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1.
Lasers Surg Med ; 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34412154

RESUMO

OBJECTIVES: Minimally invasive fat sculpting techniques are becoming more widespread with the development of office-based devices and therapies. Electrochemical lipolysis (ECLL) is a needle-based technology that uses direct current (DC) to electrolyze tissue water creating acid and base in situ. In turn, fat is saponified and adipocyte cell membrane lysis occurs. The electrolysis of water can be accomplished using a simple open-loop circuit (V-ECLL) or by incorporating a feedback control circuit using a potentiostat (P-ECLL). A potentiostat utilizes an operational amplifier with negative feedback to allow users to precisely control voltage at specific electrodes. To date, the variation between the two approaches has not been studied. The aim of this study was to assess current and charge transfer variation and lipolytic effect created by the two approaches in an in vivo porcine model. METHODS: Charge transfer measurements from ex vivo V-ECLL and P-ECLL treated porcine skin and fat were recorded at -1 V P-ECLL, -2 V P-ECLL, -3 V P-ECLL, and -5 V V-ECLL each for 5 min to guide dosimetry parameters for in vivo studies. In follow-up in vivo studies, a sedated female Yorkshire pig was treated with both V-ECLL and P-ECLL across the dorsal surface over a range of dosimetry parameters, including -1.5 V P-ECLL, -2.5 V P-ECLL, -3.5 V P-ECLL, and 5 V V-ECLL each treated for 5 min. Serial biopsies were performed at baseline before treatment, 1, 2, 7, 14, and 28 days after treatment. Tissue was examined using fluorescence microscopy and histology to compare the effects of the two ECLL approaches. RESULTS: Both V-ECLL and P-ECLL treatments induced in-vivo fat necrosis evident by adipocyte membrane lysis, adipocyte denuclearization, and an acute inflammatory response across a 28-day longitudinal study. However, -1.5 V P-ECLL produced a smaller spatial necrotic effect compared to 5 V V-ECLL. In addition, 5 V V-ECLL produced a comparable necrotic effect to that of -2.5 V and -3.5 V P-ECLL. CONCLUSIONS: V-ECLL and P-ECLL at the aforementioned dosimetry parameters both achieved fat necrosis by adipocyte membrane lysis and denuclearization. The -2.5 V and -3.5 V P-ECLL treatments created spatially similar fat necrotic effects when compared to the 5 V V-ECLL treatment. Quantitatively, total charge transfer between dosimetry parameters suggests that -2.5 V P-ECLL and 5 V V-ECLL produce comparable electrochemical reactions. Such findings suggest that a low-voltage closed-loop potentiostat-based system is capable of inducing fat necrosis to a similar extent compared to that of a higher voltage direct current system.

2.
Surg Innov ; 28(6): 776-779, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33629890

RESUMO

Need. Battery-powered Light Emitting Diode (LED) surgical headlights are necessary for improved intraoperative illumination but may be costly. Technical Solution. The objective of this study was to develop a low-cost surgical headlight using a consumer-grade LED headlight and 3D-printed mount. Proof of Concept. Eighteen surgical residents performed simulation exercises that mimicked suturing in the oral cavity using both a custom prototype headlight and a commercial surgical headlight. The time required to complete the task with each headlight was recorded along with an exit survey. A second device was created based on the critiques of the first device and was tested by ten additional surgical trainees. Surgical residents completed the simulation task in 27 ± 8.6 seconds and 21 ± 5.6 seconds with the commercially available headlight and first prototype, respectively. In the second experiment, the simulation task was completed in 23 ± 11.1 and 23 ± 12.2 seconds with the commercially available headlight and second device, respectively. Survey results showed an overall positive consensus, with critiques about headband security, suggestions for smaller LED chassis, and a more robust mounting bracket. Some preferred the prototype headlight due to the wider field of illumination compared to the commercially available unit (ie, beam spread/beam angle). Next Steps. Future adjustments are required to optimize the location of the headlight and the battery to modify the weight distribution of the device. Conclusion. These findings demonstrate that our prototype models are viable alternatives to conventional surgical headlights and warrant continued optimization for broader adoption by surgeons and trainees for whom higher-cost alternatives are not an option.

3.
Ann Otol Rhinol Laryngol ; 130(2): 167-172, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32680431

RESUMO

PURPOSE: To evaluate endoscopic long-range optical coherence tomography system combined with a pressure sensor to concurrently measure internal nasal valve cross-sectional area and intraluminal pressure. METHODS: A pressure sensor was constructed using an Arduino platform and calibrated using a limiter-controlled vacuum system and industrial absolute pressure gauge. Long-range optical coherence tomography imaging and pressure transduction were performed concurrently in the naris of eight healthy adult subjects during normal respiration and forced inspiration. The internal nasal valve was manually segmented using Mimics software and cross-sectional area was measured. Internal nasal valve cross-sectional area measurements were correlated with pressure recordings. RESULTS: Mean cross-sectional area during forced inspiration was 6.49 mm2. The mean change in pressure between normal respiration and forceful inspiration was 12.27 mmHg. The direct correlation between pressure and cross-sectional area as measured by our proposed system was reproducible among subjects. CONCLUSIONS: Our results demonstrate a direct correlation between internal nasal valve cross-sectional area and nasal airflow during inspiration cycles. Endoscopic long-range optical coherence tomography coupled with a pressure sensor serves as a useful tool to quantify the dynamic behavior of the internal nasal valve.


Assuntos
Cavidade Nasal/diagnóstico por imagem , Cavidade Nasal/fisiologia , Tomografia de Coerência Óptica , Transdutores de Pressão , Feminino , Voluntários Saudáveis , Humanos , Inalação , Masculino , Respiração
4.
Sci Rep ; 10(1): 20745, 2020 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-33247200

RESUMO

Body contouring achieved via subcutaneous adipose tissue reduction has notably advanced over the past century, from suction assisted lipectomy to techniques with reduced degrees of invasiveness including laser, radiofrequency, high frequency focused ultrasound, cryolipolysis, and drug-based injection approaches. These costly techniques have focused on damaging adipocyte cell membranes, hydrolyzing triglycerides (TGs), or inducing apoptosis. Here, we present a simple, low-cost technique, termed electrochemical lipolysis (ECLL). During ECLL, saline is injected into the subcutaneous adipose tissue, followed by insertion of needle electrodes and application of an electrical potential. Electrolysis of saline creates localized pH gradients that drive adipocyte death and saponification of TGs. Using pH mapping, various optical imaging techniques, and biochemical assays, we demonstrate the ability of ECLL to induce acid and base injury, cell death, and the saponification of triglycerides in ex vivo porcine adipose tissue. We define ECLL's potential role as a minimally-invasive, ultra-low-cost technology for reducing and contouring adipose tissue, and present ECLL as a potential new application of an emerging electrochemical redox based treatment modality.


Assuntos
Tecido Adiposo/patologia , Contorno Corporal/métodos , Técnicas Eletroquímicas/métodos , Lipólise , Triglicerídeos/metabolismo , Tecido Adiposo/metabolismo , Animais , Apoptose , Concentração de Íons de Hidrogênio , Suínos
6.
J Dermatol Sci ; 97(3): 179-186, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32169274

RESUMO

BACKGROUND: Minimally-invasive methods to treat scars address a common pathway of altering collagen structure, leading to collagen remodeling. OBJECTIVE: In this study, we employed in situ redox chemistry to create focal pH gradients in skin, altering dermal collagen, in a process we refer to as electrochemical therapy (ECT). The effects of ECT to induce biochemical and structural changes in ex vivo porcine skin were examined. METHODS: During ECT, two platinum electrodes were inserted into fresh porcine skin, and following saline injection, an electrical potential was applied. pH mapping, high frequency ultrasonography, and two photon excitation microscopy and second harmonic generation (SHG) microscopy were used to evaluate treatment effects. Findings were correlated with histology. RESULTS: Following ECT, pH mapping depicted acid and base production at anode and cathode sites respectively, with increasing voltage and application time. Gas formation during ECT was observed with ultrasonography. Anode sites showed significant loss of SHG signal, while cathode sites showed disorganized collagen structure with fewer fibrils emitting an attainable signal. Histologically, collagen denaturation at both sites was confirmed. CONCLUSION: We demonstrated the production of in situ acid and base in skin occurring via ECT. The effects chemically and precisely alter collagen structure through denaturation, giving insight on the potential of ECT as a simple, low-cost, and minimally-invasive means to remodel skin and treat scars.


Assuntos
Cicatriz/terapia , Colágeno/química , Terapia por Estimulação Elétrica/métodos , Pele/química , Animais , Fenômenos Biofísicos , Cicatriz/patologia , Terapia por Estimulação Elétrica/instrumentação , Eletrodos , Humanos , Concentração de Íons de Hidrogênio , Microscopia de Fluorescência por Excitação Multifotônica , Modelos Animais , Pele/diagnóstico por imagem , Pele/patologia , Suínos , Ultrassonografia
7.
J Biophotonics ; 13(3): e201900221, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31710775

RESUMO

Incomplete surgical resection of head and neck squamous cell carcinoma (HNSCC) is the most common cause of local HNSCC recurrence. Currently, surgeons rely on preoperative imaging, direct visualization, palpation and frozen section to determine the extent of tissue resection. It has been demonstrated that optical coherence tomography (OCT), a minimally invasive, nonionizing near infrared mesoscopic imaging modality can resolve subsurface differences between normal and abnormal head and neck mucosa. Previous work has utilized two-dimensional OCT imaging which is limited to the evaluation of small regions of interest generated frame by frame. OCT technology is capable of performing rapid volumetric imaging, but the capacity and expertise to analyze this massive amount of image data is lacking. In this study, we evaluate the ability of a retrained convolutional neural network to classify three-dimensional OCT images of head and neck mucosa to differentiate normal and abnormal tissues with sensitivity and specificity of 100% and 70%, respectively. This method has the potential to serve as a real-time analytic tool in the assessment of surgical margins.


Assuntos
Neoplasias de Cabeça e Pescoço , Tomografia de Coerência Óptica , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Mucosa Bucal/diagnóstico por imagem , Redes Neurais de Computação , Carcinoma de Células Escamosas de Cabeça e Pescoço
8.
Cornea ; 39(6): 793-794, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31809286

RESUMO

PURPOSE: To describe the feasibility of an attachment-free iOS-based cobalt blue light application to accurately detect corneal injury. METHODS: Corneal epithelium from New Zealand White rabbits was removed by gentle scraping with a dulled scalpel or by using a classic biopsy punch (2 mm in diameter). Each cornea was then examined using a smartphone-enabled blue light after applying a fluorescein sodium ophthalmic strip. Photographs of each cornea before and after using the smartphone-based light were captured with a second smartphone device. RESULTS: The iOS-based (Apple Inc., Cuptertino, CA) cobalt blue light effectively illuminated fluorescein dye in all ex vivo samples. Both circular punch biopsy and linear scalpel-induced corneal injuries were readily identified. CONCLUSIONS: The iOS-based cobalt blue light is a portable, low-cost, and effective alternative to commercially available cobalt blue lights.


Assuntos
Córnea/diagnóstico por imagem , Lesões da Córnea/diagnóstico , Software , Animais , Modelos Animais de Doenças , Coelhos
9.
J Biomed Opt ; 24(9): 1-8, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31493317

RESUMO

Subglottic stenosis (SGS) is a challenging disease to diagnose in neonates. Long-range optical coherence tomography (OCT) is an optical imaging modality that has been described to image the subglottis in intubated neonates. A major challenge associated with OCT imaging is the lack of an automated method for image analysis and micrometry of large volumes of data that are acquired with each airway scan (1 to 2 Gb). We developed a tissue segmentation algorithm that identifies, measures, and conducts image analysis on tissue layers within the mucosa and submucosa and compared these automated tissue measurements with manual tracings. We noted small but statistically significant differences in thickness measurements of the mucosa and submucosa layers in the larynx (p < 0.001), subglottis (p = 0.015), and trachea (p = 0.012). The automated algorithm was also shown to be over 8 times faster than the manual approach. Moderate Pearson correlations were found between different tissue texture parameters and the patient's gestational age at birth, age in days, duration of intubation, and differences with age (mean age 17 days). Automated OCT data analysis is necessary in the diagnosis and monitoring of SGS, as it can provide vital information about the airway in real time and aid clinicians in making management decisions for intubated neonates.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Laringoestenose/diagnóstico por imagem , Laringe/diagnóstico por imagem , Tomografia de Coerência Óptica/métodos , Algoritmos , Humanos , Recém-Nascido
10.
Lasers Surg Med ; 2019 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-30681167

RESUMO

OBJECTIVES: There have been many advancements in laryngeal imaging using optical coherence tomography (OCT), with varying system design and probes for use in research, office, and operating room settings. We evaluated the performance of six distinct OCT systems in imaging porcine vocal folds (cords) using computational image processing and segmentation. METHODS: Porcine vocal folds were scanned using six OCT systems. Imaging system and probe performance were quantitatively assessed for signal penetration, layer differentiation, and epithelium (EP) measurement. Fitted exponential decay curves with corresponding α constant and intensity thresholding segmentation were utilized to quantify the aforementioned parameters. RESULTS: The smallest average α constant and deepest signal penetration was of the SS-OCT 1700 nm 90 kHz microscope system (α = -1.74), followed by the SS-OCT 1310 nm 200 kHz VCSEL microscope system (α = -1.99), and SS-OCT 1310 nm 50 kHz rigid forward viewing endoscope system (α = -2.23). The EP was not readily visualized for three out of six systems, but was detected using automated segmentation. Average EP thickness (mean ± SD) was calculated as 55.79 ± 31.86 µm which agrees favorably with previous literature. CONCLUSION: Comparisons of OCT systems are challenging, as they encompass different probe design, optical path, and lasers, depending on application. Practical evaluation of different systems using computer based quantitative image processing and segmentation revealed basic, constructive information, such as EP measurements. To further validate the comparisons of system performance with clinical usability, in vivo human laryngeal imaging will be conducted. Further development of automated image processing and segmentation can be useful in rapid analysis of information. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

12.
Am J Respir Crit Care Med ; 192(12): 1504-13, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26214043

RESUMO

RATIONALE: Subglottic edema and acquired subglottic stenosis are potentially airway-compromising sequelae in neonates following endotracheal intubation. At present, no imaging modality is capable of in vivo diagnosis of subepithelial airway wall pathology as signs of intubation-related injury. OBJECTIVES: To use Fourier domain long-range optical coherence tomography (LR-OCT) to acquire micrometer-resolution images of the airway wall of intubated neonates in a neonatal intensive care unit setting and to analyze images for histopathology and airway wall thickness. METHODS: LR-OCT of the neonatal laryngotracheal airway was performed a total of 94 times on 72 subjects (age, 1-175 d; total intubation, 1-104 d). LR-OCT images of the airway wall were analyzed in MATLAB. Medical records were reviewed retrospectively for extubation outcome. MEASUREMENTS AND MAIN RESULTS: Backward stepwise regression analysis demonstrated a statistically significant association between log(duration of intubation) and both laryngeal (P < 0.001; multiple r(2) = 0.44) and subglottic (P < 0.001; multiple r(2) = 0.55) airway wall thickness. Subjects with positive histopathology on LR-OCT images had a higher likelihood of extubation failure (odds ratio, 5.9; P = 0.007). Longer intubation time was found to be significantly associated with extubation failure. CONCLUSIONS: LR-OCT allows for high-resolution evaluation and measurement of the airway wall in intubated neonates. Our data demonstrate a positive correlation between laryngeal and subglottic wall thickness and duration of intubation, suggestive of progressive soft tissue injury. LR-OCT may ultimately aid in the early diagnosis of postintubation subglottic injury and help reduce the incidences of failed extubation caused by subglottic edema or acquired subglottic stenosis in neonates. Clinical trial registered with www.clinicaltrials.gov (NCT 00544427).


Assuntos
Intubação Intratraqueal/efeitos adversos , Laringoestenose/diagnóstico , Tomografia de Coerência Óptica/métodos , Diagnóstico Precoce , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Retrospectivos
13.
Opt Express ; 23(26): 33992-4006, 2015 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-26832057

RESUMO

We present an automatic segmentation method for the delineation and quantitative thickness measurement of multiple layers in endoscopic airway optical coherence tomography (OCT) images. The boundaries of the mucosa and the sub-mucosa layers are accurately extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested with sheep airway OCT images. Quantitative thicknesses of the mucosal layers are obtained automatically for smoke inhalation injury experiments.


Assuntos
Algoritmos , Automação/métodos , Endoscopia/métodos , Aumento da Imagem/métodos , Sistema Respiratório/patologia , Lesão por Inalação de Fumaça/diagnóstico , Tomografia de Coerência Óptica/métodos , Animais , Modelos Animais de Doenças , Reprodutibilidade dos Testes , Mucosa Respiratória/patologia , Ovinos , Lesão por Inalação de Fumaça/patologia
14.
J Biomed Opt ; 20(12): 126010, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26720877

RESUMO

Biofilm formation has been linked to ventilator-associated pneumonia, which is a prevalent infection in hospital intensive care units. Currently, there is no rapid diagnostic tool to assess the degree of biofilm formation or cellular biofilm composition. Optical coherence tomography (OCT) is a minimally invasive, nonionizing imaging modality that can be used to provide high-resolution cross-sectional images. Biofilm deposited in critical care patients' endotracheal tubes was analyzed in vitro. This study demonstrates that OCT could potentially be used as a diagnostic tool to analyze and assess the degree of biofilm formation and extent of airway obstruction caused by biofilm in endotracheal tubes.


Assuntos
Biofilmes , Endoscopia/métodos , Contaminação de Equipamentos , Intubação Intratraqueal/efeitos adversos , Tomografia de Coerência Óptica/métodos , Artefatos , Cuidados Críticos , Infecção Hospitalar/diagnóstico , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Unidades de Terapia Intensiva , Interferometria/métodos , Microscopia Eletrônica de Varredura , Fenótipo , Pneumonia Associada à Ventilação Mecânica/diagnóstico
15.
J Biomech ; 47(3): 755-8, 2014 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-24388166

RESUMO

The mechanical behavior of an atherosclerotic plaque may encode information about the type, composition, and vulnerability to rupture. Human arterial segments with varying plaque burden were analyzed ex vivo with optical coherence tomography (OCT) to determine plaque type and to determine compliance during pulsatile inflation in their native geometry. Calcifications and lipid filled plaques showed markedly different compliance when analyzed with OCT wall motion analysis. There was also a trend towards increased circumferential variation in arterial compliance with increasing plaque burden.


Assuntos
Calcinose/patologia , Artéria Femoral/patologia , Placa Aterosclerótica/patologia , Tomografia de Coerência Óptica/métodos , Idoso , Idoso de 80 Anos ou mais , Cadáver , Calcinose/fisiopatologia , Complacência (Medida de Distensibilidade) , Feminino , Artéria Femoral/fisiopatologia , Humanos , Masculino , Placa Aterosclerótica/fisiopatologia , Sensibilidade e Especificidade , Adulto Jovem
16.
JAMA Otolaryngol Head Neck Surg ; 139(5): 502-9, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23681033

RESUMO

IMPORTANCE: Subglottic stenosis (SGS) is a severe, acquired, potentially life-threatening disease that can be caused by endotracheal tube intubation. Newborns and neonates are particularly susceptible to SGS owing to the small caliber of their airway. OBJECTIVE: To demonstrate optical coherence tomography (OCT) capabilities in detecting injury and scar formation using a rabbit model. Optical coherence tomography may provide a noninvasive, bedside or intensive care unit modality for the identification of early airway trauma with the intention of preventing progression to SGS and can image the upper airway through an existing endotracheal tube coupled with a small fiber-optic probe. DESIGN: Rabbits underwent suspension laryngoscopy with induction of of SGS via epithelial injury. This model was used to test and develop our advanced, high-speed, high-resolution OCT imaging system using a 3-dimensional microelectromechanical systems-based scanning device integrated with a fiber-optic probe to acquire high-resolution anatomic images of the subglottic epithelium and lamina propria. SETTING: All experiments were performed at the Beckman Laser Institute animal operating room. INTERVENTION OR EXPOSURE: Optical coherence tomography and endoscopy was performed with suspension laryngoscopy at 6 different time intervals and compared with conventional digital endoscopic images and histologic sections. Fifteen rabbits were killed at 3, 7, 14, 21, and 42 days after the induction of SGS. The laryngotracheal complexes were serially sectioned for histologic analysis. MAIN OUTCOME AND MEASURE: Histologic sections, endoscopic images, and OCT images were compared with one another to determine if OCT could accurately delineate the degree of SGS achieved. RESULTS: The rabbit model was able to reliably and reproducibly achieve grade I SGS. The real-time OCT imaging system was able to (1) identify multiple structures in the airway; (2) delineate different tissue planes, such as the epithelium, basement membrane, lamina propria, and cartilage; and (3) detect changes in each tissue plane produced by trauma. Optical coherence tomography was also able demonstrate a clear picture of airway injury that correlated with the endoscopic and histologic images. With subjective review, 3 patients had high correlation between OCT and histologic images, 10 demonstrated some correlation with histologic images, and 2 showed little to no correlation with histologic images. CONCLUSIONS AND RELEVANCE: Optical coherence tomography, coupled with a fiber-optic probe, identifies subglottic scarring and can detect tissue changes in the rabbit airway to a depth of 1 mm. This technology brings us 1 step closer to minimally invasive subglottic airway monitoring in the intubated neonate, with the ultimate goal of preventing SGS and better managing the airway.


Assuntos
Interpretação de Imagem Assistida por Computador , Intubação Intratraqueal/efeitos adversos , Laringoestenose/diagnóstico por imagem , Laringoestenose/patologia , Tomografia de Coerência Óptica/métodos , Animais , Cicatriz/patologia , Modelos Animais de Doenças , Tecnologia de Fibra Óptica , Intubação Intratraqueal/métodos , Laringoscopia/métodos , Laringoestenose/etiologia , Coelhos , Radiografia , Distribuição Aleatória , Medição de Risco , Sensibilidade e Especificidade , Índice de Gravidade de Doença
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