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Sánchez CA, De Vries E, Gil F, Niño ME. Prediction model for lower limb amputation in hospitalized diabetic foot patients using classification and regression trees. Foot Ankle Surg 2024:S1268-7731(24)00068-7. [PMID: 38575484 DOI: 10.1016/j.fas.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/01/2024] [Accepted: 03/16/2024] [Indexed: 04/06/2024]
Abstract
BACKGROUND The decision to perform amputation of a limb in a patient with diabetic foot ulcer (DFU) is not an easy task. Prediction models aim to help the surgeon in decision making scenarios. Currently there are no prediction model to determine lower limb amputation during the first 30 days of hospitalization for patients with DFU. METHODS Classification And Regression Tree analysis was applied on data from a retrospective cohort of patients hospitalized for the management of diabetic foot ulcer, using an existing database from two Orthopaedics and Traumatology departments. The secondary analysis identified independent variables that can predict lower limb amputation (mayor or minor) during the first 30 days of hospitalization. RESULTS Of the 573 patients in the database, 290 feet underwent a lower limb amputation during the first 30 days of hospitalization. Six different models were developed using a loss matrix to evaluate the error of not detecting false negatives. The selected tree produced 13 terminal nodes and after the pruning process, only one division remained in the optimal tree (Sensitivity: 69%, Specificity: 75%, Area Under the Curve: 0.76, Complexity Parameter: 0.01, Error: 0.85). Among the studied variables, the Wagner classification with a cut-off grade of 3 exceeded others in its predicting capacity. CONCLUSIONS Wagner classification was the variable with the best capacity for predicting amputation within 30 days. Infectious state and vascular occlusion described indirectly by this classification reflects the importance of taking quick decisions in those patients with a higher compromise of these two conditions. Finally, an external validation of the model is still required. LEVEL OF EVIDENCE III.
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Affiliation(s)
- C A Sánchez
- Department of Orthopedics and Traumatology, Department of Epidemiology and Biostatistics, Pontificia Universidad Javeriana, Hospital de la Samaritana, Bogotá, Colombia; Department of Epidemiology and Biostatistics, Pontificia Universidad Javeriana, Bogotá, Colombia.
| | - E De Vries
- Department of Epidemiology and Biostatistics, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - F Gil
- Department of Epidemiology and Biostatistics, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - M E Niño
- Department of Orthopedics and Traumatology, Pontificia Universidad Javeriana, Foot and Ankle Surgery, Clínica del Country and Hospital Militar Central, Bogotá, Colombia
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Wu X, Sánchez CA, Lloyd JE, Borgard H, Fels S, Paydarfar JA, Halter RJ. Estimating tongue deformation during laryngoscopy using a hybrid FEM-multibody model and intraoperative tracking - a cadaver study. Comput Methods Biomech Biomed Engin 2024:1-11. [PMID: 38193213 DOI: 10.1080/10255842.2023.2301672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/31/2023] [Indexed: 01/10/2024]
Abstract
Throat tumour margin control remains difficult due to the tight, enclosed space of the oral and throat regions and the tissue deformation resulting from placement of retractors and scopes during surgery. Intraoperative imaging can help with better localization but is hindered by non-image-compatible surgical instruments, cost, and unavailability. We propose a novel method of using instrument tracking and FEM-multibody modelling to simulate soft tissue deformation in the intraoperative setting, without requiring intraoperative imaging, to improve surgical guidance accuracy. We report our first empirical study, based on four trials of a cadaveric head specimen with full neck anatomy, yields a mean TLE of 10.8 ± 5.5 mm, demonstrating methodological feasibility.
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Affiliation(s)
- Xiaotian Wu
- Gordon Center for Medical Imaging, MA General Hospital and Harvard Medical School, Boston, MA, USA
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - C Antonio Sánchez
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada
| | - John E Lloyd
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada
| | - Heather Borgard
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada
| | - Sidney Fels
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada
| | - Joseph A Paydarfar
- Section of Otolaryngology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Ryan J Halter
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
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Khallaghi S, Sánchez CA, Rasoulian A, Nouranian S, Romagnoli C, Abdi H, Chang SD, Black PC, Goldenberg L, Morris WJ, Spadinger I, Fenster A, Ward A, Fels S, Abolmaesumi P. Statistical Biomechanical Surface Registration: Application to MR-TRUS Fusion for Prostate Interventions. IEEE Trans Med Imaging 2015; 34:2535-2549. [PMID: 26080380 DOI: 10.1109/tmi.2015.2443978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A common challenge when performing surface-based registration of images is ensuring that the surfaces accurately represent consistent anatomical boundaries. Image segmentation may be difficult in some regions due to either poor contrast, low slice resolution, or tissue ambiguities. To address this, we present a novel non-rigid surface registration method designed to register two partial surfaces, capable of ignoring regions where the anatomical boundary is unclear. Our probabilistic approach incorporates prior geometric information in the form of a statistical shape model (SSM), and physical knowledge in the form of a finite element model (FEM). We validate results in the context of prostate interventions by registering pre-operative magnetic resonance imaging (MRI) to 3D transrectal ultrasound (TRUS). We show that both the geometric and physical priors significantly decrease net target registration error (TRE), leading to TREs of 2.35 ± 0.81 mm and 2.81 ± 0.66 mm when applied to full and partial surfaces, respectively. We investigate robustness in response to errors in segmentation, varying levels of missing data, and adjusting the tunable parameters. Results demonstrate that the proposed surface registration method is an efficient, robust, and effective solution for fusing data from multiple modalities.
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Khallaghi S, Sánchez CA, Rasoulian A, Sun Y, Imani F, Khojaste A, Goksel O, Romagnoli C, Abdi H, Chang S, Mousavi P, Fenster A, Ward A, Fels S, Abolmaesumi P. Biomechanically Constrained Surface Registration: Application to MR-TRUS Fusion for Prostate Interventions. IEEE Trans Med Imaging 2015; 34:2404-2414. [PMID: 26054062 DOI: 10.1109/tmi.2015.2440253] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In surface-based registration for image-guided interventions, the presence of missing data can be a significant issue. This often arises with real-time imaging modalities such as ultrasound, where poor contrast can make tissue boundaries difficult to distinguish from surrounding tissue. Missing data poses two challenges: ambiguity in establishing correspondences; and extrapolation of the deformation field to those missing regions. To address these, we present a novel non-rigid registration method. For establishing correspondences, we use a probabilistic framework based on a Gaussian mixture model (GMM) that treats one surface as a potentially partial observation. To extrapolate and constrain the deformation field, we incorporate biomechanical prior knowledge in the form of a finite element model (FEM). We validate the algorithm, referred to as GMM-FEM, in the context of prostate interventions. Our method leads to a significant reduction in target registration error (TRE) compared to similar state-of-the-art registration algorithms in the case of missing data up to 30%, with a mean TRE of 2.6 mm. The method also performs well when full segmentations are available, leading to TREs that are comparable to or better than other surface-based techniques. We also analyze robustness of our approach, showing that GMM-FEM is a practical and reliable solution for surface-based registration.
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Fedorov A, Khallaghi S, Sánchez CA, Lasso A, Fels S, Tuncali K, Sugar EN, Kapur T, Zhang C, Wells W, Nguyen PL, Abolmaesumi P, Tempany C. Open-source image registration for MRI-TRUS fusion-guided prostate interventions. Int J Comput Assist Radiol Surg 2015; 10:925-34. [PMID: 25847666 DOI: 10.1007/s11548-015-1180-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/17/2015] [Indexed: 11/30/2022]
Abstract
PURPOSE We propose two software tools for non-rigid registration of MRI and transrectal ultrasound (TRUS) images of the prostate. Our ultimate goal is to develop an open-source solution to support MRI-TRUS fusion image guidance of prostate interventions, such as targeted biopsy for prostate cancer detection and focal therapy. It is widely hypothesized that image registration is an essential component in such systems. METHODS The two non-rigid registration methods are: (1) a deformable registration of the prostate segmentation distance maps with B-spline regularization and (2) a finite element-based deformable registration of the segmentation surfaces in the presence of partial data. We evaluate the methods retrospectively using clinical patient image data collected during standard clinical procedures. Computation time and Target Registration Error (TRE) calculated at the expert-identified anatomical landmarks were used as quantitative measures for the evaluation. RESULTS The presented image registration tools were capable of completing deformable registration computation within 5 min. Average TRE was approximately 3 mm for both methods, which is comparable with the slice thickness in our MRI data. Both tools are available under nonrestrictive open-source license. CONCLUSIONS We release open-source tools that may be used for registration during MRI-TRUS-guided prostate interventions. Our tools implement novel registration approaches and produce acceptable registration results. We believe these tools will lower the barriers in development and deployment of interventional research solutions and facilitate comparison with similar tools.
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Ahn SJ, Tsou L, Antonio Sánchez C, Fels S, Kwon HB. Analyzing center of rotation during opening and closing movements of the mandible using computer simulations. J Biomech 2015; 48:666-671. [DOI: 10.1016/j.jbiomech.2014.12.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 12/15/2014] [Accepted: 12/18/2014] [Indexed: 10/24/2022]
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Sánchez CA, Asuero MS. [Controversy over the use of hydroxyethyl starch solutions. Is the use of low molecular weight hydroxyethyl starch contraindicated?]. Rev Esp Anestesiol Reanim 2014; 61:299-303. [PMID: 24838121 DOI: 10.1016/j.redar.2014.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 04/07/2014] [Indexed: 06/03/2023]
Affiliation(s)
- C A Sánchez
- Servicio de Anestesiología y Reanimación, Hospital General Universitario de Elda Virgen de la Salud, Elda, Alicante, España.
| | - M S Asuero
- Servicio de Anestesiología y Reanimación, Hospital Universitario Ramón y Cajal, Madrid, España
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Sánchez CA, Lloyd JE, Fels S, Abolmaesumi P. Embedding digitized fibre fields in finite element models of muscles. Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization 2014. [DOI: 10.1080/21681163.2013.862861] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Van Oppen MJH, Mieog JC, Sánchez CA, Fabricius KE. Diversity of algal endosymbionts (zooxanthellae) in octocorals: the roles of geography and host relationships. Mol Ecol 2005; 14:2403-17. [PMID: 15969723 DOI: 10.1111/j.1365-294x.2005.02545.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The presence, genetic identity and diversity of algal endosymbionts (Symbiodinium) in 114 species from 69 genera (20 families) of octocorals from the Great Barrier Reef (GBR), the far eastern Pacific (EP) and the Caribbean was examined, and patterns of the octocoral-algal symbiosis were compared with patterns in the host phylogeny. Genetic analyses of the zooxanthellae were based on ribosomal DNA internal transcribed spacer 1 (ITS1) region. In the GBR samples, Symbiodinium clades A and G were encountered with A and G being rare. Clade B zooxanthellae have been previously reported from a GBR octocoral, but are also rare in octocorals from this region. Symbiodinium G has so far only been found in Foraminifera, but is rare in these organisms. In the Caribbean samples, only Symbiodinium clades B and C are present. Hence, Symbiodinium diversity at the level of phylogenetic clades is lower in octocorals from the Caribbean compared to those from the GBR. However, an unprecedented level of ITS1 diversity was observed within individual colonies of some Caribbean gorgonians, implying either that these simultaneously harbour multiple strains of clade B zooxanthellae, or that ITS1 heterogeneity exists within the genomes of some zooxanthellae. Intracladal diversity based on ITS should therefore be interpreted with caution, especially in cases where no independent evidence exists to support distinctiveness, such as ecological distribution or physiological characteristics. All samples from EP are azooxanthellate. Three unrelated GBR taxa that are described in the literature as azooxanthellate (Junceella fragilis, Euplexaura nuttingi and Stereonephthya sp. 1) contain clade G zooxanthellae, and their symbiotic association with zooxanthellae was confirmed by histology. These corals are pale in colour, whereas related azooxanthellate species are brightly coloured. The evolutionary loss or gain of zooxanthellae may have altered the light sensitivity of the host tissues, requiring the animals to adopt or reduce pigmentation. Finally, we superimposed patterns of the octocoral-algal symbiosis onto a molecular phylogeny of the host. The data show that many losses/gains of endosymbiosis have occurred during the evolution of octocorals. The ancestral state (azooxanthellate or zooxanthellate) in octocorals remains unclear, but the data suggest that on an evolutionary timescale octocorals can switch more easily between mixotrophy and heterotrophy compared to scleractinian corals, which coincides with a low reliance on photosynthetic carbon gain in the former group of organisms.
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Affiliation(s)
- M J H Van Oppen
- Australian Institute of Marine Science, PMB no. 3, Townsville MC, Qld 4810, Australia.
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Zazueta C, Reyes-Vivas H, Zafra G, Sánchez CA, Vera G, Chávez E. Mitochondrial permeability transition as induced by cross-linking of the adenine nucleotide translocase. Int J Biochem Cell Biol 1998; 30:517-27. [PMID: 9675885 DOI: 10.1016/s1357-2725(97)00157-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mitochondrial permeability transition is caused by the opening of a transmembrane pore whose chemical nature has not been well established yet. The present work was aimed to further contribute to the knowledge of the membrane entity comprised in the formation of the non-specific channel. The increased permeability was established by analyzing the inability of rat kidney mitochondria to take up and accumulate Ca2+, as well as their failure to build up a transmembrane potential, after the cross-linking of membrane proteins by copper plus ortho-phenanthroline. To identify the cross-linked proteins, polyacrylamide gel electrophoresis was performed. The results are representative of at least three separate experiments. It is indicated that 30 microM Cu2+ induced the release of 4.3 nmol Ca2+ per mg protein. However, in the presence of 100 microM ortho-phenanthroline only 2 microM Cu2+ was required to attain the total release of the accumulated Ca2+; it should be noted that such a reaction is not inhibited by cyclosporin. The increased permeability corresponds to cross-linking of membrane proteins in which approximately 4 nmol thiol groups per mg protein appear to be involved. Such a linking process is inhibited by carboxyatractyloside. By using the fluorescent probe eosin-5-maleimide the label was found in a cross-linking 60 kDa dimer of two 30 kDa monomers. From the data presented it is concluded that copper-o-phenanthroline induces the intermolecular cross-linking of the adenine nucleotide translocase which in turn is converted to non-specific pore.
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Affiliation(s)
- C Zazueta
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Mexico, D.F., Mexico
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Verástegui MA, Sánchez CA, Heredia NL, García-Alvarado JS. Antimicrobial activity of extracts of three major plants from the Chihuahuan desert. J Ethnopharmacol 1996; 52:175-177. [PMID: 8771460 DOI: 10.1016/0378-8741(96)84802-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Dilution methods were employed to determine the effect of ethanolic extracts of Agave lecheguilla Torr. (Agavaceae), Baccharis glutinosa Pers. (Compositae) and Larrea tridentata (DC.) Cov. (Zygophyllaceae) on growth of yeasts, molds and bacteria. The three extracts analyzed showed good antimicrobial activity against more than one organism. The minimal inhibitory concentration of the extracts was also determined.
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Affiliation(s)
- M A Verástegui
- Departamento de Microbiología e Immunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo Leön, San Nicoläs, Mëxico
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