Evolution of Meso-Structure of Intact Loess during Loading

2011 ◽  
Vol 243-249 ◽  
pp. 2460-2463
Author(s):  
Chun Ni Shen ◽  
Xiang Wei Fang ◽  
He Wen Wang ◽  
Yun Xie ◽  
Gang Li
Keyword(s):  
Ct Images ◽  
Structure Parameter ◽  
Shear Tests ◽  
Triaxial Apparatus ◽  
Ct Data ◽  
Intact Loess

A series of triaxial shear tests on unsaturated intact loess were conducted using CT-multi-function triaxial apparatus. The distinct CT images and relevant CT data were obtained nondestructively during triaxial shear. CT data was used to define a structure parameter and an evolution variable which characterized the evolution of meso-structure. An equation is proposed to describe the evolution of meso-structure of unsaturated intact loess during loading, which reflects the influences of net cell pressure and suction on the evolution of meso-structure.

Evolution of Meso-Structure of Intact Loess during Wetting

2012 ◽  
Vol 204-208 ◽  
pp. 188-191
Author(s):  
Xiang Wei Fang ◽  
Chun Ni Shen ◽  
Pei Jiang Cheng ◽  
Long Wang
Keyword(s):  
Volumetric Strain ◽  
Ct Images ◽  
Deviatoric Stress ◽  
Cell Stress ◽  
Degree Of Saturation ◽  
Triaxial Apparatus ◽  
Evolution Of Structure ◽  
Ct Data ◽  
Intact Loess

To study the evolution of meso-structure of unsaturated intact loess during wetting, a series of CT-triaxial-collapse tests were conducted using CT-multi-function triaxial apparatus. The distinct CT images and detailed CT data were attained nondestructively during wetting. A parameter and an evolution variable which characterized evolution of meso-structure were defined based CT data. An equation describing the evolution of structure during wetting was proposed. The equation reflected the influences of net cell stress, deviatoric stress and suction on the evolution of meso-structure. In the equation, volumetric strain, deviatoric strain and incremental degree of saturation are included.

scholarly journals AUTOMATIC LUNG NODULE DETECTION BASED ON STATISTICAL REGION MERGING AND SUPPORT VECTOR MACHINES

2017 ◽  
Vol 36 (2) ◽  
pp. 65 ◽  
Author(s):  
Elaheh Aghabalaei Khordehchi ◽  
Ahmad Ayatollahi ◽  
Mohammad Reza Daliri
Keyword(s):  
Lung Nodule ◽  
Three Dimensional ◽  
Pulmonary Nodules ◽  
Ct Images ◽  
Support Vector ◽  
Svm Classifier ◽  
Region Merging ◽  
Three Dimensional Objects ◽  
Ct Data ◽  
Statistical Region Merging

Lung cancer is one of the most common diseases in the world that can be treated if the lung nodules are detected in their early stages of growth. This study develops a new framework for computer-aided detection of pulmonary nodules thorough a fully-automatic analysis of Computed Tomography (CT) images. In the present work, the multi-layer CT data is fed into a pre-processing step that exploits an adaptive diffusion-based smoothing algorithm in which the parameters are automatically tuned using an adaptation technique. After multiple levels of morphological filtering, the Regions of Interest (ROIs) are extracted from the smoothed images. The Statistical Region Merging (SRM) algorithm is applied to the ROIs in order to segment each layer of the CT data. Extracted segments in consecutive layers are then analyzed in such a way that if they intersect at more than a predefined number of pixels, they are labeled with a similar index. The boundaries of the segments in adjacent layers which have the same indices are then connected together to form three-dimensional objects as the nodule candidates. After extracting four spectral, one morphological, and one textural feature from all candidates, they are finally classified into nodules and non-nodules using the Support Vector Machine (SVM) classifier. The proposed framework has been applied to two sets of lung CT images and its performance has been compared to that of nine other competing state-of-the-art methods. The considerable efficiency of the proposed approach has been proved quantitatively and validated by clinical experts as well.

Study on Mechanical Property of Structural Damaged Expansive Soil with CT-Triaxial Shear Test

2012 ◽  
Vol 599 ◽  
pp. 811-814
Author(s):  
Lang Jing Shi ◽  
Xian Li ◽  
Zhen Peng ◽  
Shi Ji Wang ◽  
Fan Wu
Keyword(s):  
Mechanical Property ◽  
Axial Stress ◽  
Axial Strain ◽  
Expansive Soil ◽  
Confining Pressure ◽  
Ct Images ◽  
Shear Tests ◽  
Triaxial Shear Test ◽  
Damage Area ◽  
Damage Degree

A series of CT-triaxial shear tests were conducted on expancive soil specimens under controlled suction and confining pressure as 50kPa and 100kPa. The derivative and axial stress in each stage and CT images of inner structure of specimens were obtained .The results show that the different damage location and damage degree on expansive soil samples have different effect on soil mechanical property. The deviatoric stress of smaller damage area sample is larger than of bigger damage area specimen when the damage locates at the same place. The deviatoric strain is independent of the damage degree of samples. The CT images show that with the axial strain increasing, the fissures in soil close gradually, the density of soil increases, and the deformation of samples gets larger with the increase of confining pressure.

Architecture Concrete Mesostructure Analysis Based on CT Image Fracture Process

2011 ◽  
Vol 368-373 ◽  
pp. 2638-2641
Author(s):  
Liang Zhao ◽  
Chang Hua Li ◽  
Fa Ning Dang ◽  
Deng Feng Chen
Keyword(s):  
Spatial Distribution ◽  
Volume Expansion ◽  
Fracture Process ◽  
Ct Images ◽  
Spatial Distributions ◽  
Ct Image ◽  
Destruction Process ◽  
Ct Data ◽  
The Relationship ◽  
Variation Process

Scanning observation on meso evolution of fracture in concrete is carried out by means of computerized tomography (CT) on uniaxial compressive condition. The cracks in the mortar expansion, in particular, the bond of mortar and aggregate which is key regions of concrete damaged, are drawn out through CT image and CT data, and the destruction process of the concrete can be divided into four stakes, compression, enlargement, the expansion of the CT crack,and destruction. According to the character of CT image，MMD is used to analyze the CT images of the concrete specimens in 4 stages of deformation. The components of the CT images are classified and the spatial distributions of crack or cavity, mortar and aggregate are obtained. The variation process of the relationship between distributions of crack or cavity magnitude and stress are obtained from classification maps. The specimens experienced the process of condensed, volume expansion, crack propagation, coalescence and failure. The method can not only reflect the spatial distribution of the materials but also simplify the following analyses that follow.

scholarly journals MRI-based Treatment Planning with Electron Density Information Mapped from CT Images: A Preliminary Study

2008 ◽  
Vol 7 (5) ◽  
pp. 341-347 ◽  
Author(s):  
C. Wang ◽  
M. Chao ◽  
L. Lee ◽  
L. Xing
Keyword(s):  
Electron Density ◽  
Radiation Treatment ◽  
Dose Calculation ◽  
Ct Images ◽  
Planar Imaging ◽  
Mr Images ◽  
Dosimetric Accuracy ◽  
Tissue Contrast ◽  
Preliminary Study ◽  
Ct Data

Nowadays magnetic resonance imaging (MRI) has been profoundly used in radiotherapy (RT) planning to aid the contouring of targets and critical organs in brain and intracranial cases, which is attributable to its excellent soft tissue contrast and multi-planar imaging capability. However, the lack of electron density information in MRI, together with the image distortion issues, precludes its use as the sole image set for RT planning and dose calculation. The purpose of this preliminary study is to probe the feasibility and evaluate an MRI-based radiation dose calculation process by providing MR images the necessary electron density (ED) information from a patient's readily available diagnostic/staging computed tomography (CT) images using an image registration model. To evaluate the dosimetric accuracy of the proposed approach, three brain and three intracranial cases were selected retrospectively for this study. For each patient, the MR images were registered to the CT images, and the ED information was then mapped onto the MR images by in-house developed software generating a modified set of MR images. Another set of MR images with voxel values assigned with the density of water was also generated. The original intensity modulated radiation treatment (IMRT) plan was then applied to the two sets of MR images and the doses were calculated. The dose distributions from the MRI-based calculations were compared to that of the original CT-based calculation. In all cases, the MRI-based calculations with mapped ED yielded dose values very close (within 2%) to that of the CT-based calculations. The MRI-based calculations with voxel values assigned with water density indicated a dosimetric error of 3–5%, depending on the treatment site. The present approach offers a means of utilizing MR images for accurate dose calculation and affords a potential to eliminate the redundant simulation CT by planning a patient's treatment with only simulation MRI and any available diagnostic/staging CT data.

scholarly journals TEMPORAL REGISTRATION OF RADIOFREQUENCY INFORMATION AND CT IMAGES FOR RADIOFREQUENCY ABLATION PROCEDURE

2010 ◽  
Vol 10 (04) ◽  
pp. 675-681
Author(s):  
YIK HOAY MAH ◽  
BASRI JOHAN JEET ABDULLAH ◽  
KWAN HOONG NG ◽  
LI KUO TAN ◽  
JEANNIE HSIU DING WONG
Keyword(s):  
Graphical User Interface ◽  
Ct Images ◽  
Ablation Zone ◽  
Rf Ablation ◽  
Ct Scanner ◽  
Ablation Procedure ◽  
Post Operation ◽  
Output Efficiency ◽  
Temporal Registration ◽  
Ct Data

A computed tomography (CT) scanner is often used for visualization during the radiofrequency (RF) ablation (RFA) procedure. Temperatures at the ablation zone, power output, efficiency, and annotation are recorded once per second in the RF generator. Radiologists often review the RF and CT data post-operation for diagnostic and research purposes. However, they often rely on the CT data solely as it is difficult to relate the RF information to its CT counterpart. This paper describes the development of a graphical user interface application to co-register the CT images and the information from the RF generator temporally. Information from the RF generator, CT images during the RFA, and the pre-RFA CT images are displayed together. Users pinpoint a specific timestamp based on the RFA operation, and the corresponding CT images are retrieved and displayed.

scholarly journals Features of CT scan for the diagnosis of hypertrophy of the styloid processes of the temporal bone and Eagle’s syndrome

2021 ◽  
pp. 54-59
Author(s):  
Sergey M. Pukhlik ◽  
Anatolii P. Shchelkunov ◽  
Oleksandr A. Shchelkunov
Keyword(s):  
Temporal Bone ◽  
Neurological Diseases ◽  
Styloid Process ◽  
Ct Images ◽  
Growth Options ◽  
Eagle’S Syndrome ◽  
X Ray ◽  
Great Vessels ◽  
Histological Data ◽  
Ct Data

Topicality: The Eagle's syndrome is a disease that is caused by irritation of the nervous, vascular and muscular structures that surround the subcutaneous process of the temporal bone. A syndrome manifested by chronic pain at the deep part of the lateral region of the face, which irradiates into the root of the tongue, pharynx and ear, dysphagia, symptoms of disorders of the circulation of the brain. Symptoms of Eagle’s syndrome are found in various otolaryngological, dental, neurological diseases. Purpose of the study: determine and evaluate the most significant and distinctive X-ray signs of hypertrophied styloid processes of the temporal bone; reveal differences in growth options and X-ray structure of the styloid processes of the temporal bone in accordance with histological data; eEvaluate the effect of conservative treatment of stylohyoid syndrome depending on different growth options for the styloid process of the temporal bone, according of the data of computed tomography. Materials and methods of research: at the process of our work based on diagnostics and treatment of stylohyoid syndrome, we analyzed 86 clinical cases: 61 women and 25 men. Patients age varies from 35 till 70 years. CT images with contrasting of the great vessels of the neck and functional tests. Based on the analysis, we developed a scheme for determining the variants of the styloid process growth, based on the CT data, in relation to the data of the histological examination of the styloid processes of the patients we operated on. Results: The analysis of CT images and histological studies allows us to divide the lengthening of the styloid processes of the temporal bone into two groups, which we give the name "ossification", that is, the actual growth of the styloid process and "calcification", that is, dystrophic changes and deposits of calcium salts in the ligament. Accordingly, we are developing approaches to conservative or to surgical treatment of this pathology, taking into account the CT data, depending on the growth options of the styloid process of the temporal bone.

scholarly journals Impact of respiratory motion on breast tangential radiotherapy using the field-in-field technique compared to irradiation using physical wedges

2014 ◽  
Vol 48 (1) ◽  
pp. 94-98 ◽  
Author(s):  
Hidekazu Tanaka ◽  
Shinya Hayashi ◽  
Kazuhiro Ohtakara ◽  
Hiroaki Hoshi
Keyword(s):  
Respiratory Motion ◽  
Early Stage ◽  
Free Breathing ◽  
Ct Images ◽  
Data Set ◽  
Acceptable Range ◽  
Treatment Plans ◽  
Prescription Dose ◽  
Ct Data ◽  
The Impact

Abstract Background. This study aimed to evaluate whether the field-in-field (FIF) technique was more vulnerable to the impact of respiratory motion than irradiation using physical wedges (PWs). Patients and methods. Ten patients with early stage breast cancer were enrolled. Computed tomography (CT) was performed during free breathing (FB). After the FB-CT data set acquisition, 2 additional CT scans were obtained during a held breath after light inhalation (IN) and light exhalation (EX). Based on the FB-CT images, 2 different treatment plans were created for the entire breast for each patient and copied to the IN-CT and EX-CT images. The amount of change in the volume of the target receiving 107%, 95%, and 90% of the prescription dose (V107%, V95%, and V90%, respectively), on the IN-plan and EX-plan compared with the FB-plan were evaluated. Results. The V107%, V95%, and V90% were significantly larger for the IN-plan than for the FB-plan in both the FIF technique and PW technique. While the amount of change in the V107% was significantly smaller in the FIF than in the PW plan, the amount of change in the V95% and V90% was significantly larger in the FIF plan. Thus, the increase in the V107% was smaller while the increases in the V95% and V90% were larger in the FIF than in the PW plan. Conclusions. During respiratory motion, the dose parameters stay within acceptable range irrespective of irradiation technique used although the amount of change in dose parameters was smaller with FIF technique.

scholarly journals Weakly-supervised lesion analysis with a CNN-based framework for COVID-19

2021 ◽  
Author(s):  
Kaichao Wu ◽  
Beth Jelfs ◽  
Xiangyuan Ma ◽  
Ruitian Ke ◽  
Xuerui Tan ◽  
...  
Keyword(s):  
State Of The Art ◽  
Ground Glass Opacity ◽  
Ct Images ◽  
Lesion Detection ◽  
Ct Image ◽  
Medical College ◽  
Lesion Analysis ◽  
Ct Data ◽  
Weakly Supervised

Abstract Lesions of COVID-19 can be visualized clearly by chest CT images, therefore, providing valuable evidence for clinicians when making a diagnosis. However, due to the variety of COVID-19 lesions and the complexity of the manual delineation procedure, automatic analysis of lesions with unknown and diverse types from a CT image remains a challenging task. In this paper we propose a weakly-supervised framework for this task, requiring only a series of normal and abnormal CT images without the need for annotations of the specific locations and types of lesions. Specifically, this framework employs a deep learning-based diagnosis branch for the classification of the CT image and then leverages a lesion identification branch to capture multiple types of lesions. We verify our framework on publicly available datasets and CT data collected from 13 patients of the First Affiliated Hospital of Shantou University Medical College, China. The results show that the proposed framework can achieve state-of-the-art diagnosis prediction, and the extracted lesion features are capable of distinguishing between lesions showing ground glass opacity and consolidation. Further exploration also demonstrates that this framework has the potential to discover lesion types that have not been reported and can potentially be generalized to lesion detection of other chest-based diseases.

Sign in / Sign up

Export Citation Format

Share Document