Národní úložiště šedé literatury Nalezeno 3 záznamů.  Hledání trvalo 0.00 vteřin. 
DEEP LEARNING FOR SINGLE-VOXEL AND MULTIDIMENSIONAL MR-SPECTROSCOPIC SIGNAL QUANTIFICATION, AND ITS COMPARISON WITH NONLINEAR LEAST-SQUARES FITTING
Shamaei, Amirmohammad ; Latta,, Peter (oponent) ; Kozubek, Michal (oponent) ; Jiřík, Radovan (vedoucí práce)
Preprocessing, analysis, and quantification of Magnetic resonance spectroscopy (MRS) signals are required for obtaining the metabolite concentrations of the tissue under investigation. However, a fast, accurate, and efficient post-acquisition workflow (preprocessing, analysis, and quantification) of MRS is challenging. This thesis introduces novel deep learning (DL)-based approaches for preprocessing, analysis, and quantification of MRS data. The proposed methods achieved the objectives of robust data preprocessing, fast and efficient MR spectra quantification, in-vivo concentration quantification, and the uncertainty estimation of quantification. The results showed that the proposed approaches significantly improved the speed of MRS signal preprocessing and quantification in a self-supervised manner. Our proposed methods showed comparable results with the traditional methods in terms of accuracy. Furthermore, a standard data format was introduced to facilitate data sharing among research groups for artificial intelligence applications. The findings of this study suggest that the proposed DL-based approaches have the potential to improve the accuracy and efficiency of MRS for medical diagnosis. The dissertation is structured into four parts: an introduction, a review of state-of-the-art research, a summary of the aims and objectives, and a collection of publications that showcase the author's contribution to the field of DL applications in MRS.
Deep Learning For Magnetic Resonance Spectroscopy Quantification: A Time-Frequency Analysis Approach
Shamaei, Amirmohammad
Magnetic resonance spectroscopy (MRS) is a technique capable of detecting chemical compounds from localized volumes in living tissues. Quantification of MRS signals is required for obtaining the metabolite concentrations of the tissue under investigation. However, reliable quantification of MRS is difficult. Recently deep learning (DL) has been used for metabolite quantification of MRS signals in the frequency domain. In another study, it was shown that DL in combination with time-frequency analysis could be used for artifact detection in MRS. In this study, we verify the hypothesis that DL in combination with time-frequency analysis can also be used for metabolite quantification and yields results more robust than DL trained with MR signals in the frequency domain. We used the complex matrix of absolute wavelet coefficients (WC) for the timefrequency representation of the signal, and convolutional neural network (CNN) implementation for DL. The comparison with DL used for quantification of data in the frequency domain is presented.
Deep learning for magnetic resonance spectroscopy quantification: A time frequency analysis approach
Shamaei, Amirmohammad
Magnetic resonance spectroscopy (MRS) is a technique capable of detecting chemical compounds from localized volumes in living tissues. Quantification of MRS signals is required for obtaining the metabolite concentrations of the tissue under investigation. However, reliable quantification of MRS is difficult. Recently deep learning (DL) has been used for metabolite quantification of MRS signals in the frequency domain. In another study, it was shown that DL in combination with time-frequency analysis could be used for artifact detection in MRS. In this study, we verify the hypothesis that DL in combination with time-frequency analysis can also be used for metabolite quantification and yields results more robust than DL trained with MR signals in the frequency domain. We used the complex matrix of absolute wavelet coefficients (WC) for the time-frequency representation of the signal, and convolutional neural network (CNN) implementation for DL. The comparison with DL used for quantification of data in the frequency domain is presented.

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