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Stretchable strain sensors in motion detection, health monitoring, and human-machine interfaces are limited by device sensitivity, linearity, hysteresis, stability, and reproducibility in addition to stretchability. Engineering defect structures in sensing material is an effective approach in modulating the material's physical properties, particularly those associated with mechanical responses. Here, we demonstrate that bilayers of carbon nanotubes deposited on an elastomer substrate are mechanically coupled. The microcrack size, density, and distribution in the nanotube thin film can be engineered through uniaxial tensile training to exhibit highly tunable and stable piezoresistive responses with sensitivity, linearity, range, and reproducibility. These responses far exceeding those in uniform metallic films, patterned structures, and composites. In addition, numerical analyses performed on a two-dimensional network model of the cracked nanotube film provide quantitative explanations of how crack configuration, and evolvement under strain, lead to the significant enhancements in stretchable sensor performance using current bilayer structures.
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OBJECTIVES: To introduce an ultrasound-based scoring system for radiation-induced breast toxicity and test its reliability. METHODS: Breast ultrasound (BUS) was performed on 32 patients receiving breast radiotherapy (RT) to assess the radiation-induced acute toxicity. For each patient, both the untreated and irradiated breasts were scanned at five locations: 12:00, 3:00, 6:00, 9:00, and tumor bed to evaluate for heterogenous responses to radiation within the entire breast. In total, 314 images were analyzed. Based on ultrasound findings such as skin thickening, dermis boundary irregularity, and subcutaneous edema, a 4-level, Likert-like grading scheme is proposed: none (G0), mild (G1), moderate (G2), and severe (G3) toxicity. Two ultrasound experts graded the severity of breast toxicity independently and reported the inter- and intra-observer reliability of the grading system. Imaging findings were compared with standard clinical toxicity assessments using Common Terminology Criteria for Adverse Events (CTCAE). RESULTS: The inter-observer Pearson correlation coefficient (PCC) was 0.87 (95% CI: 0.83-0.90, P < .001). For intra-observer repeatability, the PCC of the repeated scores was 0.83 (95% CI: 0.78-0.87, P < .001). Imaging findings were compared with standard clinical toxicity assessments using CTCAE scales. The PCC between BUS scores and CTCAE results was 0.62 (95% CI: 0.35-0.80, P < .001). Among all locations, 6:00 and tumor bed showed significantly greater toxicity compared with 12:00 (P = .04). CONCLUSIONS: BUS can investigate the cutaneous and subcutaneous tissue changes after RT. This BUS-based grading system can complement subjective clinical assessments of radiation-induced breast toxicity with cutaneous and subcutaneous sonographic information.
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Neoplasias de la Mama , Neoplasias , Traumatismos por Radiación , Femenino , Humanos , Reproducibilidad de los Resultados , Mama/diagnóstico por imagen , Piel/diagnóstico por imagen , Traumatismos por Radiación/diagnóstico por imagen , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/radioterapiaRESUMEN
Quantitative ultrasound (QUS) imaging is a safe, reliable, inexpensive, and real-time technique to extract physically descriptive parameters for assessing pathologies. Compared with other major imaging modalities such as computed tomography and magnetic resonance imaging, QUS suffers from several major drawbacks: poor image quality and inter- and intra-observer variability. Therefore, there is a great need to develop automated methods to improve the image quality of QUS. In recent years, there has been increasing interest in artificial intelligence (AI) applications in medical imaging, and a large number of research studies in AI in QUS have been conducted. The purpose of this review is to describe and categorize recent research into AI applications in QUS. We first introduce the AI workflow and then discuss the various AI applications in QUS. Finally, challenges and future potential AI applications in QUS are discussed.
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Inteligencia Artificial , Aprendizaje Automático , Humanos , Tomografía Computarizada por Rayos X , Ultrasonografía , Flujo de TrabajoRESUMEN
OBJECTIVES: The aim of this study was to assess bleomycin-induced pulmonary fibrosis on ex vivo mouse lungs using ultrasound image grading and texture analysis. METHODS: Excised mouse lungs were divided into 3 groups: control, mild fibrosis, and severe fibrosis based on the monitored indicators of health. B-mode ultrasound images were obtained via scanning the mouse lungs ex vivo. The surface smoothness, echo density, and angle of lesions or the lung margin were graded, and the imaging contrast, correlation, homogeneity, and entropy were assessed via texture analysis. RESULTS: The grades of surface smoothness, echo density, and angle were statistically higher for the severe fibrosis group compared with those of the control and mild fibrosis groups (P < .05). In addition, statistically significant differences in the contrast, correlation, and homogeneity between mild and severe fibrosis groups were observed (P < .05). CONCLUSIONS: The results obtained in this study suggest that ultrasound image grading and texture analysis are valuable and meaningful methods for assessing pulmonary fibrosis in a bleomycin mouse model.
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Bleomicina , Fibrosis Pulmonar , Animales , Modelos Animales de Enfermedad , Procesamiento de Imagen Asistido por Computador , Pulmón/diagnóstico por imagen , Ratones , Ratones Endogámicos C57BL , Fibrosis Pulmonar/inducido químicamente , Fibrosis Pulmonar/diagnóstico por imagenRESUMEN
OBJECTIVE: The objective of this study is to predict in vivo lung mass density for patients with interstitial lung disease using different gradient boosting decision tree (GBDT) algorithms based on measurements from lung ultrasound surface wave elastography (LUSWE) and pulmonary function testing (PFT). METHODS: Age and weight of study subjects (57 patients with interstitial lung disease and 20 healthy subjects), surface wave speeds at three vibration frequencies (100, 150, and 200 Hz) from LUSWE, and predicted forced expiratory volume (FEV1% pre) and ratio of forced expiratory volume to forced vital capacity (FEV1%/FVC%) from PFT were used as inputs while lung mass densities based on the Hounsfield Unit from high resolution computed tomography (HRCT) were used as labels to train the regressor in three GBDT algorithms, XGBoost, CatBoost, and LightGBM. 80% (20%) of the dataset was used for training (testing). RESULTS: The results showed that predictions using XGBoost regressor obtained an accuracy of 0.98 in the test dataset. CONCLUSION: The obtained results suggest that XGBoost regressor based on the measurements from LUSWE and PFT may be able to noninvasively assess lung mass density in vivo for patients with pulmonary disease.
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Diagnóstico por Imagen de Elasticidad , Enfermedades Pulmonares , Humanos , Pulmón/diagnóstico por imagen , Aprendizaje Automático , Pruebas de Función RespiratoriaRESUMEN
Medical imaging is widely used in the diagnosis and treatment of cancer, and artificial intelligence (AI) has achieved tremendous success in medical image analysis. This paper reviews AI-based tumor subregion analysis in medical imaging. We summarize the latest AI-based methods for tumor subregion analysis and their applications. Specifically, we categorize the AI-based methods by training strategy: supervised and unsupervised. A detailed review of each category is presented, highlighting important contributions and achievements. Specific challenges and potential applications of AI in tumor subregion analysis are discussed.
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Inteligencia Artificial , Neoplasias , Diagnóstico por Imagen , Humanos , Neoplasias/diagnóstico por imagenRESUMEN
BACKGROUND: Lymphedema treatment is an ongoing challenge. It impacts quality of life due to pain, loss of range of motion of the extremity, and repeated episodes of cellulitis. Different modalities have been used to evaluate lymphedema; some are more error-prone and some are more invasive. However, these measurements are poorly standardized, and intrarater and interrater reliabilities are difficult to achieve. This pilot study aims to assess the feasibility of ultrasound vibroelastography for assessing patients with extremity lymphedema via measuring shear wave speeds of subcutaneous tissues. METHODS: Patients with clinical and lymphoscintigraphic diagnosis of secondary lymphedema in the extremities without prior surgical treatment were included. A 0.1-s harmonic vibration was generated at three frequencies (100, 150, and 200 Hz) by the indenter of a handheld shaker on the skin. An ultrasound probe was used for noninvasively capturing of wave propagation in the subcutaneous tissue. Wave speeds were measured in the subcutaneous tissues of both the control and affected extremities. RESULTS: A total of 11 female patients with secondary lymphedema in the extremities were enrolled in this study. The magnitudes of the wave speeds of the region of interest in the subcutaneous tissue at lymphedema sites in the upper extremity (3.9 ± 0.17 m/s, 5.96 ± 0.67 m/s, and 7.41 ± 1.09 m/s) were statistically higher than those of the control sites (2.1 ± 0.27 m/s, 2.93 ± 0.57 m/s, and 3.56 ± 0.76 m/s) at 100, 150, and 200 Hz (P < 0.05), and at 100 and 200 Hz (P < 0.05) between lymphedema (4.33 ± 0.35 m/s, 4.17 ± 1.00 m/s, and 4.56 ± 0.37 m/s) and controls sites (2.48 ± 0.43 m/s, 2.77 ± 0.55 m/s, and 3.06 ± 0.29 m/s) in the lower extremity. CONCLUSIONS: These preliminary data suggest that ultrasound vibroelastography may be useful in the evaluation of secondary lymphedema and can be a valuable tool to noninvasively track treatment progress.
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Linfedema , Calidad de Vida , Femenino , Humanos , Extremidad Inferior/diagnóstico por imagen , Linfedema/diagnóstico por imagen , Linfedema/etiología , Proyectos Piloto , Ultrasonografía , Extremidad SuperiorRESUMEN
Background Lung US surface wave elastography (SWE) can noninvasively quantify lung surface stiffness or fibrosis by evaluating the rate of surface wave propagation. Purpose To assess the utility of lung US SWE for evaluation of interstitial lung disease. Materials and Methods In this prospective study, lung US SWE was used to assess 91 participants (women, 51; men, 40; mean age ± standard deviation [SD], 62.4 years ± 12.9) with interstitial lung disease and 30 healthy subjects (women, 16; men, 14; mean age, 45.4 years ± 14.6) from February 2016 through May 2017. Severity of interstitial lung disease was graded as none (healthy lung [F0]), mild (F1), moderate (F2), or severe (F3) based on pulmonary function tests, high-resolution CT, and clinical assessments. We propagated surface waves on the lung through gentle mechanical excitation of the external chest wall and measured the lung surface wave speed with a US probe. Lung US SWE performance was assessed, and the optimal cutoff wave speed values for fibrosis grades F0 through F3 were determined with receiver operating characteristic (ROC) curve analysis. Results Lung US SWE had a sensitivity of 92% (95% confidence intervals [CI]: 84%, 96%; P < .001) and a specificity of 89% (95% CI: 81%, 94%; P < .001) for differentiating between healthy subjects (F0) and participants with any grade of interstitial lung disease (F1-F3). It had a sensitivity of 50% and a specificity of 81% for differentiating interstitial lung disease grades F0-F2 from F3. The sensitivity was 88% and the specificity was 97% for differentiating between F0 and F1. The highest area under the ROC curve (AUC) values were obtained at 200 Hz and ranged from 0.83 to 0.94 to distinguish between healthy subjects and study participants with any interstitial lung disease. Conclusion Lung US surface wave elastography may be adjunct to high-resolution CT for noninvasive evaluation of interstitial lung disease. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Verschakelen in this issue.
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Diagnóstico por Imagen de Elasticidad/métodos , Enfermedades Pulmonares Intersticiales/diagnóstico por imagen , Anciano , Área Bajo la Curva , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Pulmón/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
The mechanical response of intact blood vessels to applied loads can be delineated into passive and active components using an isometric decomposition approach. Whereas the passive response is due predominantly to the extracellular matrix (ECM) proteins and amorphous ground substance, the active response depends on the presence of smooth muscle cells (SMCs) and the contractile machinery activated within those cells. To better understand determinants of active stress generation within the vascular wall, we subjected porcine common carotid arteries (CCAs) to biaxial inflation-extension testing under maximally contracted or passive SMC conditions and semiquantitatively measured two known markers of the contractile SMC phenotype: smoothelin and smooth muscle-myosin heavy chain (SM-MHC). Using isometric decomposition and established constitutive models, an intuitive but novel correlation between the magnitude of active stress generation and the relative abundance of smoothelin and SM-MHC emerged. Our results reiterate the importance of stretch-dependent active stress generation to the total mechanical response. Overall these findings can be used to decouple the mechanical contribution of SMCs from the ECM and is therefore a powerful tool in the analysis of disease states and potential therapies where both constituent are altered.
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Arteria Carótida Común/fisiología , Contracción Muscular , Músculo Liso/fisiología , Estrés Mecánico , Animales , Fenómenos Biomecánicos , PorcinosRESUMEN
Accurate assessment of radiation-induced breast toxicity is crucial for the management of breast radiation therapy (RT). Standard assessment of breast toxicity based on clinicians' visual inspection and palpation has considerable inter- and intra-observer variability. To overcome this challenge, we present an ultrasound histogram method that objectively evaluates radiation-induced breast toxicity longitudinally. In a prospective study, patients enrolled (n = 67) received ultrasound scans at four time points: prior to RT, last day of RT, 3-4 wk post-RT and 9-12-wk post-RT. Ultrasound scans were acquired at five locations (tumor bed and 3, 6, 9 and 12 o'clock) on both breasts. Two hundred sixty-four ultrasound scans and 2640 B-mode images were analyzed. The histogram differences between irradiated and contralateral breasts were calculated to evaluate radiation-induced breast changes. On the basis of the B-mode images, the severity of breast toxicity was graded as absent, mild, moderate or severe. The performance of the histogram method was assessed with the receiver operating characteristic (ROC) curve. The areas under the ROC curve ranged from 0.78 to 0.9 (sensitivity: 0.88-0.96, specificity: 0.53-0.83) at the lower quadrant for differentiating absent/mild from moderate/severe toxicity at various time points. This study provides preliminary evidence that ultrasound histogram differences can serve as an imaging biomarker to longitudinally assess radiation-induced acute toxicity.
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Neoplasias de la Mama , Traumatismos por Radiación , Humanos , Femenino , Estudios Prospectivos , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/radioterapia , Estudios Longitudinales , Mama/diagnóstico por imagen , Ultrasonografía , Traumatismos por Radiación/diagnóstico por imagen , Traumatismos por Radiación/etiologíaRESUMEN
Ultrasound imaging of the lung has played an important role in managing patients with COVID-19-associated pneumonia and acute respiratory distress syndrome (ARDS). During the COVID-19 pandemic, lung ultrasound (LUS) or point-of-care ultrasound (POCUS) has been a popular diagnostic tool due to its unique imaging capability and logistical advantages over chest X-ray and CT. Pneumonia/ARDS is associated with the sonographic appearances of pleural line irregularities and B-line artefacts, which are caused by interstitial thickening and inflammation, and increase in number with severity. Artificial intelligence (AI), particularly machine learning, is increasingly used as a critical tool that assists clinicians in LUS image reading and COVID-19 decision making. We conducted a systematic review from academic databases (PubMed and Google Scholar) and preprints on arXiv or TechRxiv of the state-of-the-art machine learning technologies for LUS images in COVID-19 diagnosis. Openly accessible LUS datasets are listed. Various machine learning architectures have been employed to evaluate LUS and showed high performance. This paper will summarize the current development of AI for COVID-19 management and the outlook for emerging trends of combining AI-based LUS with robotics, telehealth, and other techniques.
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PRECIS: Ocular biomechanics were compared between treated glaucoma patients and healthy subjects matched for age, intraocular pressure (IOP), and axial length. There was no difference in corneal wave propagation speed, but ocular rigidity was lower in glaucomatous eyes. PURPOSE: Ocular biomechanical properties are important in understanding glaucoma pathogenesis but the affected tissues are unclear. In this study, we compared corneal wave speed (a measure of corneal elasticity) and ocular rigidity coefficient between glaucomatous and normal eyes. MATERIALS AND METHODS: Twenty glaucomatous eyes from 10 patients and 20 normal eyes from 13 controls, matched for age, IOP, and axial length were included. Ocular rigidity was calculated based on the difference in supine IOP by pneumatonometry with and without a 10-g weight. Corneal wave speed was determined by ultrasound surface wave elastography. A small, 0.1-second harmonic vibration at 100 Hz was generated through the closed eyelids. Wave propagation was captured by an ultrasound transducer, and wave speed was determined from the phase change with distance. Comparisons were performed using generalized estimating equation models. RESULTS: There were no significant differences in corneal wave speed between glaucomatous and normal eyes (2.16±0.25 vs. 2.07±0.16 m/s, P=0.17). However, ocular rigidity was significantly lower in glaucomatous eyes (0.0218±0.0033 vs. 0.0252±0.0050/µL, P=0.01). Corneal wave speed was not correlated with age and IOP in either group (P≥0.23) but was correlated with ocular rigidity (R=0.48, P=0.02) and inversely correlated with axial length (R=-0.53, P=0.01) in glaucomatous eyes. CONCLUSION: Glaucomatous eyes tend to have lower ocular rigidity than healthy eyes with similar age, IOP, and axial length. However, the lack of a difference in corneal wave speed suggests that corneal tissue may not be significantly affected, and scleral changes likely play a more important role in glaucoma.
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Glaucoma , Presión Intraocular , Córnea/diagnóstico por imagen , Elasticidad , Glaucoma/diagnóstico , Humanos , Tonometría OcularRESUMEN
B-Mode ultrasound insonation of lungs that are dense with extravascular lung water (EVLW) produces characteristic reverberation artifacts termed B-lines. The number of B-lines present demonstrates reasonable correlation to the amount of EVLW. However, analysis of B-line artifacts generated by this modality is semi-quantitative relying on visual interpretation, and as a result, can be subject to inter-observer variability. The purpose of this study was to translate the use of a novel, quantitative lung ultrasound surface wave elastography technique (LUSWE) into the bedside assessment of pulmonary edema in patients admitted with acute congestive heart failure. B-mode lung ultrasound and LUSWE assessment of the lungs were performed using anterior and lateral intercostal spaces in the supine patient. 14 patients were evaluated at admission with reassessment performed 1-2 days after initiation of diuretic therapy. Each exam recorded the total lung B-lines, lung surface wave speeds (at 100, 150, and 200 Hz) and net fluid balance. The patient cohort experienced effective diuresis (average net fluid balance of negative 2.1 liters) with corresponding decrease in pulmonary edema visualized by B-mode ultrasound (average decrease of 13 B-Lines). In addition, LUSWE demonstrated a statistically significant reduction in the magnitude of wave speed from admission to follow-up. The reduction in lung surface wave speed suggests a decrease in lung stiffness (decreased elasticity) mediated by successful reduction of pulmonary edema. In summary, LUSWE is a noninvasive technique for quantifying elastic properties of superficial lung tissue that may prove useful as a diagnostic test, performed at the bedside, for the quantitative assessment of pulmonary edema.
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Diagnóstico por Imagen de Elasticidad , Edema Pulmonar , Artefactos , Humanos , Pulmón/diagnóstico por imagen , Edema Pulmonar/diagnóstico por imagen , UltrasonografíaRESUMEN
OBJECTIVES: The purpose of this study was to explore the utility of an injectable purified exosome product derived from human apheresis blood to (1) augment surgical closure of vaginal mesh exposures, and (2) serve as a stand-alone therapy for vaginal mesh exposure. METHODS: Sixteen polypropylene meshes (1×1-3×3 cm) were implanted in the vaginas of 7 Yorkshire-crossed pigs by urogynecologic surgeons (day 0). On day 7, group 1 underwent surgical intervention via vaginal tissue suture reclosure with (n=2 pigs, n=4 meshes) or without (n=2 pigs, n=4 meshes) exosome injection; group 2 underwent medical intervention with an exosome injection (n=3, n=8 meshes). One animal in group 2 was given oral 2'-deoxy-5-ethynyluridine to track cellular regeneration. Euthansia occurred at 5 weeks. RESULTS: Mesh exposures treated with surgical closure alone experienced reexposure of the mesh. Exosome treatment with or without surgical closure resulted in partial to full mesh exposure resolution up to 3×3 cm. Exosome-treated tissues had significantly thicker regenerated epithelial tissue (208 µm exosomes-only and 217 µm surgery+exosomes, versus 80 µm for surgery-only; P < 0.05); evaluation of 2'-deoxy-5-ethynyluridine confirmed de novo regeneration throughout the epithelium and underlying tissues. Capillary density was significantly higher in the surgery+exosomes group (P = 0.03). Surgery-only tissues had a higher inflammatory and fibrosis response as compared with exosome-treated tissues. CONCLUSIONS: In this pilot study, exosome treatment augmented healing in the setting of vaginal mesh exposure, reducing the incidence of mesh reexposure after suture closure and decreasing the area of mesh exposure through de novo tissue regeneration after exosome injection only. Further study of varied local tissue conditions and mesh configurations is warranted.
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Exosomas , Mallas Quirúrgicas , Animales , Femenino , Humanos , Proyectos Piloto , Polipropilenos , Mallas Quirúrgicas/efectos adversos , Porcinos , Vagina/cirugíaRESUMEN
Carpal tunnel syndrome (CTS) is a disorder that affects the median nerve at the wrist sufficient to cause impairment of nerve function. Elevated carpal tunnel pressure (CTP) leads to median nerve pathology, sensory, and motor changes in CTS patient. The techniques to quantify CTP used in clinic are invasive. This study aimed to investigate the feasibility of a noninvasive ultrasound vibro-elastography (UVE) to predict CTP in CTS patients and healthy individuals. The magnitudes of shear wave speed ratio (rSWS) of the 10 CTS patients (10 hands) and 6 healthy individuals (12 hands), and 10 cadaveric hands were compared using UVE. The ratios of intra to extra-carpal tunnel SWS in CTS patients was significantly higher than those in the healthy individuals (p = 0.0008) and cadaveric hands (p = 0.0015) with 500-g tendon tension. We estimated the CTP in the carpal tunnel using the mean rSWS of each group obtained from the present study and the linear approximation obtain from cadaveric hands data with 500-g tendon tension (y = 0.0036x + 1.1413). These results indicated that the elevated pressure applied to the 3rd flexor digitorum superficialis tendon in the carpal tunnel of CTS patients resulted in faster shear wave propagation. These results show that UVE was useful to indirectly estimate the CTP by measuring the rSWS; thus, they are potentially useful for the early diagnosis and assessment of CTS.
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Síndrome del Túnel Carpiano , Diagnóstico por Imagen de Elasticidad , Síndrome del Túnel Carpiano/diagnóstico por imagen , Humanos , Nervio Mediano/diagnóstico por imagen , Tendones/diagnóstico por imagen , MuñecaRESUMEN
Scleroderma, or systemic sclerosis (SSc), is a multi-organ connective tissue disease characterized by immune dysregulation and tissue fibrosis. Skin disease is both a disabling feature of SSc and a predictor of visceral involvement and increased mortality. The Modified Rodnan Skin Score (MRSS) is currently the most common clinical method for assessing skin. We developed ultrasound surface wave elastography (USWE) techniques to measure skin surface wave speeds and analyze skin viscoelasticity. The objective of this research was to determine the correlations of skin surface wave speed and skin viscoelasticity with MRSS. Twenty-six SSc patients were studied using USWE and the MRSS. The subject was tested in a sitting position while his or her left or right forearm and upper arm were placed horizontally on a pillow in a relaxed state. The skin of both left and right forearms and upper arms of patients was tested using USWE. Surface wave speeds are positively correlated with the MRSS. Skin elasticity is also positively correlated with the MRSS. However, there was no correlation between skin viscosity and the MRSS for these SSc patients. We will further study if skin viscosity is sensitive enough to detect early edema from inflammation changes of SSc.
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Diagnóstico por Imagen de Elasticidad , Esclerodermia Localizada/diagnóstico por imagen , Piel/diagnóstico por imagen , Anciano , Anciano de 80 o más Años , Elasticidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerodermia Localizada/fisiopatología , Piel/fisiopatologíaRESUMEN
Zebrafish are being increasingly used as animal models for human diseases such as cardiomyopathy and neuroblastoma. Owing to a nearly fully sequenced genome and efficient genetics/chemical genetics, zebrafish open new research opportunities for human diseases research. The purpose of this study was to develop zebrafish ultrasound vibro-elastography (ZUVE) for measuring the shear wave speed of zebrafish. An adult female zebrafish was anesthetized for three minutes for the ZUVE testing. A 0.1 s gentle harmonic vibration was generated on the tail using a sphere tip indenter with 3 mm diameter. Shear wave propagation in the zebrafish was measured using a high frequency 18 MHz ultrasound probe. Shear wave speeds were measured at 300, 400, and 500 Hz. Shear wave speeds were, respectively, 3.13 ± 1.20 (m/s) for 300 Hz, 4.28 ± 1.36 (m/s) for 400 Hz, and 5.07 ± 1.45 (m/s) for 500 Hz for zebrafish 1 in a region of interest (ROI) which covered the central body. The shear wave speed dispersions were similar for four zebrafish and shear wave speeds ranged between 2.5 (m/s) and 5 (m/s) from 300 Hz to 500 Hz. The experimental setup and testing for a zebrafish lasted less than three minutes. All tested zebrafish were alive after testing. ZUVE is safe, fast, and noninvasive, making the testing of elastic properties of zebrafish feasible.
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Diagnóstico por Imagen de Elasticidad/métodos , Cola (estructura animal)/diagnóstico por imagen , Pez Cebra , Animales , Estudios de Factibilidad , Modelos Animales , VibraciónRESUMEN
The Hounsfield unit (HU) obtained from high resolution computed tomography (HRCT) has been used to assess lung pathology. However, lung mass density has not been quantified in vivo noninvasively. The objective of this study was to develop a method for analyzing lung mass density of superficial lung tissue of patients with interstitial lung disease (ILD) and healthy subjects using a deep neural network (DNN) and lung ultrasound surface wave elastography (LUSWE). Surface wave speeds at three vibration frequencies (100, 150 and 200 Hz) from LUSWE and a pulmonary function test (PFT) including predicted forced expiratory volume (FEV1% pre) and ratio of forced expiratory volume to forced vital capacity (FEV1%/FVC%) were used. Predefined lung mass densities based on the HU for ILD patients and healthy subjects (77 in total) were also used to train the DNN model. The DNN was composed of four hidden layers of 1024 neurons for each layer and trained for 80 epochs with a batch size of 20. The learning rate was 0.001. Performances of two types of activation functions in the DNN, rectified linear activation unit (ReLU) and exponential linear unit (ELU), as well as, machine learning models (support vector regression, random forest, Adaboost) were evaluated. The test dataset of wave speeds, FEV1% pre and FEV%/FVC%, was used to predict lung mass density. The results showed that predictions using a DNN with ELU obtained a comparatively better performance in the testing dataset (accuracy = 0.89) than those of DNN with ReLU or machine learning models. This method may be useful to noninvasively analyze lung mass density by using the DNN model together with the measurements from LUSWE and PFT.
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Diagnóstico por Imagen de Elasticidad , Enfermedades Pulmonares Intersticiales , Voluntarios Sanos , Humanos , Pulmón/diagnóstico por imagen , Enfermedades Pulmonares Intersticiales/diagnóstico por imagen , Redes Neurales de la ComputaciónRESUMEN
BACKGROUND: The aim of this study was to use ultrasound vibro-elastography (UVE) for measuring surface wave speed and assessing mechanical properties of ex vivo porcine reproductive tissues, including the uterus, bladder, cornua and cervix. METHODS: In UVE, a 0.1-s harmonic vibration at low frequency was generated on the tissue surface with a handheld shaker. A linear-array ultrasound probe was used to measure the resulting surface wave propagation. Surface wave speeds of tissues were measured in the frequency range of 100-300 Hz. Mechanical properties of the tissue were calculated based on wave speed dispersion with frequency. FINDINGS: The obtained results showed that the surface wave speeds of porcine bladder, cervix, cornua and uterus increased with frequency. There were no statistically significant differences in the wave speeds or mechanical properties among the porcine bladder, cervix, cornua and uterus. INTERPRETATION: Experimental data obtained in this study may be used as a reference to study in vivo surface wave speed or mechanical properties for porcine or human reproductive tissues.
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Diagnóstico por Imagen de Elasticidad , Fenómenos Mecánicos , Reproducción , Animales , Fenómenos Biomecánicos , Femenino , Humanos , Pruebas Mecánicas , Porcinos , Ultrasonografía , VibraciónRESUMEN
The purpose of this research is to demonstrate the feasibility of a 2 dimensional (2D) penile ultrasound vibro-elastography (PUVE) technique for measuring the shear wave speed map over an area of regional of interest (ROI) in the penis. In PUVE, a 0.1 s harmonic vibration at a low frequency is generated on the surface of the penis using a handheld vibrator. An ultrasound probe is used to measure the resulting shear wave propagation in the penis. The shear wave speed is analyzed in the ROI of corpus cavernosum from both sides of penis using a 2D wave speed analysis technique. The shear wave speed of the penis is measured at three excitation frequencies of 100 Hz, 150 Hz, and 200 Hz. The viscoelasticity of penis is analyzed based on the wave speed dispersion with frequency. A pilot study was performed in men with ED and/or PD. It is found that both elasticity and viscosity of corpus cavernosa positively correlate with the peak systolic velocity (PSV) from penile ultrasonography. Both elasticity and viscosity of corpus cavernosa negatively correlate with the cardiovascular (CV) risk for patients with ED and/or PD. These results suggest that PUVE may provide a noninvasive and painless technique for assessing patients with ED/PD and their future CV risk. We will further evaluate PUVE in a large cohort of patients with ED/PD.