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1.
Technol Health Care ; 27(S1): 229-238, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31045542

RESUMO

BACKGROUND: Previous studies showed that compared with single-bundle (SB) precedures, double-bundle (DB) anterior cruciate ligament (ACL) reconstruction perform better. OBJECTIVE: To make assurance that distance of TT-TG may be altered along with ACL rupture and reconstruction. METHODS: Imaging study of 201 patients's related cases by MRI and CT scans. RESULTS: Compared with the intact knee's overall mean TT-TG value, the mean overall pre/postoperative TT-TG values showed a significant difference. For SB reconstruction, the mean pre/postoperative TT-TG values were 15.67± 2.46 mm and 14.72± 2.48 mm, respectively. Postoperative and intact knee TT-TG values were significantly different (p< 0.001). For DB reconstruction, the pre/postoperative mean TT-TG values were 15.11± 1.99 mm and 13.11± 1.71 mm. Postoperative and intact knee TT-TG values were not significantly different (p= 0.141). CONCLUSIONS: The increased TT-TG value from a ruptured ACL was significantly restored after ACL reconstruction. The TT-TG value after SB reconstruction was still obviously larger than that of the intact knee. It showed no significant difference between the postoperative TT-TG of the DB group and intact knees. The original TT-TG values of the knees were much closer to restoration after DB reconstruction.


Assuntos
Reconstrução do Ligamento Cruzado Anterior/métodos , Tíbia/diagnóstico por imagem , Adolescente , Adulto , Reconstrução do Ligamento Cruzado Anterior/reabilitação , Feminino , Humanos , Instabilidade Articular , Imagem por Ressonância Magnética , Masculino , Estudos Retrospectivos , Tíbia/cirurgia , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Adulto Jovem
2.
Materials (Basel) ; 12(10)2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31137468

RESUMO

The effects of V vacancy on the thermoelectric performance of the half-Heusler compound VCoSb have been investigated in this study. A certain amount of CoSb secondary phase is generated in the VCoSb matrix when the content of V vacancy is more than 0.1 at%. According to the results, a ZT value of 0.6, together with a power factor of 29 µW cm-1 K-2 at 873 K, were achieved for the nonstoichiometric sample V0.9CoSb. This proved that moderate V vacancy could improve the thermoelectric (TE) properties of VCoSb. The noticeable improvements are mainly owing to the incremental Seebeck coefficient, which may benefit from the optimized carrier concentration. However, too much V vacancy will result in more CoSb impurity and deteriorate the TE performances of VCoSb owing to the increased thermal conductivity.

3.
Genome ; 62(5): 317-328, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30998854

RESUMO

Picea asperata and P. crassifolia have sympatric ranges and are closely related, but the differences between these species at the plastome level are unknown. To better understand the patterns of variation among Picea plastomes, the complete plastomes of P. asperata and P. crassifolia were sequenced. Then, the plastomes were compared with the complete plastomes of P. abies and P. morrisonicola, which are closely and distantly related to the focal species, respectively. We also used these sequences to construct phylogenetic trees to determine the relationships among and between the four species as well as additional taxa from Pinaceae and other gymnosperms. Analysis of our sequencing data allowed us to identify 438 single nucleotide polymorphism (SNPs) point mutation events, 95 indel events, four inversion events, and seven highly variable regions, including six gene spacer regions (psbJ-petA, trnT-psaM, trnS-trnD, trnL-rps4, psaC-ccsA, and rps7-trnL) and one gene (ycf1). The highly variable regions are appropriate targets for future use in the phylogenetic reconstructions of closely related, sympatric species of Picea as well as Pinaceae in general.


Assuntos
Genomas de Plastídeos/genética , Picea/genética , Simpatria , Mutação INDEL , Filogenia , Plastídeos/genética , Polimorfismo de Nucleotídeo Único/genética , Inversão de Sequência/genética
4.
Int J Comput Assist Radiol Surg ; 14(8): 1285-1294, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31016562

RESUMO

Purpose Video see-through augmented reality (VST-AR) navigation for laparoscopic partial nephrectomy (LPN) can enhance intraoperative perception of surgeons by visualizing surgical targets and critical structures of the kidney tissue. Image registration is the main challenge in the procedure. Existing registration methods in laparoscopic navigation systems suffer from limitations such as manual alignment, invasive external marker fixation, relying on external tracking devices with bulky tracking sensors and lack of deformation compensation. To address these issues, we present a markerless automatic deformable registration framework for LPN VST-AR navigation. METHOD: Dense stereo matching and 3D reconstruction, automatic segmentation and surface stitching are combined to obtain a larger dense intraoperative point cloud of the renal surface. A coarse-to-fine deformable registration is performed to achieve a precise automatic registration between the intraoperative point cloud and the preoperative model using the iterative closest point algorithm followed by the coherent point drift algorithm. Kidney phantom experiments and in vivo experiments were performed to evaluate the accuracy and effectiveness of our approach. RESULTS: The average segmentation accuracy rate of the automatic segmentation was 94.9%. The mean target registration error of the phantom experiments was found to be 1.28 ± 0.68 mm (root mean square error). In vivo experiments showed that tumor location was identified successfully by superimposing the tumor model on the laparoscopic view. CONCLUSION: Experimental results have demonstrated that the proposed framework could accurately overlay comprehensive preoperative models on deformable soft organs automatically in a manner of VST-AR without using extra intraoperative imaging modalities and external tracking devices, as well as its potential clinical use.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Imagem Tridimensional , Rim/diagnóstico por imagem , Laparoscopia , Nefrectomia , Cirurgia Assistida por Computador/métodos , Tomografia Computadorizada por Raios X , Algoritmos , Calibragem , Humanos , Modelos Teóricos , Distribuição Normal , Reconhecimento Automatizado de Padrão , Imagens de Fantasmas , Análise de Componente Principal , Linguagens de Programação , Reprodutibilidade dos Testes
5.
Int J Med Robot ; 15(4): e1997, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30900789

RESUMO

BACKGROUND: Human-related factors affect the accuracy and safety of the oral and maxillofacial surgery (OMS). This study proposed an autonomous surgical system aiming to conduct the OMS under the assistance and surveillance of the surgeon. METHODS: A markerless navigation module and a compact OMS robot were seamlessly integrated into this system. The specifications of each module and the working concept of the system were elaborated in this paper. A drilling experiment was conducted on five 3D-printed mandible models to test the pose detecting capability and evaluate the operational performance. RESULTS: The experiment showed that this system could successfully guide the robot finishing the operation regardless of the mandible pose. The accuracy of software and hardware are acceptable and potential performance improvement can be achieved in positioning accuracy. CONCLUSION: This system proposed a novel concept and a practical solution to decrease the human-related factors on the OMS, which may change the role of the surgeon in the future operating room and finally benefit the outcomes of OMS.


Assuntos
Mandíbula/cirurgia , Procedimentos Cirúrgicos Bucais , Procedimentos Cirúrgicos Robóticos/métodos , Cirurgia Assistida por Computador/métodos , Desenho de Equipamento , Humanos , Imagem Tridimensional , Osteotomia , Imagens de Fantasmas , Impressão Tridimensional , Reprodutibilidade dos Testes , Software , Tomografia Computadorizada por Raios X
6.
Int J Comput Assist Radiol Surg ; 14(5): 763-773, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30825070

RESUMO

BACKGROUND: Image registration lies in the core of augmented reality (AR), which aligns the virtual scene with the reality. In AR surgical navigation, the performance of image registration is vital to the surgical outcome. METHODS: This paper presents a practical marker-less image registration method for AR-guided oral and maxillofacial surgery where a virtual scene is generated and mixed with reality to guide surgical operation or provide surgical outcome visualization in the manner of video see-through overlay. An intraoral 3D scanner is employed to acquire the patient's teeth shape model intraoperatively. The shape model is then registered with a custom-made stereo camera system using a novel 3D stereo matching algorithm and with the patient's CT-derived 3D model using an iterative closest point scheme, respectively. By leveraging the intraoral 3D scanner, the CT space and the stereo camera space are associated so that surrounding anatomical models and virtual implants could be overlaid on the camera's view to achieve AR surgical navigation. RESULTS: Jaw phantom experiments were performed to evaluate the target registration error of the overlay, which yielded an average error of less than 0.50 mm with the time cost less than 0.5 s. Volunteer trial was also conducted to show the clinical feasibility. CONCLUSIONS: The proposed registration method does not rely on any external fiducial markers attached to the patient. It performs automatically so as to maintain a correct AR scene, overcoming the misalignment difficulty caused by patient's movement. Therefore, it is noninvasive and practical in oral and maxillofacial surgery.


Assuntos
Imagem Tridimensional/métodos , Mandíbula/diagnóstico por imagem , Maxila/diagnóstico por imagem , Procedimentos Cirúrgicos Bucais/métodos , Imagens de Fantasmas , Cirurgia Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Humanos , Mandíbula/cirurgia , Maxila/cirurgia , Impressão Tridimensional
7.
Gene ; 696: 95-104, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30779945

RESUMO

The high-osmolarity glycerol (HOG) signaling pathway regulates the adaptation of fungi to environmental stressors. The mitogen-activated protein kinase kinase (MAPKK) PBS2 of Saccharomyces cerevisiae serves as a scaffold protein in the HOG pathway. We characterized the pgpbs gene of Pyrenophora graminea, which encodes a MAPKK that is 56% orthologous to PBS2 of S. cerevisiae. A cloning technique based on homology was applied to amplify the pgpbs gene. Specific silent mutations then were generated in pgpbs. We evaluated the potential roles of PGPBS in the osmotic response, vegetative differentiation, cell wall integrity, drug resistance, and pathogenicity. Our findings indicated that the pgpbs coding region comprises 2075 base pairs and encodes a protein of 676 amino acids. Mutants deficient in pgpbs expression had significant reductions in vegetative growth and were sensitive to calcofluor white (CFW), an inhibitor of cell wall synthesis. Mutants also lost pathogenicity and were sensitive to an osmotic stress-inducing medium containing NaCl and sorbitol. Moreover, mutants had increased resistance to the dicarboximide fungicide iprodione and the triazole fungicide tebuconazole. These findings suggest that pgpbs is involved in the osmotic and ionic stress responses, vegetative differentiation, cell wall integrity, virulence, and tolerance to iprodione and tebuconazole. We expect that our findings will help elucidate the pathogenesis of barley leaf stripe and will inform strategies for breeding resistance to this disease.


Assuntos
Ascomicetos/patogenicidade , Proteínas Fúngicas/genética , Hordeum/microbiologia , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Doenças das Plantas/microbiologia , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Ascomicetos/genética , Ascomicetos/metabolismo , Benzenossulfonatos/farmacologia , Parede Celular/efeitos dos fármacos , Parede Celular/genética , Parede Celular/metabolismo , Farmacorresistência Fúngica Múltipla/genética , Proteínas Fúngicas/metabolismo , Fungicidas Industriais/farmacologia , Hidantoínas/farmacologia , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mutação , Folhas de Planta/microbiologia , Triazóis/farmacologia , Virulência/genética
8.
Sci Rep ; 8(1): 15250, 2018 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-30323196

RESUMO

Head and neck squamous cell carcinoma (HNSCC) is a common malignant cancer that accounts for 5-10% of all cancers. This study aimed to identify essential genes associated with the prognosis of HNSCC and construct a powerful prognostic model for the risk assessment of HNSCC. RNAseq expression profile data for the patients with HNSCC were obtained from the TCGA database (GEO). A total of 500 samples with full clinical following-up were randomly divided into a training set and a validation set. The training set was used to screen for differentially expressed lncRNAs. Single-factor survival analysis was performed to obtain lncRNAs that associated with prognosis. A robust likelihood-based survival model was constructed to identify the lncRNAs that are essential for the prognosis of HNSCC. A co-expression network between genes and lncRNAs was also constructed to identify lncRNAs co-expressed with genes to serve as the final signature lncRNAs for prognosis. Finally, the prognostic effect of the signature lncRNAs was tested by multi-factor survival analysis and a scoring model for the prognosis of HNSCC was constructed. Moreover, the results of the validation set and the relative expression levels of the signature lncRNAs in the tumour and the adjacent tissue were consistent with the results of the training set. The 5 lncRNAs were distributed among 3 expression modules. Further KEGG pathway enrichment analysis showed that these 3 co-expressed modules participate in different pathways, and many of these pathways are associated with the development and progression of disease. Therefore, we proposed that the 5 validated lncRNAs can be used to predict the prognosis of HNSCC patients and can be applied in postoperative treatment and follow-up.


Assuntos
Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/genética , RNA Longo não Codificante/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Transcriptoma , Idoso , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço/mortalidade , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Análise de Sobrevida
9.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 35(4): 571-577, 2018 08 25.
Artigo em Chinês | MEDLINE | ID: mdl-30124020

RESUMO

Pectus carinatum (PC) is one of the most common chest wall anomalies, which is characterized by the protrusion of the anterior chest wall including the sternum and adjacent costal cartilages. Mildly patients suffer from mental problems such as self-abasement, while severely suffering patients are disturbed by significant cardiopulmonary symptoms. The traditional Haller index, which is widely used clinically to evaluate the severity of PC, is deficient in diagnosis efficiency and classification. This paper presents an improved Haller index algorithm for PC: first, the contour of the patient chest in the axial computed tomography (CT) slice where the most convex thorax presents is extracted; and then a cubic B-spline curve is employed to fit the extracted contour followed by an eclipse fitting procedure; finally, the improved Haller index and the classification index are automatically calculated based on the analytic curves. The results of CT data analysis using 22 preoperative and postoperative patient CT datasets show that the proposed diagnostic index for PC can diagnose and classify PC patients correctly, which confirms the feasibility of the evaluation index. Furthermore, digital measurement techniques can be employed to improve the diagnostic efficiency of PC, achieving one small step towards the computer-aided intelligent diagnosis and treatment for pediatric chest wall malformations.

10.
Int J Med Robot ; 14(5): e1925, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29901283

RESUMO

BACKGROUND: The limited field of view of the X-ray image intensifier makes it difficult to cover a large target area with a single X-ray image. X-ray image stitching techniques have been proposed to produce a panoramic X-ray image. METHODS: This paper presents an efficient intensity-based X-ray image stitcher, which does not rely on accurate C-arm motion control or auxiliary devices and hence is ready to use in clinic. The stitcher consumes sequentially captured X-ray images with overlap areas and automatically produces a panoramic image. The gradient information for optimization of image alignment is obtained using a back-propagation scheme so that it is convenient to adopt various image warping models. RESULTS: The proposed stitcher has the following advantages over existing methods: (1) no additional hardware modification or auxiliary markers are needed; (2) it is robust against feature-based approaches; (3) arbitrary warping models and shapes of the region of interest are supported; (4) seamless stitching is achieved using multi-band blending. Experiments have been performed to confirm the effectiveness of the proposed method. CONCLUSION: The proposed X-ray image stitcher is efficient, accurate and ready to use in clinic.


Assuntos
Osso e Ossos/diagnóstico por imagem , Reconhecimento Automatizado de Padrão/métodos , Interpretação de Imagem Radiográfica Assistida por Computador , Raios X , Algoritmos , Artroplastia do Joelho , Cadáver , Diagnóstico por Imagem , Humanos , Processamento de Imagem Assistida por Computador , Movimento (Física) , Radiografia Torácica , Software , Técnica de Subtração
11.
Materials (Basel) ; 11(5)2018 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-29751606

RESUMO

NbCoSb with nominal 19 valence electrons, and is supposed to be metallic, has recently been reported to also exhibit the thermoelectric properties of a heavily doped n-type semiconductor. In this study, we prepared Co-rich NbCo1+xSb samples (x = 0, 0.2, 0.3, 0.4, 0.5), and their phase compositions, microstructures and thermoelectric properties were investigated. The Seebeck coefficient increased a great deal with increasing x, due to decreasing carrier concentration, and the total thermal conductivity reduced mainly because of declining κe. Finally, a peak thermoelectric figure of merit, ZT, was about 0.46 for NbCo1.3Sb at 973 K. This enhancement was mainly attributed to the reduction of electric thermal conductivity and the increase of Seebeck coefficient. The excess Co had effects on the carrier concentration, deformation potential Edef and DOS effective mass m*. Adding an excessive amount of Co leads to a very high Edef, which was detrimental for transport characteristics.

12.
IEEE Trans Biomed Eng ; 65(2): 378-389, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29346106

RESUMO

We develop a spatial position measurement system using three-dimensional (3-D) image marker-based tracking tools targeted at surgical navigation in minimally invasive surgery. We generate 3-D image markers with spatial information encoded to 2-D images, design tracking tools with the 3-D image markers, and analyze the tracking tools' theoretical spatial errors, which are primarily limited by the spatial distribution of reconstructed fiducial 3-D markers. A pattern analysis-based positional measurement algorithm is developed to calculate the tool's spatial information using its spatial configuration. Evaluation experiments were conducted to demonstrate the accuracy and effectiveness of the proposed system. Furthermore, surgical navigation feasibility studies were performed. With a patient-image registration algorithm, a navigation interface that shows preoperative medical data and intraoperative information about the tool can intuitively and accurately assist surgeons. The results demonstrate that the proposed tracking tools, which have compact volume and spatial positional information, are of potential use in minimally invasive surgery in a limited space.


Assuntos
Imagem Tridimensional/métodos , Cirurgia Assistida por Computador/métodos , Algoritmos , Marcadores Fiduciais , Mãos/diagnóstico por imagem , Mãos/cirurgia , Humanos , Imagens de Fantasmas , Crânio/diagnóstico por imagem , Crânio/cirurgia
13.
Int J Med Robot ; 13(2)2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27283505

RESUMO

BACKGROUND: Oral and maxillofacial surgery has not been benefitting from image guidance techniques owing to the limitations in image registration. METHODS: A real-time markerless image registration method is proposed by integrating a shape matching method into a 2D tracking framework. The image registration is performed by matching the patient's teeth model with intraoperative video to obtain its pose. The resulting pose is used to overlay relevant models from the same CT space on the camera video for augmented reality. RESULTS: The proposed system was evaluated on mandible/maxilla phantoms, a volunteer and clinical data. Experimental results show that the target overlay error is about 1 mm, and the frame rate of registration update yields 3-5 frames per second with a 4 K camera. CONCLUSIONS: The significance of this work lies in its simplicity in clinical setting and the seamless integration into the current medical procedure with satisfactory response time and overlay accuracy. Copyright © 2016 John Wiley & Sons, Ltd.


Assuntos
Arcada Osseodentária/diagnóstico por imagem , Procedimentos Cirúrgicos Bucais/métodos , Procedimentos Cirúrgicos Ortognáticos , Técnica de Subtração , Cirurgia Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Interface Usuário-Computador , Humanos , Imagens de Fantasmas , Intensificação de Imagem Radiográfica/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Gravação em Vídeo/métodos
14.
Oncotarget ; 7(35): 56628-56642, 2016 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-27447749

RESUMO

Human cancers exhibit significant cellular heterogeneity featuring tumorigenic cancer stem cells (CSCs) in addition to more differentiated progeny with limited tumor-initiating capabilities. Recent studies suggest that microRNAs (miRNAs) regulate CSCs and tumor development. A previous library screening for differential miRNA expression in CD44+ (and other) prostate CSC vs. non-CSC populations identified miR-199a-3p to be among the most highly under-expressed miRNAs in CSCs. In this study, we characterized the biological functions of miR-199a-3p in CD44+ prostate cancer (PCa) cells and in tumor regeneration. Overexpression of miR-199a-3p in purified CD44+ or bulk PCa cells, including primary PCa, inhibited proliferation and clonal expansion without inducing apoptosis. miR-199a-3p overexpression also diminished tumor-initiating capacities of CD44+ PCa cells as well as tumor regeneration from bulk PCa cells. Importantly, inducible miR-199a-3p expression in pre-established prostate tumors in NOD/SCID mice inhibited tumor growth. Using target prediction program and luciferase assays, we show mechanistically that CD44 is a direct functional target of miR-199a-3p in PCa cells. Moreover, miR-199a-3p also directly or indirectly targeted several additional mitogenic molecules, including c-MYC, cyclin D1 (CCND1) and EGFR. Taken together, our results demonstrate how the aberrant loss of a miRNA-mediated mechanism can lead to the expansion and tumorigenic activity of prostate CSCs, further supporting the development and implementation of miRNA mimics for cancer treatment.


Assuntos
Regulação Neoplásica da Expressão Gênica , MicroRNAs/metabolismo , Células-Tronco Neoplásicas/metabolismo , Neoplasias da Próstata/metabolismo , Animais , Apoptose/genética , Carcinogênese/genética , Linhagem Celular Tumoral , Proliferação de Células , Ciclina D1/metabolismo , Receptores ErbB/metabolismo , Humanos , Receptores de Hialuronatos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Transplante de Neoplasias , Neoplasias da Próstata/genética , Transdução de Sinais
15.
Biomed Rep ; 4(5): 589-594, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27123252

RESUMO

The side-to-side difference in bone mineral content and soft tissue composition of extremities and their associations have been observed in patients with stroke and the results are inconsistent. The aim of the present study was to investigate the interaction between bone mineral content (BMC), lean mass (LM) and fat mass (FM) in the paretic extremities in patients following stroke and to determine the effectiveness of electrical muscle stimulation (EMS) following sciatic neurectomy (SN) in rats. BMC, LM and FM were measured by dual-energy X-ray absorptiometry in 61 hemiplegic patients following stroke. In the rat model study, groups of 10 Sprague-Dawley rats were divided into EMS and non-EMS subgroups. Myostatin expression and tetracycline interlabel width were measured. There were significant decreases in BMC, LM and FM in paretic limbs compared to non-paretic limbs. Compared to non-EMS, downregulated myostatin mRNA, and upregulated mechano growth factor (MGF) and insulin-like growth factor 1 (IGF-1) mRNA expression levels were observed in the EMS subgroup (P<0.05). In conclusion, muscle may have an important role in maintaining BMC. EMS-induced muscle contraction effectively downregulated myostatin mRNA, upregulated MGF and IGF-1 mRNA expression in muscle fiber, and mitigated amyotrophy and cortical bone loss from SN.

16.
Int J Med Robot ; 12(3): 375-86, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26443691

RESUMO

BACKGROUND: Visualization of the vast placental vasculature is crucial in fetoscopic laser photocoagulation for twin-to-twin transfusion syndrome treatment. However, vasculature mosaic is challenging due to the fluctuating imaging conditions during fetoscopic surgery. METHOD: A scene adaptive feature-based approach for image correspondence in free-hand endoscopic placental video is proposed. It contributes towards existing techniques by introducing a failure detection method based on statistical attributes of the feature distribution, and an updating mechanism that self-tunes parameters to recover from registration failures. RESULTS: Validations on endoscopic image sequences of a phantom and a monkey placenta are carried out to demonstrate mismatch recovery. In two 100-frame sequences, automatic self-tuned results improved by 8% compared with manual experience-based tuning and a slight 2.5% deterioration against exhaustive tuning (gold standard). CONCLUSION: This scene-adaptive image correspondence approach, which is not restricted to a set of generalized parameters, is suitable for applications associated with dynamically changing imaging conditions. Copyright © 2015 John Wiley & Sons, Ltd.


Assuntos
Fetoscopia/métodos , Placenta/irrigação sanguínea , Cirurgia Assistida por Computador , Animais , Feminino , Haplorrinos , Humanos , Gravidez
17.
Surg Endosc ; 30(9): 4136-49, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26659243

RESUMO

BACKGROUND: Surgical navigation technology directed at fetoscopic procedures is relatively underdeveloped compared with other forms of endoscopy. The narrow fetoscopic field of views and the vast vascular network on the placenta make examination and photocoagulation treatment of twin-to-twin transfusion syndrome challenging. Though ultrasonography is used for intraoperative guidance, its navigational ability is not fully exploited. This work aims to integrate 3D ultrasound imaging and endoscopic vision seamlessly for placental vasculature mapping through a self-contained framework without external navigational devices. METHODS: This is achieved through development, integration, and experimentation of novel navigational modules. Firstly, a framework design that addresses the current limitations based on identified gaps is conceptualized. Secondly, integration of navigational modules including (1) ultrasound-based localization, (2) image alignment, and (3) vision-based tracking to update the scene texture map is implemented. This updated texture map is projected to an ultrasound-constructed 3D model for photorealistic texturing of the 3D scene creating a panoramic view of the moving fetoscope. In addition, a collaborative scheme for the integration of the modular workflow system is proposed to schedule updates in a systematic fashion. Finally, experiments are carried out to evaluate each modular variation and an integrated collaborative scheme of the framework. RESULTS: The modules and the collaborative scheme are evaluated through a series of phantom experiments with controlled trajectories for repeatability. The collaborative framework demonstrated the best accuracy (5.2 % RMS error) compared with all the three single-module variations during the experiment. Validation on an ex vivo monkey placenta shows visual continuity of the freehand fetoscopic panorama. CONCLUSIONS: The proposed developed collaborative framework and the evaluation study of the framework variations provide analytical insights for effective integration of ultrasonography and endoscopy. This contributes to the development of navigation techniques in fetoscopic procedures and can potentially be extended to other applications in intraoperative imaging.


Assuntos
Fetoscopia/métodos , Imagem Tridimensional/métodos , Imagens de Fantasmas , Placenta/irrigação sanguínea , Placenta/diagnóstico por imagem , Cirurgia Assistida por Computador/métodos , Ultrassonografia Pré-Natal/métodos , Endoscópios , Feminino , Humanos , Gravidez
19.
Stem Cells ; 33(8): 2381-90, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25821200

RESUMO

The homeobox domain transcription factor NANOG, a key regulator of embryonic development and cellular reprogramming, has been reported to be broadly expressed in human cancers. Functional studies have provided strong evidence that NANOG possesses protumorigenic attributes. In addition to promoting self-renewal and long-term proliferative potential of stem-like cancer cells, NANOG-mediated oncogenic reprogramming may underlie clinical manifestations of malignant disease. In this review, we examine the molecular origin, expression, biological activities, and mechanisms of action of NANOG in various malignancies. We also consider clinical implications such as correlations between NANOG expression and cancer prognosis and/or response to therapy. We surmise that NANOG potentiates the molecular circuitry of tumorigenesis, and thus may represent a novel therapeutic target or biomarker for the diagnosis, prognosis, and treatment outcome of cancer. Finally, we present critical pending questions relating NANOG to cancer stem cells and tumor development.


Assuntos
Transformação Celular Neoplásica , Reprogramação Celular , Proteínas de Homeodomínio/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Células-Tronco Neoplásicas/metabolismo , Animais , Humanos , Proteína Homeobox Nanog , Neoplasias/patologia , Células-Tronco Neoplásicas/patologia
20.
Comput Med Imaging Graph ; 40: 147-59, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25465067

RESUMO

Autostereoscopic 3D image overlay for augmented reality (AR) based surgical navigation has been studied and reported many times. For the purpose of surgical overlay, the 3D image is expected to have the same geometric shape as the original organ, and can be transformed to a specified location for image overlay. However, how to generate a 3D image with high geometric fidelity and quantitative evaluation of 3D image's geometric accuracy have not been addressed. This paper proposes a graphics processing unit (GPU) based computer-generated integral imaging pipeline for real-time autostereoscopic 3D display, and an automatic closed-loop 3D image calibration paradigm for displaying undistorted 3D images. Based on the proposed methods, a novel AR device for 3D image surgical overlay is presented, which mainly consists of a 3D display, an AR window, a stereo camera for 3D measurement, and a workstation for information processing. The evaluation on the 3D image rendering performance with 2560×1600 elemental image resolution shows the rendering speeds of 50-60 frames per second (fps) for surface models, and 5-8 fps for large medical volumes. The evaluation of the undistorted 3D image after the calibration yields sub-millimeter geometric accuracy. A phantom experiment simulating oral and maxillofacial surgery was also performed to evaluate the proposed AR overlay device in terms of the image registration accuracy, 3D image overlay accuracy, and the visual effects of the overlay. The experimental results show satisfactory image registration and image overlay accuracy, and confirm the system usability.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Imagem Tridimensional/métodos , Procedimentos Cirúrgicos Bucais/métodos , Reconhecimento Automatizado de Padrão/métodos , Cirurgia Assistida por Computador/métodos , Interface Usuário-Computador , Algoritmos , Calibragem/normas , Sistemas de Computação , Humanos , Aumento da Imagem/métodos , Aumento da Imagem/normas , Interpretação de Imagem Assistida por Computador/normas , Imagem Tridimensional/normas , Procedimentos Cirúrgicos Bucais/normas , Reconhecimento Automatizado de Padrão/normas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Cirurgia Assistida por Computador/normas
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