RESUMO
OBJECTIVE: The aim of this study was to investigate whether consumer-grade mobile audio equipment can be reliably used as a platform for the notched-noise test, including when the test is conducted outside the laboratory. DESIGN: Two studies were conducted: Study 1 was a notched-noise masking experiment with three different setups: in a psychoacoustic test booth with a standard laboratory PC; in a psychoacoustic test booth with a mobile device; and in a quiet office room with a mobile device. Study 2 employed the same task as Study 1, but compared circumaural headphones to insert earphones. STUDY SAMPLE: Nine and ten young, normal-hearing participants completed studies 1 and 2, respectively. RESULTS: The test-retest accuracy of the notched-noise test on the mobile implementation did not differ from that for the laboratory setup. A possible effect of the earphone design was identified in Study 1, which was corroborated by Study 2, where test-retest variability was smallest when comparing results from experiments conducted using identical acoustic transducers. CONCLUSIONS: Results and test-retest repeatability comparable to standard laboratory settings for the notched-noise test can be obtained with mobile equipment outside the laboratory.
Assuntos
Acústica, Ruído, Humanos, Ruído/efeitos adversos, Psicoacústica, Computadores de Mão, TransdutoresRESUMO
This study characterizes the speech phenotype of spinocerebellar ataxia type 1 (SCA1) using both perceptual and objective acoustic analysis of speech in a cohort of SCA1 patients. Twenty-seven symptomatic SCA1 patients in various disease stages (SARA score range: 3-32 points) and 18 sex and age matched healthy controls underwent a clinical assessment addressing ataxia severity, non-ataxia signs, cognitive functioning, and speech. Speech samples were perceptually rated by trained speech therapists, and acoustic metrics representing speech timing, vocal control, and voice quality were extracted. Perceptual analysis revealed reduced intelligibility and naturalness in speech samples of SCA1 patients. Acoustically, SCA1 patients presented with slower speech rate and diadochokinetic rate as well as longer syllable duration compared to healthy controls. No distinct abnormalities in voice quality in the acoustic analysis were detected at group level. Both the affected perceptual and acoustic variables correlated with ataxia severity. Longitudinal assessment of speech is needed to place changes in speech in the context of disease progression and potential response to treatment.
Assuntos
Fala, Ataxias Espinocerebelares, Humanos, Ataxias Espinocerebelares/complicações, Ataxias Espinocerebelares/genética, Acústica, Qualidade da Voz, FenótipoRESUMO
To study the possibility of using acoustic parameters, i.e., Acoustic Voice Quality Index (AVQI) and Maximum Phonation Time (MPT) for predicting the degree of lung involvement in COVID-19 patients. This cross-sectional case-control study was conducted on the voice samples collected from 163 healthy individuals and 181 patients with COVID-19. Each participant produced a sustained vowel/a/, and a phonetically balanced Persian text containing 36 syllables. AVQI and MPT were measured using Praat scripts. Each patient underwent a non-enhanced chest computed tomographic scan and the Total Opacity score was rated to assess the degree of lung involvement. The results revealed significant differences between patients with COVID-19 and healthy individuals in terms of AVQI and MPT. A significant difference was also observed between male and female participants in AVQI and MPT. The results from the receiver operating characteristic curve analysis and area under the curve indicated that MPT (0.909) had higher diagnostic accuracy than AVQI (0.771). A significant relationship was observed between AVQI and TO scores. In the case of MPT, however, no such relationship was observed. The findings indicated that MPT was a better classifier in differentiating patients from healthy individuals, in comparison with AVQI. The results also showed that AVQI can be used as a predictor of the degree of patients' and recovered individuals' lung involvement. A formula is suggested for calculating the degree of lung involvement using AVQI.
Assuntos
COVID-19, Disfonia, Humanos, Masculino, Feminino, Disfonia/diagnóstico, Acústica da Fala, Estudos de Casos e Controles, Estudos de Viabilidade, Estudos Transversais, Reprodutibilidade dos Testes, Índice de Gravidade de Doença, Acústica, Tomografia, Medida da Produção da Fala/métodosRESUMO
Previous research has shown that native listeners benefit from clearly produced speech, as well as from predictable semantic context when these enhancements are delivered in native speech. However, it is unclear whether native listeners benefit from acoustic and semantic enhancements differently when listening to other varieties of speech, including non-native speech. The current study examines to what extent native English listeners benefit from acoustic and semantic cues present in native and non-native English speech. Native English listeners transcribed sentence final words that were of different levels of semantic predictability, produced in plain- or clear-speaking styles by Native English talkers and by native Mandarin talkers of higher- and lower-proficiency in English. The perception results demonstrated that listeners benefited from semantic cues in higher- and lower-proficiency talkers' speech (i.e., transcribed speech more accurately), but not from acoustic cues, even though higher-proficiency talkers did make substantial acoustic enhancements from plain to clear speech. The current results suggest that native listeners benefit more robustly from semantic cues than from acoustic cues when those cues are embedded in non-native speech.
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Semântica, Percepção da Fala, Humanos, Fala, Ruído, Fonética, Acústica, Inteligibilidade da FalaRESUMO
The present article describes a modified and extended replication of a corpus study by Brewer (2008. Phonetic reflexes of orthographic characteristics in lexical representation. Tucson, AZ: University of Arizona PhD thesis) which reports differences in the acoustic duration of homophonous but heterographic sounds. The original findings point to a quantity effect of spelling on acoustic duration, i.e., the more letters are used to spell a sound, the longer the sound's duration. Such a finding would have extensive theoretical implications and necessitate more research on how exactly spelling would come to influence speech production. However, the effects found by Brewer (2008) did not consistently reach statistical significance and the analysis did not include many of the covariates which are known by now to influence segment duration, rendering the robustness of the results at least questionable. Employing a more nuanced operationalization of graphemic units and a more advanced statistical analysis, the current replication fails to find the reported effect of letter quantity. Instead, we find an effect of graphemic complexity. Speakers realize consonants that do not have a visible graphemic correlate with shorter durations: the /s/ in tux is shorter that the /s/ in fuss. The effect presumably resembles orthographic visibility effects found in perception. In addition, our results highlight the need for a more rigorous approach to replicability in linguistics.
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Idioma, Fonética, Humanos, Fala, Acústica, Projetos de PesquisaRESUMO
Phase aberration caused by human skulls severely degrades the quality of transcranial ultrasound images, posing a major challenge in the practical application of transcranial ultrasound techniques in adults. Aberration can be corrected if the skull profile (i.e., thickness distribution) and speed of sound (SOS) are known. However, accurately estimating the skull profile and SOS using ultrasound with a physics-based approach is challenging due to the complexity of the interaction between ultrasound and the skull. A deep learning approach is proposed herein to estimate the skull profile and SOS using ultrasound radiofrequency (RF) signals backscattered from the skull. A numerical study was performed to test the approach's feasibility. Realistic numerical skull models were constructed from computed tomography (CT) scans of five ex vivo human skulls in this numerical study. Acoustic simulations were performed on 3595 skull segments to generate array-based ultrasound backscattered signals. A deep learning model was developed and trained to estimate skull thickness and SOS from RF channel data. The trained model was shown to be highly accurate. The mean absolute error (MAE) was 0.15 mm (2% error) for thickness estimation and 13 m/s (0.5% error) for SOS estimation. The Pearson correlation coefficient between the estimated and ground-truth values was 0.99 for thickness and 0.95 for SOS. Aberration correction performed using deep-learning-estimated skull thickness and SOS values yielded significantly improved beam focusing (e.g., narrower beams) and transcranial imaging quality (e.g., improved spatial resolution and reduced artifacts) compared with no aberration correction. The results demonstrate the feasibility of the proposed approach for transcranial phase aberration correction.
Assuntos
Aprendizado Profundo, Humanos, Ultrassonografia/métodos, Crânio/diagnóstico por imagem, Tomografia Computadorizada por Raios X/métodos, AcústicaRESUMO
PURPOSE: Teachers spend a significant amount of time in classrooms, which can be noisy environments. The aim of this scoping review was to determine what is known from the literature about the effect of classroom acoustic conditions on teachers' health and well-being. METHOD: This scoping review followed the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) protocol. Four bibliographic databases were searched: ERIC, PubMed, Scopus, and Web of Science. RESULTS: Thirty-three articles were deemed relevant for the review. The most studied health aspect was teachers' vocal health. The majority of results showed higher noise levels or a higher number of students have a negative effect on teachers' health and well-being (61% and 60%, respectively), while 39% showed a negative effect of longer reverberation times. Most other results showed no effect. CONCLUSIONS: These results show that poor classroom acoustic conditions can have a negative effect on teachers' health and well-being. Therefore, creating classrooms with good acoustic conditions and controlling noise is vital. Limitations are discussed, and future research to better understand the relationship between classroom acoustic conditions and teachers' health and well-being is proposed. This future research will help in understanding the acoustic conditions that are needed to optimize teachers' health and well-being in the classroom.
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Distúrbios da Voz, Voz, Humanos, Instituições Acadêmicas, Acústica, Ruído, Professores EscolaresRESUMO
PURPOSE: Literature on apraxia of speech (AOS) in Chinese speakers is sparse compared to the English literature. This study aims to examine the pitch variation skills of Cantonese adults with AOS poststroke in terms of perceptual tone accuracy, acoustic fundamental frequency (fo) changes, and repetition durations on items with different syllable structures, lexical status, and tone syllables in various positions in a sequencing context. METHOD: Six Cantonese adults with AOS poststroke (AOS group), six adults without AOS poststroke (nAOS group), and six healthy controls (HC group) performed the tone sequencing task (TST), which was adapted from oral diadochokinetic tasks, with three different tone syllables. Tone accuracy, fo values across 10 time points, and acoustic repetition durations were compared within and between the groups. RESULTS: The AOS group produced significantly lower tone accuracy and different fo changes on the three Cantonese tone syllables compared with the control groups and significantly longer repetition durations than the HC group. The AOS group showed more difficulty with the tone syllables with the consonant-vowel structure, while a priming effect was observed on the T2 (high-rising) syllables with lexical meanings. A unique lowering of fo in the final syllable of the trisyllabic items was observed only in the AOS group. CONCLUSIONS: The AOS group showed degraded pitch variation skills. The effects of the three linguistic elements were discussed. Future investigations are called for to adapt the TST in other tonal languages to determine if degraded pitch variation skills are present in other tonal language speakers with AOS.
Assuntos
Apraxias, Percepção da Fala, Acidente Vascular Cerebral, Adulto, Humanos, Fala, Apraxias/etiologia, Acidente Vascular Cerebral/complicações, Acústica, Percepção da Altura SonoraRESUMO
This is an acoustic and articulatory study of the two rhotic schwas in Southwestern Mandarin (SWM), i.e., the er-suffix (a functional morpheme) and the rhotic schwa phoneme. Electromagnetic Articulography (EMA) and ultrasound results from 10 speakers show that the two rhotic schwas were both produced exclusively with the bunching of the tongue body. No retroflex versions of the two rhotic schwas were found, nor was retraction of the tongue root into the pharynx observed. On the other hand, the er-suffix and the rhotic schwa, though homophonous, significantly differ in certain types of acoustic and articulatory measurements. In particular, more pronounced lip protrusion is involved in the production of the rhotic schwa phoneme than in the er-suffix. It is equally remarkable that contrast preservation is not an issue because the two rhotic schwas are in complementary distribution. Taken together, the present results suggest that while morphologically-induced phonetic variation can be observed in articulation, gestural economy may act to constrain articulatory variability, resulting in the absence of retroflex tongue variants in the two rhotic schwas, the only two remaining r-colored sounds in SWM.
Assuntos
Acústica, Laringe, Humanos, Acústica da Fala, Fonética, LínguaRESUMO
Deep generative models with latent variables have been used lately to learn joint representations and generative processes from multi-modal data, which depict an object from different viewpoints. These two learning mechanisms can, however, conflict with each other and representations can fail to embed information on the data modalities. This research studies the realistic scenario in which all modalities and class labels are available for model training, e.g. images or handwriting, but where some modalities and labels required for downstream tasks are missing, e.g. text or annotations. We show, in this scenario, that the variational lower bound limits mutual information between joint representations and missing modalities. We, to counteract these problems, introduce a novel conditional multi-modal discriminative model that uses an informative prior distribution and optimizes a likelihood-free objective function that maximizes mutual information between joint representations and missing modalities. Extensive experimentation demonstrates the benefits of our proposed model, empirical results show that our model achieves state-of-the-art results in representative problems such as downstream classification, acoustic inversion, and image and annotation generation.
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Aprendizagem por Discriminação, Aprendizagem, Acústica, Pesquisa Empírica, Escrita ManualRESUMO
Wind energy appears to place global environmental benefits against local human health, particularly sleep. The result is a significant challenge to wind-energy development for the achievement of large-scale alternative energy. Our purpose is to examine noise from wind turbines and its potential to disrupt sleep, to examine the human health literature addressing these concerns, and to provide insight into how developers and communities can employ these concepts to pursue wind energy without impacting human health. The latest and most rigorous research on noise from wind turbines points to healthy sleep, when turbines are sited reasonably. This includes audible noise, low-frequency noise, and infrasound. Recent advances in acoustical standards provide practical methods to ensure adherence to these scientific findings. There now exist key data concerning wind-turbine noise, and its impact on sleep. Knowing that information, and how to deploy it with modern engineering standards should simultaneously facilitate wind development and protect human health.
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Ruído, Transtornos do Sono-Vigília, Humanos, Ruído/efeitos adversos, Sono, AcústicaRESUMO
BACKGROUND: Cellulite is an aesthetically displeasing rippling or dimpling of the skin, primarily on the buttocks/thighs. A recent study showed a novel acoustic subcision device produced significant short-term (12-week) improvement in the appearance of cellulite after a single rapid acoustic pulse (RAP) treatment. OBJECTIVE: To evaluate the long-term (>52-weeks) efficacy and safety of RAP treatment for improvement in the appearance of cellulite. MATERIALS AND METHODS: In this prospective, multicenter trial, female participants ( n = 42) with severe cellulite were treated with the acoustic subcision device in a single visit. At >52 weeks, blinded board-certified dermatologists assessed efficacy by correctly identifying post-treatment photographs and using a 6-point simplified Cellulite Severity Scale (CSS). Participant satisfaction was also collected. Safety was assessed throughout. RESULTS: The blinded panel correctly identified post-treatment photographs at a rate of 95.2%; 70.4% of participants had a >1-point reduction in the CSS score from baseline (mean reduction of 1.09). All participants (100%) reported improved cellulite appearance. Overall pain during treatment was rated as 2.4 and 0.3 post-treatment (pain scale 0-10). No device or treatment-related adverse events were reported at the >52-week follow-up. CONCLUSION: Rapid acoustic pulse treatment significantly improved the long-term appearance of cellulite and was well-tolerated.
Assuntos
Celulite, Técnicas Cosméticas, Humanos, Feminino, Satisfação do Paciente, Celulite/cirurgia, Estudos Prospectivos, Nádegas, Coxa da Perna, Acústica, Dor, Resultado do TratamentoRESUMO
A bubble-based acoustofluidic filtration (BAF) microfluidic device, which employs cross-flow filtration (CFF) and acoustic streaming, separates cells with high efficiency for forensic analysis. Forensic samples are typically complex and contain a substantial number of squamous epithelial cells from the female vagina, which tend to have fouling problems during filtration due to their morphological and cell adhesion differences. To overcome this issue, the BAF device utilizes bubble oscillation by bulk acoustic wave (BAW) to generate acoustic streaming, which offers additional hydrodynamic forces for side flushing cleaning and achieves effective removal within a mere 0.5 seconds. Our device is tested with imbalanced cell mixtures of sperm and epithelial cells with large disparity ratios. By concurrently employing CFF and acoustic streaming, the samples with our sperm-enrichment can achieve 91.72-97.78% for the recovery rate and 74.58-89.26% for the purity in the sperm enrichment. They are further subjected to short tandem repeat (STR) profiling, enabling the identification of perpetrators. Notably, even samples with minimal sperm cells demonstrated a significant increase in the male donor DNA ratio, while the peak heights of female alleles became virtually undetectable. The exceptional cell separation capability demonstrated by our BAF device highlights its potential applications in forensic sciences and other areas of cell biology.
Assuntos
Sêmen, Espermatozoides, Masculino, Humanos, Feminino, Acústica, Som, Repetições de MicrossatélitesRESUMO
Previous studies have shown that in challenging listening situations, people find it hard to equally divide their attention between two simultaneous talkers and tend to favor one talker over the other. The aim here was to investigate whether talker onset/offset, sex and location determine the favored talker. Fifteen people with normal hearing were asked to recognize as many words as possible from two sentences uttered by two talkers located at 45° and +45° azimuth, respectively. The sentences were from the same corpus, were time-centered and had equal sound level. In Conditions 1 and 2, the talkers had different sexes (male at +45°), sentence duration was not controlled for, and sentences were presented at 65 and 35 dB SPL, respectively. Listeners favored the male over the female talker, even more so at 35 dB SPL (62 % vs 43 % word recognition, respectively) than at 65 dB SPL (74 % vs 64 %, respectively). The greater asymmetry in intelligibility at the lower level supports that divided listening is harder and more 'asymmetric' in challenging acoustic scenarios. Listeners continued to favor the male talker when the experiment was repeated with sentences of equal average duration for the two talkers (Condition 3). This suggests that the earlier onset or later offset of male sentences (52 ms on average) was not the reason for the asymmetric intelligibility in Conditions 1 or 2. When the location of the talkers was switched (Condition 4) or the two talkers were the same woman (Condition 5), listeners continued to favor the talker to their right albeit non-significantly. Altogether, results confirm that in hard divided listening situations, listeners tend to favor the talker to their right. This preference is not affected by talker onset/offset delays less than 52 ms on average. Instead, the preference seems to be modulated by the voice characteristics of the talkers.
Assuntos
Percepção da Fala, Voz, Humanos, Masculino, Feminino, Inteligibilidade da Fala, Idioma, AcústicaRESUMO
BACKGROUND: Sulcus Vocalis (SV) is a voice disorder characterized by the parallel invagination of the vocal fold epithelium that adheres to the vocal ligament. This condition disrupts the vibratory function, leading to glottal incompetence, hoarseness, and vocal impairment. Despite various proposed surgical techniques, a standardized treatment approach remains elusive. METHODS: We conducted a comprehensive search across PubMed/Medline, Embase, Web of Science, Scholar, and the Cochrane Library for studies on SV treatment. The inclusion criteria comprised original studies comparing pre- and post-treatment vocal outcomes in SV patients, published in English. We excluded case reports, reviews, studies without continuous data, and patients with vocal scar/atrophy. RESULTS: Fifteen observational studies were included (361 patients, 53.73 % male, average age 41.64 years). 80 % of these studies employed self-reported outcomes, while 81.25 % analyzed acoustic/aerodynamic data. The follow-up period varied from 4 to 44 months. All techniques significantly improved Voice Handicap Index (VHI) scores (p < 0.001). Dissective and combined techniques exhibited greater reductions in VHI-30/10 (p < 0.001). Maximum Phonation Time (MPT) improved significantly across all techniques (p < 0.001), with dissective techniques demonstrating superior MPT outcomes (p < 0.001). Jitter improved significantly for dissective and injective techniques (p < 0.001), as did Shimmer for all techniques (p < 0.001). Notably, combined techniques displayed the most significant reductions (p < 0.001). CONCLUSIONS: Surgical treatments significantly improve subjective, aerodynamic, and acoustic outcomes in SV patients. Dissective and combined dissective/injective techniques appear to yield better perceptual and phonatory outcomes compared to injective techniques alone. Further research is necessary to establish the optimal treatment approach for SV.
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Distúrbios da Voz, Qualidade da Voz, Humanos, Acústica, Resultado do Tratamento, Prega Vocal/cirurgia, Distúrbios da Voz/cirurgia, Distúrbios da Voz/etiologiaRESUMO
Using liver phantoms for mimicking human tissue in clinical training, disease diagnosis, and treatment planning is a common practice. The fabrication material of the liver phantom should exhibit mechanical properties similar to those of the real liver organ in the human body. This tissue-equivalent material is essential for qualitative and quantitative investigation of the liver mechanisms in producing nutrients, excretion of waste metabolites, and tissue deformity at mechanical stimulus. This paper reviews the mechanical properties of human hepatic tissues to develop liver-mimicking phantoms. These properties include viscosity, elasticity, acoustic impedance, sound speed, and attenuation. The advantages and disadvantages of the most common fabrication materials for developing liver tissue-mimicking phantoms are also highlighted. Such phantoms will give a better insight into the real tissue damage during the disease progression and preservation for transplantation. The liver tissue-mimicking phantom will raise the quality assurance of patient diagnostic and treatment precision and offer a definitive clinical trial data collection.
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Técnicas de Imagem por Elasticidade, Humanos, Elasticidade, Fígado, Imagens de Fantasmas, AcústicaRESUMO
OBJECTIVE: To investigate and quantify age-related changes in lower limb muscle stiffness in typically developing children and adolescents using acoustic radiation force impulse shear wave elastography. MATERIALS AND METHODS: Shear wave velocities of bilateral rectus femoris, tibialis anterior, and medial gastrocnemius muscles at rest were obtained in typically developing children and adolescents aged 3 to 18 years. The participants were classified into three age groups: Group 1 (children), 3 to 7 years old; Group 2, 8 to 12 (pre-adolescent); and Group 3 (adolescent), 13 to 18. The shear wave velocities of muscle were compared across the three age groups, as well as compared between right- and left-side limbs. The correlation between shear wave velocities and body weight or body mass index was assessed. RESULTS: Of the 47 participants, 21 were in Group 1, 17 in Group 2, and 9 in Group 3. There were no significant differences among the three age groups' shear wave velocities of bilateral lower limb muscles, and no significant differences between right and left sides. There was no correlation between muscle stiffness and body weight or body mass index. CONCLUSION: The present pilot study applied acoustic radiation force impulse shear wave elastography to quantify lower limb muscle stiffness in typically developing children and adolescents aged 3 to 18 years, suggesting no marked change in muscle stiffness occurs as they develop.
Assuntos
Técnicas de Imagem por Elasticidade, Criança, Humanos, Adolescente, Pré-Escolar, Projetos Piloto, Músculo Esquelético/diagnóstico por imagem, Extremidade Inferior/diagnóstico por imagem, Peso Corporal, AcústicaRESUMO
OBJECTIVE: The study aims to investigate the estrogen-agonistic effects of tamoxifen on voice parameters in premenopausal women diagnosed with breast cancer. METHODS: A total of 108 premenopausal women were included, segmented into distinct treatment groups and a control group. Objective sound analysis was conducted using robust statistical methods, employing SPSS 25.0 for data analysis. RESULTS: The study identified a statistically significant reduction in Jitter values across all treatment groups compared to the control group. No significant changes were observed in other voice quality parameters such as F0, Shimmer, NHR, and HNR. CONCLUSIONS: The findings suggest that tamoxifen may have an estrogen-agonistic effect on voice quality, thereby potentially influencing future treatment protocols. This research fills a critical void in existing literature and sets the stage for more comprehensive studies that consider affects of hormonal therapies to voice.
Assuntos
Neoplasias da Mama, Voz, Humanos, Feminino, Tamoxifeno/uso terapêutico, Neoplasias da Mama/tratamento farmacológico, Qualidade da Voz, Estrogênios, Acústica da Fala, AcústicaRESUMO
Measuring cellular and tissue mechanics inside intact living organisms is essential for interrogating the roles of force in physiological and disease processes. Current agents for studying the mechanobiology of intact, living organisms are limited by poor light penetration and material stability. Magnetomotive ultrasound is an emerging modality for real-time in vivo imaging of tissue mechanics. Nonetheless, it has poor sensitivity and spatiotemporal resolution. Here we describe magneto-gas vesicles (MGVs), protein nanostructures based on gas vesicles and magnetic nanoparticles that produce differential ultrasound signals in response to varying mechanical properties of surrounding tissues. These hybrid nanomaterials significantly improve signal strength and detection sensitivity. Furthermore, MGVs enable non-invasive, long-term and quantitative measurements of mechanical properties within three-dimensional tissues and in vivo fibrosis models. Using MGVs as novel contrast agents, we demonstrate their potential for non-invasive imaging of tissue elasticity, offering insights into mechanobiology and its application to disease diagnosis and treatment.
Assuntos
Nanopartículas, Nanoestruturas, Diagnóstico por Imagem/métodos, Proteínas/química, Acústica, Nanopartículas/químicaRESUMO
BACKGROUND: The generation of transcranial ultrasound is usually based on the piezoelectric effect, so it is necessary to attach transducers around the skull. However, the skull will cause serious attenuation and scattering of ultrasound, which makes it particularly difficult for transcranial ultrasound imaging and modulation. PURPOSE: In transcranial ultrasound imaging, there is significant attenuation and scattering of ultrasound waves by the skull bone. To mitigate this influence and enable precise imaging and high-efficient transcranial ultrasound for specific patients (such as stroke patients who already require craniotomy as part of their surgical care), this paper proposes to use EMAT to excite metal plates placed inside the skull based on the excellent penetration characteristics of EM waves into the skull, generating ultrasound signals, which can completely avoid the influence of skull on ultrasound transmission. METHODS: Based on an efficient wireless transcranial ultrasound experimental platform, we first verified that the skull would not affect the propagation of electromagnetic waves generated by EMAT. In addition, the distribution of the transcranial sound field generated by EMAT was measured. RESULTS: EMAT can generate 1.0 MHz ultrasound by wireless excitation of a 0.1 mm thick copper plate through an adult skull with a thickness of â¼1 cm, and the frequency and amplitude of the generated ultrasound are not affected by the skull. The results indicated that the electromagnetic waves successfully penetrated the skull, with a recorded strength of approximately 2 mV. We also found that the ultrasound signals generated by the EMAT probe through the skull remained unaffected, measuring around 2 mV. In addition, the measurement of the transcranial sound field distribution (80*50 mm2 ) generated by EMAT shows that compared with the traditional extracranial ultrasound generation method, the sound field distribution generated by the wireless excitation of the intracranial copper plate based on EAMT is no longer affected by the uneven and irregular skull. CONCLUSION: Our experiments involved validating the penetration capabilities of electromagnetic waves utilizing the EMAT probe through a 7 (5+2) mm thick organic glass plate and a real human skull ranging from 8 to 15 mm in thickness. The efficient and wireless transcranial ultrasound excitation proposed in this paper may be possible for transcranial ultrasound imaging and therapy.
