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Radon domain can be filled by the Fourier transforms for projection images in a polar gridding format (radial lines for parallel projections, radon arcs for fan-beam projections). The Radon-based tomographic reconstruction requires regridding a polar radon domain into a rectilinear lattice before inverse Fourier transform. Since the radon domain is irregularly sampled by Fourier-transformed projections,...
In order to emphasize the significance of CT simulation and to help students to understand CT working principle, especially the graphic reconstruction principle, a reflection type ultrasonic CT experimental device based on the Stm32 is designed for the teaching of CT. The device consists of a transceiver ultrasonic module, a MCU module, a serial communication module, a 3D mechanical platform, a stepper...
To investigate the CT findings of gastrocolic ligament involved by acute pancreatitis(AP) and study the correlation between CT findings and CT Severity Index (CTSI) of AP. Methods: Seventy-nine patients with AP were retrospectively reviewed. Balthazar's CT classification of all the patients' was C grade or more. Emphasis was placed on the following findings: the CTSI, the thickness and density of...
The objective of this study was to observe the age-related changes of sulfated glycosaminoglycan (sGAG) content and surface roughness of hip joint cartilage of elderly people based on Equilibrium Partitioning of an Ionic Contrast Agent (EPIC) Micro-CT. 35 human hip cartilage-bone samples were prepared from hip-fracture patients whose age were from 50 to 100 years old and divided into 5 groups (10...
Currently, dental CBCT(Cone-Beam Computed Tomography) is wildly used in the tooth implantation, maxillofacial surgery and the treatment of temporomandibular joint disorders. The three-dimensional images of Dental CBCT are reconstructed based on the projection images, which are obtained at each degree of 360º. The projected image should have a precise correspondence with the angle of rotation of arm...
Magnetic resonance (MR) images can be used to detect lesions in the brains of multiple sclerosis (MS) patients and is essential for diagnosing the disease and monitoring its progression. An automatic method is presented for segmentation of MS lesions in multispectral MR images. Firstly a PD-w image is subtracted from its corresponding T1-w image to get an image in which the cerebral spinal fluid (CSF)...
Since the birth of diffusion tensor imaging (DTI), diffusion characteristic has become a powerful tool to probe the internal structure of the subject. The diffusion anisotropy indices (DAIs) are parameters derived from DTI data which describe the morphological characteristics of diffusion tensor within specific range. It is of great importance to select a proper DAI for the analysis and interpretation...
Purpose: Using 1.5 T proton magnetic resonance spectroscopy (1H-MRS) with high resolution 23mm special coil in vivo to monitor the metabolic changes of the nerves in the striatum of Parkinson's disease (PD) rat before and after mesenchymal stem cells (MSCs) transplantation, in result to explore the value of 1.5T clinical MR spectral analysis in evaluating the therapeutic effects of MSCs transplantation...
The purpose of this paper is to investigate the feasibility of similarity coefficient map (SCM) in improving the quality of MR images of spleen by improving signal to noise ratio (SNR) and contrast to noise ratio (CNR), revealing fine structures buried in noise, and integrating the information of each individual image in a series together into one image. To achieve these goals, in vivo experiments...
Transmit/receive MTL (Microstrip Transmission Line) array has been widely used for ultra-high-field MRI because of its low mutual coupling characteristics. However, several design issues such as limit to the length of a single coil element still remains. For traditional MTL coils, two capacitors (one fixed, one variable) were put at both ends of the coil element for tuning. Based on our experimental...
Binocular disparity is of vital importance in stereoscopic vision. It determines the depth magnitude and effects the impression formation when human watch three-dimensional things. However so far how binocular disparity activates the brain regions hasn't got consistent conclusions. So a fMRI(functional magnetic resonance imaging) experiment was designed to locate cortex areas related with stereoscopic...
A block-based adaptive median filter, which aims to purify impulse noise from an MRI image, is discussed in the paper. The proposed filter blocks the image into several sub-images, and calculates the standard deviation of each sub-image. During filtering process, each point of the sub-image needs to be judged whether it is noise point or not, according to the average value of the filtering window...
Existing maximum a posteriori probability and Markov random field (MRF) models have limitations associated with that the ordinary neighborhood system being unable to differentiate subtle changes due to several-to-one correspondence within the neighborhood. Aiming at overcoming the limitations and applications to segmentation of cerebral vessels from magnetic resonance angiography images, we proposed...
The segmentation of brain tumor using Magnetic Resonance Image (MRI) plays an important role in the medical image process. This paper presents a comprehensive survey on brain tumor methods and technology using MRI images. Generally, brain tumor segmentation methods can divided into two main categories, spatial continuous and spatial discrete methods. Several methods, techniques, related advantage...
The implementation of MRI reconstruction algorithms based on a multi-core DSP (TMS320C6678) is described in this paper. As a state-of-the-art device, TMS320C6678 has powerful computing capability and high data throughput. The tasks of Fourier reconstruction and image combination (sum-of-squares) of multi-channels are assigned to different cores of the DSP; K-space data import, data processing and...
Osteoarthritis (OA) is a degenerative joint disease that leads to the articular cartilage (AC) degeneration and joint function loss. Early stage OA is primarily associated with proteoglycan (PG) loss and collagen structure changes. The MR T2 imaging is a promising non-invasive diagnostic tool that has shown the potential to reflect changes in the biochemical composition of cartilage with early OA...
Purpose: To identify the regions responding to the stereoscopic motion induced by binocular disparity and investigate the relationship between the response intensity of these regions and speeds of spatial motion. Methods: The stereoscopic stimulus applied Random Dot Stereogram (RDS) distributed as checkerboard and a series of continuous disparities formed a dynamic stereoscopic stimulus. Observer...
Since the optical flow method can't estimate the large displacement, the two-dimensional compression expansion method is proposed in this article to compensate for the large-scale movements in the image before the optical flow estimation. As a result, the related effects of decorrelation caused by the lateral displacement of the longitudinal compression can be effectively eliminated. Experimental...
Ultrasound image fusion has been widely used in interventional surgeries, providing surgeons both detailed structural information via CT/MRI and real-time ultrasound information. However, patient respiration induced quasi-periodic organ motion usually leads to unacceptable registration and fusion errors. In this paper, we propose a method to build a patient specific respiratory motion model and make...
A new image registration and fusion method based on Multi-Atlas was proposed in this thesis. It treats all Atlas images as a series of data nodes and clusters them through massage propagation to obtain different exemplars, then uses these exemplars to participate in the normal atlas segmentation, orders them based on the dice similar coefficient, iterate, gets the final accurate segmentation. In term...
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