scholarly journals Automatically hemodynamic analysis of AAA from CT images based on deep learning and CFD approaches

2021 ◽  
Vol 2119 (1) ◽  
pp. 012069
Author(s):  
Y V Fedotova ◽  
R UI Epifanov ◽  
A A Karpenko ◽  
R I Mullyadzhanov
Keyword(s):  
Deep Learning ◽  
Aortic Rupture ◽  
Three Dimensional ◽  
Software Tool ◽  
Patient Specific ◽  
Patient Death ◽  
Computed Tomography Images ◽  
Risk Of Rupture ◽  
Serious Disease ◽  
Health Complications

Abstract Abdominal aortic aneurysm is a serious disease which course is accompanied by the development of health complications and often leads to patient death due to aortic rupture. One of the powerful methods to estimate the risk of rupture is three-dimensional patient-specific hemodynamic analysis. In this study, we develop a software tool based on deep learning and CFD methods to perform automated computational hemodynamics with patient-specific geometry reconstructed from computed tomography images.

scholarly journals Application of subject-specific adaptive mechanical loading for bone healing in a mouse tail vertebral defect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Angad Malhotra ◽  
Matthias Walle ◽  
Graeme R. Paul ◽  
Gisela A. Kuhn ◽  
Ralph Müller
Keyword(s):  
Mechanical Loading ◽  
Bone Defect ◽  
Bone Healing ◽  
Three Dimensional ◽  
Patient Specific ◽  
Dependent Manner ◽  
Micro Computed Tomography ◽  
Computed Tomography Images ◽  
Bone Defect Healing ◽  
Subject Specific

AbstractMethods to repair bone defects arising from trauma, resection, or disease, continue to be sought after. Cyclic mechanical loading is well established to influence bone (re)modelling activity, in which bone formation and resorption are correlated to micro-scale strain. Based on this, the application of mechanical stimulation across a bone defect could improve healing. However, if ignoring the mechanical integrity of defected bone, loading regimes have a high potential to either cause damage or be ineffective. This study explores real-time finite element (rtFE) methods that use three-dimensional structural analyses from micro-computed tomography images to estimate effective peak cyclic loads in a subject-specific and time-dependent manner. It demonstrates the concept in a cyclically loaded mouse caudal vertebral bone defect model. Using rtFE analysis combined with adaptive mechanical loading, mouse bone healing was significantly improved over non-loaded controls, with no incidence of vertebral fractures. Such rtFE-driven adaptive loading regimes demonstrated here could be relevant to clinical bone defect healing scenarios, where mechanical loading can become patient-specific and more efficacious. This is achieved by accounting for initial bone defect conditions and spatio-temporal healing, both being factors that are always unique to the patient.

scholarly journals A computationally efficient approach to segmentation of the aorta and coronary arteries using deep learning

2021 ◽  
Author(s):  
Wing Keung Cheung ◽  
Robert Bell ◽  
Arjun Nair ◽  
Leon Menezies ◽  
Riyaz Patel ◽  
...  
Keyword(s):  
Deep Learning ◽  
Coronary Arteries ◽  
Automatic Segmentation ◽  
Three Dimensional ◽  
Regions Of Interest ◽  
Dice Similarity Coefficient ◽  
Processing Unit ◽  
Two Dimensional ◽  
Computed Tomography Images ◽  
Graphical Processing

AbstractA fully automatic two-dimensional Unet model is proposed to segment aorta and coronary arteries in computed tomography images. Two models are trained to segment two regions of interest, (1) the aorta and the coronary arteries or (2) the coronary arteries alone. Our method achieves 91.20% and 88.80% dice similarity coefficient accuracy on regions of interest 1 and 2 respectively. Compared with a semi-automatic segmentation method, our model performs better when segmenting the coronary arteries alone. The performance of the proposed method is comparable to existing published two-dimensional or three-dimensional deep learning models. Furthermore, the algorithmic and graphical processing unit memory efficiencies are maintained such that the model can be deployed within hospital computer networks where graphical processing units are typically not available.

Patient-specific three-dimensional simulation of LDL accumulation in a human left coronary artery in its healthy and atherosclerotic states

2009 ◽  
Vol 296 (6) ◽  
pp. H1969-H1982 ◽  
Author(s):  
Ufuk Olgac ◽  
Dimos Poulikakos ◽  
Stefan C. Saur ◽  
Hatem Alkadhi ◽  
Vartan Kurtcuoglu
Keyword(s):  
Shear Stress ◽  
Coronary Artery ◽  
Left Coronary Artery ◽  
Three Dimensional ◽  
Arterial Blood Flow ◽  
Patient Specific ◽  
Computed Tomography Images ◽  
Arterial Blood ◽  
Diseased State ◽  
Stress Dependent

We calculate low-density lipoprotein (LDL) transport from blood into arterial walls in a three-dimensional, patient-specific model of a human left coronary artery. The in vivo anatomy data are obtained from computed tomography images of a patient with coronary artery disease. Models of the artery anatomy in its healthy and diseased states are derived after segmentation of the vessel lumen, with and without the detected plaque, respectively. Spatial shear stress distribution at the endothelium is determined through the reconstruction of the arterial blood flow field using computational fluid dynamics. The arterial endothelium is represented by a shear stress-dependent, three-pore model, taking into account blood plasma and LDL passage through normal junctions, leaky junctions, and the vesicular pathway. Intraluminal pressures of 70 and 120 mmHg are employed as the normal and hypertensive operating pressures, respectively. By applying our model to both the healthy and diseased states, we show that the location of the plaque in the diseased state corresponds to one of the two sites with predicted high-LDL concentration in the healthy state. We further show that, in the diseased state, the site with high-LDL concentration has shifted distal to the plaque, which is in agreement with the clinical observation that plaques generally grow in the downstream direction. We also demonstrate that hypertension leads to increased number of regions with high-LDL concentration, elucidating one of the ways in which hypertension may promote atherosclerosis.

RISK OF ANEURYSMAL RUPTURE

Neurosurgery ◽  
2008 ◽  
Vol 62 (4) ◽  
pp. 767-775 ◽  
Author(s):  
Tomotaka Ohshima ◽  
Shigeru Miyachi ◽  
Ken-ichi Hattori ◽  
Ichiro Takahashi ◽  
Katsuya Ishii ◽  
...  
Keyword(s):  
Flow Separation ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Type A ◽  
Patient Specific ◽  
Parent Artery ◽  
Type B ◽  
Unruptured Aneurysms ◽  
Risk Of Rupture ◽  
Type C

Abstract OBJECTIVE The aim of the present study was to clarify the risk of rupture in terminal-type intracranial aneurysms using computational flow simulation analysis. METHODS First, idealized three-dimensional aneurysmal models were built from a solid voxel on the computer. We focused on round terminal-type aneurysms with the positioning of the neck orifice set according to the following three patterns in relationship to the axis of the parent artery: the Type-A neck orifice was positioned directly in line with the flow of the parent artery; the Type-B neck orifice was shifted 1.5 mm offline toward the unilateral branch; and the Type-C neck orifice was shifted 3 mm offline. Computational flow simulations were applied with Fujitsu α-Flow software (Fujitusu, Tokyo, Japan). We analyzed flow patterns using modified patient-specific models. We also investigated actual clinical situations to evaluate the differences in neck-orifice positioning between 20 ruptured aneurysms and 26 unruptured ones using three-dimensional angiograms. RESULTS The Type-A neck orifice showed completely symmetrical stream lines in the aneurysm, whereas the Type-C orifice showed a clear round circulation. The Type-B neck orifice, on the other hand, exhibited intra-aneurysmal flow separation. The clinical research demonstrated that Type-B aneurysms were more likely to be found in the ruptured group (P < 0.05). CONCLUSION Flow separation, recognized as one of the causes of intimal injury, could be observed only in Type-B aneurysms, a result that corresponded well with our clinical experience. From the flow-dynamics point of view, this positioning of the neck orifice may be one of the risk factors most likely to induce the rupture of unruptured aneurysms.

scholarly journals Three-dimensional printing of patient-specific lung phantoms for CT imaging: emulating lung tissue with accurate attenuation profiles and textures

2021 ◽  
Author(s):  
Kai Mei ◽  
Michael Geagen ◽  
Leonid Roshkovan ◽  
Harold I. Litt ◽  
Grace J. Gang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Software Tool ◽  
Image Texture ◽  
Patient Specific ◽  
Ct Image ◽  
Ct Scanner ◽  
Hounsfield Units ◽  
Calibration Phantom ◽  
Attenuation Profiles ◽  
High Level

Purpose: Phantoms are a basic tool for assessing and verifying performance in CT research and clinical practice. Patient-based realistic lung phantoms accurately representing textures and densities are essential in developing and evaluating novel CT hardware and software. This study introduces PixelPrint, a 3D printing solution to create patient-based lung phantoms with accurate attenuation profiles and textures. Methods: PixelPrint, a software tool, was developed to convert Patient DICOM images directly into printer instructions (G-code). The density was modeled as the ratio of filament to voxel volume to emulate attenuation profiles for each voxel. A calibration phantom was designed to determine the mapping between filament line width and Hounsfield Units (HU) within the range of human lungs. For evaluation of PixelPrint, a phantom based on a human lung slice was manufactured and scanned with the same CT scanner and protocol used for the patient scan. Density and geometrical accuracy between phantom and patient CT data was evaluated for various anatomical features in the lung. Results: For the calibration phantom, measured mean Hounsfield units show a very high level of linear correlation with respect to the utilized filament line widths, (r > 0.999). Qualitatively, the CT image of the patient-based phantom closely resembles the original CT image both in texture and contrast levels, with clearly visible vascular and parenchymal structures. Regions-of-interest (ROIs) comparing attenuation illustrated differences below 15 HU. Manual size measurements performed by an experienced thoracic radiologist reveal a high degree of geometrical correlation of details between identical patient and phantom features, with differences smaller than the intrinsic spatial resolution of the scans. Conclusion: The present study demonstrates the feasibility of 3D printed patient-based lung phantoms with accurate organ geometry, image texture, and attenuation profiles. PixelPrint will enable applications in the research and development of CT technology, including further development in radiomics.

COMPUTATIONAL FLUID DYNAMICS OF TWO PATIENT-SPECIFIC SYSTEMIC TO PULMONARY SHUNTS

2013 ◽  
Vol 13 (01) ◽  
pp. 1350005 ◽  
Author(s):  
JINLI DING ◽  
YOUJUN LIU ◽  
LINJUAN CHAI ◽  
XUE CAO ◽  
FENG WANG
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Innominate Artery ◽  
Patient Specific ◽  
Pulmonary Shunt ◽  
Computed Tomography Images ◽  
Systemic Artery

Tetralogy of Fallot is the most common cyanotic congenital heart defect. For severe cases, inserting a systemic to pulmonary shunt, which distributes part of systemic artery blood into the pulmonary artery, is the preferable palliative surgery. Based on the computed tomography images and three-dimensional geometry technologies, two patient-specific anatomical options of systemic to pulmonary shunts including the aorta to pulmonary shunt (APS) and innominate artery to pulmonary shunt (IPS) have been simulated for computational fluid dynamics. The objective of this study was to predict the hemodynamics within the shunts and confirm, through patient-specific simulations, the shunt with the optimal performance. Results indicated that both options created high velocity gradients and pressure gradients at the proximal end of the shunts. Obvious flow recirculation appeared at the inner region near the proximal end of the shunts. Part of the reverse flow from the descending aorta, left subclavian artery, left carotid artery and innominate artery was driven into the shunts during the diastolic period. The IPS provided better balanced and more adequate blood flow distributions between the systemic and pulmonary circulations. The APS provided slightly excessive pulmonary blood flow which can ultimately result in cardiac failure and pulmonary hypertension.

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