scholarly journals Factors Associated with Energy Efficiency of Focused Ultrasound Through the Skull: A Study of 3D-Printed Skull Phantoms and Its Comparison with Clinical Experiences

2021 ◽  
Vol 9 ◽  
Author(s):  
Chanho Kong ◽  
So Hee Park ◽  
Jaewoo Shin ◽  
Hee Gyu Baek ◽  
Juyoung Park ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Trabecular Bone ◽  
Focused Ultrasound ◽  
Density Ratio ◽  
Sound Field ◽  
Field Energy ◽  
Clinical Experiences ◽  
Ultrasonic Sound ◽  
3D Printed ◽  
Ultrasound Energy

While focused ultrasound (FUS) is non-invasive, the ultrasound energy is attenuated by the skull which results in differences in energy efficiency among patients. In this study, we investigated the effect of skull variables on the energy efficiency of FUS. The thickness and density of the skull and proportion of the trabecular bone were selected as factors that could affect ultrasound energy transmittance. Sixteen 3D-printed skull models were designed and fabricated to reflect the three factors. The energy of each phantom was measured using an ultrasonic sound field energy measurement system. The thickness and proportion of trabecular bone affected the attenuation of transmitted energy. There was no difference in the density of the trabecular bone. In clinical data, the trabecular bone ratio showed a significantly greater correlation with dose/delivered energy than that of thickness and the skull density ratio. Currently, for clinical non-thermal FUS, the data are not sufficient, but we believe that the results of this study will be helpful in selecting patients and appropriate parameters for FUS treatment.

scholarly journals The Distribution of Skull Score and Skull Density Ratio in Tremor Patients for MR-Guided Focused Ultrasound Thalamotomy

2021 ◽  
Vol 15 ◽  
Author(s):  
Kevin Wen-Kai Tsai ◽  
Jui-Cheng Chen ◽  
Hui-Chin Lai ◽  
Wei-Chieh Chang ◽  
Takaomi Taira ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Cortical Bone ◽  
Focused Ultrasound ◽  
Density Ratio ◽  
Ct Images ◽  
Image Feature ◽  
Cumulative Distribution ◽  
Invasive Surgical Approach ◽  
Highly Correlated ◽  
The Brain

ObjectiveMagnetic resonance-guided focused ultrasound (MRgFUS) is a minimum-invasive surgical approach to non-incisionally cause the thermos-coagulation inside the human brain. The skull score (SS) has already been approved as one of the most dominant factors related to a successful MRgFUS treatment. In this study, we first reveal the SS distribution of the tremor patients, and correlate the SS with the image feature from customized skull density ratio (cSDR). This correlation might give a direction to future clinical studies for improving the SS.MethodsTwo hundred and forty-six patients received a computed tomography (CT) scan of the brain, and a bone-enhanced filter was applied and reconstructed to a high spatial resolution CT images. The SS of all patients would be estimated by the MRgFUS system after importing the reconstructed CT images into the MRgFUS system. The histogram and the cumulative distribution of the SS from all the patients were calculated to show the percentage of the patients whose SS lower than 0.3 and 0.4. The same CT images of all patients were utilized to calculated the cSDR by first segmented the trabecular bone and the cortical bone from the CT images and divided the average trabecular bone intensity (aTBI) by the average cortical bone intensity (aCBI). The Pearson’s correlations between the SS and the cSDR, aTBI, and the aCBI were calculated, respectively.ResultsThere were 19.19 and 50% of the patient who had the SS lower than the empirical threshold 0.3 and 0.4, respectively. The Pearson’s correlation between the SS and the cSDR, aCBI, and the aTBI were R = 0.8145, 0.5723, and 0.8842.ConclusionHalf of the patients were eligible for the MRgFUS thalamotomy based on the SS, and nearly 20% of patients were empirically difficult to achieve a therapeutic temperature during MRgFUS. The SS and our cSDR are highly correlated, and the SS had a higher correlation with aTBI than with aCBI. This is the first report to explicitly reveal the SS population and indicate a potential way to increase the chance to achieve a therapeutic temperature for those who originally have low SS.

Predictors of thermal increase in magnetic resonance–guided focused ultrasound treatment for essential tremor: histogram analysis of skull density ratio values for 1024 elements

2021 ◽  
pp. 1-6
Author(s):  
Ken Iijima ◽  
Hajime Yokota ◽  
Toshio Yamaguchi ◽  
Masayuki Nakano ◽  
Takahiro Ouchi ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Operating Characteristic ◽  
Focused Ultrasound ◽  
Characteristic Curve ◽  
Density Ratio ◽  
Predictive Ability ◽  
Curve Analysis ◽  
Regression Analyses ◽  
Multivariate Logistic Regression ◽  
Operating Characteristic Curve

OBJECTIVE Sufficient thermal increase capable of generating thermocoagulation is indispensable for an effective clinical outcome in patients undergoing magnetic resonance–guided focused ultrasound (MRgFUS). The skull density ratio (SDR) is one of the most dominant predictors of thermal increase prior to treatment. However, users currently rely only on the average SDR value (SDRmean) as a screening criterion, although some patients with low SDRmean values can achieve sufficient thermal increase. The present study aimed to examine the numerical distribution of SDR values across 1024 elements to identify more precise predictors of thermal increase during MRgFUS. METHODS The authors retrospectively analyzed the correlations between the skull parameters and the maximum temperature achieved during unilateral ventral intermediate nucleus thalamotomy with MRgFUS in a cohort of 55 patients. In addition, the numerical distribution of SDR values was quantified across 1024 elements by using the skewness, kurtosis, entropy, and uniformity of the SDR histogram. Next, the authors evaluated the correlation between the aforementioned indices and a peak temperature > 55°C by using univariate and multivariate logistic regression analyses. Receiver operating characteristic curve analysis was performed to compare the predictive ability of the indices. The diagnostic performance of significant factors was also assessed. RESULTS The SDR skewness (SDRskewness) was identified as a significant predictor of thermal increase in the univariate and multivariate logistic regression analyses (p < 0.001, p = 0.013). Moreover, the receiver operating characteristic curve analysis indicated that the SDRskewness exhibited a better predictive ability than the SDRmean, with area under the curve values of 0.847 and 0.784, respectively. CONCLUSIONS The SDRskewness is a more accurate predictor of thermal increase than the conventional SDRmean. The authors suggest setting the SDRskewness cutoff value to 0.68. SDRskewness may allow for the inclusion of treatable patients with essential tremor who would have been screened out based on the SDRmean exclusion criterion.

scholarly journals INFLUENCE OF PRINTING AND LOADING DIRECTION ON MECHANICAL RESPONSE IN 3D PRINTED MODELS OF HUMAN TRABECULAR BONE

2018 ◽  
Vol 18 ◽  
pp. 24 ◽  
Author(s):  
Tomáš Doktor ◽  
Ivana Kumpová ◽  
Sebastian Wroński ◽  
Maciej Śniechowski ◽  
Jacek Tarasiuk ◽  
...  
Keyword(s):  
Trabecular Bone ◽  
Mechanical Response ◽  
Plastic Region ◽  
Human Donor ◽  
Deformation Response ◽  
Human Trabecular Bone ◽  
Loading Mode ◽  
Loading Direction ◽  
3D Printed ◽  
X Ray Computed

The paper deals with investigation on directional variations of mechanical response in 3D printed models of human trabecular bone. Sample of trabecular bone tissue was resected from human donor and 3D model was obtained by X-ray computed tomography. Then a series of cubical samples was prepared by additive manufacturing technique and tested by uniaxial compression loading mode. Mechanical response was compared in nine different combinations of direction of 3D printing and loading direction. The results show neglectible influence on the deformation response in elastic region (stiffness) and significant changes of the behaviour in plastic region (stress and strain at yield point, strain at full collapse).

scholarly journals Reproducibility of left atrial ablation with high-intensity focused ultrasound energy in a calf model

2010 ◽  
Vol 140 (6) ◽  
pp. 1381-1387.e1 ◽  
Author(s):  
Nestor R. Villamizar ◽  
Jennifer H. Crow ◽  
Valentino Piacentino ◽  
Louis R. DiBernardo ◽  
Mani A. Daneshmand ◽  
...  
Keyword(s):  
High Intensity ◽  
Left Atrial ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Atrial Ablation ◽  
Ultrasound Energy

scholarly journals EAP-FUS022 (Yoo): FUS Mediated Reversible Modulation of Region Specific Brain Function

2017 ◽  
Author(s):  
Seung-Schik Yoo ◽  
Jong-Hwan Lee ◽  
Yongzhi Zhang ◽  
Wonhye Lee ◽  
Krisztina Fischer ◽  
...  
Keyword(s):  
Brain Function ◽  
Focused Ultrasound ◽  
Brain Area ◽  
Brain Regions ◽  
Neural Cells ◽  
Low Intensity ◽  
Functional Modulation ◽  
Ultrasound Energy ◽  
Sonication Parameters

The goal of the proposed research is to investigate the feasibility of using low-intensity and lowfrequency focused ultrasound energy to reversibly modulate the activity of a region-specific brain area. We will modulate the cortical activity from an animal brain using FUS sonication, as monitored by real-time functional MRI. Prior to the animal experiment, in-vitro phantoms containing neural cells will be constructed and sonicated to estimate the range of suitable sonication parameters. This work is expected to provide an unprecedented opportunity for the transient functional modulation of targeted brain regions, creating a new line of applications, such as FUS-mediated functional mapping.

A two-zone sound field reproduction based on the region energy control

2021 ◽  
Vol 263 (6) ◽  
pp. 348-354
Author(s):  
Bokai Du ◽  
Xiangyang Zeng ◽  
Haitao Wang
Keyword(s):  
Control Method ◽  
Microphone Array ◽  
Free Field ◽  
Sound Field ◽  
Field Energy ◽  
Reproduction System ◽  
Physical Isolation ◽  
Multipoint Method ◽  
Reverberant Environment ◽  
Measurement Effort

Multizone sound field reproduction aims to create different acoustical environments in regions without physical isolation. For a real reproduction system, it is always expected to improve system performance and reduce measurement effort. In this paper, a two-zone sound field reproduction is investigated with a proposed region control method. Conventional multipoint method only controls sound field at limited number of measurement points. However, the proposed method tries to control the sound field energy over the whole region. Considering the system's diverse work environment, different interpolation methods are applied in the proposed method. Simulations are conducted under free field and reverberation condition in order to deeply compare with conventional method and another harmonic domain method. Simulation results show that the proposed method achieves better performance than the conventional multipoint method in free field and reverberant environment. On the other hand, the region control method proposed in this paper is free from microphone array geometry requirement, which means the method is more convenient for the practical application.

scholarly journals A new 3D printed titanium metal trabecular bone reconstruction system for early osteonecrosis of the femoral head

Medicine ◽  
2018 ◽  
Vol 97 (26) ◽  
pp. e11088 ◽  
Author(s):  
Ying Zhang ◽  
Leilei Zhang ◽  
Ruibo Sun ◽  
Yudong Jia ◽  
Xiantao Chen ◽  
...  
Keyword(s):  
Femoral Head ◽  
Trabecular Bone ◽  
Bone Reconstruction ◽  
Titanium Metal ◽  
3D Printed

scholarly journals Stochastic Geometry Analysis of Downlink Spectral and Energy Efficiency in Ultradense Heterogeneous Cellular Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jiaqi Lei ◽  
Hongbin Chen ◽  
Feng Zhao
Keyword(s):  
Energy Efficiency ◽  
Cellular Networks ◽  
Stochastic Geometry ◽  
Density Ratio ◽  
Base Station ◽  
Small Cell ◽  
Base Stations ◽  
Heterogeneous Cellular Networks ◽  
Downlink Throughput ◽  
The Impact

The energy efficiency (EE) is a key metric of ultradense heterogeneous cellular networks (HCNs). Earlier works on the EE analysis of ultradense HCNs by using the stochastic geometry tool only focused on the impact of the base station density ratio and ignored the function of different tiers. In this paper, a two-tier ultradense HCN with small-cell base stations (SBSs) and user equipments (UEs) densely deployed in a traditional macrocell network is considered. Firstly, the performance of the ultradense HCN in terms of the association probability, average link spectral efficiency (SE), average downlink throughput, and average EE is theoretically analyzed by using the stochastic geometry tool. Then, the problem of maximizing the average EE while meeting minimum requirements of the average link SE and average downlink throughput experienced by UEs in macrocell and small-cell tiers is formulated. As it is difficult to obtain the explicit expression of average EE, impacts of the SBS density ratio and signal-to-interference-plus-noise ratio (SINR) threshold on the network performance are investigated through numerical simulations. Simulation results validate the accuracy of theoretical results and demonstrate that the maximum value of average EE can be achieved by optimizing the SBS density ratio and the SINR threshold.

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