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In vivo Magnetic Resonance Spectroscopy (MRS) is the only technique that can non-invasely detect metabolites at arbitrary locations inside humans and animals. Because metabolites serve as markers of disease, estimation of their in vivo concentrations (quantitation) is important. Metabolite quantitation suffers when the model function of the in vivo MRS signal is only partially known. The present work...
Magnetic resonance spectroscopy (MRS) known for its non-invasive and nondestructive nature, has been applied in biomedical and clinical research to assess the biochemical and metabolic information in a living brain. However, the applicability and detection sensitivity of in vivo MRS are, in general, limited by low concentrations of most cerebral metabolites of interest. The newly advanced high/ultrahigh...
A modification of Singular Value Decomposition (SVD) is proposed in this aiming at de-noising and finding more accurately the statistically independent spectra of metabolite sources in Magnetic Resonance Spectroscopy (MRS) quantification. Although SVD is known in MRS applications and several efficient algorithms exist for estimating SVD summation terms in which the raw MRS data is analyzed, however,...
The following topics are dealt with: advanced medical imaging technique; PET/SPECT/CT imaging; advanced detection-and-imaging technique; molecular imaging technique; nuclear medicine technique; electrical capacitance tomography and its industrial applications; optical imaging system; image analysis-and-measurement; advanced signal processing for MRS; and MRI systems.
Magnetic Resonance Spectroscopy (MRS) is an effective diagnostic technique for monitoring biochemical changes in an organism. The lineshape of MRS signals can deviate from the theoretical Lorentzian or exponential lineshape due to inhomogeneities of magnetic field applied to the patient and to patientpsilas tissue heterogeneity. We call this deviation a distortion. Using an improved damping function,...
Tissue deterioration as induced by disease can be viewed as a continuous change of tissue from healthy to diseased and hence can be modeled as a non-linear manifold with completely healthy tissue at one end of the spectrum and fully abnormal tissue such as lesions, being on the other end. The ability to quantify this tissue deterioration as a continuous score of tissue abnormality will help determine...
Magnetic Resonance Spectroscopy (MRS) signals are being used for diagnosis of various brain diseases. Feature extraction of the MRS data is the most important step in analyzing the data. In this study a fully automated system is developed to analyze the MRS signals. The wavelet analysis is utilized in extracting signal features and the time-frequency representations. Consulting specialists in the...
In this paper, we focus on the reconstruction of iDQC MR spectroscopy data. Unlike standard 1-D MR spectroscopy schemes, iDQC acquires 2-D spectral data to decouple the magnetic field inhomogeneity effects from chemical shift information. This method suffers from a few limitations such as low intrinsic SNR, long acquisition time and the presence of a strong residual water peak. The standard IFFT based...
The purpose of this study was to explore mitochondrial activities after oxygen inhalation by 31P magnetic resonance spectroscopy. Six healthy volunteers were studied using a GE 3 T scanner. A spin-echo MRS sequence was utilized with a GE service coil. TR was 2000 msec and TE 35 msec with 128 scan averages. Before 31P scan, a 1H MRS pre-scan was performed to obtain shimming values. Exact two 31P scans...
This paper investigates variable selection (VS) and classification for biomedical datasets with a small sample size and a very high input dimension. The sequential sparse Bayesian learning methods with linear bases are used as the basic VS algorithm. Selected variables are fed to the kernel-based probabilistic classifiers: Bayesian least squares support vector machines (BayLS-SVMs) and relevance vector...
Magnetic resonance spectroscopic signals analyzed by time-domain models in order to retrieve estimates of the model parameters usually require prior knowledge about the model order. For multi-exponential signals where a superposition of peaks occurs at the same resonance frequency, but with different damping values, model order selection criteria from information theory can be used. In this study,...
The perfect shimming of 31P magnetic resonance spectroscopy (MRS) is not easy in vivo. The purpose of this study was to examine the feasibility of using 1H MRS shimming values to obtain 31P spectra in a same sequence. Both phantom and volunteer studies were carried out in this study. Phantom was a sphere filled with physiological metabolites of brain. In vivo study was performed on 4 healthy volunteers...
Short-echo time magnetic resonance (MR) spectra contain large nuisance components which should be removed in order to improve quantification of the underlying metabolite concentrations. This paper shows that powerful filtering techniques such as the maximum-phase FIR filter or HLSVD-PRO proposed by Sundin et al. and Laudadio et al., respectively, as used in long-echo time MR spectral quantification,...
Magnetic resonance spectroscopic signals analyzed by time-domain models in order to retrieve estimates of the model parameters usually require prior knowledge about the model order. For multi-exponential signals where a superposition of peaks occurs at the same resonance frequency, but with different damping values, model order selection criteria from information theory can be used. In this study,...
Short-echo time magnetic resonance (MR) spectra contain large nuisance components which should be removed in order to improve quantification of the underlying metabolite concentrations. This paper shows that powerful filtering techniques such as the maximum-phase FIR filter or HLSVD-PRO proposed by Sundin et al. and Laudadio et al., respectively, as used in long-echo time MR spectral quantification,...
The perfect shimming of 31P magnetic resonance spectroscopy (MRS) is not easy in vivo. The purpose of this study was to examine the feasibility of using 1H MRS shimming values to obtain 31P spectra in a same sequence. Both phantom and volunteer studies were carried out in this study. Phantom was a sphere filled with physiological metabolites of brain. In vivo study was performed on 4 healthy volunteers...
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