Biomedical subjects

Jiarui Lin

Publications and source records attributed to Jiarui Lin.

13 recordsLinked to original sources

PubMed2006

[Compared Markov with fractal models by using single-channel experimental and simulation data].

The gating mechanical kinetical of ion channels has been modeled as a Markov process. In these models it is assumed that the channel protein has a small number of discrete conformational states and kinetic rate constants connecting these states are constant, the transition rate constants among the states is independent both of time and of the previous channel activity. It is assumed in Liebovitch's fractal model that the channel exists in an infinite number of energy states, consequently, transitions from one conductance state to another would be governed by a continuum of rate constants. In this paper, a statistical comparison is presented of Markov and fractal models of ion channel gating, the analysis is based on single-channel data from ion channel voltage-dependence K+ single channel of neuron cell and simulation data from three-states Markov model.

Animals↗

PubMed2005

[Data reconstruction algorithm on echo-planar magnetic resonance spectroscopic imaging].

When a conventional phase-encoding magnetic resonance spectrascopic imaging(MRSI) method is in use, the data acquisition is very time consuming and thus it is not well accepted in clinical settings. Echo planar spectroscopic imaging (EPSI) technology has been applied for rapid acquisition of MRSI data. It significantly reduces scan time by simultaneously encoding the spectral dimension and the spatial dimension. Reconstruction of EPSI data is sophisticated. For the t-dimension, data are non-uniformly sampled. Fast Fourier transform (FFT) is applied in odd echoes and even echoes respectively and then shift method is used to combine them together. For the kx dimension, the data are unevenly sampled and have to be interpolated onto a Cartesian grid before FFT is applied. For the phase-encoding dimension (ky), the Fourier transform can be readily done with FFT since the data are evenly spaced.

Algorithms↗

PubMed2005

[Application of support vector machine in the detection of early cancer].

Support Vector Machine (SVM) is an efficient novel method originated from the statistical learning theory. It is powerful in machine learning to solve problems with finite samples. Due to the deficiency of cancer cells, character of patient and noise in the raw data, it is very difficult to diagnose early cancer accurately. In this paper, SVM is employed in detecting early cancer and the results are encouraged compared with conventional methods. The accuracy of Non-linear SVM classifier is especially high in all kinds of classifiers, which indicates the potential application of SVM in early cancer detection.

Algorithms↗

PubMed2004

[Advance of fast magnetic resonance spectroscopic imaging].

The required time of conventional magnetic resonance spectroscopic imaging technique is too long to be applied to clinic. It is necessary to develop the fast methods for magnetic resonance spectroscopic imaging. Nowadays there are 7 kinds of methods presented, which come from MRI techniques. In this contribution the conventional spectroscopic imaging and 7 sorts of fast spectroscopic imaging are elaborated. It is envisaged that more rapid imaging techniques will be designed, if these arbitrary trajectory reconstruction methods in MRI are applied to spectroscopic imaging.

Magnetic Resonance Imaging↗

PubMed2004

[Research on the R-PS integration technique of digital radiology].

In this paper, the R-PS integration technique of the digital radiology is discussed. By the integration of the RIS and PACS, all data and information of each system and each medical image equipment in R-PS can be exchanged according to DICOM3.0, and seamless linkage can be realized by module interfaces. R-PS has many advantages such as share, safety, compatibility, practicability and feasibility. Standardization of communication interface, modularization of application and resource share of medical information can be realized by this technique.

Computer Communication Networks↗

PubMed2003

[Adaptive filter method of enhancing ventricular late potential signals].

This paper introduces an adaptive filter method for enhancing ventricular late potentials. The adaptive filter has only one signal electrode and does not need the reference electrode. The experiment results show that this adaptive filter method can effectively improve signal-to-noise ratio of ventricular late potentials.

Action Potentials↗

PubMed2003

[Software for MR image reconstruction from data acquired on an irregular k-space trajectory].

A PC-based software was developed and programmed with VC++6 for reconstructing MR images from the data acquired on an irregular k-space trajectory. It can read clinical MRI raw data and image data, create numerical phantoms, design k-space trajectories, generate k-space data from numerical phantom, calculate weighting functions, reconstruct images, and carry out error analysis for the reconstructed images. It is helpful to the investigations of new k-space trajectories and new reconstruction algorithms.

Algorithms↗

PubMed2003

[Implementation of mutual information based medical image registration methods].

Image registration methods based on mutual information, including mutual information and normalized mutual information, have been accepted as the most accurate and efficient methods. But there are many fluctuations in the registration functions that hinder the optimization procedure and lead to registration failure in intra-modal registration. We found that besides the interpolation artifacts, the uncertainty of the changing of entropy with the changing of overlap also contributes to the fluctuations. The effect of interpolation artifacts can be eliminated, but it is difficult to eliminate the effect of uncertainty of entropy. Luckily, this effect is not significant in normalized mutual information. Normalized mutual information is more stable and robust than standard mutual information and its better performance and wider application can be expected.

Algorithms↗

PubMed2002

Direct reconstruction of MR images from data acquired on a non-Cartesian grid using an equal-phase-line algorithm.

The equal-phase line (EPL) algorithm is proposed as a means of allowing rapid Fourier transform (FT) reconstruction of MR image data acquired on a non-Cartesian grid. The pixels on the image are grouped according to their positions. The pixels in a group have the same phase in the complex exponential function -exp[j2pi(xu + yv)] and receive the same contribution from a data point. Each group is related to an EPL in the image space. The contribution of a data point can then be distributed to the pixels along the EPLs. The described EPL algorithm enables a decrease of the reconstruction time to about 40% of the direct FT (DrFT) for the non-Cartesian data. A numerical phantom and two sets of in vivo spiral data were used to investigate an optimal number of the EPLs and to measure the reconstruction time. The EPL algorithm runs nearly as fast as the look-up table (LUT) method (Dale et al. IEEE Trans Med Imaging 2001;20:207-217), but it does not require a large memory to store the coefficients in advance, as is required in the LUT method. Thus, the EPL algorithm can be used to reconstruct images up to 512 x 512 pixels in size in a PC of limited memory, and may be more conveniently applied to a multiprocessor system.

Algorithms↗

PubMed2002

Reconstruction of MR images from data acquired on an arbitrary k-space trajectory using the same-image weight.

A sampling density compensation function denoted "same-image (SI) weight" is proposed to reconstruct MR images from the data acquired on an arbitrary k-space trajectory. An equation for the SI weight is established on the SI criterion and an iterative scheme is developed to find the weight. The SI weight is then used to reconstruct images from the data calculated on a random trajectory in a numerical phantom case and from the data acquired on interleaved spirals in an in vivo experiment, respectively. In addition, Pipe and Menon's weight (MRM 1999;41:179-186) is also used in the reconstructions to make a comparison. The images obtained with the SI weight were found to be slightly more accurate than those obtained with Pipe's weight.

Brain↗

PubMed2002

[Advances in research on ion-channel gating mechanism].

The history and current situation of cell membrane ion-channel gating mechanism study were reviewed, with an emphasis on the application and the latest developments of kinetic model in gating mechanism study; the problems in present study and ion-channel gating mechanism kinetics model for future investigations were finally discussed.

Cell Membrane↗

PubMed2002

[Adaptive restoration of single ion channel signal under filtering and colored background noise].

In order to overcome the effects of the anti-aliasing filter and the colored background noise, an adaptive algorithm is proposed to estimate the parameters of ion channel kinetics and the background noise, and whereafter the ion channel signal could be restored from the strong noisy patch-clamp recordings. The algorithm cross-couples the recursive expectation-maximization algorithm, which estimates optimally the parameters of hidden Markov model, and the recursive extended least square algorithm, which estimates optimally the characteristics of the background noise. Simulation suggests that this cross-coupling algorithm convergences consistently, and is very robust to the inexact conformation number.

Algorithms↗

PubMed2002

[The computer simulation of magnetic resonance imaging].

Based on the Bloch equation, we can describe the working principle of the magnetic resonance imaging system with mathematic model, the inputs are the three templates of appropriate rho, T1 and T2. In this paper, the simulation process is illustrated by spin echo examples of the signal exciting, phase coding, reading-out and image reconstruction. The satisfactory results show that this method can be widely used in simulation researches.

Algorithms↗