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Gheysen L, Maes L, Caenen A, Segers P, Peirlinck M, Famaey N. Uncertainty quantification of the wall thickness and stiffness in an idealized dissected aorta. J Mech Behav Biomed Mater 2024; 151:106370. [PMID: 38224645 DOI: 10.1016/j.jmbbm.2024.106370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 12/21/2023] [Accepted: 01/01/2024] [Indexed: 01/17/2024]
Abstract
Personalized treatment informed by computational models has the potential to markedly improve the outcome for patients with a type B aortic dissection. However, existing computational models of dissected walls significantly simplify the characteristic false lumen, tears and/or material behavior. Moreover, the patient-specific wall thickness and stiffness cannot be accurately captured non-invasively in clinical practice, which inevitably leads to assumptions in these wall models. It is important to evaluate the impact of the corresponding uncertainty on the predicted wall deformations and stress, which are both key outcome indicators for treatment optimization. Therefore, a physiology-inspired finite element framework was proposed to model the wall deformation and stress of a type B aortic dissection at diastolic and systolic pressure. Based on this framework, 300 finite element analyses, sampled with a Latin hypercube, were performed to assess the global uncertainty, introduced by 4 uncertain wall thickness and stiffness input parameters, on 4 displacement and stress output parameters. The specific impact of each input parameter was estimated using Gaussian process regression, as surrogate model of the finite element framework, and a δ moment-independent analysis. The global uncertainty analysis indicated minor differences between the uncertainty at diastolic and systolic pressure. For all output parameters, the 4th quartile contained the major fraction of the uncertainty. The parameter-specific uncertainty analysis elucidated that the material stiffness and relative thickness of the dissected membrane were the respective main determinants of the wall deformation and stress. The uncertainty analysis provides insight into the effect of uncertain wall thickness and stiffness parameters on the predicted deformation and stress. Moreover, it emphasizes the need for probabilistic rather than deterministic predictions for clinical decision making in aortic dissections.
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Affiliation(s)
- Lise Gheysen
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium.
| | - Lauranne Maes
- Biomechanics Section, Mechanical Engineering, KU Leuven, Belgium
| | - Annette Caenen
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium; Cardiovascular Imaging and Dynamics, Department of Cardiovascular Sciences, KU Leuven, Belgium
| | - Patrick Segers
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium
| | - Mathias Peirlinck
- Department of BioMechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, the Netherlands
| | - Nele Famaey
- Biomechanics Section, Mechanical Engineering, KU Leuven, Belgium
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Zhang X, Peng Y, Li G, Li J, Luo M, Che Y, Zheng L, Anzai H, Ohta M, Shu C. Elongation of the proximal descending thoracic aorta and associated hemodynamics increase the risk of acute type B aortic dissection. Technol Health Care 2024; 32:765-777. [PMID: 37545271 DOI: 10.3233/thc-230194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
BACKGROUND Acute type B aortic dissection (ATBAD) is a life-threatening aortic disease. However, little information is available on predicting and understanding of ATBAD. OBJECTIVE The study sought to explore the underlying mechanism of ATBAD by analyzing the morphological and hemodynamic characteristics related to aortic length. METHODS The length and tortuosity of the segment and the whole aorta in the ATBAD group (n= 163) and control group (n= 120) were measured. A fixed anatomic landmark from the distal of left subclavian artery (LSA) to the superior border of sixth thoracic vertebra was proposed as the proximal descending thoracic aorta (PDTA), and the dimensionless parameter, length ratio, was introduced to eliminate the individual differences. The significant morphological parameters were filtrated and the associations between parameters were investigated using statistical approaches. Furthermore, how aortic morphology influenced ATBAD was explored based on idealized aortic models and hemodynamic-related metrics. RESULTS The PDTA length was significantly increased in the ATBAD group compared with the control group and had a strong positive correlation with the whole aortic length (r= 0.89). The length ratio (LR2) and tortuosity (T2) of PDTA in the ATBAD group were significantly increased (0.15 ± 0.02 vs 0.12 ± 0.02 and 1.73 ± 0.48 vs 1.50 ± 0.36; P< 0.001), and LR2 was positive correlation with T2 (r= 0.73). In receiver-operating curve analysis, the area under the curve was 0.835 for LR2 and 0.641 for T2. Low and oscillatory shear (LOS) was positive correlation with LR2, and the elevated LOS occurred in the distal of LSA. CONCLUSION Elongation of PDTA is associated with ATBAD, and the length ratio is a novel predictor. Elongated PDTA induced more aggressive hemodynamic forces, and high LOS regions may correspond to the entry tear location. The synergy of the morphological variation and aggressive hemodynamics creates contributory conditions for ATBAD.
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Affiliation(s)
- Xuelan Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| | - Yuan Peng
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Gaoyang Li
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Jiehua Li
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mingyao Luo
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
| | - Yue Che
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
| | - Liancun Zheng
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, China
| | - Hitomi Anzai
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Makoto Ohta
- Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Chang Shu
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, China
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Zhang X, Mao B, Che Y, Kang J, Luo M, Qiao A, Liu Y, Anzai H, Ohta M, Guo Y, Li G. Physics-informed neural networks (PINNs) for 4D hemodynamics prediction: An investigation of optimal framework based on vascular morphology. Comput Biol Med 2023; 164:107287. [PMID: 37536096 DOI: 10.1016/j.compbiomed.2023.107287] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/06/2023] [Accepted: 07/28/2023] [Indexed: 08/05/2023]
Abstract
Hemodynamic parameters are of great significance in the clinical diagnosis and treatment of cardiovascular diseases. However, noninvasive, real-time and accurate acquisition of hemodynamics remains a challenge for current invasive detection and simulation algorithms. Here, we integrate computational fluid dynamics with our customized analysis framework based on a multi-attribute point cloud dataset and physics-informed neural networks (PINNs)-aided deep learning modules. This combination is implemented by our workflow that generates flow field datasets within two types of patient personalized models - aorta with fine coronary branches and abdominal aorta. Deep learning modules with or without an antecedent hierarchical structure model the flow field development and complete the mapping from spatial and temporal dimensions to 4D hemodynamics. 88,000 cases on 4 randomized partitions in 16 controlled trials reveal the hemodynamic landscape of spatio-temporal anisotropy within two types of personalized models, which demonstrates the effectiveness of PINN in predicting the space-time behavior of flow fields and gives the optimal deep learning framework for different blood vessels in terms of balancing the training cost and accuracy dimensions. The proposed framework shows intentional performance in computational cost, accuracy and visualization compared to currently prevalent methods, and has the potential for generalization to model flow fields and corresponding clinical metrics within vessels at different locations. We expect our framework to push the 4D hemodynamic predictions to the real-time level, and in statistically significant fashion, applicable to morphologically variable vessels.
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Affiliation(s)
- Xuelan Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, China
| | - Baoyan Mao
- Beijing University of Chinese Medicine, Beijing 100029, China
| | - Yue Che
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, China
| | - Jiaheng Kang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, China
| | - Mingyao Luo
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, 100037, China; Department of Vascular Surgery, Fuwai Yunnan Cardiovascular Hospital, Affiliated Cardiovascular Hospital of Kunming Medical University, Kunming, 650102, China
| | - Aike Qiao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Youjun Liu
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Hitomi Anzai
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Makoto Ohta
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Yuting Guo
- Department of Mechanical Engineering and Science, Kyoto University, Kyoto, 615-8540, Japan
| | - Gaoyang Li
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.
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Chen H, Yan S, Xie M, Huang J. Application of cascaded GAN based on CT scan in the diagnosis of aortic dissection. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 226:107130. [PMID: 36202023 DOI: 10.1016/j.cmpb.2022.107130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 08/13/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
PURPOSE Currently, Computed Tomography Angiography (CTA) is the most commonly used clinical method for the diagnosis of aortic dissection, which is much better than plain CT. However, CTA examination has some disadvantages such as time-consuming image processing, complicated procedure and injection of developer. CT plain scanning is widely used in the early diagnosis of arterial dissection because of its convenience, speed and popularity. In order not to delay the optimal diagnosis and treatment time of patients, we use deep learning technology and network model to synthesize plain CT images into CTA images. Patients can be timely professional related departments of clinical diagnosis and treatment, and reduce the rate of missed diagnosis. In this paper, we propose a CTA image synthesis technique for cardiac aortic dissection based on the cascaded generative adjunctive network model. METHOD Firstly, we registered CT images, and then used nnU-Net segmentation network model to obtain CT and CTA paired images containing only the aorta. Then we proposed a CTA image synthesis method for aortic dissection based on cascaded generative adversarial. The core idea is to build a cascade generator and double discriminator network based on DCT channel attention mechanism to further enhance the synthesis effect of CTA. RESULTS The model is trained and tested on CT plain scan and CTA image data set of aortic dissection. The results show that the proposed model achieves good results in CTA image synthesis. In the CT data set, the nnU-Net model improves 8.63% and reduces 10.87mm errors in the key index DSC and HD, respectively, compared with the benchmark model U-Net. In CTA data set, nnU-Net model improves 10.27% and reduces 6.56mm error in key index DSC and HD, respectively, compared with benchmark model U-Net. In the synthesis task, the cascaded generative adm network is superior to Pix2pix and Pix2pixHD network models in both PSNR and SSIM, which proves that our proposed model has significant advantages. CONCLUSION This study provides new possibilities for CTA image synthesis of aortic dissection, and improves the accuracy and efficiency of diagnosis, and hopes to provide substantial help for the diagnosis of aortic dissection.
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Affiliation(s)
- Hongwei Chen
- Department of Cardiac Surgery, Quanzhou First Hospital Affiliated to Fujian Medical University Quanzhou, Fujian, 362000, China.
| | - Sunang Yan
- Department of Cardiac Surgery, Quanzhou First Hospital Affiliated to Fujian Medical University Quanzhou, Fujian, 362000, China
| | - Mingxing Xie
- Department of Cardiac Surgery, Quanzhou First Hospital Affiliated to Fujian Medical University Quanzhou, Fujian, 362000, China
| | - Jianlong Huang
- Faculty of Mathematics and Computer Science, Quanzhou Normal University, Quanzhou, 362000, China; Fujian Provincial Key Laboratory of Data Intensive Computing, Quanzhou 362000, China; Key Laboratory of Intelligent Computing and Information Processing, Fujian Province University, Quanzhou 362000, China.
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Liu D, Wang X, Zhao D, Sun Z, Biekan J, Wen Z, Xu L, Liu J. Influence of MRI-based boundary conditions on type B aortic dissection simulations in false lumen with or without abdominal aorta involvement. Front Physiol 2022; 13:977275. [PMID: 36160847 PMCID: PMC9490059 DOI: 10.3389/fphys.2022.977275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Most computational hemodynamic studies of aortic dissections rely on idealized or general boundary conditions. However, numerical simulations that ignore the characteristics of the abdominal branch arteries may not be conducive to accurately observing the hemodynamic changes below the branch arteries. In the present study, two men (M-I and M-II) with type B aortic dissection (TBAD) underwent arterial-phase computed tomography angiography and four-dimensional flow magnetic resonance imaging (MRI) before and after thoracic endovascular aortic repair (TEVAR). The finite element method was used to simulate the computational fluid dynamic parameters of TBAD [false lumen (FL) with or without visceral artery involvement] under MRI-specific and three idealized boundary conditions in one cardiac cycle. Compared to the results of zero pressure and outflow boundary conditions, the simulations with MRI boundary conditions were closer to the initial MRI data. The pressure difference between true lumen and FL after TEVAR under the other three boundary conditions was lower than that of the MRI-specific results. The results of the outflow boundary conditions could not characterize the effect of the increased wall pressure near the left renal artery caused by the impact of Tear-1, which raised concerns about the distal organ and limb perfused by FL. After TEVAR, the flow velocity and wall pressure in the FL and the distribution areas of high time average wall shear stress and oscillating shear index were reduced. The difference between the calculation results for different boundary conditions was lower in M-II, wherein FL did not involve the abdominal aorta branches than in M-I. The boundary conditions of the abdominal branch arteries from MRI data might be valuable in elucidating the hemodynamic changes of the descending aorta in TBAD patients before and after treatment, especially those with FL involving the branch arteries.
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Affiliation(s)
- Dongting Liu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xuan Wang
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Dongliang Zhao
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Zhonghua Sun
- Discipline of Medical Radiation Science, Curtin Medical School, Curtin University, Perth, WA, Australia
- *Correspondence: Jiayi Liu, ; Zhonghua Sun,
| | | | - Zhaoying Wen
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Lei Xu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Jiayi Liu
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
- *Correspondence: Jiayi Liu, ; Zhonghua Sun,
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An integrated fluid-structure interaction and thrombosis model for type B aortic dissection. Biomech Model Mechanobiol 2022; 21:261-275. [PMID: 35079931 PMCID: PMC8807468 DOI: 10.1007/s10237-021-01534-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 10/11/2021] [Indexed: 11/29/2022]
Abstract
False lumen thrombosis (FLT) in type B aortic dissection has been associated with the progression of dissection and treatment outcome. Existing computational models mostly assume rigid wall behavior which ignores the effect of flap motion on flow and thrombus formation within the FL. In this study, we have combined a fully coupled fluid–structure interaction (FSI) approach with a shear-driven thrombosis model described by a series of convection–diffusion reaction equations. The integrated FSI-thrombosis model has been applied to an idealized dissection geometry to investigate the interaction between vessel wall motion and growing thrombus. Our simulation results show that wall compliance and flap motion can influence the progression of FLT. The main difference between the rigid and FSI models is the continuous development of vortices near the tears caused by drastic flap motion up to 4.45 mm. Flap-induced high shear stress and shear rates around tears help to transport activated platelets further to the neighboring region, thus speeding up thrombus formation during the accelerated phase in the FSI models. Reducing flap mobility by increasing the Young’s modulus of the flap slows down the thrombus growth. Compared to the rigid model, the predicted thrombus volume is 25% larger using the FSI-thrombosis model with a relatively mobile flap. Furthermore, our FSI-thrombosis model can capture the gradual effect of thrombus growth on the flow field, leading to flow obstruction in the FL, increased blood viscosity and reduced flap motion. This model is a step closer toward simulating realistic thrombus growth in aortic dissection, by taking into account the effect of intimal flap and vessel wall motion.
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Peng Y, Zhang X, Li J, Zhang X, He H, Li X, Fang K, Zheng L, Shu C. Enlarged Lumen Volume of Proximal Aortic Segment and Acute Type B Aortic Dissection: A Computer Fluid Dynamics Study of Ideal Aortic Models. Int J Gen Med 2022; 15:535-543. [PMID: 35046712 PMCID: PMC8763263 DOI: 10.2147/ijgm.s343403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/01/2021] [Indexed: 11/23/2022] Open
Abstract
Background Recent study has revealed that enlarged diameters of the ascending aorta and proximal aortic arch enhance the probability of ATBAD. However, little is understood about the relation to ATBAD. Objective This study explored the differences in proximal aortic segment (PAS) morphology in patients with acute type B aortic dissection (ATBAD), and performed hemodynamic simulations to provide proof of principle. Materials and Methods The morphological characteristics of PAS in the ATBAD group (n = 163) and corresponding segment in the control group (n = 120) were retrospectively measured. The morphological parameters were analyzed using comprehensive statistical approaches. Ridge regression analysis was also performed to determine the association between independent variable and dependent variable. P < 0.01 was considered significant. Idealized aortic models were established based on variables of statistical significance, and hemodynamic simulations were performed to evaluate blood flow changes caused by morphology. Results Diameters at landmarks of PAS were significantly larger in the ATBAD group. The lumen volume (VPAS) of PAS in the ATBAD group was significantly enlarged than that of the control group (124,659.07 ± 34,089.27 mm3 vs 89,796.65 ± 30,334.40 mm3; P < 0.001). Furthermore, the VPAS was positively correlated to diameters. As the VPAS increased, the fluid kinetic energy in PAS enhanced linearly, and time-averaged wall shear stress and oscillatory shear index at the distal area of the left subclavian artery increased significantly. Conclusion In the ATBAD group, the enlarged VPAS and increased diameters of PAS are positively correlated. Meanwhile, the enlarged VPAS leads to more aggressive hemodynamic parameters at the distal area of the left subclavian artery, which may create a contributory condition for ATBAD.
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Affiliation(s)
- Yuan Peng
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Xuelan Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, People’s Republic of China
| | - Jiehua Li
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Xiaolong Zhang
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Hao He
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Xin Li
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
| | - Kun Fang
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, 100037, People’s Republic of China
| | - Liancun Zheng
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, People’s Republic of China
| | - Chang Shu
- Department of Vascular Surgery, Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China
- Department of Vascular Surgery, Fuwai Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, 100037, People’s Republic of China
- Correspondence: Chang Shu Tel +86-731-85295832 Email
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Wang Y, Luo K, Qiao Y, Fan J. An integrated fluid-chemical model toward modeling the thrombus formation in an idealized model of aortic dissection. Comput Biol Med 2021; 136:104709. [PMID: 34365279 DOI: 10.1016/j.compbiomed.2021.104709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/05/2021] [Accepted: 07/23/2021] [Indexed: 10/20/2022]
Abstract
Type B aortic dissection is a major aortic catastrophe that can be acutely complicated by rapid expansion, rupture, and malperfusion syndromes. The separation of the intima from aortic walls will form a second blood-filled lumen defined as "false lumen (FL)", where the thrombus is more likely to form due to the local stasis hemodynamic conditions. Complete thrombosis of FL is associated with a beneficial outcome while patency and partial thrombosis will lead to later complications. However, the thrombosis mechanism is still unclear and little is known about the impact of chemical species transported by blood flow on this process. The proteins involved in the coagulation cascade (CC) may play an important role in the process of thrombosis, especially in the activation and stabilization of platelets. Based on this hypothesis, a reduced-order fluid-chemical model was established to simulate CC in an aortic dissection phantom with two tears. A high level of fibrin is continuously observed at the top of the FL and some time-varying areas between two tears, indicating a high likelihood of thrombus formation there. This finding is consistent with the clinical observation. The time evolution of coagulation factors is greatly affected by local hemodynamics, especially in the high disturbance zone where the evolution has characteristics of periodic changes consistent with the flow field. The ability of the proposed model to reproduce the CC response provides a potential application to integrate with a model that can simulate platelet activities, forming a biochemical-based model which would help unveil the mechanisms of thrombosis in FL and the clinical decision of appropriate treatment.
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Affiliation(s)
- Yan Wang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Kun Luo
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
| | - Yonghui Qiao
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Jianren Fan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
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The role of the aortic area in type A aortic dissection. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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A computational fluid study on hemodynamics in visceral arteries in a complicated type B aortic dissection after thoracic endovascular repair. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2020.100054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Li Z, Liang S, Xu H, Zhu M, Mei Y, Xiong J, Chen D. Flow analysis of aortic dissection: comparison of inflow boundary conditions for computational models based on 4D PCMRI and Doppler ultrasound. Comput Methods Biomech Biomed Engin 2021; 24:1251-1262. [PMID: 33522843 DOI: 10.1080/10255842.2021.1876036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Computational hemodynamics quantifying the flow environment is an important tool in understanding aortic dissection. In this study, various inflow boundaries were applied on a patient-specific model and compared to the individualized velocimetry. The results indicated that the computations generally overestimated the flow volume and underestimated the wall shear stress. By quantifying the accuracy of the simulation results, two inflow settings were suggested. One was individualized, the PCMRI-extracted 4D flow information, and the other was averaged by healthy data, the ultrasound-extracted averaged flow waveform with parabolic velocity profile. This study might contribute to improving the precise computation of aortic dissection hemodynamics.
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Affiliation(s)
- Zhenfeng Li
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Shichao Liang
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Huanming Xu
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Minjia Zhu
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Yuqian Mei
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Duanduan Chen
- School of Life Science, Beijing Institute of Technology, Beijing, China
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Nishida K, Yokoi Y, Yamada A, Takaya N, Yamagiwa K, Kawada S, Mori K, Manabe S, Kanda E, Fujioka T, Kishino M, Tateishi U. Optimal phase analysis of electrocardiogram-gated computed tomography angiography in patients with Stanford type A acute aortic dissection. Eur J Radiol Open 2020; 7:100289. [PMID: 33318968 PMCID: PMC7726336 DOI: 10.1016/j.ejro.2020.100289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 10/27/2022] Open
Abstract
Objective To determine the phase that facilitates flap observation of the ascending aorta in Stanford type A acute aortic dissection with perfused false lumen. Methods We reconstructed retrospective Electrocardiogram-gated Computed Tomography Angiography images of the ascending aorta of all 20 patients to 20 phases of curved-multiplanar reconstruction in 5% increment. One radiologist created and randomized 10 cross-sectional images of each phase for every patient and two radiologists scored these images on a 5-point scale depending on the degree of flap stoppage. We calculated the average score for each phase of each case and compared them among the three groups. Results Image scores were significantly better in the 65 %-100 % R-R interval group than those in the 5%-30 % (p < 2e-16) and 35 %-60 % R-R interval groups(p = 7.2e-10). Similar scores were observed in the Heart Rate > 70 group (p = 0.00039, 2.2e-14). Moreover a similar tendency was observed in the arrhythmia group (p = 0.0035, 0.294). No difference was found in the degree of flap stoppage in the 65 %-100 % R-R interval group between the Heart Rate > 70 and Heart Rate ≤ 70 groups (p = 0.466) and between the arrhythmia and non-arrhythmia groups (p = 0.1240). Conclusion In observing the ascending aorta, We obtained a good image at 65 %-100 % R-R interval and similar tendency was observed in the patients with arrhythmia.
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Key Words
- AAD, acute aortic dissection
- AC, atrial contraction phase
- AEC, automatic exposure control
- AR, Aortic Regurgitation
- Aorta thoracic
- CTA, computed tomography angiography
- Computed tomography angiography
- D, diastolic phase
- DLP, dose-length-product
- Dissecting
- E, effective dose
- ECG, electrocardiogram
- Electrocardiography
- HR, heart rate
- IVR, isovolumetric relaxation phase
- MPR, multiplanar reconstruction
- RF, rapid filling phase
- RR, R-R interval
- Radiation dose
- S, systolic phase
- SF, slow filling phase
- bpm, beats per minute
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Affiliation(s)
- Kenji Nishida
- Department of Diagnostic Radiology, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan.,Department of Diagnostic Radiology and Nuclear Medicine, Graduate School of Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Yuki Yokoi
- Department of Diagnostic Radiology, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan
| | - Ayumi Yamada
- Department of Diagnostic Radiology, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan
| | - Nobuhiro Takaya
- Department of Diagnostic Radiology, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan
| | - Ken Yamagiwa
- Department of Diagnostic Radiology, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan
| | - Shuichi Kawada
- Department of Diagnostic Radiology, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan
| | - Koichi Mori
- Department of Diagnostic Radiology, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan
| | - Susumu Manabe
- Department of Cardiovascular Surgery, Tsuchiura Kyodo General Hospital, 4-1-1 Otsuno, Tsuchiura, Ibaraki, Japan
| | - Eiichiro Kanda
- Department of Nephrology, Kawasaki Medical School Hospital, 577 Matsushima, Kurashiki, Okayama, Japan
| | - Tomoyuki Fujioka
- Department of Diagnostic Radiology and Nuclear Medicine, Graduate School of Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Mitsuhiro Kishino
- Department of Diagnostic Radiology and Nuclear Medicine, Graduate School of Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
| | - Ukihide Tateishi
- Department of Diagnostic Radiology and Nuclear Medicine, Graduate School of Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-0034, Japan
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13
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Chong MY, Gu B, Chan BT, Ong ZC, Xu XY, Lim E. Effect of intimal flap motion on flow in acute type B aortic dissection by using fluid-structure interaction. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3399. [PMID: 32862487 DOI: 10.1002/cnm.3399] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/18/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
A monolithic, fully coupled fluid-structure interaction (FSI) computational framework was developed to account for dissection flap motion in acute type B aortic dissection (TBAD). Analysis of results included wall deformation, pressure, flow, wall shear stress (WSS), von Mises stress and comparison of hemodynamics between rigid wall and FSI models. Our FSI model mimicked realistic wall deformation that resulted in maximum compression of the distal true lumen (TL) by 21.4%. The substantial movement of intimal flap mostly affected flow conditions in the false lumen (FL). Flap motion facilitated more flow entering the FL at peak systole, with the TL to FL flow split changing from 88:12 in the rigid model to 83:17 in the FSI model. There was more disturbed flow in the FL during systole (5.8% FSI vs 5.2% rigid) and diastole (13.5% FSI vs 9.8% rigid), via a λ2 -criterion. The flap-induced disturbed flow near the tears in the FSI model caused an increase of local WSS by up to 70.0% during diastole. This resulted in a significant reduction in the size of low time-averaged WSS (TAWSS) regions in the FL (113.11 cm2 FSI vs 177.44 cm2 rigid). Moreover, the FSI model predicted lower systolic pressure, higher diastolic pressure, and hence lower pulse pressure. Our results provided new insights into the possible impact of flap motion on flow in aortic dissections, which are particularly important when evaluating hemodynamics of acute TBAD. NOVELTY STATEMENT: Our monolithic fully coupled FSI computational framework is able to reproduce experimentally measured range of flap deformation in aortic dissection, thereby providing novel insights into the influence of physiological flap motion on the flow and pressure distributions. The drastic flap movement increases the flow resistance in the true lumen and causes more disturbed flow in the false lumen, as visualized through the λ2 criterion. The flap-induced luminal pressure is dampened, thereby affecting pressure measures, which may serve as potential prognostic indicators for late complications in acute uncomplicated TBAD patients.
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Affiliation(s)
- Mei Yan Chong
- Department of Biomedical Engineering, University of Malaya, Kuala Lumpur, Malaysia
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Boram Gu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Bee Ting Chan
- Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham, UK
| | - Zhi Chao Ong
- Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, Malaysia
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Einly Lim
- Department of Biomedical Engineering, University of Malaya, Kuala Lumpur, Malaysia
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14
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Zhang X, Luo M, Fang K, Li J, Peng Y, Zheng L, Shu C. Analysis of the formation mechanism and occurrence possibility of Post-Stenotic Dilatation of the aorta by CFD approach. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 194:105522. [PMID: 32422474 DOI: 10.1016/j.cmpb.2020.105522] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/24/2020] [Accepted: 04/25/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVE Post-Stenotic Dilatation (PSD), the common complication of coarctation of the aorta (COA), is a progressive disease involving aortic aneurysm and even rupture. However, there has been no definitive method that could investigate the mechanism of PSD formation, progression and rupture. The purpose of the present work is to analyze the mechanism behind PSD formation and to further assess the risk of COA patients with different coarctation degrees deteriorating into PSD. METHOD Three-dimensional non-Newtonian (Carreau-Yasuda) hemodynamic simulations are performed throughout the cardiac cycle, and a novel parameter (λci¯ intensity) is proposed to evaluate the intensity of vortices within the aorta. The PSD geometry is reconstructed from Computed Tomography scans. To analyze the formation mechanism and occurrence possibility of PSD, the computer technology is utilized to restore the expansive and/or narrow regions to obtain its previous state (COA) and control group (Normal), and to modify the minimum diameter to obtain the aortas with different coarctation degrees. The clinical cases of pre- and post-operation are further introduced to verify the analysis. RESULTS Compared with the Normal, the vortical structures with higher swirling strength are generated and accumulated at the downstream of the coarctation segment after COA occurrence, and partially disappear in the wake of PSD formation. The sequence of λci¯ intensity is COA > PSD > Normal and pre-operation > post-operation. With increasing the degree of coarctation, the λci¯ intensity is higher and the jet-flow becomes more drastic. CONCLUSIONS The formation of PSD is caused by the vortical structures with higher swirling strength accumulating at the downstream of the coarctation segment. An increase in coarctation degree elevates the risk of PSD occurrence and even aneurysmal dilatation.
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Affiliation(s)
- Xuelan Zhang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 10083, China; School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Mingyao Luo
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Kun Fang
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China
| | - Jiehua Li
- Department of Vascular Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Yuan Peng
- Department of Vascular Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Liancun Zheng
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China.
| | - Chang Shu
- Department of Vascular Surgery, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
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15
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The effect of the entry and re-entry size in the aortic dissection: a two-way fluid-structure interaction simulation. Biomech Model Mechanobiol 2020; 19:2643-2656. [PMID: 32621161 DOI: 10.1007/s10237-020-01361-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 06/20/2020] [Indexed: 12/16/2022]
Abstract
Aortic dissection (AD) is one of the most catastrophic cardiovascular diseases. AD occurs when a layer inside the aorta is disrupted and gives rise to the formation of a true lumen and a false lumen. These lumens can be connected through tears in the intimal flap which are known as entries. Despite being known for about two centuries, the effects of many factors on the morbidity and mortality of this disease are still unknown. As the blood interaction with the aorta is crucial in the severity and the progression of the aortic dissection, a biomechanical approach is chosen to investigate the influence of different morphologies on the severity of this disease. Using the finite element method (FEM) and the fluid-structure interaction (FSI) approach, we have evaluated the blood flow characteristics along the diseased aorta, in conjunction with the deformation of the aortic wall. In this study, an idealized geometry of a dissected descending aorta (type B) with two entries has been studied. The values for the diameter of the entry tear were chosen to be 5 mm and 10 mm. Therefore, a total of four conditions were investigated. According to our results, the retrograde flow through the proximal tear is dependent on the size of the distal re-entry and vice versa. Our results revealed that when both entry and re-entry tears are 10 mm in diameter, the flow passes through the true and false lumens with smaller resistance, resulting in a smaller flutter of the intimal flap, and therefore more stable intimal flap. Major oscillation frequencies of 2.5 Hz and 7.4 Hz were observed for the oscillation of the intimal flap, and amplitudes of the waves with higher frequencies were negligible.
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16
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Matsushita A, Tabata M, Mihara W, Shimamoto T, Komiya T, Takanashi S, Tobaru T, Nakao T, Nakamura S, Sato Y. Risk score system for late aortic events in patients with uncomplicated type B aortic dissection. J Thorac Cardiovasc Surg 2020; 159:2173-2183.e1. [DOI: 10.1016/j.jtcvs.2019.06.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 06/06/2019] [Accepted: 06/14/2019] [Indexed: 01/16/2023]
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17
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Xu H, Xiong J, Han X, Mei Y, Shi Y, Wang D, Zhang M, Chen D. Computed tomography-based hemodynamic index for aortic dissection. J Thorac Cardiovasc Surg 2020; 162:e165-e176. [PMID: 32217023 DOI: 10.1016/j.jtcvs.2020.02.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 10/25/2022]
Abstract
OBJECTIVE In this study we aimed to propose a new computed tomography-based hemodynamic indicator to quantify the functional significance of aortic dissection and predict post intervention luminal remodeling. METHODS Computational hemodynamics and 3D structural analyses were conducted in 51 patients with type B aortic dissection, at initial presentation and at approximately 1 month, 3 months, and 1 year post intervention. A functional index was proposed on the basis of luminal pressure difference. Statistical relationships between the proposed indicator and longitudinal luminal development were analyzed. RESULTS The computed luminal pressure difference (true lumen pressure minus false lumen pressure) varied overall from positive to negative along the aorta. The first balance position at which the pressure difference equals 0 was proposed as the functional indicator. A more distally located first balance position indicated better functional status. Implantation of stent graft distally shifted this balance position. Patients with the balance position shifted out of the dissected region (43%) presented the highest functional improvement after intervention; whereas those with the balance position shifted to the abdominal region (25%) showed unsatisfactory results. The magnitude of distal shifting of the first balance position at 3 months post intervention was statistically related to the subsequent true lumen expansion and false lumen reduction. CONCLUSIONS The first balance position of luminal pressure difference quantified the hemodynamic status of the dissected aorta. The magnitude of distal shifting of the balance position after intervention was associated with functional improvement and might be used predict longitudinal aortic remodeling.
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Affiliation(s)
- Huanming Xu
- Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Xiaofeng Han
- Department of Diagnostic and Interventional Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Yuqian Mei
- Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Yue Shi
- Department of Engineering and Technology, Meiyin (Beijing) Medical Device Development Ltd, Beijing, China
| | - Dianpeng Wang
- Department of Probability and Statistics, School of Mathematics and Statistics, Beijing Institute of Technology, Beijing, China
| | - Mingchen Zhang
- Department of Mathematics, University of California Santa Barbara, Santa Barbara, Calif
| | - Duanduan Chen
- Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Beijing, China.
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18
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Bäumler K, Vedula V, Sailer AM, Seo J, Chiu P, Mistelbauer G, Chan FP, Fischbein MP, Marsden AL, Fleischmann D. Fluid-structure interaction simulations of patient-specific aortic dissection. Biomech Model Mechanobiol 2020; 19:1607-1628. [PMID: 31993829 DOI: 10.1007/s10237-020-01294-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 01/14/2020] [Indexed: 12/01/2022]
Abstract
Credible computational fluid dynamic (CFD) simulations of aortic dissection are challenging, because the defining parallel flow channels-the true and the false lumen-are separated from each other by a more or less mobile dissection membrane, which is made up of a delaminated portion of the elastic aortic wall. We present a comprehensive numerical framework for CFD simulations of aortic dissection, which captures the complex interplay between physiologic deformation, flow, pressures, and time-averaged wall shear stress (TAWSS) in a patient-specific model. Our numerical model includes (1) two-way fluid-structure interaction (FSI) to describe the dynamic deformation of the vessel wall and dissection flap; (2) prestress and (3) external tissue support of the structural domain to avoid unphysiologic dilation of the aortic wall and stretching of the dissection flap; (4) tethering of the aorta by intercostal and lumbar arteries to restrict translatory motion of the aorta; and a (5) independently defined elastic modulus for the dissection flap and the outer vessel wall to account for their different material properties. The patient-specific aortic geometry is derived from computed tomography angiography (CTA). Three-dimensional phase contrast magnetic resonance imaging (4D flow MRI) and the patient's blood pressure are used to inform physiologically realistic, patient-specific boundary conditions. Our simulations closely capture the cyclical deformation of the dissection membrane, with flow simulations in good agreement with 4D flow MRI. We demonstrate that decreasing flap stiffness from [Formula: see text] to [Formula: see text] kPa (a) increases the displacement of the dissection flap from 1.4 to 13.4 mm, (b) decreases the surface area of TAWSS by a factor of 2.3, (c) decreases the mean pressure difference between true lumen and false lumen by a factor of 0.63, and (d) decreases the true lumen flow rate by up to 20% in the abdominal aorta. We conclude that the mobility of the dissection flap substantially influences local hemodynamics and therefore needs to be accounted for in patient-specific simulations of aortic dissection. Further research to accurately measure flap stiffness and its local variations could help advance future CFD applications.
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Affiliation(s)
- Kathrin Bäumler
- 3D and Quantitative Imaging Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA.
| | - Vijay Vedula
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, 94305, USA
| | - Anna M Sailer
- 3D and Quantitative Imaging Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Jongmin Seo
- Department of Pediatrics (Cardiology), Stanford University, Stanford, CA, 94305, USA
| | - Peter Chiu
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, 94305, USA
| | - Gabriel Mistelbauer
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Frandics P Chan
- 3D and Quantitative Imaging Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA
| | - Michael P Fischbein
- Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, 94305, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Dominik Fleischmann
- 3D and Quantitative Imaging Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA
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19
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Zhao S, Gu H, Chen B, Yang S, Cheng Z, Duan Y, Lin Y, Wang X. Dynamic Indicators That Impact the Outcomes of Thoracic Endovascular Aortic Repair in Complicated Type B Aortic Dissection. J Vasc Interv Radiol 2020; 31:760-768.e1. [PMID: 31982315 DOI: 10.1016/j.jvir.2019.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/04/2019] [Accepted: 11/09/2019] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To investigate dynamic variables obtained from retrospective computed tomography angiography for ability to predict thoracic endovascular aortic repair (TEVAR) outcomes in patients with complicated type B aortic dissection (cTBAD). MATERIALS AND METHODS Seventy-nine patients with cTBAD who received TEVAR from March 2009 to June 2018 were retrospectively enrolled. Relative true lumen area (r-TLA) was computed at the level of tracheal bifurcation every 5% of all R-R intervals. Parameters that reflect the state of intimal motion were evaluated, including difference between maximum and minimum r-TLA (D-TLA) and true lumen collapse. The endpoints comprised early (≤ 30 days) and late (> 30 days) outcomes after intervention. RESULTS Overall early mortality rate was 13.9% (11/79), and early adverse events rate was 24.1% (19/79). Patients who received TEVAR within 2 days of symptom onset demonstrated the worst outcomes. A longer time of r-TLA < 25% in 1 cardiac cycle (P = .049) and larger D-TLA (P < .001) were correlated to an increased early death. In addition, D-TLA was an independent predictor of early mortality. Area under the curve of D-TLA was 0.849 (95% confidence interval 0.730-0.967) for predicting early mortality and 0.742 (95% CI 0.611-0.873) for predicting early adverse events. Survival and event-free survival rates during follow-up were decreased in the D-TLA > 21.5% group compared with the D-TLA ≤ 21.5% group (all P < .001). CONCLUSIONS Larger D-TLA is correlated with worse postoperative outcomes and might be a crucial parameter for future risk stratification in patients with cTBAD.
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Affiliation(s)
- Shuo Zhao
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, China
| | - Hui Gu
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, China
| | - Baojin Chen
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, China
| | - Shifeng Yang
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, China
| | - Zhaoping Cheng
- Department of Radiology, Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong 250021, China
| | - Yanhua Duan
- Department of Radiology, Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong 250021, China
| | - Yang Lin
- Siemens Healthcare Diagnostics Shanghai Co Ltd, Shanghai, China
| | - Ximing Wang
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, China.
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20
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Zhao S, Gu H, Chen B, Cheng Z, Yang S, Duan Y, Ghavamian A, Wang X. Dynamic Imaging Features of Retrospective Cardiac Gating CT Angiography Influence Delayed Adverse Events in Acute Uncomplicated Type B Aortic Dissections. Cardiovasc Intervent Radiol 2019; 43:620-629. [PMID: 31848671 DOI: 10.1007/s00270-019-02395-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 12/10/2019] [Indexed: 11/29/2022]
Abstract
PURPOSE To investigate the correlation between dynamic morphological parameters of retrospective cardiac gating CT angiography (CTA) and delayed adverse event (DAE) in uncomplicated type B acute aortic dissection (uTB-AAD) patients. MATERIALS AND METHODS Eighty-seven patients initially diagnosed with uTB-AAD were retrospectively reviewed. Dynamic variables obtained by dose-regulated retrospective CTA were recorded, including the minimum relative true lumen diameter (RTLAmin), ratio of the minimum to maximum true lumen relative area (r-RTLA), the maximum diameter of the descending aorta, false lumen, and primary entry tear. Outcome analysis comprised incidences of DAE and early mortality within 3 to 14 days since symptom occurring. RESULTS Twenty-six patients (29.9%) developed DAE, and two of which (7.7%) died before any interventions. Smaller values of RTLAmin (P = 0.01) and r-RTLA at the upper thoracic descending aorta (UTDA) (P < 0.001), and r-RTLA at the renal artery level (P = 0.016) demonstrated higher incidences of DAE; maximum diameter of the descending aorta (P < 0.001), the false lumen (P = 0.008), and entry tear size (P = 0.007) were positively associated with the occurrence of DAE. r-RTLA at the UTDA level yielded the highest diagnostic accuracy (82.0%) in detecting DAE at an optimal cutoff value of 61.7% (AUC = 0.839). Performance of dynamic characteristics was superior to static features obtained from single-phase image in the detection of DAE (P < 0.001). CONCLUSION Dynamic morphological features of retrospective cardiac gating CTA might aid in identifying a high risk of DAE in uTB-AAD patients and guiding early targeted interventions.
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Affiliation(s)
- Shuo Zhao
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, 250021, Shandong, People's Republic of China
| | - Hui Gu
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, 250021, Shandong, People's Republic of China
| | - Baojin Chen
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, 250021, Shandong, People's Republic of China
| | - Zhaoping Cheng
- Department of Radiology, Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong, People's Republic of China
| | - Shifeng Yang
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, 250021, Shandong, People's Republic of China
| | - Yanhua Duan
- Department of Radiology, Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong, People's Republic of China
| | - Armin Ghavamian
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, 250021, Shandong, People's Republic of China
| | - Ximing Wang
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, 250021, Shandong, People's Republic of China.
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Munshi B, Parker LP, Norman PE, Doyle BJ. The application of computational modeling for risk prediction in type B aortic dissection. J Vasc Surg 2019; 71:1789-1801.e3. [PMID: 31831314 DOI: 10.1016/j.jvs.2019.09.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/04/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE New tools are urgently needed to help with surgical decision-making in type B aortic dissection (TBAD) that is uncomplicated at the time of initial presentation. This narrative review aims to answer the clinical question, Can computational modeling be used to predict risk in acute and chronic Stanford TBAD? METHODS The review (PROSPERO 2018 CRD42018104472) focused on risk prediction in TBAD. A comprehensive search of the Ovid MEDLINE database, using terms related to computational modeling and aortic dissection, was conducted to find studies of any form published between 1998 and 2018. Cohort studies, case series, and case reports of adults (older than 18 years) with computed tomography or magnetic resonance imaging diagnosis of TBAD were included. Computational modeling was applied in all selected studies. RESULTS There were 37 studies about computational modeling of TBAD identified from the search, and the findings were synthesized into a narrative review. Computational modeling can produce numerically calculated values of stresses, pressures, and flow velocities that are difficult to measure in vivo. Hemodynamic parameters-high or low wall shear stress, high pressure gradient between lumens during the cardiac cycle, and high false lumen flow rate-have been linked to the pathogenesis of branch malperfusion and aneurysm formation by numerous studies. Considering the major outcomes of end-organ failure, aortic rupture, and stabilization and remodeling, hypotheses have been generated about inter-relationships of measurable parameters in computational models with observable anatomic and pathologic changes, resulting in specific clinical outcomes. CONCLUSIONS There is consistency in study findings about computational modeling in TBAD, although a limited number of patients have been analyzed using various techniques. The mechanistic patterns of association found in this narrative review should be investigated in larger cohort prospective studies to further refine our understanding. It highlights the importance of patient-specific computational hemodynamic parameters in clinical decision-making algorithms. The current challenge is to develop and to test a risk assessment method that can be used by clinicians for TBAD.
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Affiliation(s)
- Bijit Munshi
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; Medical School, The University of Western Australia, Perth, Australia; Department of Vascular Surgery, Fiona Stanley Hospital, Perth, Australia
| | - Louis P Parker
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia
| | - Paul E Norman
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; Medical School, The University of Western Australia, Perth, Australia; Department of Vascular Surgery, Fiona Stanley Hospital, Perth, Australia
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Australia; Centre for Medical Research, The University of Western Australia, Perth, Australia; School of Engineering, The University of Western Australia, Perth, Australia.
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22
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Zhao S, Gu H, Duan Y, Cheng Z, Chen B, Yang S, Wang X. Impact of the Intima Dynamic Motion in Type B Acute Aortic Dissection on Renal Injury: Quantificationally Assessed by Dose-Regulated Retrospective ECG-Gated Dual-Source CT Angiography. Acad Radiol 2019; 26:1320-1327. [PMID: 30658929 DOI: 10.1016/j.acra.2018.12.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 01/04/2023]
Abstract
BACKGROUND Little is known about the influence of intima dynamic motion on organ ischemia and related outcomes. The purpose of this study is to quantitatively evaluate intima oscillation by CT angiography (CTA), determine its impact on acute kidney injury (AKI) in patients with type B acute aortic dissection (TB-AAD) before thoracic endovascular aortic repair (TEVAR), and further analyze its association with early adverse events postoperatively. METHODS Totally, 108 patients with TB-AAD who underwent retrospective ECG-gated CTA and received TEVAR were enrolled. Patients were divided into AKI and non-AKI groups. Area of the true lumen (TLA) was computed at R-R intervals at the upper level of kidney vessel origin every 5% step from 0% to 95%. Additionally, other morphologic parameters that have been identified as risk predictors for adverse events in uncomplicated TB-AAD were evaluated. RESULTS Forty-three (39.8%) patients were sorted into the AKI group. Patients with AKI exhibited a larger value for the relative change of TLA (Crel-TLA) than patients in the non-AKI group (p < 0.001), as well as a larger maximum diameter of the descending aorta (p = 0.023) and the primary entry tear (p = 0.012). Crel-TLA and elevated systolic blood pressure were independent predictors of AKI. Patients with Crel-TLA ≥ 42.6% were associated with a high incidence of renal ischemia before TEVAR and early adverse events postoperatively (all p < 0.001). CONCLUSION Intima dynamic motion, as quantitatively evaluated by CTA, has a significant influence on renal injury before and after the aortic intervention, as well as other adverse events, which might guide clinical therapy in high-risk patients.
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Affiliation(s)
- Shuo Zhao
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, PR China
| | - Hui Gu
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, PR China
| | - Yanhua Duan
- Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, PR China
| | - Zhaoping Cheng
- Shandong Medical Imaging Research Institute, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, Jinan, Shandong, PR China
| | - Baojin Chen
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, PR China
| | - Shifeng Yang
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, PR China
| | - Ximing Wang
- Department of Radiology, Shandong Provincial Hospital, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Disease, Shandong University, #324, Jingwu Road, Jinan, Shandong 250021, PR China.
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High intimal flap mobility assessed by intravascular ultrasound is associated with better short-term results after TEVAR in chronic aortic dissection. Sci Rep 2019; 9:7267. [PMID: 31086282 PMCID: PMC6513991 DOI: 10.1038/s41598-019-43856-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 05/02/2019] [Indexed: 01/16/2023] Open
Abstract
Thoracic endovascular aortic repair (TEVAR) in chronic aortic dissection remains controversial. We analysed whether a high intimal flap mobility (IFM) of the dissection membrane has an impact on aortic remodelling after TEVAR in chronic Type B aortic dissection. Patients undergoing TEVAR with intravascular ultrasound (IVUS) were analysed and IFM was calculated. High IFM was defined as maximum flap amplitude >3 mm. For determining aortic remodelling, the degree of true lumen (TL) expansion was analysed in the last available follow-up CT. Fifty-two patients (63.6 ± 15.4 years) with a mean follow-up of 26.6 ± 20.7 months were analysed. The mobile flap group (n = 29) showed higher absolute TL expansion at the distal stent-graft (5.9 ± 3.1 vs. 3.3 ± 5.4 mm; p = 0.036) and a higher increase in TL diameter (18 ± 10 vs. 9 ± 15%; p = 0.017) compared to the non-mobile group (n = 23). Basic TEVAR-related outcome characteristics were comparable, but the mobile intimal flap group showed a lower re-intervention rate (3 vs. 8pts.; p = 0.032) in chronic dissections. High IFM in chronic Type B aortic dissection is linked to improved aortic remodelling and is associated with a lower re-intervention rate over time. IVUS assessment of IFM in chronic Type B aortic dissection might be helpful in identifying patients with better remodelling after TEVAR.
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24
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Bonfanti M, Balabani S, Greenwood JP, Puppala S, Homer-Vanniasinkam S, Díaz-Zuccarini V. Computational tools for clinical support: a multi-scale compliant model for haemodynamic simulations in an aortic dissection based on multi-modal imaging data. J R Soc Interface 2018; 14:rsif.2017.0632. [PMID: 29118115 PMCID: PMC5721167 DOI: 10.1098/rsif.2017.0632] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/13/2017] [Indexed: 11/12/2022] Open
Abstract
Aortic dissection (AD) is a vascular condition with high morbidity and mortality rates. Computational fluid dynamics (CFD) can provide insight into the progression of AD and aid clinical decisions; however, oversimplified modelling assumptions and high computational cost compromise the accuracy of the information and impede clinical translation. To overcome these limitations, a patient-specific CFD multi-scale approach coupled to Windkessel boundary conditions and accounting for wall compliance was developed and used to study a patient with AD. A new moving boundary algorithm was implemented to capture wall displacement and a rich in vivo clinical dataset was used to tune model parameters and for validation. Comparisons between in silico and in vivo data showed that this approach successfully captures flow and pressure waves for the patient-specific AD and is able to predict the pressure in the false lumen (FL), a critical variable for the clinical management of the condition. Results showed regions of low and oscillatory wall shear stress which, together with higher diastolic pressures predicted in the FL, may indicate risk of expansion. This study, at the interface of engineering and medicine, demonstrates a relatively simple and computationally efficient approach to account for arterial deformation and wave propagation phenomena in a three-dimensional model of AD, representing a step forward in the use of CFD as a potential tool for AD management and clinical support.
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Affiliation(s)
- Mirko Bonfanti
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Stavroula Balabani
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - John P Greenwood
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK.,Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK
| | - Sapna Puppala
- Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK
| | - Shervanthi Homer-Vanniasinkam
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.,Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK.,University of Warwick Medical School & University Hospitals Coventry and Warwickshire NHS Trust, Coventry CV2 2DX, UK
| | - Vanessa Díaz-Zuccarini
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
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25
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Bonfanti M, Balabani S, Alimohammadi M, Agu O, Homer-Vanniasinkam S, Díaz-Zuccarini V. A simplified method to account for wall motion in patient-specific blood flow simulations of aortic dissection: Comparison with fluid-structure interaction. Med Eng Phys 2018; 58:S1350-4533(18)30074-2. [PMID: 29759947 DOI: 10.1016/j.medengphy.2018.04.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 04/16/2018] [Accepted: 04/30/2018] [Indexed: 10/16/2022]
Abstract
Aortic dissection (AD) is a complex and highly patient-specific vascular condition difficult to treat. Computational fluid dynamics (CFD) can aid the medical management of this pathology, yet its modelling and simulation are challenging. One aspect usually disregarded when modelling AD is the motion of the vessel wall, which has been shown to significantly impact simulation results. Fluid-structure interaction (FSI) methods are difficult to implement and are subject to assumptions regarding the mechanical properties of the vessel wall, which cannot be retrieved non-invasively. This paper presents a simplified 'moving-boundary method' (MBM) to account for the motion of the vessel wall in type-B AD CFD simulations, which can be tuned with non-invasive clinical images (e.g. 2D cine-MRI). The method is firstly validated against the 1D solution of flow through an elastic straight tube; it is then applied to a type-B AD case study and the results are compared to a state-of-the-art, full FSI simulation. Results show that the proposed method can capture the main effects due to the wall motion on the flow field: the average relative difference between flow and pressure waves obtained with the FSI and MBM simulations was less than 1.8% and 1.3%, respectively and the wall shear stress indices were found to have a similar distribution. Moreover, compared to FSI, MBM has the advantage to be less computationally expensive (requiring half of the time of an FSI simulation) and easier to implement, which are important requirements for clinical translation.
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Affiliation(s)
- Mirko Bonfanti
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK.
| | - Stavroula Balabani
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK
| | - Mona Alimohammadi
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK
| | | | - Shervanthi Homer-Vanniasinkam
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK; Leeds Teaching Hospitals NHS Trust, LS1 3EX, UK; University of Warwick Medical School & University Hospitals Coventry and Warwickshire NHS Trust, CV4 7AL, UK
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26
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Wan Ab Naim WN, Ganesan PB, Sun Z, Lei J, Jansen S, Hashim SA, Ho TK, Lim E. Flow pattern analysis in type B aortic dissection patients after stent-grafting repair: Comparison between complete and incomplete false lumen thrombosis. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2961. [PMID: 29331052 DOI: 10.1002/cnm.2961] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 12/17/2017] [Accepted: 01/04/2018] [Indexed: 06/07/2023]
Abstract
Endovascular stent graft repair has become a common treatment for complicated Stanford type B aortic dissection to restore true lumen flow and induce false lumen thrombosis. Using computational fluid dynamics, this study reports the differences in flow patterns and wall shear stress distribution in complicated Stanford type B aortic dissection patients after endovascular stent graft repair. Five patients were included in this study: 2 have more than 80% false lumen thrombosis (group 1), while 3 others had less than 80% false lumen thrombosis (group 2) within 1 year following endovascular repair. Group 1 patients had concentrated re-entry tears around the abdominal branches only, while group 2 patients had re-entry tears that spread along the dissection line. Blood flow inside the false lumen which affected thrombus formation increased with the number of re-entry tears and when only small amounts of blood that entered the false lumen exited through the branches. In those cases where dissection extended below the abdominal branches (group 2), patients with fewer re-entry tears and longer distance between the tears had low wall shear stress contributing to thrombosis. This work provides an insight into predicting the development of complete or incomplete false lumen thrombosis and has implications for patient selection for treatment.
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Affiliation(s)
- Wan Naimah Wan Ab Naim
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Poo Balan Ganesan
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, Curtin University, Perth, 6845, Australia
| | - Jing Lei
- Department of Medical Imaging, First Affiliated Hospital of Kunming Medical University, Yunnan, 650032, China
| | - Shirley Jansen
- Department of Vascular and Endovascular Surgery, Sir Charles Gairdner Hospital, Perth, Western Australia, 6009, Australia
- Centre for Population Health Research, Curtin University, Perth, Western Australia, 6845, Australia
- Faculty of Health and Medical Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Shahrul Amry Hashim
- Department of Surgery, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Teik Kok Ho
- KPJ Damansara Specialist Hospital, 47400, Petaling Jaya, Malaysia
| | - Einly Lim
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
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27
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Lu CY, Diao YK, Guo YQ, Zhang XH, Bai HL, Li ZL. Can multiphase dynamic CT angiography provide a better assessment of aortic dissection compared with the standard triphasic protocol? Acta Radiol 2018; 59:58-64. [PMID: 28440669 DOI: 10.1177/0284185117704236] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Background Acute aortic dissection (AD) is a life-threatening medical emergency. It has been debated whether the multiphase dynamic computed tomography angiography (CTA) protocol is superior to the standard triphasic protocol for revealing the characteristics of AD. Purpose To examine two multiphase dynamic protocols, Dynamic four-dimensional (4D) CTA using the shuttle mode and Flash 4D CTA using the high-pitch mode for the assessment of AD and to compare them with the standard triphasic protocol. Material and Methods A total of 54 consecutive patients were randomly and equally assigned to three groups and scanned with a second-generation DSCT scanner. Groups A, B, and C were assessed with the Dynamic 4D CTA in the shuttle mode, the Flash 4D CTA in the high-pitch mode, and the standard triphasic acquisition protocol, respectively. Image quality of all patients was evaluated. The effective radiation dose (ED) was recorded. Results In 54 patients, CTA images could display the true and false lumens, the intimal flap, the entry tear, and branch vessel involvement in the AD. Compared with group C, additional diagnostic information was obtained in groups A and B, including the dynamic enhancement delay between the true and false lumens (A = 18, B = 18); the presence of membrane oscillation (A = 8, B = 14); dynamic ejection of the contrast material from the true lumen into the false lumen (A = 6, B = 7); and the dynamic obstruction of the left renal artery (B = 2). The ED in these three groups was significantly different ( P < 0.05). Conclusion Compared to the standard triphasic protocol, the multiphase dynamic CTA protocol is feasible and is able to reveal additional diagnostic information. Therefore, we recommend using the high-pitch, dual-source multiphase dynamic CTA to assess ADs.
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Affiliation(s)
- Chun-yan Lu
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China
| | - Yi-ke Diao
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China
| | - Ying-qiang Guo
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China
| | - Xiao-hui Zhang
- Department of Healthcare Imaging & Therapy Division, Siemens Ltd. China, Nanhui, Shanghai, PR China
| | - Hong-li Bai
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China
| | - Zhen-lin Li
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China
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Xu H, Li Z, Dong H, Zhang Y, Wei J, Watton PN, Guo W, Chen D, Xiong J. Hemodynamic parameters that may predict false-lumen growth in type-B aortic dissection after endovascular repair: A preliminary study on long-term multiple follow-ups. Med Eng Phys 2017; 50:12-21. [PMID: 28890304 DOI: 10.1016/j.medengphy.2017.08.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 08/03/2017] [Accepted: 08/21/2017] [Indexed: 01/16/2023]
Abstract
Thoracic endovascular aortic repair (TEVAR) is commonly applied in type-B aortic dissection. For patients with dissection affects descending aorta and extends downward to involve abdominal aorta and possibly iliac arteries, false lumen (FL) expansion might occur post-TEVAR. Predictions of dissection development may assist in medical decision on re-intervention or surgery. In this study, two patients are selected with similar morphological features at initial presentation but with different long-term FL development post-TEVAR (stable and enlarged FL). Patient-specific models are established for each of the follow-ups. Flow boundaries and computational validations are obtained from Doppler ultrasound velocimetry. By analyzing the hemodynamic parameters, the false-to-true luminal pressure difference (PDiff) and particle relative residence time (RRT) are found related to FL remodeling. It is found that (i) the position of the first FL flow entry is the watershed of negative-and-positive PDiff and, in long-term follow-ups, and the position of largest PDiff is consistent with that of the greatest increase of FL width; (ii) high RRT occurs at the FL proximal tip and similar magnitude of RRT is found in both stable and enlarged cases; (iii) comparing to the RRT at 7days post-TEVAR, an increase of RRT afterwards in short-term is found in the stable case while a slight decrease of this parameter is found in the enlarged case, indicating that the variation of RRT in short-term post-TEVAR might be potential to predict long-term FL remodeling.
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Affiliation(s)
- Huanming Xu
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China; Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, The Ministry of Industry and Information Technology, Beijing Institute of Technology, China
| | - Zhenfeng Li
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China; Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, The Ministry of Industry and Information Technology, Beijing Institute of Technology, China
| | - Huiwu Dong
- Department of Ultrasound Diagnosis, Chinese PLA General Hospital, China
| | - Yilun Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Jianyong Wei
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Paul N Watton
- Department of Computer Science & INSIGNEO Institute, University of Sheffield, UK; Department of Mechanical Engineering and Material Science, University of Pittsburgh, United States
| | - Wei Guo
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing 100853, China
| | - Duanduan Chen
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, China; Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, The Ministry of Industry and Information Technology, Beijing Institute of Technology, China.
| | - Jiang Xiong
- Department of Vascular and Endovascular Surgery, Chinese PLA General Hospital, Beijing 100853, China.
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29
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Chen H, Peelukhana S, Berwick Z, Kratzberg J, Krieger J, Roeder B, Chambers S, Kassab G. Editor's Choice – Fluid–Structure Interaction Simulations of Aortic Dissection with Bench Validation. Eur J Vasc Endovasc Surg 2016; 52:589-595. [DOI: 10.1016/j.ejvs.2016.07.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 07/02/2016] [Indexed: 10/21/2022]
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30
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Peterss S, Mansour AM, Ross JA, Vaitkeviciute I, Charilaou P, Dumfarth J, Fang H, Ziganshin BA, Rizzo JA, Adeniran AJ, Elefteriades JA. Changing Pathology of the Thoracic Aorta From Acute to Chronic Dissection. J Am Coll Cardiol 2016; 68:1054-65. [DOI: 10.1016/j.jacc.2016.05.091] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/25/2016] [Accepted: 05/24/2016] [Indexed: 01/16/2023]
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31
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Role of Pulse Pressure and Geometry of Primary Entry Tear in Acute Type B Dissection Propagation. Ann Biomed Eng 2016; 45:592-603. [PMID: 27510916 PMCID: PMC5331108 DOI: 10.1007/s10439-016-1705-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/03/2016] [Indexed: 11/06/2022]
Abstract
The hemodynamic and geometric factors leading to propagation of acute Type B dissections are poorly understood. The objective is to elucidate whether geometric and hemodynamic parameters increase the predilection for aortic dissection propagation. A pulse duplicator set-up was used on porcine aorta with a single entry tear. Mean pressures of 100 and 180 mmHg were used, with pulse pressures ranging from 40 to 200 mmHg. The propagation for varying geometric conditions (%circumference of the entry tear: 15–65%, axial length: 0.5–3.2 cm) were tested for two flap thicknesses (1/3rd and 2/3rd of the thickness of vessel wall, respectively). To assess the effect of pulse and mean pressure on flap dynamics, the %true lumen (TL) cross-sectional area of the entry tear were compared. The % circumference for propagation of thin flap (47 ± 1%) was not significantly different (p = 0.14) from thick flap (44 ± 2%). On the contrary, the axial length of propagation for thin flap (2.57 ± 0.15 cm) was significantly different (p < 0.05) from the thick flap (1.56 ± 0.10 cm). TL compression was observed during systolic phase. For a fixed geometry of entry tear (%circumference = 39 ± 2%; axial length = 1.43 ± 0.13 cm), mean pressure did not have significant (p = 0.84) effect on flap movement. Increase in pulse pressure resulted in a significant change (p = 0.02) in %TL area (52 ± 4%). The energy acting on the false lumen immediately before propagation was calculated as 75 ± 9 J/m2 and was fairly uniform across different specimens. Pulse pressure had a significant effect on the flap movement in contrast to mean pressure. Hence, mitigation of pulse pressure and restriction of flap movement may be beneficial in patients with type B acute dissections.
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Alimohammadi M, Sherwood JM, Karimpour M, Agu O, Balabani S, Díaz-Zuccarini V. Aortic dissection simulation models for clinical support: fluid-structure interaction vs. rigid wall models. Biomed Eng Online 2015; 14:34. [PMID: 25881252 PMCID: PMC4407424 DOI: 10.1186/s12938-015-0032-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 04/02/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The management and prognosis of aortic dissection (AD) is often challenging and the use of personalised computational models is being explored as a tool to improve clinical outcome. Including vessel wall motion in such simulations can provide more realistic and potentially accurate results, but requires significant additional computational resources, as well as expertise. With clinical translation as the final aim, trade-offs between complexity, speed and accuracy are inevitable. The present study explores whether modelling wall motion is worth the additional expense in the case of AD, by carrying out fluid-structure interaction (FSI) simulations based on a sample patient case. METHODS Patient-specific anatomical details were extracted from computed tomography images to provide the fluid domain, from which the vessel wall was extrapolated. Two-way fluid-structure interaction simulations were performed, with coupled Windkessel boundary conditions and hyperelastic wall properties. The blood was modelled using the Carreau-Yasuda viscosity model and turbulence was accounted for via a shear stress transport model. A simulation without wall motion (rigid wall) was carried out for comparison purposes. RESULTS The displacement of the vessel wall was comparable to reports from imaging studies in terms of intimal flap motion and contraction of the true lumen. Analysis of the haemodynamics around the proximal and distal false lumen in the FSI model showed complex flow structures caused by the expansion and contraction of the vessel wall. These flow patterns led to significantly different predictions of wall shear stress, particularly its oscillatory component, which were not captured by the rigid wall model. CONCLUSIONS Through comparison with imaging data, the results of the present study indicate that the fluid-structure interaction methodology employed herein is appropriate for simulations of aortic dissection. Regions of high wall shear stress were not significantly altered by the wall motion, however, certain collocated regions of low and oscillatory wall shear stress which may be critical for disease progression were only identified in the FSI simulation. We conclude that, if patient-tailored simulations of aortic dissection are to be used as an interventional planning tool, then the additional complexity, expertise and computational expense required to model wall motion is indeed justified.
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Affiliation(s)
- Mona Alimohammadi
- Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
| | - Joseph M Sherwood
- Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK. .,Bioengineering, Imperial College London, South Kensington Campus, London, SW7 2BP, UK.
| | - Morad Karimpour
- Mechanical Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
| | - Obiekezie Agu
- Vascular Unit, University College Hospital, 235 Euston Road, London, NW1 2BU, UK.
| | - Stavroula Balabani
- Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
| | - Vanessa Díaz-Zuccarini
- Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
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Sherrah AG, Grieve SM, Jeremy RW, Bannon PG, Vallely MP, Puranik R. MRI in Chronic Aortic Dissection: A Systematic Review and Future Directions. Front Cardiovasc Med 2015; 2:5. [PMID: 26664877 PMCID: PMC4671340 DOI: 10.3389/fcvm.2015.00005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 02/05/2015] [Indexed: 01/16/2023] Open
Abstract
The acute event of thoracic aortic dissection carries with it high mortality and morbidity. Despite optimal initial surgical or medical management strategies, the risk of further complications in the long-term, including aneurysmal dilatation and false lumen (FL) expansion, are not insignificant. Adequate follow-up of such conditions requires dedicated imaging where relevant prognostic indicators are accurately assessed. We perform a systematic review of the literature and report the current evidence for the use of magnetic resonance imaging (MRI) in assessment of chronic aortic dissection. We then make a comparison with traditional imaging modalities including computed tomography and echocardiography. We discuss new ways in which MRI may extend existing aortic assessment, including identification of blood-flow dynamics within the TL and FL using phase-contrast imaging.
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Affiliation(s)
- Andrew G. Sherrah
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- The Baird Institute, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Stuart M. Grieve
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- Department of Radiology, Royal Prince Alfred Hospital, Sydney, NSW, Australia
- Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia
- Heart Research Institute, University of Sydney, Sydney, NSW, Australia
| | - Richmond W. Jeremy
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- The Baird Institute, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Paul G. Bannon
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- The Baird Institute, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Michael P. Vallely
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- The Baird Institute, Royal Prince Alfred Hospital, Sydney, NSW, Australia
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
| | - Rajesh Puranik
- Sydney Medical School, University of Sydney, Sydney, NSW, Australia
- Cardiovascular Magnetic Resonance Sydney, Sydney, NSW, Australia
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Sun Z, Al Moudi M, Cao Y. CT angiography in the diagnosis of cardiovascular disease: a transformation in cardiovascular CT practice. Quant Imaging Med Surg 2014; 4:376-96. [PMID: 25392823 DOI: 10.3978/j.issn.2223-4292.2014.10.02] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 09/26/2014] [Indexed: 12/11/2022]
Abstract
Computed tomography (CT) angiography represents the most important technical development in CT imaging and it has challenged invasive angiography in the diagnostic evaluation of cardiovascular abnormalities. Over the last decades, technological evolution in CT imaging has enabled CT angiography to become a first-line imaging modality in the diagnosis of cardiovascular disease. This review provides an overview of the diagnostic applications of CT angiography (CTA) in cardiovascular disease, with a focus on selected clinical challenges in some common cardiovascular abnormalities, which include abdominal aortic aneurysm (AAA), aortic dissection, pulmonary embolism (PE) and coronary artery disease. An evidence-based review is conducted to demonstrate how CT angiography has changed our approach in the diagnosis and management of cardiovascular disease. Radiation dose reduction strategies are also discussed to show how CT angiography can be performed in a low-dose protocol in the current clinical practice.
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Affiliation(s)
- Zhonghua Sun
- 1 Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, Perth, 6102, Western Australia, Australia ; 2 Department of Medical Imaging and Nuclear Medicine, King Saud Medical City, Riyadh, Saudi Arabia ; 3 Department of Medical Imaging, Shandong Medical College, Jinan 276000, China
| | - Mansour Al Moudi
- 1 Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, Perth, 6102, Western Australia, Australia ; 2 Department of Medical Imaging and Nuclear Medicine, King Saud Medical City, Riyadh, Saudi Arabia ; 3 Department of Medical Imaging, Shandong Medical College, Jinan 276000, China
| | - Yan Cao
- 1 Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, Perth, 6102, Western Australia, Australia ; 2 Department of Medical Imaging and Nuclear Medicine, King Saud Medical City, Riyadh, Saudi Arabia ; 3 Department of Medical Imaging, Shandong Medical College, Jinan 276000, China
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Cheng Z, Juli C, Wood NB, Gibbs RGJ, Xu XY. Predicting flow in aortic dissection: comparison of computational model with PC-MRI velocity measurements. Med Eng Phys 2014; 36:1176-84. [PMID: 25070022 DOI: 10.1016/j.medengphy.2014.07.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 06/09/2014] [Accepted: 07/02/2014] [Indexed: 01/12/2023]
Abstract
Aortic dissection is a life-threatening process in which the weakened wall develops a tear, causing separation of wall layers. The dissected layers separate the original true aortic lumen and a newly created false lumen. If untreated, the condition can be fatal. Flow rate in the false lumen is a key feature for false lumen patency, which has been regarded as one of the most important predictors of adverse early and later outcomes. Detailed flow analysis in the dissected aorta may assist vascular surgeons in making treatment decisions, but computational models to simulate flow in aortic dissections often involve several assumptions. The purpose of this study is to assess the computational models adopted in previous studies by comparison with in vivo velocity data obtained by means of phase-contrast magnetic resonance imaging (PC-MRI). Aortic dissection geometry was reconstructed from computed tomography (CT) images, while PC-MRI velocity data were used to define inflow conditions and to provide distal velocity components for comparison with the simulation results. The computational fluid dynamics (CFD) simulation incorporated a laminar-turbulent transition model, which is necessary for adequate flow simulation in aortic conditions. Velocity contours from PC-MRI and CFD in the two lumens at the distal plane were compared at four representative time points in the pulse cycle. The computational model successfully captured the complex regions of flow reversal and recirculation qualitatively, although quantitative differences exist. With a rigid wall assumption and exclusion of arch branches, the CFD model over-predicted the false lumen flow rate by 25% at peak systole. Nevertheless, an overall good agreement was achieved, confirming the physiological relevance and validity of the computational model for type B aortic dissection with a relatively stiff dissection flap.
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Affiliation(s)
- Z Cheng
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - C Juli
- Department of Radiology, St Mary's Hospital, Imperial College Healthcare NHS Trust, London W2 1NY, UK
| | - N B Wood
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - R G J Gibbs
- Imperial Vascular Unit, St Mary's Hospital, Imperial College Healthcare NHS Trust, London W2 1NY, UK
| | - X Y Xu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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Rinaudo A, D’Ancona G, Lee JJ, Pilato G, Amaducci A, Baglini R, Follis F, Pilato M, Pasta S. Predicting Outcome of Aortic Dissection with Patent False Lumen by Computational Flow Analysis. Cardiovasc Eng Technol 2014. [DOI: 10.1007/s13239-014-0182-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Yang S, Li X, Chao B, Wu L, Cheng Z, Duan Y, Wu D, Zhan Y, Chen J, Liu B, Ji X, Nie P, Wang X. Abdominal aortic intimal flap motion characterization in acute aortic dissection: assessed with retrospective ECG-gated thoracoabdominal aorta dual-source CT angiography. PLoS One 2014; 9:e87664. [PMID: 24503676 PMCID: PMC3913653 DOI: 10.1371/journal.pone.0087664] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 12/27/2013] [Indexed: 11/23/2022] Open
Abstract
Objectives To evaluate the feasibility of dose-modulated retrospective ECG-gated thoracoabdominal aorta CT angiography (CTA) assessing abdominal aortic intimal flap motion and investigate the motion characteristics of intimal flap in acute aortic dissection (AAD). Materials and Methods 49 patients who had thoracoabdominal aorta retrospective ECG-gated CTA scan were enrolled. 20 datasets were reconstructed in 5% steps between 0 and 95% of the R-R interval in each case. The aortic intimal flap motion was assessed by measuring the short axis diameters of the true lumen and false lumen 2 cm above of celiac trunk ostium in different R-R intervals. Intimal flap motion and configuration was assessed by two independent observers. Results In these 49 patients, 37 had AAD, 7 had intramural hematoma, and 5 had negative result for acute aortic disorder. 620 datasets of 31 patients who showed double lumens in abdominal aorta were enrolled in evaluating intimal flap motion. The maximum and minimum true lumen diameter were 12.2±4.1 mm (range 2.6∼17.4) and 6.7±4.1 mm (range 0∼15.3) respectively. The range of intimal flap motion in all patients was 5.5±2.6 mm (range 1.8∼10.2). The extent of maximum true lumen diameter decreased during a cardiac cycle was 49.5%±23.5% (range 12%∼100%). The maximum motion phase of true lumen diameter was in systolic phase (5%∼40% of R-R interval). Maximum and minimum intimal flap motion was at 15% and 75% of the R-R interval respectively. Intimal flap configuration had correlation with the phase of cardiac cycle. Conclusions Abdominal intimal flap position and configuration varied greatly during a cardiac cycle. Retrospective ECG-gated thoracoabdominal aorta CTA can reflect the actual status of the true lumen and provide more information about true lumen collapse. This information may be helpful to diagnosis and differential diagnosis of dynamic abstraction.
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Affiliation(s)
- Shifeng Yang
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Xia Li
- Departments of Ultrasound, Shandong Provincial Hospital, Jinan, Shandong, P. R. China
| | - Baoting Chao
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Lebin Wu
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Zhaoping Cheng
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Yanhua Duan
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Dawei Wu
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Yiqiang Zhan
- Unit of Periodontology, University of Greifswald, Greifswald, Germany
| | - Jiuhong Chen
- CT Research Collaboration, Siemens Ltd., China, Beijing, P.R. China
| | - Bo Liu
- Healthcare Sector, Siemens Ltd., China, Shanghai, P.R. China
| | - Xiaopeng Ji
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Pei Nie
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
| | - Ximing Wang
- Shandong Medical Imaging Research Institute, Shandong University, Jinan, Shandong, P.R. China
- * E-mail:
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Alimohammadi M, Agu O, Balabani S, Díaz-Zuccarini V. Development of a patient-specific simulation tool to analyse aortic dissections: assessment of mixed patient-specific flow and pressure boundary conditions. Med Eng Phys 2013; 36:275-84. [PMID: 24290844 DOI: 10.1016/j.medengphy.2013.11.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 10/10/2013] [Accepted: 11/06/2013] [Indexed: 10/26/2022]
Abstract
Aortic dissection has high morbidity and mortality rates and guidelines regarding surgical intervention are not clearly defined. The treatment of aortic dissection varies with each patient and detailed knowledge of haemodynamic and mechanical forces would be advantageous in the process of choosing a course of treatment. In this study, a patient-specific dissected aorta geometry is constructed from computed tomography scans. Dynamic boundary conditions are implemented by coupling a three element Windkessel model to the 3D domain at each outlet, in order to capture the essential behaviour of the downstream vasculature. The Windkessel model parameters are defined based on clinical data. The predicted minimum and maximum pressures are close to those measured invasively. Malperfusion is indicated and complex flow patterns are observed. Pressure, flow and wall shear stress distributions are analysed. The methodology presented here provides insight into the haemodynamics in a patient-specific dissected aorta and represents a development towards the use of CFD simulations as a diagnostic tool for aortic dissection.
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Affiliation(s)
- Mona Alimohammadi
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK
| | | | - Stavroula Balabani
- Department of Mechanical Engineering, University College London, WC1E 7JE, UK
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Schlicht MS, Khanafer K, Duprey A, Cronin P, Berguer R. Experimental foundation for in vivo measurement of the elasticity of the aorta in computed tomography angiography. Eur J Vasc Endovasc Surg 2013; 46:447-52. [PMID: 23932205 DOI: 10.1016/j.ejvs.2013.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 07/11/2013] [Indexed: 11/29/2022]
Abstract
OBJECTIVE This study was performed to determine the feasibility of measuring the elastic properties of the arterial wall in vivo. To prove this concept, elastic parameters were calculated from an aortic model of elastic behavior similar to a human aorta using computed tomography angiography (CTA) images. METHODS We first constructed an aortic model from polydimethylsiloxane (PDMS). This model was inserted into a pulsatile flow loop. The model was then placed inside a computed tomography scanner. To estimate the elasticity values, we measured the cross-sectional area and the pressure changes in the model during each phase of the simulated cardiac cycle. A discrete wavelet transform (DWT) algorithm was applied to the CTA data to calculate the geometric changes in the pulsatile model over a simulated cardiac cycle for various pulsatile rates and elasticity values of the PDMS material. The elastic modulus of the aortic model wall was derived from these geometric changes. The elastic moduli derived from the CTA data were compared with those obtained by testing strips of the same PDMS material in a tensile testing machine. Our two aortic models had elastic values at both extremes of those found in normal human aortas. RESULTS The results show a good comparison between the elastic values derived from the CTA data and those obtained in a tensile testing machine. In addition, the elasticity values were found to be independent of the pulsatile rate for mixing ratios of 6:1 and 9:1 (p = .12 and p = .22, respectively). CONCLUSIONS The elastic modulus of a pulsatile aortic model may be measured by electrocardiographically-gated multi-detector CTA protocol. This preliminary study suggests the possibility of determining non-invasively the elastic properties of a living, functioning aorta using CTA data.
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Affiliation(s)
- M S Schlicht
- Vascular Mechanics Laboratory, Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
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Chen D, Müller-Eschner M, von Tengg-Kobligk H, Barber D, Böckler D, Hose R, Ventikos Y. A patient-specific study of type-B aortic dissection: evaluation of true-false lumen blood exchange. Biomed Eng Online 2013; 12:65. [PMID: 23829346 PMCID: PMC3734007 DOI: 10.1186/1475-925x-12-65] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/01/2013] [Indexed: 01/14/2023] Open
Abstract
Background Aortic dissection is a severe pathological condition in which blood penetrates between layers of the aortic wall and creates a duplicate channel – the false lumen. This considerable change on the aortic morphology alters hemodynamic features dramatically and, in the case of rupture, induces markedly high rates of morbidity and mortality. Methods In this study, we establish a patient-specific computational model and simulate the pulsatile blood flow within the dissected aorta. The k-ω SST turbulence model is employed to represent the flow and finite volume method is applied for numerical solutions. Our emphasis is on flow exchange between true and false lumen during the cardiac cycle and on quantifying the flow across specific passages. Loading distributions including pressure and wall shear stress have also been investigated and results of direct simulations are compared with solutions employing appropriate turbulence models. Results Our results indicate that (i) high velocities occur at the periphery of the entries; (ii) for the case studied, approximately 40% of the blood flow passes the false lumen during a heartbeat cycle; (iii) higher pressures are found at the outer wall of the dissection, which may induce further dilation of the pseudo-lumen; (iv) highest wall shear stresses occur around the entries, perhaps indicating the vulnerability of this region to further splitting; and (v) laminar simulations with adequately fine mesh resolutions, especially refined near the walls, can capture similar flow patterns to the (coarser mesh) turbulent results, although the absolute magnitudes computed are in general smaller. Conclusions The patient-specific model of aortic dissection provides detailed flow information of blood transport within the true and false lumen and quantifies the loading distributions over the aorta and dissection walls. This contributes to evaluating potential thrombotic behavior in the false lumen and is pivotal in guiding endovascular intervention. Moreover, as a computational study, mesh requirements to successfully evaluate the hemodynamic parameters have been proposed.
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Affiliation(s)
- Duanduan Chen
- Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, Beijing, China.
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Chen D, Müller-Eschner M, Kotelis D, Böckler D, Ventikos Y, von Tengg-Kobligk H. A longitudinal study of Type-B aortic dissection and endovascular repair scenarios: computational analyses. Med Eng Phys 2013; 35:1321-30. [PMID: 23523079 DOI: 10.1016/j.medengphy.2013.02.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/07/2013] [Accepted: 02/27/2013] [Indexed: 11/24/2022]
Abstract
Conservative medical treatment is commonly first recommended for patients with uncomplicated Type-B aortic dissection (AD). However, if dissection-related complications occur, endovascular repair or open surgery is performed. Here we establish computational models of AD based on radiological three-dimensional images of a patient at initial presentation and after 4-years of best medical treatment (BMT). Computational fluid dynamics analyses are performed to quantitatively investigate the hemodynamic features of AD. Entry and re-entries (functioning as entries and outlets) are identified in the initial and follow-up models, and obvious variations of the inter-luminal flow exchange are revealed. Computational studies indicate that the reduction of blood pressure in BMT patients lowers pressure and wall shear stress in the thoracic aorta in general, and flattens the pressure distribution on the outer wall of the dissection, potentially reducing the progressive enlargement of the false lumen. Finally, scenario studies of endovascular aortic repair are conducted. The results indicate that, for patients with multiple tears, stent-grafts occluding all re-entries would be required to effectively reduce inter-luminal blood communication and thus induce thrombosis in the false lumen. This implicates that computational flow analyses may identify entries and relevant re-entries between true and false lumen and potentially assist in stent-graft planning.
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Affiliation(s)
- Duanduan Chen
- Department of Biomedical Engineering, School of Life Science, Beijing Institute of Technology, China
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Beller C, von Tengg-Kobligk H. Computermodellierung und multimodale 4D-Bildgebung für Risikostratifizierung und Operationsplanung bei Erkrankungen der thorakalen Aorta. ZEITSCHRIFT FUR HERZ THORAX UND GEFASSCHIRURGIE 2012. [DOI: 10.1007/s00398-012-0922-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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CT Angiography of the Aorta and Aortic Diseases. CURRENT CARDIOVASCULAR IMAGING REPORTS 2012. [DOI: 10.1007/s12410-012-9156-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Karmonik C, Duran C, Shah DJ, Anaya-Ayala JE, Davies MG, Lumsden AB, Bismuth J. Preliminary findings in quantification of changes in septal motion during follow-up of type B aortic dissections. J Vasc Surg 2012; 55:1419-26. [PMID: 22342152 DOI: 10.1016/j.jvs.2011.10.127] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/24/2011] [Accepted: 10/30/2011] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To quantify longitudinal changes in intra-arterial septum (IS) motion with two-dimensional (2D) phase-contrast magnetic resonance imaging (2D pcMRI) in type B aortic dissections (AD) to improve the understanding of AD and its midterm development. METHODS From a database of 42 patients who underwent a dynamic magnetic resonance imaging (MRI) examination at the Acute Aortic Treatment Center of The Methodist DeBakey Heart & Vascular Center, 2D pcMRI image data was available from 10 patients with type B AD for both short-term (mean, 6.6 days; range, 1-10 days; n = 7) and midterm follow-up (mean, 155 days; range, 60-324; n = 5). IS motion was quantified as motion of IS boundary points averaged over the cardiac cycle. Relative change in IS motion was expressed as percent change compared with initial presentation. Maximum IS extension (true lumen [TL] expansion) and contraction (TL compression), IS fraction in phase with aortic flow and correlation of IS motion with aortic flow (IS compliance) were quantified. RESULTS IS motion at initial presentation was 0.68 ± 0.2 mm and was reduced at short-term (0.48 ± 0.3 mm; P = .07) and midterm (0.5 ± 0.2 mm; P = .1) follow-up. Trend in relative change of IS motion was variable during short-term follow-up: reduced in three subjects (-75% ± 6%) and elevated in four subjects (48% ± 23%). During midterm follow-up, relative change in IS motion was reduced in four subjects (28% ± 19%) and slightly elevated in one (6.2%). IS contraction decreased with follow-up while IS extension slightly increased. Fraction of IS moving in phase with aortic flow increased but IS compliance decreased, suggesting increasing IS stiffness. CONCLUSIONS Reduction of IS motion in AD is seen with short-term and midterm follow-up. Intersubject variability of this trend is high at short-term follow-up but low at midterm follow-up. Detailed analysis of IS motion parameters indicate reduction of IS contraction and IS compliance with time. This has potential implications for endovascular management of type B aortic dissections, as expansion of aortic stent grafts can be limited by a stiff IS.
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Affiliation(s)
- Christof Karmonik
- Methodist Hospital, Methodist DeBakey Heart & Vascular Center, Houston, TX, USA.
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Schernthaner RE, Stadler A, Beitzke D, Homolka P, Weber M, Lammer J, Czerny M, Loewe C. Dose modulated retrospective ECG-gated versus non-gated 64-row CT angiography of the aorta at the same radiation dose: comparison of motion artifacts, diagnostic confidence and signal-to-noise-ratios. Eur J Radiol 2011; 81:e585-90. [PMID: 21820829 DOI: 10.1016/j.ejrad.2011.06.053] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/23/2011] [Accepted: 06/27/2011] [Indexed: 11/17/2022]
Abstract
PURPOSE To compare ECG-gated and non-gated CT angiography of the aorta at the same radiation dose, with regard to motion artifacts (MA), diagnostic confidence (DC) and signal-to-noise-ratios (SNRs). MATERIALS AND METHODS Sixty consecutive patients prospectively randomized into two groups underwent 64-row CT angiography, with or without dose-modulated ECG-gating, of the entire aorta, due to several pathologies of the ascending aorta. MA and DC were both assessed using a four-point scale. SNRs were calculated by dividing the mean enhancement by the standard deviation. The dose-length-product (DLP) of each examination was recorded and the effective dose was estimated. RESULTS Dose-modulated ECG-gating showed statistically significant advantages over non-gated CT angiography, with regard to MA (p<0.001) and DC (p<0.001), at the aortic valve, at the origin of the coronary arteries, and at the dissection membrane, with a significant correlation (p<0.001) between MA and DC. At the aortic wall, however, ECG-gated CT angiography showed statistically significant fewer MA (p<0.001), but not a statistically significant higher DC (p=0.137) compared to non-gated CT angiography. At the supra-aortic vessels and the descending aorta, the ECG-triggering showed no statistically significant differences with regard to MA (p=0.861 and 0.526, respectively) and DC (p=1.88 and 0.728, respectively). The effective dose of ECG-gated CT angiography (23.24mSv; range, 18.43-25.94mSv) did not differ significantly (p=0.051) from that of non-gated CT angiography (24.28mSv; range, 19.37-29.27mSv). CONCLUSION ECG-gated CT angiography of the entire aorta reduces MA and results in a higher DC with the same SNR, compared to non-gated CT angiography at the same radiation dose.
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Durmus T, Rogalla P, Lembcke A, Mühler MR, Hamm B, Hein PA. Low-dose triple-rule-out using 320-row-detector volume MDCT – less contrast medium and lower radiation exposure. Eur Radiol 2011; 21:1416-23. [PMID: 21347640 DOI: 10.1007/s00330-011-2088-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Revised: 01/13/2011] [Accepted: 01/25/2011] [Indexed: 11/26/2022]
Affiliation(s)
- Tahir Durmus
- Department of Radiology, Charité-University Hospital Berlin, Campus Mitte, 10117 Berlin, Germany.
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Cheng Z, Tan FPP, Riga CV, Bicknell CD, Hamady MS, Gibbs RGJ, Wood NB, Xu XY. Analysis of flow patterns in a patient-specific aortic dissection model. J Biomech Eng 2010; 132:051007. [PMID: 20459208 DOI: 10.1115/1.4000964] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Aortic dissection is the most common acute catastrophic event affecting the thoracic aorta. The majority of patients presenting with an uncomplicated type B dissection are treated medically, but 25% of these patients develop subsequent aneurysmal dilatation of the thoracic aorta. This study aimed at gaining more detailed knowledge of the flow phenomena associated with this condition. Morphological features and flow patterns in a dissected aortic segment of a presurgery type B dissection patient were analyzed based on computed tomography images acquired from the patient. Computational simulations of blood flow in the patient-specific model were performed by employing a correlation-based transitional version of Menter's hybrid k-epsilon/k-omega shear stress transport turbulence model implemented in ANSYS CFX 11. Our results show that the dissected aorta is dominated by locally highly disturbed, and possibly turbulent, flow with strong recirculation. A significant proportion (about 80%) of the aortic flow enters the false lumen, which may further increase the dilatation of the aorta. High values of wall shear stress have been found around the tear on the true lumen wall, perhaps increasing the likelihood of expanding the tear. Turbulence intensity in the tear region reaches a maximum of 70% at midsystolic deceleration phase. Incorporating the non-Newtonian behavior of blood into the same transitional flow model has yielded a slightly lower peak wall shear stress and higher maximum turbulence intensity without causing discernible changes to the distribution patterns. Comparisons between the laminar and turbulent flow simulations show a qualitatively similar distribution of wall shear stress but a significantly higher magnitude with the transitional turbulence model.
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Affiliation(s)
- Z Cheng
- Department of Chemical Engineering, Imperial College London, London, UK
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