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1.
Sci Rep ; 14(1): 14649, 2024 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-38918552

RESUMO

Cognitive impairment (CI) is prevalent in central nervous system demyelinating diseases, such as multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). We developed a novel tablet-based modified digital Symbol Digit Modalities Test (MD-SDMT) with adjustable protocols that feature alternating symbol-digit combinations in each trial, lasting one or two minutes. We assessed 144 patients (99 with MS and 45 with NMOSD) using both MD-SDMT protocols and the traditional paper-based SDMT. We also gathered participants' feedback through a questionnaire regarding their preferences and perceived reliability. The results showed strong correlations between MD-SDMT and paper-based SDMT scores (Pearsons correlation: 0.88 for 2 min; 0.85 for 1 min, both p < 0.001). Among the 120 respondents, the majority preferred the digitalized SDMT (55% for the 2 min, 39% for the 1 min) over the paper-based version (6%), with the 2 min MD-SDMT reported as the most reliable test. Notably, patients with NMOSD and older individuals exhibited a preference for the paper-based test, as compared to those with MS and younger patients. In summary, even with short test durations, the digitalized SDMT effectively evaluates cognitive function in MS and NMOSD patients, and is generally preferred over the paper-based method, although preferences may vary with patient characteristics.


Assuntos
Esclerose Múltipla , Neuromielite Óptica , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Esclerose Múltipla/psicologia , Esclerose Múltipla/fisiopatologia , Neuromielite Óptica/fisiopatologia , Testes Neuropsicológicos , Disfunção Cognitiva/diagnóstico , Reprodutibilidade dos Testes , Idoso , Doenças Desmielinizantes , Inquéritos e Questionários , Adulto Jovem , Computadores de Mão
2.
Sci Rep ; 13(1): 10817, 2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37402750

RESUMO

A mini basket type mapping catheter consists of thin film flexible sensors and is applied in the medical field to measure the electrocardiography (ECG) signals in order to localize and quantize the physiological condition/status of heart. The flexible nature of the thin film changes the configuration with respect to the contact boundary conditions when it contacts a target surface. Therefore, to accurately localize the flexible sensor, the thin film flexible sensor's configuration must be determined accurately in an on-line fashion. As a study of localizing the thin film flexible sensor, this study proposes an on-line thin film buckling configuration determination method using parametric optimization and interpolation technique. With the specific modulus of elasticity and dimensions of the thin film flexible sensor of the mapping catheter prototype, the buckling configuration with two point boundary condition under axial load can be calculated in desktop environment. The proposed calculation method is validated by mapping catheter sensor prototype test. The calculation/test results showed that the maximum overall length L, x[Formula: see text], and y[Formula: see text] value error between the calculation and experiment are approximately 0.16 mm, - 0.12 mm. - 0.10 mm in 50 ms calculation time. The calculation result of the proposed method is also compared with that of the numerical simulation by FEM, which has approximately 0.44 mm y[Formula: see text] value error compared with that of the experiment.

3.
Radiology ; 306(1): 20-31, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36346314

RESUMO

Adequate clinical evaluation of artificial intelligence (AI) algorithms before adoption in practice is critical. Clinical evaluation aims to confirm acceptable AI performance through adequate external testing and confirm the benefits of AI-assisted care compared with conventional care through appropriately designed and conducted studies, for which prospective studies are desirable. This article explains some of the fundamental methodological points that should be considered when designing and appraising the clinical evaluation of AI algorithms for medical diagnosis. The specific topics addressed include the following: (a) the importance of external testing of AI algorithms and strategies for conducting the external testing effectively, (b) the various metrics and graphical methods for evaluating the AI performance as well as essential methodological points to note in using and interpreting them, (c) paired study designs primarily for comparative performance evaluation of conventional and AI-assisted diagnoses, (d) parallel study designs primarily for evaluating the effect of AI intervention with an emphasis on randomized clinical trials, and (e) up-to-date guidelines for reporting clinical studies on AI, with an emphasis on guidelines registered in the EQUATOR Network library. Sound methodological knowledge of these topics will aid the design, execution, reporting, and appraisal of clinical evaluation of AI.


Assuntos
Algoritmos , Inteligência Artificial , Humanos , Estudos Prospectivos , Projetos de Pesquisa , Ensaios Clínicos Controlados Aleatórios como Assunto
4.
Adv Mater ; 35(43): e2204938, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35917488

RESUMO

Hydroxyapatite (HAP) is a green catalyst that has a wide range of applications in catalysis due to its high flexibility and multifunctionality. These properties allow HAP to accommodate a large number of catalyst modifications that can selectively improve the catalytic performance in target reactions. To date, many studies have been conducted to elucidate the effect of HAP modification on the catalytic activities for various reactions. However, systematic design strategies for HAP catalysts are not established yet due to an incomplete understanding of underlying structure-activity relationships. In this review, tuning methods of HAP for improving the catalytic performance are discussed: 1) ionic composition change, 2) morphology control, 3) incorporation of other metal species, and 4) catalytic support engineering. Detailed mechanisms and effects of structural modulations on the catalytic performances for attaining the design insights of HAP catalysts are investigated. In addition, computational studies to understand catalytic reactions on HAP materials are also introduced. Finally, important areas for future research are highlighted.

5.
Medicine (Baltimore) ; 101(9): e28890, 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35244042

RESUMO

ABSTRACT: The aim of this study was to determine which of 4 laryngoscopes, including A-LRYNGO, a newly developed channel-type video-laryngoscope with an embedded artificial intelligence-based glottis guidance system, is appropriate for tracheal intubation training in novice medical students wearing personal protective equipment (PPE).Thirty healthy senior medical school student volunteers were recruited. The participants underwent 2 tests with 4 laryngoscopes: Macintosh, McGrath, Pentax Airway-Scope and A-LRYNGO. The first test was conducted just after a lecture without any hands-on workshop. The second test was conducted after a one-on-one hands-on workshop. In each test, we measured the time required for tracheal intubation, intubation success rate, etc, and asked all participants to complete a short questionnaire.The time to completely insert the endotracheal tube with the Macintosh laryngoscope did not change significantly (P = .177), but the remaining outcomes significantly improved after the hands-on workshop (all P < .05). Despite being novice practitioners with no intubation experience and wearing PPE, the, 2 channel-type video-laryngoscopes were associated with good intubation-related performance before the hands-on workshop (all P < .001). A-LRYNGO's artificial intelligence-based glottis guidance system showed 93.1% accuracy, but 20.7% of trials were guided by the vocal folds.To prepare to manage the airway of critically ill patients during the coronavirus disease 2019 pandemic, a channel-type video-laryngoscope is appropriate for tracheal intubation training for novice practitioners wearing PPE.


Assuntos
COVID-19/prevenção & controle , Intubação Intratraqueal/instrumentação , Laringoscópios , Laringoscopia/instrumentação , Equipamento de Proteção Individual/efeitos adversos , Adulto , Inteligência Artificial , Desenho de Equipamento , Feminino , Glote , Humanos , Masculino , Manequins , SARS-CoV-2 , Estudantes de Medicina
6.
Tissue Eng Regen Med ; 19(2): 363-375, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34870799

RESUMO

BACKGROUND: In vitro generation of three-dimensional vessel network is crucial to investigate and possibly improve vascularization after implantation in vivo. This work has the purpose of engineering complex tissue regeneration of a vascular network including multiple cell-type, an extracellular matrix, and perfusability for clinical application. METHODS: The two electrospun membranes bonded with the vascular network shape are cultured with endothelial cells and medium flow through the engineered vascular network. The flexible membranes are bonded by amine-epoxy reaction and examined the perfusability with fluorescent beads. Also, the perfusion culture for 7 days of the endothelial cells is compared with static culture on the engineered vascular network membrane. RESULTS: The engineered membranes are showed perfusability through the vascular network, and the perfused network resulted in more cell proliferation and variation of the shear stress-related genes expression compared to the static culture. Also, for the generation of the complex vascularized network, pericytes are co-cultured with the engineered vascular network, which results in the Collagen I is expressed on the outer surface of the engineered structure. CONCLUSION: This study is showing the perfusable in vitro engineered vascular network with electrospun membrane. In further, the 3D vascularized network module can be expected as a platform for drug screening and regenerative medicine.


Assuntos
Células Endoteliais , Engenharia Tecidual , Técnicas de Cocultura , Matriz Extracelular , Medicina Regenerativa/métodos , Engenharia Tecidual/métodos
7.
Biosensors (Basel) ; 11(9)2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34562918

RESUMO

Conventional vascular intervention procedures present issues including X-ray exposure during operation, and an experience-dependent success rate and clinical outcome. This paper presents a novel robotic system using modularized bi-motional roller cartridge assemblies for robotic vascular interventions, specifically percutaneous coronary interventions (PCIs). The patient-side robot manipulates instruments such as the guiding catheter, guidewire, balloon/stent catheter, and diagnostic sensor catheter via commands from the user interface device, which is controlled by the physician. The proposed roller cartridge assembly can accommodate instruments of various sizes with an active clamping mechanism, and implements simultaneous translation and rotation motions. It also implements force feedback in the physician-side system, to effectively monitor the patient-side system's status. The positioning accuracy and precision in using the robotic system showed satisfactory performance in a phantom-based test. It was also confirmed, through animal experiments and a pilot clinical trial, that the system demonstrates feasibility for clinical use.


Assuntos
Cateterismo/métodos , Desenho de Equipamento , Retroalimentação , Humanos , Fenômenos Mecânicos , Movimento (Física) , Procedimentos Cirúrgicos Robóticos
8.
Biosensors (Basel) ; 11(7)2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34356714

RESUMO

Skeletal muscle mass deficiency and quality degradation constitute sarcopenia for elderly people. Sarcopenia can result in musculoskeletal damage and accompany various metabolic problems, which make early sarcopenia diagnosis important. Various modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), have been developed for screening sarcopenia. Recently, ultrasound scanning was suggested for screening sarcopenia because of its safety, usability, and cost effectiveness. However, there has been no standardized assessment methodology for screening sarcopenia with ultrasound scanning. Therefore, prior to this study, we developed a four-degrees-of-freedom (DOF) sarcopenia detection system using an RGB-D camera and an ultrasound probe to automatically scan the human thigh without operator dependency. However, due to the eye-to-hand approach with the RGB-D camera, the system has limited usability for clinical trials. Therefore, in this study we modified the system such that it became eye-in-hand by attaching the RGB-D camera to the upper part of the system with an enhanced arc fitting algorithm. The modified system and enhanced algorithm were verified by an in-vitro test with bean curd-gelatin phantom. The results showed that the thickness of bean curd in the gelatin phantom was maintained at approximately 12.7 ± 0.35 mm over the 71.5∘ scanning range with 2.49 ± 0.15 N radial force at various thickness measuring points.


Assuntos
Sarcopenia/diagnóstico por imagem , Ultrassonografia/métodos , Idoso , Humanos , Imageamento por Ressonância Magnética , Músculo Esquelético/diagnóstico por imagem , Sarcopenia/patologia , Coxa da Perna/diagnóstico por imagem , Tomografia Computadorizada por Raios X
9.
Korean J Radiol ; 22(3): 442-453, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33629545

RESUMO

Artificial intelligence (AI) will likely affect various fields of medicine. This article aims to explain the fundamental principles of clinical validation, device approval, and insurance coverage decisions of AI algorithms for medical diagnosis and prediction. Discrimination accuracy of AI algorithms is often evaluated with the Dice similarity coefficient, sensitivity, specificity, and traditional or free-response receiver operating characteristic curves. Calibration accuracy should also be assessed, especially for algorithms that provide probabilities to users. As current AI algorithms have limited generalizability to real-world practice, clinical validation of AI should put it to proper external testing and assisting roles. External testing could adopt diagnostic case-control or diagnostic cohort designs. A diagnostic case-control study evaluates the technical validity/accuracy of AI while the latter tests the clinical validity/accuracy of AI in samples representing target patients in real-world clinical scenarios. Ultimate clinical validation of AI requires evaluations of its impact on patient outcomes, referred to as clinical utility, and for which randomized clinical trials are ideal. Device approval of AI is typically granted with proof of technical validity/accuracy and thus does not intend to directly indicate if AI is beneficial for patient care or if it improves patient outcomes. Neither can it categorically address the issue of limited generalizability of AI. After achieving device approval, it is up to medical professionals to determine if the approved AI algorithms are beneficial for real-world patient care. Insurance coverage decisions generally require a demonstration of clinical utility that the use of AI has improved patient outcomes.


Assuntos
Inteligência Artificial , Aprovação de Equipamentos , Cobertura do Seguro , Área Sob a Curva , Estudos de Casos e Controles , Tomada de Decisões , Atenção à Saúde , Humanos , Neoplasias Pulmonares/diagnóstico , Curva ROC
10.
JMIR Mhealth Uhealth ; 8(9): e17057, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32909951

RESUMO

BACKGROUND: Endoscopes are widely used for visualizing the respiratory tract, urinary tract, uterus, and gastrointestinal tracts. Despite high demand, people in underdeveloped and developing countries cannot obtain proper access to endoscopy. Moreover, commercially available endoscopes are mostly nonarticulable as well as not actively controlled, limiting their use. Articulating endoscopes are required for some diagnosis procedures, due to their ability to image wide areas of internal organs. Furthermore, actively controlled articulating endoscopes are less likely to harm the lumen than rigid endoscopes because they can avoid contact with endothelial tissues. OBJECTIVE: The study aimed to demonstrate the feasibility and acceptability of smartphone-based wide-field articulable endoscope system for minimally invasive clinical applications in developing and less developed countries. METHODS: A thin articulable endoscope system that can be attached to and actively controlled by a smartphone was designed and constructed. The system consists of a flexible endoscopic probe with a continuum mechanism, 4 motor modules for articulation, a microprocessor for controlling the motor with a smartphone, and a homebuilt app for streaming, capturing, adjusting images and video, and controlling the motor module with a joystick-like user interface. The smartphone and motor module are connected via an integrated C-type On-The-Go (OTG) USB hub. RESULTS: We tested the device in several human-organ phantoms to evaluate the usability and utility of the smartphone-based articulating endoscope system. The resolution (960 × 720 pixels) of the device was found to be acceptable for medical diagnosis. The maximum bending angle of 110° was designed. The distance from the base of the articulating module to the tip of the endoscope was 45 mm. The angle of the virtual arc was 40.0°, for a curvature of 0.013. The finest articulation resolution was 8.9°. The articulating module succeeded in imaging all 8 octants of a spherical target, as well as all 4 quadrants of the indices marked in human phantoms. CONCLUSIONS: The portable wide-field endoscope was successfully controlled using a smartphone, yielding clear images with a resolution of 960 × 720 pixels at realistic focal distances. Actively and precisely controlled articulating movements have resulted in minimally invasive monitoring in the narrow space of internal organs providing a wide-area view. We found our smartphone-based active articulated endoscope to be suitable for point-of-care applications in developing and less developed countries.


Assuntos
Países em Desenvolvimento , Smartphone , Análise Custo-Benefício , Endoscópios , Endoscopia , Feminino , Humanos
11.
Sensors (Basel) ; 20(16)2020 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-32784914

RESUMO

Sarcopenia is defined as muscle mass and strength loss with aging. As places, such as South Korea, Japan, and Europe have entered an aged society, sarcopenia is attracting global attention with elderly health. However, only few developed devices can quantify sarcopenia diagnosis modalities. Thus, the authors developed a sarcopenia detection system with 4 degrees of freedom to scan the human thigh with ultrasound probe and determine whether he/she has sarcopenia by inspecting the length of muscle thickness in the thigh by ultrasound image. To accurately measure the muscle thickness, the ultrasound probe attached to the sarcopenia detection system, must be moved angularly along the convex surface of the thigh with predefined pressure maintained. Therefore, the authors proposed an angular thigh scanning method for the aforementioned reason. The method first curve-fits the angular surface of the subject's thigh with piecewise arcs using D information from a fixed RGB-D camera. Then, it incorporates a Jacobian-based ultrasound probe moving method to move the ultrasound probe along the curve-fitted arc and maintains radial interface force between the probe and the surface by force feedback control. The proposed method was validated by in-vitro test with a human thigh mimicked ham-gelatin phantom. The result showed the ham tissue thickness was maintained within approximately 26.01 ± 1.0 mm during 82° scanning with a 2.5 N radial force setting and the radial force between probe and surface of the phantom was maintained within 2.50 ± 0.1 N.


Assuntos
Sarcopenia , Ultrassonografia , Idoso , Europa (Continente) , Feminino , Humanos , Japão , Masculino , Músculo Esquelético/diagnóstico por imagem , República da Coreia , Sarcopenia/diagnóstico por imagem , Ultrassonografia/instrumentação
12.
Appl Bionics Biomech ; 2019: 1495289, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31737093

RESUMO

BACKGROUND: Robotic locomotion rehabilitation systems have been used for gait training in patients who have had a stroke. Most commercialized systems allow patients to perform simple exercises such as balancing or level walking, but an additional function such as stair-walk training is required to provide a wide range of recovery cycle rehabilitation. In this study, we analyzed stair-gait patterns and applied the result to a robotic rehabilitation system that can provide a vertical motion of footplates. METHODS: To obtain applicable data for the robotic system with vertically movable footplates, stair-walk action was measured using an optical marker-based motion capture system. The spatial position data of joints during stair walking was obtained from six healthy adults who participated in the experiment. The measured marker data were converted into joint kinematic data by using an algorithm that included resampling and normalization. The spatial position data are represented as angular trajectories and the relative displacement of each joint on the anatomical sagittal plane and movements of hip joints on the anatomical transverse plane. RESULTS: The average range of motion (ROM) of each joint was estimated as (-6.75°, 48.69°) at the hip, (8.20°, 93.78°) at the knee, and (-17.78°, 11.75°) at the ankle during ascent and as (6.41°, 31.67°) at the hip, (7.38°, 91.93°) at the knee, and (-24.89°, 24.18°) at the ankle during descent. Additionally, we attempted to create a more natural stair-gait pattern by analyzing the movement of the hip on the anatomical transverse plane. The hip movements were estimated to within ±1.57 cm and ±2.00 cm for hip translation and to within ±2.52° and ±2.70° for hip rotation during stair ascent and stair descent, respectively. CONCLUSIONS: Based on the results, standard patterns of stair ascent and stair descent were derived and applied to a lower-limb rehabilitation robot with vertically movable footplates. The relative trajectory from the experiment ascertained that the function of stair walking in the robotic system properly worked within a normal ROM.

13.
J Clin Med ; 8(9)2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505848

RESUMO

Although the stroke volume (SV) estimation by arterial blood pressure has been widely used in clinical practice, its accuracy is questionable, especially during periods of hemodynamic instability. We aimed to create novel SV estimating model based on deep-learning (DL) method. A convolutional neural network was applied to estimate SV from arterial blood pressure waveform data recorded from liver transplantation (LT) surgeries. The model was trained using a gold standard referential SV measured via pulmonary artery thermodilution method. Merging a gold standard SV and corresponding 10.24 seconds of arterial blood pressure waveform as an input/output data set with 2-senconds of sliding overlap, 484,384 data sets from 34 LT surgeries were used for training and validation of DL model. The performance of DL model was evaluated by correlation and concordance analyses in another 491,353 data sets from 31 LT surgeries. We also evaluated the performance of pre-existing commercialized model (EV1000), and the performance results of DL model and EV1000 were compared. The DL model provided an acceptable performance throughout the surgery (r = 0.813, concordance rate = 74.15%). During the reperfusion phase, where the most severe hemodynamic instability occurred, DL model showed superior correlation (0.861; 95% Confidence Interval, (CI), 0.855-0.866 vs. 0.570; 95% CI, 0.556-0.584, P < 0.001) and higher concordance rate (90.6% vs. 75.8%) over EV1000. In conclusion, the DL-based model was superior for estimating intraoperative SV and thus might guide physicians to precise intraoperative hemodynamic management. Moreover, the DL model seems to be particularly promising because it outperformed EV1000 in circumstance of rapid hemodynamic changes where physicians need most help.

14.
Biotechnol Bioeng ; 116(11): 3041-3052, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31294818

RESUMO

The purpose of this study was to demonstrate self-organizing in vitro multicellular tumor spheroid (MCTS) formation in a microfluidic system and to observe the behavior of MCTSs under controlled microenvironment. The employed microfluidic system was designed for simple and effective formation of MCTSs by generating nutrient and oxygen gradients. The MCTSs were composed of cancer cells, vascular endothelial cells, and type I collagen matrix to mimic the in vivo tumor microenvironment (TME). Cell culture medium was perfused to the microfluidic device loaded with MCTSs by a passive fluidic pump at a constant flow rate. The dose response to an MMPs inhibitor was investigated to demonstrate the effects of biochemical substances. The result of long-term stability of MCTSs revealed that continuous perfusion of cell culture medium is one of the major factors for the successful MCTS formation. A continuous flow of cell culture medium in the in vitro TME greatly affected both the proliferation of cancer cells in the micro-wells and the sustainability of the endothelial cell-layer integrity in the lumen of microfluidic channels. Addition of MMP inhibitor to the cell culture medium improved the stability of the collagen matrix by preventing the detachment and shrinkage of the collagen matrix surrounding the MCTSs. In summary, the present constant flow assisted microfluidic system is highly advantageous for long-term observation of the MCTS generation, tumorous tissue formation process and drug responses. MCTS formation in a microfluidic system may serve as a potent tool for studying drug screening, tumorigenesis and metastasis.


Assuntos
Técnicas de Cultura de Células , Dispositivos Lab-On-A-Chip , Neoplasias Pulmonares/metabolismo , Técnicas Analíticas Microfluídicas , Esferoides Celulares/metabolismo , Microambiente Tumoral , Células A549 , Humanos , Neoplasias Pulmonares/patologia , Esferoides Celulares/patologia
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 774-777, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30440509

RESUMO

In this paper, we propose a new technique to recognize vessels in robot-assisted laparoscopic surgery images by using surgical instruments. The proposed method does not require additional hardware or parameter adjustment because it detects blood vessels by using only the color information of the image. The concept of a hessian matrix is used in the HSV color space of the image to detect the edges of the blood vessels. In addition, the histogram equalization technique, clustering technique, and region growing are used to remove the surgical tools. Images of actual robot-assisted laparoscopic surgery videos were used. The processing speed was approximately 0.3 s per frame at 640p and approximately 0.8 s per frame at 1280p. The average recall was 92.67%.


Assuntos
Laparoscopia , Instrumentos Cirúrgicos
16.
J Healthc Eng ; 2018: 8079713, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29854366

RESUMO

Although the use of the surgical robot is rapidly expanding for various medical treatments, there still exist safety issues and concerns about robot-assisted surgeries due to limited vision through a laparoscope, which may cause compromised situation awareness and surgical errors requiring rapid emergency conversion to open surgery. To assist surgeon's situation awareness and preventive emergency response, this study proposes situation information guidance through a vision-based common algorithm architecture for automatic detection and tracking of intraoperative hemorrhage and surgical instruments. The proposed common architecture comprises the location of the object of interest using feature texture, morphological information, and the tracking of the object based on Kalman filter for robustness with reduced error. The average recall and precision of the instrument detection in four prostate surgery videos were 96% and 86%, and the accuracy of the hemorrhage detection in two prostate surgery videos was 98%. Results demonstrate the robustness of the automatic intraoperative object detection and tracking which can be used to enhance the surgeon's preventive state recognition during robot-assisted surgery.


Assuntos
Perda Sanguínea Cirúrgica , Laparoscopia/métodos , Neoplasias da Próstata/cirurgia , Procedimentos Cirúrgicos Robóticos/métodos , Cirurgiões , Algoritmos , Conscientização , Reações Falso-Positivas , Humanos , Processamento de Imagem Assistida por Computador/métodos , Período Intraoperatório , Masculino , Reconhecimento Automatizado de Padrão , Reprodutibilidade dos Testes
17.
Artigo em Inglês | MEDLINE | ID: mdl-24110827

RESUMO

This paper presents a compliant mechanism for fine motion of a medical robot for needle intervention procedure. The concept of this mechanism is created with the purpose of correcting a needle axis by translating a main robot for needle driving when an unexpected slip happens in needle insertion. In order to specify the concept, a planar compliant mechanism is designed so that the mechanism has maximized workspace for some given design condition. A simplified mathematical model for the designed mechanism is derived and then a pose controller is designed to track a desired trajectory in a plane, which is a similar situation that the compliant mechanism translates a needle driving robot to correct the direction of a needle. The simulation result shows good tracking performance.


Assuntos
Biópsia/instrumentação , Biópsia/métodos , Agulhas , Procedimentos Cirúrgicos Robóticos/métodos , Algoritmos , Simulação por Computador , Desenho de Equipamento , Humanos , Pulmão/patologia , Modelos Teóricos , Movimento (Física) , Robótica/instrumentação
18.
J Biosci Bioeng ; 116(2): 224-30, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23562089

RESUMO

The fabrication of patterned microstructures within three-dimensional (3D) matrices is a challenging subject in tissue engineering and regenerative medicine. A 3D, free-moving bioprinting system was developed and hydrogels were patterned by varying the process parameters of z-axis moving velocity and ejection velocity. The patterning of hydrogel based microfibers in a 3D matrigel was achieved with dimensions of 4.5 mm length and widths from 79 to 200 µm. Hyaluronan-based hydrogels mixed with fibroblasts (L929), mouse endothelial cells (MS1), or human mesenchymal stem cells (hMSCs) were patterned using a 3D moving axis bioprinter and cell behavior was monitored in culture for up to 16 days. L929 and MS1 cells and hMSCs in patterned hydrogel revealed cell-cell interactions and a morphological dependency on cell types. HMSCs formed spheres through cell aggregation, while L929 cells increased in cellular mass without cell aggregation and MS1 dispersed into the matrix instead of aggregating. The aggregation of hMSCs was attenuated by treatment with Rho kinase (ROCK) inhibitor and cadherin antibody. This reflected the close relationship between cell aggregation and migration with RhoA and cell-cell adhesion molecules. Angiogenic-specific gene expression profiles showed that expression of CD105 decreased to 22% in the ROCK inhibitor group compared to control group. These results showed that cell-based patterns in a 3D matrix are highly dependent on both cell aggregation and migration over time.


Assuntos
Bioimpressão/métodos , Movimento Celular , Hidrogéis/química , Animais , Agregação Celular , Diferenciação Celular , Linhagem Celular Tumoral , Colágeno , Combinação de Medicamentos , Fibroblastos/citologia , Expressão Gênica , Humanos , Ácido Hialurônico , Laminina , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos , Proteoglicanas , Engenharia Tecidual/métodos
19.
Artif Organs ; 37(4): 368-79, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23461583

RESUMO

This study seeks to improve the mechanical performance of stents by conducting reliability performance testing and finite element method (FEM)-based simulations for coronary stents. Three commercially available stent designs and our own new design were tested to measure the factors affecting performance, specifically foreshortening, recoil, radial force, and flexibility. The stents used in the present experiments were 3 mm in working diameter and 18 mm of working length. The results of the experiments indicate that the foreshortening of stents A, B, C, and our new design, D, was equivalent to 2.25, 0.67, 0.46, and 0.41%, respectively. The recoil of stents A, B, C, and D was 6.00, 4.35, 3.50, and 4.36%, respectively. Parallel plate radial force measurements were A, 3.72 ± 0.28 N; B, 3.81 ± 0.32 N; C, 4.35 ± 0.18 N; and D, 4.02 ± 0.24 N. Radial forces determined by applying uniform pressure in the circumferential direction were A, 28.749 ± 0.81 N; B, 32.231 ± 1.80 N; C, 34.522 ± 3.06 N; and D, 42.183 ± 2.84 N. The maximum force of crimped stent at 2.2-mm deflection was 1.01 ± 0.08 N, 0.82 ± 0.08 N, 0.92 ± 0.12 N, and 0.68 ± 0.07 N for each of stents A, B, C and D. The results of this study enabled us to identify several factors to enhance the performance of stents. In comparing these stents, we found that our design, stent D, which was designed by a collaborative team from seven universities, performed better than the commercial stents across all parameter of foreshortening, recoil, radial force, and flexibility.


Assuntos
Stents , Análise de Elementos Finitos , Humanos , Maleabilidade , Desenho de Prótese , Reprodutibilidade dos Testes , Estresse Mecânico
20.
Korean J Radiol ; 14(2): 139-53, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23482650

RESUMO

Within six months of the discovery of X-ray in 1895, the technology was used to scan the interior of the human body, paving the way for many innovations in the field of medicine, including an ultrasound device in 1950, a CT scanner in 1972, and MRI in 1980. More recent decades have witnessed developments such as digital imaging using a picture archiving and communication system, computer-aided detection/diagnosis, organ-specific workstations, and molecular, functional, and quantitative imaging. One of the latest technical breakthrough in the field of radiology has been imaging genomics and robotic interventions for biopsy and theragnosis. This review provides an engineering perspective on these developments and several other megatrends in radiology.


Assuntos
Diagnóstico por Computador/tendências , Diagnóstico por Imagem/tendências , Processamento de Imagem Assistida por Computador/tendências , Sistemas de Informação em Radiologia/tendências , Biomarcadores/análise , Engenharia Biomédica , Desenho de Equipamento , Genômica , Humanos , Robótica , Integração de Sistemas , Interface Usuário-Computador
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