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Rajaeirad M, Karimpour M, Hairi Yazdi MR. Comparative finite element analysis of contact and stress distribution in tibiotalar articular cartilage: Healthy versus varus ankles. J Orthop 2024; 55:16-22. [PMID: 38646467 PMCID: PMC11026722 DOI: 10.1016/j.jor.2024.04.002] [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: 03/28/2024] [Accepted: 04/02/2024] [Indexed: 04/23/2024] Open
Abstract
Background The distribution of forces within the ankle joint plays a crucial role in joint health and longevity. Loading disorders affecting the ankle joint can have significant detrimental effects on daily life and activity levels. This study aimed to enhance our understanding of the mechanical behavior of tibiotalar joint articular cartilages in the presence of varus deformity using finite element analysis (FEA) applied to patient-specific models. Methods Two personalized ankle models, one healthy and another with varus deformity, were created based on CT scan images. Four static loading scenarios were simulated at the center of pressure (COP), coupled to the hindfoot complex. The contact area, contact pressure, and von Mises stress were computed for each cartilage. Results It was found that the peak contact pressure increased by 54% in the ankle with varus deformity compared to the healthy ankle model. Furthermore, stress concentrations moving medially were observed, particularly beneath the medial malleolus, with an average peak contact pressure of 3.5 MPa and 4.7 MPa at the tibial and talar articular cartilages, respectively. Conclusion Varus deformities in the ankle region have been consistently linked to elevated contact pressure, increasing the risk of thinning, degeneration, and eventual onset of osteoarthritis (OA), emphasizing the need for prompt interventions aimed at mitigating complications.
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Affiliation(s)
- Mohadese Rajaeirad
- School of Mechanical Engineering, University of Tehran, Tehran, Iran
- Department of Biomedical Engineering, University of Isfahan, Isfahan, Iran
| | - Morad Karimpour
- School of Mechanical Engineering, University of Tehran, Tehran, Iran
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2
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Jagoš J, Kohút J, Novotný T, Křivka T, Hájek P, Formánek M, Lisický O, Burša J. In silico hemodynamical simulations show additional benefits of artery wall softening induced by antihypertensive drugs. Comput Methods Programs Biomed 2024; 245:108016. [PMID: 38237451 DOI: 10.1016/j.cmpb.2024.108016] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 01/04/2024] [Accepted: 01/09/2024] [Indexed: 02/15/2024]
Abstract
BACKGROUND AND OBJECTIVES Age-related arterial stiffening increases peripheral resistance and decreases arterial distensibility, thus contributing to hypertension, an important risk factor of atherosclerosis. It causes abnormal blood flow, endothelial dysfunction, higher pulse wave velocity, and consequently elevated pressure wave amplitude. METHODS This paper presents the influence of these changes via multiscale 3D-0D transient computational fluid dynamics simulations of blood flow in five patient-specific geometries of human carotid bifurcation using archetypal flow waveforms for young and old subjects. RESULTS The proposed model shows a significant decrease in the time-averaged wall shear stress (TAWSS) for the old archetypal flow waveform. This is in good agreement with clinical data on a straight segment of common carotid arteries available for young and old subjects. Moreover, our study showed that the decrease of area-averaged TAWSS related to the old flow waveform is much more pronounced (2.5 ÷ 4.5 times higher) at risk areas (areas showing TAWSS below its threshold value of 0.48 Pa) than in straight segments commonly considered in clinical studies. CONCLUSIONS Since arterial stiffness can be lowered through long-term usage of any of the five basic groups of antihypertensives, possible benefits of such medical therapy could be not only lowering blood pressure and peripheral resistance but also in increasing the TAWSS and thus attenuating an important mechanism of the atherosclerotic process.
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Affiliation(s)
- Jiří Jagoš
- Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69, Brno, Czech Republic.
| | - Jiří Kohút
- Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69, Brno, Czech Republic
| | - Tomáš Novotný
- St. Anne's University Hospital Brno, Medical Faculty, Masaryk University, Pekařská 664/53, 602 00, Brno, Czech Republic
| | - Tomáš Křivka
- St. Anne's University Hospital Brno, Medical Faculty, Masaryk University, Pekařská 664/53, 602 00, Brno, Czech Republic
| | - Petr Hájek
- Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69, Brno, Czech Republic
| | - Martin Formánek
- Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69, Brno, Czech Republic
| | - Ondřej Lisický
- Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69, Brno, Czech Republic
| | - Jiří Burša
- Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69, Brno, Czech Republic
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Mazier A, Bordas SPA. Breast simulation pipeline: From medical imaging to patient-specific simulations. Clin Biomech (Bristol, Avon) 2024; 111:106153. [PMID: 38061204 DOI: 10.1016/j.clinbiomech.2023.106153] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 01/16/2024]
Abstract
BACKGROUND Breast-conserving surgery is the most acceptable operation for breast cancer removal from an invasive and psychological point of view. Before the surgical procedure, a preoperative MRI is performed in the prone configuration, while the surgery is achieved in the supine position. This leads to a considerable movement of the breast, including the tumor, between the two poses, complicating the surgeon's task. METHODS In this work, a simulation pipeline allowing the computation of patient-specific geometry and the prediction of personalized breast material properties was put forward. Through image segmentation, a finite element model including the subject-specific geometry is established. By first computing an undeformed state of the breast, the geometrico-material model is calibrated by surface acquisition in the intra-operative stance. FINDINGS Using an elastic corotational formulation, the patient-specific mechanical properties of the breast and skin were identified to obtain the best estimates of the supine configuration. The final results are a shape-fitting closest point residual of 4.00 mm for the mechanical parameters Ebreast=0.32 kPa and Eskin=22.72 kPa, congruent with the current state-of-the-art. The Covariance Matrix Adaptation Evolution Strategy optimizer converges on average between 5 to 30 min depending on the initial parameters, reaching a simulation speed of 20 s. To our knowledge, our model offers one of the best compromises between accuracy and speed. INTERPRETATION Satisfactory results were obtained for the estimation of breast deformation from preoperative to intra-operative configuration. Furthermore, we have demonstrated the clinical feasibility of such applications using a simulation framework that aims at the smallest disturbance of the actual surgical pipeline.
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Affiliation(s)
- Arnaud Mazier
- Institute of Computational Engineering, Department of Engineering, Université du Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Stéphane P A Bordas
- Institute of Computational Engineering, Department of Engineering, Université du Luxembourg, Esch-sur-Alzette, Luxembourg.
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Guo X, Gong C, Zhai Y, Yu H, Li J, Sun H, Wang L, Tang D. Biomechanical characterization of normal and pathological human ascending aortic tissues via biaxial testing Experiment, constitutive modeling and finite element analysis. Comput Biol Med 2023; 166:107561. [PMID: 37857134 DOI: 10.1016/j.compbiomed.2023.107561] [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: 07/22/2023] [Revised: 09/27/2023] [Accepted: 10/10/2023] [Indexed: 10/21/2023]
Abstract
BACKGROUND Aortic dissection and atherosclerosis are two common pathological conditions affecting the aorta. Aortic biomechanics are believed to be closely associated with the pathological development of these diseases. However, the biomechanical environment that predisposes the aortic wall to these pathological conditions remains unclear. METHODS Sixteen ascending aortic specimens were harvested from 16 human subjects and further categorized into three groups according to their disease states: aortic dissection group, aortic dissection with accompanied atherosclerosis group and healthy group. Experimental stress-strain data from biaxial tensile testing were used to fit the anisotropic Mooney-Rivlin model to determine material parameters. Computed tomography images or transesophageal echocardiography images were collected to construct computational models to simulate the stress/strain distributions in aortas at the pre-dissection state. Statistical analyses were performed to identify the biomechanical factors to distinguish three groups of aortic tissues. RESULTS Material parameters of anisotropic Mooney-Rivlin model were fitted with average R2 value 0.9749. The aortic diameter showed no significant difference among three groups. Changes of maximum and average stress values from minimum pressure to maximum pressure (△MaxStress and △AveStress) had significantly difference between dissection group and dissection with accompanied atherosclerosis group (p = 0.0201 and 0.0102). Changes of maximum and average strain values from minimum pressure to maximum pressure (△MaxStrain and △AveStrain) from dissection group were significant different from healthy group (p = 0.0171 and 0.0281). CONCLUSION Changes of stress and strain values during the cardiac cycle are good biomechanical factors for predicting potential aortic dissection and aortic dissection accompanied with atherosclerosis.
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Affiliation(s)
- Xiaoya Guo
- College of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210023, China
| | - Chanjuan Gong
- Department of Anesthesiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Yali Zhai
- Department of Pathophysiology, Nanjing Medical University, Nanjing, 211166, China
| | - Han Yu
- School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Jiantao Li
- Department of Pathophysiology, Nanjing Medical University, Nanjing, 211166, China
| | - Haoliang Sun
- Department of Cardiovascular Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
| | - Liang Wang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
| | - Dalin Tang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China; Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
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Zimmermann R, Seitz S. The Impact of Technological Innovation on Dentistry. Adv Exp Med Biol 2023; 1406:79-102. [PMID: 37016112 DOI: 10.1007/978-3-031-26462-7_5] [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] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
Technology has revolutionized the way dentists are able to treat their patients. These technological advances have paved the way for the creation of virtual patient models utilizing these 3-dimensional intra-oral patient models, cone bean computer tomography (CBCT) radiograph scans, extraoral 3-dimensional scans, and jaw motion tracings to create a patient-specific model. These models are advantageous in planning surgical treatments by providing 3-dimensional views of vital anatomical structures to accurately identify the location, size, and shape of a structure or defect in order to plan accordingly. Virtual augmentation of either hard tissue (bone) and/or soft tissue (i.e., gingiva) can also be accomplished.Technology has allowed the capture of the dynamic motions of the jaw and combined them with the virtual patient to develop permanent restorations in harmony with the patient's orofacial complex. With the introduction of new technology in the realm of digital dentistry, patient care is being brought to a new and higher level. This creates a level of more optimal care that a dentist can deliver to patients.
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Affiliation(s)
- Richard Zimmermann
- Department of Comprehensive Dentistry, UT Health San Antonio, San Antonio, TX, USA
| | - Stefanie Seitz
- Department of Comprehensive Dentistry, UT Health San Antonio, San Antonio, TX, USA.
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Zhu Y, Babazadeh-Naseri A, Dunbar NJ, Brake MRW, Zandiyeh P, Li G, Leardini A, Spazzoli B, Fregly BJ. Finite element analysis of screw fixation durability under multiple boundary and loading conditions for a custom pelvic implant. Med Eng Phys 2023; 111:103930. [PMID: 36792235 DOI: 10.1016/j.medengphy.2022.103930] [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: 06/09/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022]
Abstract
Despite showing promising functional outcomes for pelvic reconstruction after sarcoma resection, custom-made pelvic implants continue to exhibit high complication rates due to fixation failures. Patient-specific finite element models have been utilized by researchers to evaluate implant durability. However, the effect of assumed boundary and loading conditions on failure analysis results of fixation screws remains unknown. In this study, the postoperative stress distributions in the fixation screws of a state-of-the-art custom-made pelvic implant were simulated, and the risk of failure was estimated under various combinations of two bone-implant interaction models (tied vs. frictional contact) and four load cases from level-ground walking and stair activities. The study found that the average weighted peak von Mises stress could increase by 22-fold when the bone-implant interactions were modeled with a frictional contact model instead of a tied model, and the likelihood of fatigue and pullout failure for each screw could change dramatically when different combinations of boundary and loading conditions were used. The inclusion of additional boundary and loading conditions led to a more reliable analysis of fixation durability. These findings demonstrated the importance of simulating multiple boundary conditions and load cases for comprehensive implant design evaluation using finite element analysis.
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Affiliation(s)
- Yuhui Zhu
- Department of Mechanical Engineering, Rice University, Houston, Texas, USA
| | | | - Nicholas J Dunbar
- Department of Mechanical Engineering, Rice University, Houston, Texas, USA
| | - Matthew R W Brake
- Department of Mechanical Engineering, Rice University, Houston, Texas, USA
| | - Payam Zandiyeh
- Department of Orthopedic Surgery, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Geng Li
- Department of Mechanical Engineering, Rice University, Houston, Texas, USA
| | - Alberto Leardini
- Movement Analysis Laboratory, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Benedetta Spazzoli
- Clinica Ortopedica III, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Benjamin J Fregly
- Department of Mechanical Engineering, Rice University, Houston, Texas, USA.
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Helbock RT, Anam SB, Kovarovic BJ, Slepian MJ, Hamdan A, Haj-Ali R, Bluestein D. Designing a Novel Asymmetric Transcatheter Aortic Valve for Stenotic Bicuspid Aortic Valves Using Patient-Specific Computational Modeling. Ann Biomed Eng 2023; 51:58-70. [PMID: 36042099 DOI: 10.1007/s10439-022-03039-3] [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: 05/04/2022] [Accepted: 07/25/2022] [Indexed: 01/13/2023]
Abstract
Bicuspid aortic valve (BAV), the most common congenital heart malformation, is characterized by the presence of only two valve leaflets with asymmetrical geometry, resulting in elliptical systolic opening. BAV often leads to early onset of calcific aortic stenosis (AS). Following the rapid expansion of transcatheter aortic valve replacement (TAVR), designed specifically for treating conventional tricuspid AS, BAV patients with AS were initially treated "off-label" with TAVR, which recently gained FDA and CE regulatory approval. Despite its increasing use in BAV, pathological BAV anatomy often leads to complications stemming from mismatched anatomical features. To mitigate these complications, a novel eccentric polymeric TAVR valve incorporating asymmetrical leaflets was designed specifically for BAV anatomies. Computational modeling was used to optimize its asymmetric leaflets for lower functional stresses and improved hemodynamic performance. Deployment and flow were simulated in patient-specific BAV models (n = 6) and compared to a current commercial TAVR valve (Evolut R 29 mm), to assess deployment and flow parameters. The novel eccentric BAV-dedicated valve demonstrated significant improvements in peak systolic orifice area, along with lower jet velocity and wall shear stress (WSS). This feasibility study demonstrates the clinical potential of the first known BAV-dedicated TAVR design, which will foster advancement of patient-dedicated valvular devices.
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Affiliation(s)
- Ryan T Helbock
- Biofluids Research Group, Department of Biomedical Engineering, T8-050 Health Sciences Center, Stony Brook University, Stony Brook, NY11794-8084, USA
| | - Salwa B Anam
- Biofluids Research Group, Department of Biomedical Engineering, T8-050 Health Sciences Center, Stony Brook University, Stony Brook, NY11794-8084, USA
| | - Brandon J Kovarovic
- Biofluids Research Group, Department of Biomedical Engineering, T8-050 Health Sciences Center, Stony Brook University, Stony Brook, NY11794-8084, USA
| | - Marvin J Slepian
- Department of Medicine and Biomedical Engineering Sarver Heart Center, University of Arizona, Tucson, AZ, 85721, USA
| | - Ashraf Hamdan
- Department of Cardiology, Rabin Medical Center, 4941492, Petah Tikva, Israel
| | - Rami Haj-Ali
- School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, 69978, Tel Aviv, Ramat Aviv, Israel
| | - Danny Bluestein
- Biofluids Research Group, Department of Biomedical Engineering, T8-050 Health Sciences Center, Stony Brook University, Stony Brook, NY11794-8084, USA.
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Toniolo I, Berardo A, Foletto M, Fiorillo C, Quero G, Perretta S, Carniel EL. Patient-specific stomach biomechanics before and after laparoscopic sleeve gastrectomy. Surg Endosc 2022; 36:7998-8011. [PMID: 35451669 PMCID: PMC9028903 DOI: 10.1007/s00464-022-09233-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/29/2022] [Indexed: 01/06/2023]
Abstract
BACKGROUND Obesity has become a global epidemic. Bariatric surgery is considered the most effective therapeutic weapon in terms of weight loss and improvement of quality of life and comorbidities. Laparoscopic sleeve gastrectomy (LSG) is one of the most performed procedures worldwide, although patients carry a nonnegligible risk of developing post-operative GERD and BE. OBJECTIVES The aim of this work is the development of computational patient-specific models to analyze the changes induced by bariatric surgery, i.e., the volumetric gastric reduction, the mechanical response of the stomach during an inflation process, and the related elongation strain (ES) distribution at different intragastric pressures. METHODS Patient-specific pre- and post-surgical models were extracted from Magnetic Resonance Imaging (MRI) scans of patients with morbid obesity submitted to LSG. Twenty-three patients were analyzed, resulting in forty-six 3D-geometries and related computational analyses. RESULTS A significant difference between the mechanical behavior of pre- and post-surgical stomach subjected to the same internal gastric pressure was observed, that can be correlated to a change in the global stomach stiffness and a minor gastric wall tension, resulting in unusual activations of mechanoreceptors following food intake and satiety variation after LSG. CONCLUSIONS Computational patient-specific models may contribute to improve the current knowledge about anatomical and physiological changes induced by LSG, aiming at reducing post-operative complications and improving quality of life in the long run.
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Affiliation(s)
- Ilaria Toniolo
- Department of Industrial Engineering, University of Padova, Padova, Italy
- Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy
| | - Alice Berardo
- Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy.
- Department of Civil, Environmental and Architectural Engineering, University of Padova, Padova, Italy.
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
| | - Mirto Foletto
- Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy
- Bariatric Surgery Unit, Azienda Ospedaliera, University of Padova, Padova, Italy
| | - Claudio Fiorillo
- Digestive Surgery Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Giuseppe Quero
- Digestive Surgery Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
- Catholic University of Sacred Heart of Rome, Rome, Italy
| | - Silvana Perretta
- IHU Strasbourg, Strasbourg, France
- IRCAD France, Strasbourg, France
- Department of Digestive and Endocrine Surgery, NHC, Strasbourg, France
| | - Emanuele Luigi Carniel
- Department of Industrial Engineering, University of Padova, Padova, Italy
- Centre for Mechanics of Biological Materials, University of Padova, Padova, Italy
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Ozturk AM, Ozer MA, Suer O, Derin O, Govsa F, Aktuglu K. Evaluation of the effects of using 3D - patient specific models of displaced intra - articular calcaneal fractures in surgery. Injury 2022; 53 Suppl 2:S40-S51. [PMID: 32456955 DOI: 10.1016/j.injury.2020.04.057] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [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: 03/23/2020] [Revised: 04/26/2020] [Accepted: 04/29/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND It was aimed to compare conventional surgery and three-dimensional (3D) model-assisted surgery used in the treatment of calcaneal fractures. MATERIALS & METHODS A total of 37 patients with unilateral calcaneal fractures were randomly divided into two groups as a conventional surgery group (n: 19) and a 3D model-assisted surgery group (n: 18). The preoperative, postoperative and last follow up angles of the Bohler and Gissane, calcaneal width and facet height were measured. The duration of the operation, blood loss volume, fluoroscopy usage, instrumentation time for both groups were recorded. Finally, the follow-up AOFAS scores were evaluated. A questionnaire was used to determine the perceptions of the resident doctors about the 3D model. RESULTS The duration of the operation, blood loss volume, fluoroscopy usage, instrumentation time for 3D model-assisted surgery group were 83.3 ± 4.6 minutes, 83.6 ± 4.6 ml, 6.8 ± 1.4 times and 13.0 ± 0.8 weeks, and as for conventional group they were 130.0 ± 5.8 minutes, 105.1 ± 5.6 minutes, 11.7 ± 1.5 ml, 22.2 ± 2.4 times and 13.3 ± 0.8 weeks, respectively (p < 0.0001). The both groups significantly restored Bohler angle, Gissane angle, calcaneal width and calcaneal facet height after operation (p < 0.0001). The 3D model-assisted group was significantly more succesful in restoration and protection of achieved correction of calcanel facet height (p < 0.0001). The difference was determined among the groups at the final follow-up examination with respect to the amount of change according the values achieved post-op. were significant in Bohler angle (p < 0.001), calcaneal facet height (p < 0.0001) and calcaneal widht (p = 0.017). There was no significant difference between AOFAS scores of the two groups at last follow-up. Resident doctors exhibited high scores of overall satisfaction with the use of a 3D printing model. CONCLUSIONS Compared to the conventional group, the 3D model-assisted group provide successful intervention and reduce operation, instrumentation time and the fluoroscopy usage with less blood loss. Performing 3D-assisted surgery helps the quality of reduction during the surgery and stability of internal fixation to protect achieved reduction at follow-up more succesfully.
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Affiliation(s)
- Anil Murat Ozturk
- Department of Ortopaedic Surgery, Faculty of Medicine, Ege University, Izmir, TURKEY
| | - Mehmet Asim Ozer
- Department of Anatomy Digital Imaging and 3D Modelling Laboratory, Faculty of Medicine, Ege University, Izmir, TURKEY
| | - Onur Suer
- Department of Ortopaedic Surgery, Faculty of Medicine, Ege University, Izmir, TURKEY
| | - Okan Derin
- Department of Anatomy Digital Imaging and 3D Modelling Laboratory, Faculty of Medicine, Ege University, Izmir, TURKEY
| | - Figen Govsa
- Department of Anatomy Digital Imaging and 3D Modelling Laboratory, Faculty of Medicine, Ege University, Izmir, TURKEY
| | - Kemal Aktuglu
- Department of Ortopaedic Surgery, Faculty of Medicine, Ege University, Izmir, TURKEY.
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Huang X, Liu D, Wang X. Morphological and hemodynamic analysis of the patient-specific renal cell carcinoma models. J Biomech 2021; 126:110636. [PMID: 34298292 DOI: 10.1016/j.jbiomech.2021.110636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 07/09/2021] [Accepted: 07/10/2021] [Indexed: 11/24/2022]
Abstract
Although the morbidity of renal cell carcinoma (RCC) has been increasing as the seventh most common tumours, to our knowledge, there is few studies foucsing on the hemodynamics of the renal artery (RA) with RCC. The objective of this study is to perform morphological and hemodynamic analysis of the RA and abdominal aorta artery (AAA) in the control healthy and RCC patient groups. Three-dimensional (3D) geometries are reconstructed from 18 control healthy subjects and 15 RCC patients based on Computed Tomography Angiography (CTA) images. There is higer in the lumen diameter of the RA (6.21 ± 0.89 mm) and curvature of the RA (1.2 ± 0.07) in the RCC patient group compared with the control healthy group (4.29 ± 1.08 mm, 1.1 ± 0.1), respectively. In the hemodynamic analysis, the surface area ratio (%) of low time-averaged wall shear stress (SAR-TAWSS) at the RA (10.65 ± 11.65) and AAA (48.49 ± 12.79) in the RCC patient group is significantly higher than that in the control healthy group (0.23 ± 0.22, 21.57 ± 20.5), respectively. It is found that RCC altered the morphology of the RA in the RCC patient group, which could deteriorate the hemodynamic environment of the RA and AAA. The finding in this study could enhance us to understand the progression of vascular disease caused by RCC.
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Hadjicharalambous M, Stoeck CT, Weisskopf M, Cesarovic N, Ioannou E, Vavourakis V, Nordsletten DA. Investigating the reference domain influence in personalised models of cardiac mechanics : Effect of unloaded geometry on cardiac biomechanics. Biomech Model Mechanobiol 2021; 20:1579-1597. [PMID: 34047891 DOI: 10.1007/s10237-021-01464-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 11/11/2020] [Accepted: 05/03/2021] [Indexed: 01/23/2023]
Abstract
A major concern in personalised models of heart mechanics is the unknown zero-pressure domain, a prerequisite for accurately predicting cardiac biomechanics. As the reference configuration cannot be captured by clinical data, studies often employ in-vivo frames which are unlikely to correspond to unloaded geometries. Alternatively, zero-pressure domain is approximated through inverse methodologies, which, however, entail assumptions pertaining to boundary conditions and material parameters. Both approaches are likely to introduce biases in estimated biomechanical properties; nevertheless, quantification of these effects is unattainable without ground-truth data. In this work, we assess the unloaded state influence on model-derived biomechanics, by employing an in-silico modelling framework relying on experimental data on porcine hearts. In-vivo images are used for model personalisation, while in-situ experiments provide a reliable approximation of the reference domain, creating a unique opportunity for a validation study. Personalised whole-cycle cardiac models are developed which employ different reference domains (image-derived, inversely estimated) and are compared against ground-truth model outcomes. Simulations are conducted with varying boundary conditions, to investigate the effect of data-derived constraints on model accuracy. Attention is given to modelling the influence of the ribcage on the epicardium, due to its close proximity to the heart in the porcine anatomy. Our results find merit in both approaches for dealing with the unknown reference domain, but also demonstrate differences in estimated biomechanical quantities such as material parameters, strains and stresses. Notably, they highlight the importance of a boundary condition accounting for the constraining influence of the ribcage, in forward and inverse biomechanical models.
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Affiliation(s)
| | - Christian T Stoeck
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Miriam Weisskopf
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Nikola Cesarovic
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Translational Cardiovascular Technologies, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.,Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Berlin, Germany
| | - Eleftherios Ioannou
- Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus
| | - Vasileios Vavourakis
- Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus.,Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - David A Nordsletten
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.,Department of Biomedical Engineering and Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
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12
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Guo X, Maehara A, Matsumura M, Wang L, Zheng J, Samady H, Mintz GS, Giddens DP, Tang D. Predicting plaque vulnerability change using intravascular ultrasound + optical coherence tomography image-based fluid-structure interaction models and machine learning methods with patient follow-up data: a feasibility study. Biomed Eng Online 2021; 20:34. [PMID: 33823858 PMCID: PMC8025351 DOI: 10.1186/s12938-021-00868-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/13/2021] [Indexed: 02/07/2023] Open
Abstract
Background Coronary plaque vulnerability prediction is difficult because plaque vulnerability is non-trivial to quantify, clinically available medical image modality is not enough to quantify thin cap thickness, prediction methods with high accuracies still need to be developed, and gold-standard data to validate vulnerability prediction are often not available. Patient follow-up intravascular ultrasound (IVUS), optical coherence tomography (OCT) and angiography data were acquired to construct 3D fluid–structure interaction (FSI) coronary models and four machine-learning methods were compared to identify optimal method to predict future plaque vulnerability. Methods Baseline and 10-month follow-up in vivo IVUS and OCT coronary plaque data were acquired from two arteries of one patient using IRB approved protocols with informed consent obtained. IVUS and OCT-based FSI models were constructed to obtain plaque wall stress/strain and wall shear stress. Forty-five slices were selected as machine learning sample database for vulnerability prediction study. Thirteen key morphological factors from IVUS and OCT images and biomechanical factors from FSI model were extracted from 45 slices at baseline for analysis. Lipid percentage index (LPI), cap thickness index (CTI) and morphological plaque vulnerability index (MPVI) were quantified to measure plaque vulnerability. Four machine learning methods (least square support vector machine, discriminant analysis, random forest and ensemble learning) were employed to predict the changes of three indices using all combinations of 13 factors. A standard fivefold cross-validation procedure was used to evaluate prediction results. Results For LPI change prediction using support vector machine, wall thickness was the optimal single-factor predictor with area under curve (AUC) 0.883 and the AUC of optimal combinational-factor predictor achieved 0.963. For CTI change prediction using discriminant analysis, minimum cap thickness was the optimal single-factor predictor with AUC 0.818 while optimal combinational-factor predictor achieved an AUC 0.836. Using random forest for predicting MPVI change, minimum cap thickness was the optimal single-factor predictor with AUC 0.785 and the AUC of optimal combinational-factor predictor achieved 0.847. Conclusion This feasibility study demonstrated that machine learning methods could be used to accurately predict plaque vulnerability change based on morphological and biomechanical factors from multi-modality image-based FSI models. Large-scale studies are needed to verify our findings.
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Affiliation(s)
- Xiaoya Guo
- School of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210023, China. .,Department of Mathematics, Southeast University, Nanjing, 210096, China.
| | - Akiko Maehara
- The Cardiovascular Research Foundation, Columbia University, New York, NY, 10022, USA
| | - Mitsuaki Matsumura
- The Cardiovascular Research Foundation, Columbia University, New York, NY, 10022, USA
| | - Liang Wang
- School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Jie Zheng
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, 63110, USA
| | - Habib Samady
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30307, USA
| | - Gary S Mintz
- The Cardiovascular Research Foundation, Columbia University, New York, NY, 10022, USA
| | - Don P Giddens
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30307, USA.,The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Dalin Tang
- Department of Mathematics, Southeast University, Nanjing, 210096, China. .,Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA, 01609, USA.
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13
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Wang Q, Tang D, Wang L, Meahara A, Molony D, Samady H, Zheng J, Mintz GS, Stone GW, Giddens DP. Multi-patient study for coronary vulnerable plaque model comparisons: 2D/3D and fluid-structure interaction simulations. Biomech Model Mechanobiol 2021; 20:1383-97. [PMID: 33759037 DOI: 10.1007/s10237-021-01450-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/07/2021] [Indexed: 12/05/2022]
Abstract
Several image-based computational models have been used to perform mechanical analysis for atherosclerotic plaque progression and vulnerability investigations. However, differences of computational predictions from those models have not been quantified at multi-patient level. In vivo intravascular ultrasound (IVUS) coronary plaque data were acquired from seven patients. Seven 2D/3D models with/without circumferential shrink, cyclic bending and fluid–structure interactions (FSI) were constructed for the seven patients to perform model comparisons and quantify impact of 2D simplification, circumferential shrink, FSI and cyclic bending plaque wall stress/strain (PWS/PWSn) and flow shear stress (FSS) calculations. PWS/PWSn and FSS averages from seven patients (388 slices for 2D and 3D thin-layer models) were used for comparison. Compared to 2D models with shrink process, 2D models without shrink process overestimated PWS by 17.26%. PWS change at location with greatest curvature change from 3D FSI models with/without cyclic bending varied from 15.07% to 49.52% for the seven patients (average = 30.13%). Mean Max-FSS, Min-FSS and Ave-FSS from the flow-only models under maximum pressure condition were 4.02%, 11.29% and 5.45% higher than those from full FSI models with cycle bending, respectively. Mean PWS and PWSn differences between FSI and structure-only models were only 4.38% and 1.78%. Model differences had noticeable patient variations. FSI and flow-only model differences were greater for minimum FSS predictions, notable since low FSS is known to be related to plaque progression. Structure-only models could provide PWS/PWSn calculations as good approximations to FSI models for simplicity and time savings in calculation.
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14
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Alonso F, Zsigmond P, Wårdell K. Influence of Virchow-Robin spaces on the electric field distribution in subthalamic nucleus deep brain stimulation. Clin Neurol Neurosurg 2021; 204:106596. [PMID: 33813373 DOI: 10.1016/j.clineuro.2021.106596] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 05/15/2020] [Revised: 10/12/2020] [Accepted: 03/02/2021] [Indexed: 10/22/2022]
Abstract
Patient MRI from DBS implantations in the subthalamic nucleus (STN) were reviewed and it was found that around 10% had Virchow-Robin spaces (VRS). Patient-specific models were developed to evaluate changes in the electric field (EF) around DBS leads. The patients (n = 7) were implanted bilaterally either with the standard voltage-controlled lead 3389 or with the directional current-controlled lead 6180. The EF distribution was evaluated by comparing simulations using patient-specific models with homogeneous models without VRS. The EF, depicted with an isocontour of 0.2 V/mm, showed a deformation in the presence of the VRS around the DBS lead. For patient-specific models, the radial extension of the EF isocontours was enlarged regardless of the operating mode or the DBS lead used. The location of the VRS in relation to the active contact and the stimulation amplitude, determined the changes in the shape and extension of the EF. It is concluded that it is important to take the patients' brain anatomy into account as the high conductivity in VRS will alter the electric field if close to the DBS lead. This can be a cause of unexpected side effects.
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Affiliation(s)
- Fabiola Alonso
- Department of Biomedical Engineering, Linköping University, Sweden
| | - Peter Zsigmond
- Department of Neurosurgery and Department of Biomedical and Clinical Sciences, Linköping University, Sweden
| | - Karin Wårdell
- Department of Biomedical Engineering, Linköping University, Sweden; Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
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15
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Guler E, Ozer MA, Bati AH, Govsa F, Erozkan K, Vatansever S, Ersin MS, Elmas NZ. Patient-centered oncosurgical planning with cancer models in subspecialty education. Surg Oncol 2021; 37:101537. [PMID: 33711767 DOI: 10.1016/j.suronc.2021.101537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 03/13/2020] [Revised: 01/20/2021] [Accepted: 03/02/2021] [Indexed: 01/17/2023]
Abstract
BACKGROUND A fundamental aspect of oncosurgical planning in organ resections is the identification of feeder vessel details to preserve healthy organ tissue while fully resecting the tumors. The purpose of this study was to determine whether three-dimensional (3D) cancer case models of computed tomography (CT) images will assist resident-level trainees in making appropriate operative plans for organ resection surgery. METHODS This study was based on the perception of surgery residents who were presented with 5 different oncosurgical scenarios. A five-station carousel including cases of liver mass, stomach mass, annular pancreas, pelvic mass and mediastinal mass was formed for the study. The residents were required to compare their perception level of the cases with their CT images, and 3D models in terms of identifying the invasion of the mass, making differential diagnosis and preoperative planning stage. RESULTS All residents have given higher scores for models. 3D models provided better understanding of oncopathological anatomy and improved surgical planning. In all scenarios, 70-80% of the residents preferred the model for preoperative planning. For surgical choice, compared to the CT, the model provided a statistically significant difference in terms of visual assessment, such as tumor location, distal or proximal organotomy (p:0.009). In the evaluation of presacral mass, the perception of model was significantly better than the CT in terms of bone-foramen relationship of chondrosarcoma, its origin, geometric shape, localization, invasion, and surgical preference (p:0.004). The model statistically significantly provided help to evaluate and prepare the case together with the colleagues performing surgery (p:0.007). Commenting on the open-ended question, they stated that the tumor-vessel relationship was clearly demonstrated in the 3D model, which has been very useful. CONCLUSIONS With the help of 3D printing technology in this study, it is possible to implement and evaluate a well-structured real patient scenario setup in cancer surgery training. It can be used to improve the understanding of pathoanatomical changes of multidisciplinary oncologic cases. Namely, it is used in guiding the surgical strategy and determining whether patient-specific 3D models change pre-operative planning decisions made by surgeons in complex cancer mass surgical procedures.
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Affiliation(s)
- Ezgi Guler
- Department of Radiology, Ege University Faculty of Medicine, Turkey
| | - Mehmet Asim Ozer
- Department of Anatomy Digital Imaging and 3D Modelling Laboratory, Ege University Faculty of Medicine, Turkey
| | - Ayse Hilal Bati
- Department of Medical Education, Ege University Faculty of Medicine, Turkey
| | - Figen Govsa
- Department of Anatomy Digital Imaging and 3D Modelling Laboratory, Ege University Faculty of Medicine, Turkey.
| | - Kamil Erozkan
- Department of General Surgery, Ege University Faculty of Medicine, Turkey
| | - Safa Vatansever
- Department of General Surgery, Ege University Faculty of Medicine, Turkey
| | - Muhtar Sinan Ersin
- Department of General Surgery, Ege University Faculty of Medicine, Turkey
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16
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Corrado C, Williams S, Roney C, Plank G, O'Neill M, Niederer S. Using machine learning to identify local cellular properties that support re-entrant activation in patient-specific models of atrial fibrillation. Europace 2021; 23:i12-i20. [PMID: 33437987 PMCID: PMC7943361 DOI: 10.1093/europace/euaa386] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 12/15/2020] [Indexed: 11/17/2022] Open
Abstract
AIMS Atrial fibrillation (AF) is sustained by re-entrant activation patterns. Ablation strategies have been proposed that target regions of tissue that may support re-entrant activation patterns. We aimed to characterize the tissue properties associated with regions that tether re-entrant activation patterns in a validated virtual patient cohort. METHODS AND RESULTS Atrial fibrillation patient-specific models (seven paroxysmal and three persistent) were generated and validated against local activation time (LAT) measurements during an S1-S2 pacing protocol from the coronary sinus and high right atrium, respectively. Atrial models were stimulated with burst pacing from three locations in the proximity of each pulmonary vein to initiate re-entrant activation patterns. Five atria exhibited sustained activation patterns for at least 80 s. Models with short maximum action potential durations (APDs) were associated with sustained activation. Phase singularities were mapped across the atria sustained activation patterns. Regions with a low maximum conduction velocity (CV) were associated with tethering of phase singularities. A support vector machine (SVM) was trained on maximum local conduction velocity and action potential duration to identify regions that tether phase singularities. The SVM identified regions of tissue that could support tethering with 91% accuracy. This accuracy increased to 95% when the SVM was also trained on surface area. CONCLUSION In a virtual patient cohort, local tissue properties, that can be measured (CV) or estimated (APD; using effective refractory period as a surrogate) clinically, identified regions of tissue that tether phase singularities. Combing CV and APD with atrial surface area further improved the accuracy in identifying regions that tether phase singularities.
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Affiliation(s)
- Cesare Corrado
- Department of Biomedical Engineering, King's College London, 4th floor North Wing St Thomas' Hospital, Westminster Bridge Road, London SE17EH, UK
| | - Steven Williams
- Department of Biomedical Engineering, King's College London, 4th floor North Wing St Thomas' Hospital, Westminster Bridge Road, London SE17EH, UK
| | - Caroline Roney
- Department of Biomedical Engineering, King's College London, 4th floor North Wing St Thomas' Hospital, Westminster Bridge Road, London SE17EH, UK
| | - Gernot Plank
- Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Mark O'Neill
- Department of Biomedical Engineering, King's College London, 4th floor North Wing St Thomas' Hospital, Westminster Bridge Road, London SE17EH, UK
| | - Steven Niederer
- Department of Biomedical Engineering, King's College London, 4th floor North Wing St Thomas' Hospital, Westminster Bridge Road, London SE17EH, UK
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17
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Lei C, Wang Y, Zhao J, Li K, Jiang H, Wang Q. A patient specific forecasting model for human albumin based on deep neural networks. Comput Methods Programs Biomed 2020; 196:105555. [PMID: 32544776 DOI: 10.1016/j.cmpb.2020.105555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 05/06/2020] [Accepted: 05/16/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVES Hypoalbuminemia can be life threatening among critically ill patients. In this study, we develop a patient-specific monitoring and forecasting model based on deep neural networks to predict concentrations of albumin and a set of selected biochemical markers for critically ill patients in real-time. METHODS Under the assumption that metabolism of a patient follows a patient-specific dynamical process that can be determined from sufficient prior data taken from the patient, we apply a machine learning method to develop the patient-specific model for a critically ill, poly-trauma patient. Six representative biochemical markers (albumin (ALB), creatinine (Cr), osmotic pressure (OSM), alanine aminotransferase (ALT), total bilirubin (TB), direct bilirubin (DB)) were collected from the patient while scheduled exogenous albumin injection was administered to the patient for the total of 27 consecutive days. A sliding window of data in 11 consecutive days were used to train and test the neural networks in the model. RESULTS The obtained dynamical system model represented by neural networks is used to forecast the biochemical markers of the patient in the next 24 h. The relative error between the predictions and the clinical data remains consistently lower than 2%. CONCLUSIONS This study demonstrates that a patient-specific dynamical system model can be established to monitor and forecast dynamical behavior of concentrations of patients' biochemical markers (including albumin) using deep learning methods on neural networks.
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Affiliation(s)
- Cheng Lei
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Yu Wang
- Institute for Emergency and Disaster Medicine, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Jia Zhao
- Department of Mathematics and Statistics, Utah State University, Logan, UT 84322, USA
| | - Kexun Li
- Institute for Emergency and Disaster Medicine, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China
| | - Hua Jiang
- Institute for Emergency and Disaster Medicine, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610072, Sichuan, China.
| | - Qi Wang
- Department of Mathematics, University of South Carolina, Columbia, SC 29208, USA.
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18
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Emendi M, Sturla F, Ghosh RP, Bianchi M, Piatti F, Pluchinotta FR, Giese D, Lombardi M, Redaelli A, Bluestein D. Patient-Specific Bicuspid Aortic Valve Biomechanics: A Magnetic Resonance Imaging Integrated Fluid-Structure Interaction Approach. Ann Biomed Eng 2020; 49:627-641. [PMID: 32804291 DOI: 10.1007/s10439-020-02571-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [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: 01/30/2020] [Accepted: 07/14/2020] [Indexed: 12/15/2022]
Abstract
Congenital bicuspid aortic valve (BAV) consists of two fused cusps and represents a major risk factor for calcific valvular stenosis. Herein, a fully coupled fluid-structure interaction (FSI) BAV model was developed from patient-specific magnetic resonance imaging (MRI) and compared against in vivo 4-dimensional flow MRI (4D Flow). FSI simulation compared well with 4D Flow, confirming direction and magnitude of the flow jet impinging onto the aortic wall as well as location and extension of secondary flows and vortices developing at systole: the systolic flow jet originating from an elliptical 1.6 cm2 orifice reached a peak velocity of 252.2 cm/s, 0.6% lower than 4D Flow, progressively impinging on the ascending aorta convexity. The FSI model predicted a peak flow rate of 22.4 L/min, 6.7% higher than 4D Flow, and provided BAV leaflets mechanical and flow-induced shear stresses, not directly attainable from MRI. At systole, the ventricular side of the non-fused leaflet revealed the highest wall shear stress (WSS) average magnitude, up to 14.6 Pa along the free margin, with WSS progressively decreasing towards the belly. During diastole, the aortic side of the fused leaflet exhibited the highest diastolic maximum principal stress, up to 322 kPa within the attachment region. Systematic comparison with ground-truth non-invasive MRI can improve the computational model ability to reproduce native BAV hemodynamics and biomechanical response more realistically, and shed light on their role in BAV patients' risk for developing complications; this approach may further contribute to the validation of advanced FSI simulations designed to assess BAV biomechanics.
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Affiliation(s)
- Monica Emendi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.,Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Francesco Sturla
- 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Ram P Ghosh
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Matteo Bianchi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Filippo Piatti
- 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Francesca R Pluchinotta
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.,Multimodality Cardiac Imaging, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.,Department of Pediatric and Adult Congenital Heart Disease, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | | | - Massimo Lombardi
- Multimodality Cardiac Imaging, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Alberto Redaelli
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA.
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Liu J, Yang W, Dong M, Marsden AL. The nested block preconditioning technique for the incompressible Navier-Stokes equations with emphasis on hemodynamic simulations. Comput Methods Appl Mech Eng 2020; 367:113122. [PMID: 32675836 PMCID: PMC7365595 DOI: 10.1016/j.cma.2020.113122] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We develop a novel iterative solution method for the incompressible Navier-Stokes equations with boundary conditions coupled with reduced models. The iterative algorithm is designed based on the variational multiscale formulation and the generalized-α scheme. The spatiotemporal discretization leads to a block structure of the resulting consistent tangent matrix in the Newton-Raphson procedure. As a generalization of the conventional block preconditioners, a three-level nested block preconditioner is introduced to attain a better representation of the Schur complement, which plays a key role in the overall algorithm robustness and efficiency. This approach provides a flexible, algorithmic way to handle the Schur complement for problems involving multiscale and multiphysics coupling. The solution method is implemented and benchmarked against experimental data from the nozzle challenge problem issued by the US Food and Drug Administration. The robustness, efficiency, and parallel scalability of the proposed technique are then examined in several settings, including moderately high Reynolds number flows and physiological flows with strong resistance effect due to coupled downstream vasculature models. Two patient-specific hemodynamic simulations, covering systemic and pulmonary flows, are performed to further corroborate the efficacy of the proposed methodology.
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Affiliation(s)
- Ju Liu
- Department of Pediatrics (Cardiology), Department of Bioengineering, and Institute for Computational and Mathematical Engineering, Stanford University, Clark Center E1.3, 318 Campus Drive, Stanford, CA 94305, USA
| | - Weiguang Yang
- Department of Pediatrics (Cardiology), Department of Bioengineering, and Institute for Computational and Mathematical Engineering, Stanford University, Clark Center E1.3, 318 Campus Drive, Stanford, CA 94305, USA
| | - Melody Dong
- Department of Pediatrics (Cardiology), Department of Bioengineering, and Institute for Computational and Mathematical Engineering, Stanford University, Clark Center E1.3, 318 Campus Drive, Stanford, CA 94305, USA
| | - Alison L Marsden
- Department of Pediatrics (Cardiology), Department of Bioengineering, and Institute for Computational and Mathematical Engineering, Stanford University, Clark Center E1.3, 318 Campus Drive, Stanford, CA 94305, USA
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Ba D, Zhu Z, Yue X, Xu P, Yan P, Xiao D. Computational Fluid Dynamics Analysis of Carotid-Ophthalmic Aneurysms with Concomitant Ophthalmic Artery Infundibulum in a Patient-Specific Model. World Neurosurg 2019; 125:e1023-e1033. [PMID: 30771545 DOI: 10.1016/j.wneu.2019.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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: 12/17/2018] [Revised: 02/01/2019] [Accepted: 02/02/2019] [Indexed: 11/25/2022]
Abstract
BACKGROUND Although previous studies have reported cases of coexistence of carotid-ophthalmic aneurysm and ophthalmic artery (OA) infundibulum, the hemodynamic characteristics of this complicated structure and its damaging effects on vision remain to be elucidated. The aim of the present study was to analyze this artery structure using computational fluid dynamics (CFD) techniques. METHODS We have presented the case of a patient with a diagnosis of carotid-ophthalmic aneurysm, who had been experiencing blurred vision. A transient analysis was performed to investigate the blood flowing in the parent artery. Hemodynamic parameters such as streamline, wall shear stress (WSS), oscillatory shear index (OSI), and relative residence time were obtained. RESULTS When the inlet velocity of the parent artery was at the second peak, the flow rate and intensity of the vortex reached their maximum. In the aneurysm neck, a region of high time-averaged WSS (TAWSS) and a region of low TAWSS with a high OSI coexisted. In addition, a relaxation area was found. In the aneurysm dome, the minimum TAWSS was 2.5 Pa, the maximum OSI was 0.48, and the 2 regions did not overlap. In the OA infundibulum, the maximum OSI and relative residence time were 0.47 and 39.2, respectively; the minimum TAWSS was 0.59 Pa. CONCLUSIONS We detected aneurysm regions that were susceptible to further expansion and assessed the rupture risk of each region. The relaxation area could promote aneurysm progression. In addition, the location of the vortex shear force center varied with time. Finally, double vortex streamlines influenced the blood supply through the OA, impairing the vision. Infundibulum might promote thrombus formation and, hence, retard OA blood flow.
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Affiliation(s)
- Dechun Ba
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
| | - Zhipeng Zhu
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
| | - Xiangji Yue
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
| | - Ping Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Pengfei Yan
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Dongdong Xiao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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Derycke L, Perrin D, Cochennec F, Albertini JN, Avril S. Predictive Numerical Simulations of Double Branch Stent-Graft Deployment in an Aortic Arch Aneurysm. Ann Biomed Eng 2019; 47:1051-62. [PMID: 30706308 DOI: 10.1007/s10439-019-02215-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/18/2019] [Indexed: 01/04/2023]
Abstract
Total endovascular repair of the aortic arch represents a promising option for patients ineligible to open surgery. Custom-made design of stent-grafts (SG), such as the Terumo Aortic® RelayBranch device (DB), requires complex preoperative measures. Accurate SG deployment is required to avoid intraoperative or postoperative complications, which is extremely challenging in the aortic arch. In that context, our aim is to develop a computational tool able to predict SG deployment in such highly complex situations. A patient-specific case is performed with complete deployment of the DB and its bridging stents in an aneurysmal aortic arch. Deviations of our simulation predictions from actual stent positions are estimated based on post-operative scan and a sensitivity analysis is performed to assess the effects of material parameters. Results show a very good agreement between simulations and post-operative scan, with especially a torsion effect, which is successfully reproduced by our simulation. Relative diameter, transverse and longitudinal deviations are of 3.2 ± 4.0%, 2.6 ± 2.9 mm and 5.2 ± 3.5 mm respectively. Our numerical simulations show their ability to successfully predict the DB deployment in complex anatomy. The results emphasize the potential of computational simulations to assist practitioners in planning and performing complex and secure interventions.
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22
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Lee KE, Kim KT, Lee JH, Jung S, Kim JH, Shim EB. Computational analysis of the electromechanical performance of mitral valve cerclage annuloplasty using a patient-specific ventricular model. Korean J Physiol Pharmacol 2019; 23:63-70. [PMID: 30627011 PMCID: PMC6315091 DOI: 10.4196/kjpp.2019.23.1.63] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/15/2018] [Accepted: 10/18/2018] [Indexed: 01/19/2023]
Abstract
We aimed to propose a novel computational approach to predict the electromechanical performance of pre- and post-mitral valve cerclage annuloplasty (MVCA). Furthermore, we tested a virtual estimation method to optimize the left ventricular basement tightening scheme using a pre-MVCA computer model. The present model combines the three-dimensional (3D) electromechanics of the ventricles with the vascular hemodynamics implemented in a lumped parameter model. 3D models of pre- and post-MVCA were reconstructed from the computed tomography (CT) images of two patients and simulated by solving the electromechanical-governing equations with the finite element method. Computed results indicate that reduction of the dilated heart chambers volume (reverse remodeling) appears to be dependent on ventricular stress distribution. Reduced ventricular stresses in the basement after MVCA treatment were observed in the patients who showed reverse remodeling of heart during follow up over 6 months. In the case who failed to show reverse remodeling after MVCA, more virtual tightening of the ventricular basement diameter than the actual model can induce stress unloading, aiding in heart recovery. The simulation result that virtual tightening of the ventricular basement resulted in a marked increase of myocardial stress unloading provides in silico evidence for a functional impact of MVCA treatment on cardiac mechanics and post-operative heart recovery. This technique contributes to establishing a pre-operative virtual rehearsal procedure before MVCA treatment by using patient-specific cardiac electromechanical modeling of pre-MVCA.
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Affiliation(s)
- Kyung Eun Lee
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon 24340, Korea
| | - Ki Tae Kim
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon 24340, Korea
| | - Jong Ho Lee
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon 24340, Korea
| | - Sujin Jung
- Department of Cardiology, College of Medicine, Pusan National University, Busan 46241, Korea
| | - June-Hong Kim
- Department of Cardiology, College of Medicine, Pusan National University, Busan 46241, Korea
| | - Eun Bo Shim
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon 24340, Korea
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Lu YH, Mani K, Panigrahi B, Hajari S, Chen CY. A Shape Memory Alloy-Based Miniaturized Actuator for Catheter Interventions. Cardiovasc Eng Technol 2018; 9:405-13. [PMID: 29947016 DOI: 10.1007/s13239-018-0369-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 06/12/2018] [Indexed: 10/28/2022]
Abstract
In the current scenario of endovascular intervention, surgeons have to manually navigate the catheter within the complex vasculature of the human body under the guidance of X-ray. This manual intervention upsurges the possibilities of vessel damage due to frequent contact between the catheter and vasculature wall. In this context, a shape memory alloy-based miniaturized actuator was proposed in this study with a specific aim to reduce vessel wall related damage by improving the bending motions of the guidewire tip in a semi-automatic fashion. The miniaturized actuator was integrated with a FDA-approved guidewire and tested within a patient-specific vascular network model to realize its feasibility in the real surgical environment. The results illustrate that the miniaturized actuator gives a bending angle over 23° and lateral displacement over 900 µm to the guide wire tip by which the guidewire can be navigated with precision and possible vessel damage during the catheter intervention can certainly be minimized. In addition to it, the dynamic responses of the presented actuator were further investigated through numerical simulation in conjunction with the analytic analysis.
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Lee T, Turin SY, Gosain AK, Tepole AB. Multi-view stereo in the operating room allows prediction of healing complications in a patient-specific model of reconstructive surgery. J Biomech 2018; 74:202-206. [PMID: 29716722 DOI: 10.1016/j.jbiomech.2018.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 12/14/2017] [Revised: 03/26/2018] [Accepted: 04/01/2018] [Indexed: 11/27/2022]
Abstract
Excessive mechanical stress leads to wound healing complications following reconstructive surgery. However, this knowledge is not easily applicable in clinical scenarios due to the difficulty in measuring stress contours during complex tissue rearrangement procedures. Computational tools have been proposed as an alternative to address this need, but obtaining patient specific geometries with an affordable and flexible setup has remained a challenge. Here we present a methodology to determine the stress contours from a reconstructive procedure on a patient-specific finite element model based on multi-view stereo (MVS). MVS is a noninvasive technology that allows reconstruction of 3D geometries using a standard digital camera, making it ideal for the operating room. Finite element analysis can then be used on the patient-specific geometry to perform a virtual surgery and predict regions at risk of complications. We applied our approach to the case of a 7-year-old patient who was treated to correct a cranial contour deformity and resect two large areas of scalp scarring. The simulation showed several zones of high stress, particularly near the suture lines at the distal ends of the flaps. The patient did show delayed healing and partial flap tip necrosis at one of such predicted regions at the 30-day follow up visit. Our results further establish the application of computational tools in individualized medical scenarios to advance preoperative planing and anticipate regions of concern immediately after surgery.
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Affiliation(s)
- Taeksang Lee
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Sergey Y Turin
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Arun K Gosain
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Adrian Buganza Tepole
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
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25
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Ilunga-Mbuyamba E, Avina-Cervantes JG, Lindner D, Arlt F, Ituna-Yudonago JF, Chalopin C. Patient-specific model-based segmentation of brain tumors in 3D intraoperative ultrasound images. Int J Comput Assist Radiol Surg 2018; 13:331-342. [PMID: 29330658 DOI: 10.1007/s11548-018-1703-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 01/04/2018] [Indexed: 11/27/2022]
Abstract
PURPOSE Intraoperative ultrasound (iUS) imaging is commonly used to support brain tumor operation. The tumor segmentation in the iUS images is a difficult task and still under improvement because of the low signal-to-noise ratio. The success of automatic methods is also limited due to the high noise sensibility. Therefore, an alternative brain tumor segmentation method in 3D-iUS data using a tumor model obtained from magnetic resonance (MR) data for local MR-iUS registration is presented in this paper. The aim is to enhance the visualization of the brain tumor contours in iUS. METHODS A multistep approach is proposed. First, a region of interest (ROI) based on the specific patient tumor model is defined. Second, hyperechogenic structures, mainly tumor tissues, are extracted from the ROI of both modalities by using automatic thresholding techniques. Third, the registration is performed over the extracted binary sub-volumes using a similarity measure based on gradient values, and rigid and affine transformations. Finally, the tumor model is aligned with the 3D-iUS data, and its contours are represented. RESULTS Experiments were successfully conducted on a dataset of 33 patients. The method was evaluated by comparing the tumor segmentation with expert manual delineations using two binary metrics: contour mean distance and Dice index. The proposed segmentation method using local and binary registration was compared with two grayscale-based approaches. The outcomes showed that our approach reached better results in terms of computational time and accuracy than the comparative methods. CONCLUSION The proposed approach requires limited interaction and reduced computation time, making it relevant for intraoperative use. Experimental results and evaluations were performed offline. The developed tool could be useful for brain tumor resection supporting neurosurgeons to improve tumor border visualization in the iUS volumes.
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Affiliation(s)
- Elisee Ilunga-Mbuyamba
- CA Telematics, Engineering Division, Campus Irapuato-Salamanca, University of Guanajuato, Carr. Salamanca-Valle de Santiago km 3.5 + 1.8, Comunidad de Palo Blanco, 36885, Salamanca, Mexico
- Innovation Center Computer Assisted Surgery (ICCAS), University of Leipzig, 04103, Leipzig, Germany
| | - Juan Gabriel Avina-Cervantes
- CA Telematics, Engineering Division, Campus Irapuato-Salamanca, University of Guanajuato, Carr. Salamanca-Valle de Santiago km 3.5 + 1.8, Comunidad de Palo Blanco, 36885, Salamanca, Mexico.
| | - Dirk Lindner
- Department of Neurosurgery, University Hospital Leipzig, 04103, Leipzig, Germany
| | - Felix Arlt
- Department of Neurosurgery, University Hospital Leipzig, 04103, Leipzig, Germany
| | - Jean Fulbert Ituna-Yudonago
- CA Telematics, Engineering Division, Campus Irapuato-Salamanca, University of Guanajuato, Carr. Salamanca-Valle de Santiago km 3.5 + 1.8, Comunidad de Palo Blanco, 36885, Salamanca, Mexico
| | - Claire Chalopin
- Innovation Center Computer Assisted Surgery (ICCAS), University of Leipzig, 04103, Leipzig, Germany
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Huang C, Zhou Y, Mao X, Tong J, Zhang L, Chen F, Hao Y. Fusion of optical coherence tomography and angiography for numerical simulation of hemodynamics in bioresorbable stented coronary artery based on patient-specific model. Comput Assist Surg (Abingdon) 2017; 22:127-134. [PMID: 29032714 DOI: 10.1080/24699322.2017.1389390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Three-dimensional simulations of coronary artery using finite element analysis are considered as effective means to understand the biomechanical properties after the stent was deployed. Bioresorbable vascular scaffolds are new-generation stents used by people. Intravascular optical coherence tomography is an emerging technique for detecting struts. The common 3 D reconstruction methods are using Intravascular Ultrasound (IVUS) or angiographies. However, it loses the details about geometry model. Fusing of optical coherence tomography and angiography to reconstruct the bioresorbable stented coronary artery based on patient-specific mode is an innovative method to reconstruct the high fidelity geometry. This study aimed to use computer-aided design models and computational fluid dynamics research tools to conduct a systematic investigation of blood flow in an isolated artery with realistically deployed coronary stents. Some important hemodynamic factors such as wall shear stress, wall pressure and streamline were calculated. The doctors could evaluate the local hemodynamic alterations within coronary arteries after stent deployment by reconstructing the high-fidelity geometry about each clinical case.
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Affiliation(s)
- Chenxi Huang
- a Department of Computer Science and Technology , Tongji University , Shanghai , PR China
| | - Yuanhang Zhou
- b College of Bioengineering , Chongqing University , Chongqing , PR China
| | - Xiaoxin Mao
- a Department of Computer Science and Technology , Tongji University , Shanghai , PR China
| | - Jianhua Tong
- c Department of Medical Image , Shanghai East Hospital of Tongji University , Shanghai , PR China
| | - Lei Zhang
- c Department of Medical Image , Shanghai East Hospital of Tongji University , Shanghai , PR China
| | - Fei Chen
- d Department of Cardiology , Shanghai Tongji Hospital of Tongji University , Shanghai , PR China
| | - Yongtao Hao
- a Department of Computer Science and Technology , Tongji University , Shanghai , PR China
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Rezaie H, Ashrafizadeh A, Mojra A. A Patient-Specific Three-Dimensional Hemodynamic Model of the Circle of Willis. Cardiovasc Eng Technol 2017; 8:495-504. [PMID: 28913763 DOI: 10.1007/s13239-017-0330-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 09/04/2017] [Indexed: 10/18/2022]
Abstract
Circle of Willis (CoW) is one of the most important cerebral arteries in the human body and various attempts have been made to study the hemodynamic of blood flow in this vital part of the brain. In the present study, blood flow in a patient specific CoW is numerically modeled to predict disease-prone regions of the CoW. Medical images and computer aided design software are used to construct a realistic three-dimensional model of the CoW for this particular case. The arteries are considered as elastic conduits and the interactions between arterial walls and the blood flow are taken into account. Mooney-Rivlin hyperelastic model is used to describe the behavior of arterial walls and blood is considered as a non-Newtonian fluid obeying the Carreau model. An available experimental-based pulsatile velocity profile is used at the entrance of the CoW. The finite element-based commercial software, ADINA, is used to solve the governing equations. Blood pressure and velocity and arterial wall shear stress are calculated in different regions of the CoW. A simplified form of the model is also compared with the available published data. Results affirmed that the proposed computational model has the potential to capture the hemodynamic characteristics of the CoW. The computational results can be used to determine disease-prone locations for a given CoW.
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28
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Murakami T. In reply: Patient-specific simulation: a new avenue to be explored. Gen Thorac Cardiovasc Surg 2017; 65:609. [PMID: 28825179 DOI: 10.1007/s11748-017-0814-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 08/10/2017] [Indexed: 12/01/2022]
Affiliation(s)
- Takashi Murakami
- Department of Cardiovascular Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachim, Abenoku, Osaka, 545-8585, Japan.
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Sánchez C, D'Ambrosio G, Maffessanti F, Caiani EG, Prinzen FW, Krause R, Auricchio A, Potse M. Sensitivity analysis of ventricular activation and electrocardiogram in tailored models of heart-failure patients. Med Biol Eng Comput 2017; 56:491-504. [PMID: 28823052 DOI: 10.1007/s11517-017-1696-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 07/20/2017] [Indexed: 01/13/2023]
Abstract
Cardiac resynchronization therapy is not effective in a variable proportion of heart failure patients. An accurate knowledge of each patient's electroanatomical features could be helpful to determine the most appropriate treatment. The goal of this study was to analyze and quantify the sensitivity of left ventricular (LV) activation and the electrocardiogram (ECG) to changes in 39 parameters used to tune realistic anatomical-electrophysiological models of the heart. Electrical activity in the ventricles was simulated using a reaction-diffusion equation. To simulate cellular electrophysiology, the Ten Tusscher-Panfilov 2006 model was used. Intracardiac electrograms and 12-lead ECGs were computed by solving the bidomain equation. Parameters showing the highest sensitivity values were similar in the six patients studied. QRS complex and LV activation times were modulated by the sodium current, the cell surface-to-volume ratio in the LV, and tissue conductivities. The T-wave was modulated by the calcium and rectifier-potassium currents, and the cell surface-to-volume ratio in both ventricles. We conclude that homogeneous changes in ionic currents entail similar effects in all ECG leads, whereas the effects of changes in tissue properties show larger inter-lead variability. The effects of parameter variations are highly consistent between patients and most of the model tuning could be performed with only ~10 parameters.
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Affiliation(s)
- C Sánchez
- Center for Computational Medicine in Cardiology (CCMC), Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland.
- General Military Academy of Zaragoza (AGM), Defense University Centre (CUD), Zaragoza, Spain.
- Present address: Biosignal Interpretation and Computational Simulation Group (BSICoS), Engineering Research Institute of Aragon (I3A), University of Zaragoza, Zaragoza, Spain.
| | - G D'Ambrosio
- Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland
| | - F Maffessanti
- Center for Computational Medicine in Cardiology (CCMC), Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland
| | - E G Caiani
- Electronics, Information, and Bioengineering Department, Politecnico di Milano, Milan, Italy
| | - F W Prinzen
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - R Krause
- Center for Computational Medicine in Cardiology (CCMC), Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland
| | - A Auricchio
- Center for Computational Medicine in Cardiology (CCMC), Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland
- Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland
| | - M Potse
- Center for Computational Medicine in Cardiology (CCMC), Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland
- IHU LIRYC, Université de Bordeaux, Pessac, France
- Inria Bordeaux Sud-Ouest, Talence, France
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30
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Guo X, Zhu J, Maehara A, Monoly D, Samady H, Wang L, Billiar KL, Zheng J, Yang C, Mintz GS, Giddens DP, Tang D. Quantify patient-specific coronary material property and its impact on stress/strain calculations using in vivo IVUS data and 3D FSI models: a pilot study. Biomech Model Mechanobiol 2016; 16:333-344. [PMID: 27561649 DOI: 10.1007/s10237-016-0820-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [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: 06/04/2016] [Accepted: 08/17/2016] [Indexed: 01/09/2023]
Abstract
Computational models have been used to calculate plaque stress and strain for plaque progression and rupture investigations. An intravascular ultrasound (IVUS)-based modeling approach is proposed to quantify in vivo vessel material properties for more accurate stress/strain calculations. In vivo Cine IVUS and VH-IVUS coronary plaque data were acquired from one patient with informed consent obtained. Cine IVUS data and 3D thin-slice models with axial stretch were used to determine patient-specific vessel material properties. Twenty full 3D fluid-structure interaction models with ex vivo and in vivo material properties and various axial and circumferential shrink combinations were constructed to investigate the material stiffness impact on stress/strain calculations. The approximate circumferential Young's modulus over stretch ratio interval [1.0, 1.1] for an ex vivo human plaque sample and two slices (S6 and S18) from our IVUS data were 1631, 641, and 346 kPa, respectively. Average lumen stress/strain values from models using ex vivo, S6 and S18 materials with 5 % axial shrink and proper circumferential shrink were 72.76, 81.37, 101.84 kPa and 0.0668, 0.1046, and 0.1489, respectively. The average cap strain values from S18 material models were 150-180 % higher than those from the ex vivo material models. The corresponding percentages for the average cap stress values were 50-75 %. Dropping axial and circumferential shrink consideration led to stress and strain over-estimations. In vivo vessel material properties may be considerably softer than those from ex vivo data. Material stiffness variations may cause 50-75 % stress and 150-180 % strain variations.
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Affiliation(s)
- Xiaoya Guo
- Department of Mathematics, Southeast University, Nanjing, 210096, China
| | - Jian Zhu
- Department of Cardiology, Zhongda Hospital, Southeast University, Nanjing, 210009, China
| | - Akiko Maehara
- The Cardiovascular Research Foundation, Columbia University, New York, NY, 10022, USA
| | - David Monoly
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30307, USA
| | - Habib Samady
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30307, USA
| | - Liang Wang
- Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Kristen L Billiar
- Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Jie Zheng
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO, 63110, USA
| | - Chun Yang
- Network Technology Research Institute, China United Network Communications Co., Ltd., Beijing, China
| | - Gary S Mintz
- The Cardiovascular Research Foundation, Columbia University, New York, NY, 10022, USA
| | - Don P Giddens
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30307, USA.,The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Dalin Tang
- Department of Mathematics, Southeast University, Nanjing, 210096, China. .,Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA, 01609, USA.
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Wittek A, Grosland NM, Joldes GR, Magnotta V, Miller K. From Finite Element Meshes to Clouds of Points: A Review of Methods for Generation of Computational Biomechanics Models for Patient-Specific Applications. Ann Biomed Eng 2015; 44:3-15. [PMID: 26424475 DOI: 10.1007/s10439-015-1469-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [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: 05/19/2015] [Accepted: 09/22/2015] [Indexed: 11/24/2022]
Abstract
It has been envisaged that advances in computing and engineering technologies could extend surgeons' ability to plan and carry out surgical interventions more accurately and with less trauma. The progress in this area depends crucially on the ability to create robustly and rapidly patient-specific biomechanical models. We focus on methods for generation of patient-specific computational grids used for solving partial differential equations governing the mechanics of the body organs. We review state-of-the-art in this area and provide suggestions for future research. To provide a complete picture of the field of patient-specific model generation, we also discuss methods for identifying and assigning patient-specific material properties of tissues and boundary conditions.
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Affiliation(s)
- Adam Wittek
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Crawley-Perth, Western Australia, Australia.
| | - Nicole M Grosland
- Department of Biomedical Engineering, The University of Iowa, Iowa City, IA, USA.,Department of Orthopaedics and Rehabilitation, The University of Iowa, Iowa City, IA, USA.,Center for Computer Aided Design, The University of Iowa, Iowa City, IA, USA
| | - Grand Roman Joldes
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Crawley-Perth, Western Australia, Australia
| | - Vincent Magnotta
- Department of Radiology, The University of Iowa, Iowa City, IA, USA
| | - Karol Miller
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Crawley-Perth, Western Australia, Australia.,Institute of Mechanics and Advanced Materials, Cardiff School of Engineering, Cardiff University, Wales, UK
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González-Carbonell RA, Ortiz-Prado A, Jacobo-Armendáriz VH, Cisneros-Hidalgo YA, Alpízar-Aguirre A. 3D patient-specific model of the tibia from CT for orthopedic use. J Orthop 2015; 12:11-6. [PMID: 25829755 DOI: 10.1016/j.jor.2015.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [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: 07/17/2014] [Accepted: 01/04/2015] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES 3D patient-specific model of the tibia is used to determine the torque needed to initialize the tibial torsion correction. METHODS The finite elements method is used in the biomechanical modeling of tibia. The geometric model of the tibia is obtained from CT images. The tibia is modeled as an anisotropic material with non-homogeneous mechanical properties. CONCLUSIONS The maximum stress is located in the shaft of tibia diaphysis. With both meshes are obtained similar results of stresses and displacements. For this patient-specific model, the torque must be greater than 30 Nm to initialize the correction of tibial torsion deformity.
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Affiliation(s)
| | - Armando Ortiz-Prado
- Unidad de Investigación y Asistencia Técnica en Materiales, Universidad Nacional Autónoma de México, Coyoacán 04510, DF, México
| | - Victor H Jacobo-Armendáriz
- Unidad de Investigación y Asistencia Técnica en Materiales, Universidad Nacional Autónoma de México, Coyoacán 04510, DF, México
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33
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Berliner L, Lemke HU, vanSonnenberg E, Ashamalla H, Mattes MD, Dosik D, Hazin H, Shah S, Mohanty S, Verma S, Esposito G, Bargellini I, Battaglia V, Caramella D, Bartolozzi C, Morrison P. Model-guided therapy for hepatocellular carcinoma: a role for information technology in predictive, preventive and personalized medicine. EPMA J 2014; 5:16. [PMID: 25538797 PMCID: PMC4274760 DOI: 10.1186/1878-5085-5-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 08/07/2014] [Indexed: 12/18/2022]
Abstract
Predictive, preventive and personalized medicine (PPPM) may have the potential to eventually improve the nature of health care delivery. However, the tools required for a practical and comprehensive form of PPPM that is capable of handling the vast amounts of medical information that is currently available are currently lacking. This article reviews a rationale and method for combining and integrating diagnostic and therapeutic management with information technology (IT), in a manner that supports patients through their continuum of care. It is imperative that any program devised to explore and develop personalized health care delivery must be firmly rooted in clinically confirmed and accepted principles and technologies. Therefore, a use case, relating to hepatocellular carcinoma (HCC), was developed. The approach to the management of medical information we have taken is based on model theory and seeks to implement a form of model-guided therapy (MGT) that can be used as a decision support system in the treatment of patients with HCC. The IT structures to be utilized in MGT include a therapy imaging and model management system (TIMMS) and a digital patient model (DPM). The system that we propose will utilize patient modeling techniques to generate valid DPMs (which factor in age, physiologic condition, disease and co-morbidities, genetics, biomarkers and responses to previous treatments). We may, then, be able to develop a statistically valid methodology, on an individual basis, to predict certain diseases or conditions, to predict certain treatment outcomes, to prevent certain diseases or complications and to develop treatment regimens that are personalized for that particular patient. An IT system for predictive, preventive and personalized medicine (ITS-PM) for HCC is presented to provide a comprehensive system to provide unified access to general medical and patient-specific information for medical researchers and health care providers from different disciplines including hepatologists, gastroenterologists, medical and surgical oncologists, liver transplant teams, interventional radiologists and radiation oncologists. The article concludes with a review providing an outlook and recommendations for the application of MGT to enhance the medical management of HCC through PPPM.
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Affiliation(s)
- Leonard Berliner
- New York Methodist Hospital, Brooklyn, NY 11215, USA
- Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Heinz U Lemke
- Technical University of Berlin, 10623 Berlin, Germany
- University of Southern California, Los Angeles, CA, 90089, USA
| | - Eric vanSonnenberg
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- University of Arizona College of Medicine, Tucson, AZ, 85724, USA
| | - Hani Ashamalla
- New York Methodist Hospital, Brooklyn, NY 11215, USA
- Weill Medical College of Cornell University, New York, NY 10021, USA
| | | | - David Dosik
- New York Methodist Hospital, Brooklyn, NY 11215, USA
- Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Hesham Hazin
- New York Methodist Hospital, Brooklyn, NY 11215, USA
| | - Syed Shah
- New York Methodist Hospital, Brooklyn, NY 11215, USA
- Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Smruti Mohanty
- New York Methodist Hospital, Brooklyn, NY 11215, USA
- Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Sid Verma
- New York Methodist Hospital, Brooklyn, NY 11215, USA
| | | | - Irene Bargellini
- University Hospital Pisa, University of Pisa (I), 56126 Pisa, Italy
| | | | - Davide Caramella
- University Hospital Pisa, University of Pisa (I), 56126 Pisa, Italy
| | - Carlo Bartolozzi
- University Hospital Pisa, University of Pisa (I), 56126 Pisa, Italy
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Kwon SS, Chung EC, Park JS, Kim GT, Kim JW, Kim KH, Shin ES, Shim EB. A novel patient-specific model to compute coronary fractional flow reserve. Prog Biophys Mol Biol 2014; 116:48-55. [PMID: 25256102 DOI: 10.1016/j.pbiomolbio.2014.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 09/04/2014] [Accepted: 09/07/2014] [Indexed: 10/24/2022]
Abstract
The fractional flow reserve (FFR) is a widely used clinical index to evaluate the functional severity of coronary stenosis. A computer simulation method based on patients' computed tomography (CT) data is a plausible non-invasive approach for computing the FFR. This method can provide a detailed solution for the stenosed coronary hemodynamics by coupling computational fluid dynamics (CFD) with the lumped parameter model (LPM) of the cardiovascular system. In this work, we have implemented a simple computational method to compute the FFR. As this method uses only coronary arteries for the CFD model and includes only the LPM of the coronary vascular system, it provides simpler boundary conditions for the coronary geometry and is computationally more efficient than existing approaches. To test the efficacy of this method, we simulated a three-dimensional straight vessel using CFD coupled with the LPM. The computed results were compared with those of the LPM. To validate this method in terms of clinically realistic geometry, a patient-specific model of stenosed coronary arteries was constructed from CT images, and the computed FFR was compared with clinically measured results. We evaluated the effect of a model aorta on the computed FFR and compared this with a model without the aorta. Computationally, the model without the aorta was more efficient than that with the aorta, reducing the CPU time required for computing a cardiac cycle to 43.4%.
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Affiliation(s)
- Soon-Sung Kwon
- Department of Mechanical and Biomedical Engineering, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon 200-701, Republic of Korea
| | - Eui-Chul Chung
- Department of Mechanical and Biomedical Engineering, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon 200-701, Republic of Korea
| | - Jin-Seo Park
- Department of Mechanical and Biomedical Engineering, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon 200-701, Republic of Korea
| | - Gook-Tae Kim
- Department of Mechanical and Biomedical Engineering, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon 200-701, Republic of Korea
| | - Jun-Woo Kim
- Department of Mechanical and Biomedical Engineering, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon 200-701, Republic of Korea
| | - Keun-Hong Kim
- Department of Mechanical and Biomedical Engineering, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon 200-701, Republic of Korea
| | - Eun-Seok Shin
- Division of Cardiology, Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Republic of Korea
| | - Eun Bo Shim
- Department of Mechanical and Biomedical Engineering, Kangwon National University, 192-1, Hyoja 2-dong, Chuncheon, Kangwon 200-701, Republic of Korea.
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Villongco CT, Krummen DE, Stark P, Omens JH, McCulloch AD. Patient-specific modeling of ventricular activation pattern using surface ECG-derived vectorcardiogram in bundle branch block. Prog Biophys Mol Biol 2014; 115:305-13. [PMID: 25110279 DOI: 10.1016/j.pbiomolbio.2014.06.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 06/27/2014] [Indexed: 10/24/2022]
Abstract
Patient-specific computational models have promise to improve cardiac disease diagnosis and therapy planning. Here a new method is described to simulate left-bundle branch block (LBBB) and RV-paced ventricular activation patterns in three dimensions from non-invasive, routine clinical measurements. Activation patterns were estimated in three patients using vectorcardiograms (VCG) derived from standard 12-lead electrocardiograms (ECG). Parameters of a monodomain model of biventricular electrophysiology were optimized to minimize differences between the measured and computed VCG. Electroanatomic maps of local activation times measured on the LV and RV endocardial surfaces of the same patients were used to validate the simulated activation patterns. For all patients, the optimal estimated model parameters predicted a time-averaged mean activation dipole orientation within 6.7 ± 0.6° of the derived VCG. The predicted local activation times agreed within 11.5 ± 0.8 ms of the measured electroanatomic maps, on the order of the measurement accuracy.
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Affiliation(s)
| | - David E Krummen
- Department of Medicine (Cardiology), University of California, San Diego, CA 92093, USA; US Department of Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
| | - Paul Stark
- Department of Radiology, University of California, San Diego, CA 92093, USA; US Department of Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
| | - Jeffrey H Omens
- Department of Bioengineering, University of California, La Jolla, CA 92093, USA; Department of Medicine (Cardiology), University of California, San Diego, CA 92093, USA
| | - Andrew D McCulloch
- Department of Bioengineering, University of California, La Jolla, CA 92093, USA; Department of Medicine (Cardiology), University of California, San Diego, CA 92093, USA.
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Lemke HU, Golubnitschaja O. Towards personal health care with model-guided medicine: long-term PPPM-related strategies and realisation opportunities within 'Horizon 2020'. EPMA J 2014; 5:8. [PMID: 24883142 PMCID: PMC4038822 DOI: 10.1186/1878-5085-5-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 05/07/2014] [Indexed: 01/02/2023]
Abstract
At the international EPMA Summit carried out in the EU Parliament (September 2013), the main challenges in Predictive, Preventive and Personalised Medicine have been discussed and strategies outlined in order to implement scientific and technological innovation in medicine and healthcare utilising new strategic programmes such as ‘Horizon 2020’. The joint EPMA (European Association for Predictive, Preventive and Personalised Medicine) / IFCARS (International Foundation for Computer Assisted Radiology and Surgery) paper emphasises the consolidate position of the leading experts who are aware of the great responsibility of being on a forefront of predictive, preventive and personalised medicine. Both societies consider long-term international partnerships and multidisciplinary projects to create PPPM relevant innovation in science, technological tools and practical implementation in healthcare. Personalisation in healthcare urgently needs innovation in design of PPPM-related medical services, new products, research, education, didactic materials, propagation of targeted prevention in the society and treatments tailored to the person. For the paradigm shift from delayed reactive to predictive, preventive and personalised medicine, a new culture should be created in communication between individual professional domains, between doctor and patient, as well as in communication with individual social (sub)groups and patient cohorts. This is a long-term mission in personalised healthcare with the whole spectrum of instruments available and to be created in the field.
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Affiliation(s)
- Heinz U Lemke
- International Foundation for Computer Assisted Radiology and Surgery, 79790 Küssaberg, Germany
| | - Olga Golubnitschaja
- European Association for Predictive, Preventive and Personalised Medicine, 1150 Brussels, Belgium ; Radiological Clinic, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany
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van den Munckhof S, Zadpoor AA. How accurately can we predict the fracture load of the proximal femur using finite element models? Clin Biomech (Bristol, Avon) 2014; 29:373-80. [PMID: 24485865 DOI: 10.1016/j.clinbiomech.2013.12.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 12/30/2013] [Accepted: 12/31/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Current clinical methods for fracture prediction rely on two-dimensional imaging methods such as dual-energy X-ray absorptiometry and have limited predictive value. Several researchers have tried to integrate three-dimensional imaging techniques with the finite element (FE) method to improve the accuracy of fracture predictions. Before FE models could be used in clinical settings, a thorough validation of their accuracy is required. In this paper, we try to evaluate the current state of accuracy of subject-specific FE models that are used for prediction of the fracture load of proximal femora. METHODS All the studies that have used FE for prediction of fracture load and have compared the predicted fracture load with experimentally measured fracture loads in vitro are identified through a systematic search of the literature. A quantitative analysis of the results of those studies has been carried out to determine the absolute prediction error, percentage error, and linear correlations between predicted and measured fracture loads. FINDINGS The reported coefficients of determination (R(2)) vary between 0.773 and 0.96 while the percentage error in prediction of fracture load varies between 5 and 46% with most studies reporting percentage errors between 10 and 20%. INTERPRETATION We conclude that FE models, which are currently used only experimentally, are in general more accurate than clinically used fracture risk assessment techniques. However, the accuracy of FE models depends on the details of their modeling methodologies. Therefore, modeling procedures need to be optimized and standardized before FE could be used in clinical settings.
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