Lonza). They were exposed to the LIPUS under the following irradiation conditions (frequency, 0.5, 1.0, and 1.875 MHz; duty cycle, 1, 5, 10, 20, and 40%; amplitude, 0.05, 0.1, 0.15, 0.25, 0.5, 1.08, and 2.2 MPa) for 20 min (n = 12 each). The pulse repetition rate (𝑃𝑅𝑇) was fixed at 320 µs to comply with the previous reports^2–9 and safety standards¹⁵. After irradiation, the cells were stored for 6 hours in the same medium before RNA extraction. mRNA was extracted using the RNeasy Plus Mini kit (QIAGEN). mRNA (600ng) was reverse- transcribed using a QuantiTect Reverse Transcription kit (QIAGEN). Real-time PCR was performed using the Real-Time Detection System (Bio-Rad Laboratories). cDNA was synthesized by using PrimeScript RT Master Mix (Takara Bio Inc., Tokyo, Japan). The primer sequences were as follows; VEGFA, (Forward) 5’-GAGCCTTGCCTTGCTGCTCTA-3’ and (Reverse) 5’-CACCAGGGTCTCGATTGGATG-3’; FGF2, (Forward) 5′- GTGTGCTAACCGTTACCTGGCTATG-3′ and (Reverse) 5′- CCAGTTCGTTTCAGTGCCACA-3′; eNOS, (Forward) 5’-AAAGACAAGGCAGCAGTGGAAAT-3’ and (Reverse) 5’-TCCACGATGGTGACTTTGGCTA-3’; GAPDH, (Forward) 5’-GCACCGTCAAGGCTGAGAAC-3’ and (Reverse) 5’-TGGTGAAGACGCCAGTGGA-3’, all of which were designed by the Perfect Real Time Support System (Takara Bio Inc.). For the final validation, the irradiation conditions of 0.5 MHz frequency, 5% duty cycle, and 0.15 MPa, which were considered to be the optimal conditions for the LIPUS treatment, were applied to cerebral vascular endothelial cells (Lonza), and VEGF mRNA expression was also evaluated.

Statistical Analysis

Results are shown as mean ± standard deviation (SD) for all experiments. We used Student’s t-test followed by Bonferroni type multiple comparisons and 2-way ANOVA with Turkey’s HSD multiple comparison test to compare mean values (GraphPad Prism Software Inc, San Diego, CA). Differences with a P-value < 0.05 were considered to be statistically significant.

Acknowledgements

We thank Taki Hirofumi, Yumi Watanabe, and Hiromi Yamashita for their excellent technical assistance.

Author Contributions

T.S. and H.S. designed the research. T.S., K.E., and Y.M. performed the study and analyzed data. T.S. and H.S. wrote the manuscript. H.K. and S.Y. supervised the research.

Competing interests

The authors declare no competing interests.

Data availability

Data are available on request by contacting the corresponding author.

Sources of Funding

This study was supported in part by Grants-in-Aid for Scientific Research from the Japanese Ministry of Education, Culture, Sports, Science, and Technology, Tokyo, Japan, and the Japanese Ministry of Health, Labor, and Welfare, Tokyo, Japan.

Katusic ZS, Austin SA. Endothelial nitric oxide: protector of a healthy mind. Eur Heart J. 35, 888–894 (2014).
Hanawa K, et al. Low-intensity pulsed ultrasound induces angiogenesis and ameliorates left ventricular dysfunction in a porcine model of chronic myocardial ischemia. PLoS One. 9, e104863 (2014).
Shindo T, et al. Low-intensity pulsed ultrasound enhances angiogenesis and ameliorates left ventricular dysfunction in a mouse model of acute myocardial infarction. Arterioscler Thromb Vasc Biol. 36, 1220–1229 (2016).
Ogata T, et al. Low-intensity pulsed ultrasound enhances angiogenesis and ameliorates contractile dysfunction of pressure-overloaded heart in mice. PLoS One. 12, e0185555 (2017).
Monma Y, et al. Low-intensity pulsed ultrasound ameliorates cardiac diastolic dysfunction in mice -A possible novel therapy for HFpEF. Cardiovasc Res. 117, 1325–1338 (2021).
Watanabe T, et al. Low-intensity pulsed ultrasound therapy suppresses coronary adventitial inflammatory changes and hyperconstricting responses after coronary stent implantation in pigs in vivo. PLoS One. 16, e0257175 (2021).
Nakata T, et al. Beneficial effects of low-intensity pulsed ultrasound on right ventricular dysfunction in animal models. JACC Basic Transl Sci. 8, 283–297 (2022).
Ichijo S, et al. Low-intensity pulsed ultrasound therapy promotes recovery from stroke by enhancing angio-neurogenesis in mice in vivo. Sci Rep. 11, 4958 (2021).
Eguchi K, et al. Whole-brain low-intensity pulsed ultrasound therapy markedly improves cognitive dysfunctions in mouse models of dementia - Crucial roles of endothelial nitric oxide synthase. Brain Stimul. 11, 959–973 (2018).
Shimokawa H, et al. A pilot study of whole-brain low-intensity pulsed ultrasound therapy for early stage of Alzheimer's disease (LIPUS-AD): A randomized, double-blind, placebo-controlled trial. Tohoku J Exp Med. 258, 167–175 (2022).
Shindo T, Shimokawa H. Therapeutic angiogenesis with sound waves. Ann Vasc Dis. 13, 116–125 (2020).
Jeong H, et al. A pilot clinical study of low-intensity transcranial focused ultrasound in Alzheimer’s disease. Ultrasonography. 40, 512–519 (2021).
Popescu T, Pernet C, Beisteiner R. Transcranial ultrasound pulse stimulation reduced cortical atrophy in Alzheimer’s patients: A follow-up study. Alzheimers Dementia. 7, e12121 (2021).
Hardy J, Selkoe DJ. Alzheimer’s disease: progress and problems on the road to therapeutics. Science. 297, 353–356 (2002).
Barnett SB, ter Haar GR, Ziskin MC, et al. International recommendations and guidelines for the safe use of diagnostic ultrasound in medicine. Ultrasound Med Biol. 26, 355–66 (2000).

No competing interests reported.

Download PDF

Journal Publication

published 02 May, 2024

Read the published version in Journal of Medical Ultrasonics →

Version 1

posted

You are reading this latest preprint version

Optimal Treatment Conditions of the Low-intensity Pulsed Ultrasound Therapy for the Treatment of Alzheimer’s Disease -Applications from Mice to Humans-

Status:

Journal Publication

Version 1

Abstract

Background and Purpose

Methods

Results

Conclusions

Figures

Introduction

Results

Relationships between Bone Density/Thickness and Ultrasound Transmittance

In Vitro Experiments to Determine Optimal Irradiation Conditions

Discussion

Materials and Methods

Optimal Sound Field Setting of LIPUS for Intracranial Therapy

Relationships between Bone Density/Thickness and Ultrasound Transmittance

In Vitro Experiments to Determine Optimal Irradiation Conditions

Statistical Analysis

Declarations

References

Additional Declarations

Status:

Journal Publication

Version 1