|
|
Metabolic profile of human brain in vivo in MR image and spectrum
Wagnerová, Dita ; Hájek, Milan (advisor) ; Lang, Jan (referee)
Magnetic resonance imaging and spectroscopic imaging have proven to be useful to monitor a metabolism in the human brain. The thesis is concerned to repeatability and reproducibility of spectroscopic data measured on 1.5T and 3T scanners and to the development of a new method enabling the separation of pathologic and healthy tissues in patients with brain tumor using the combination of MR spectroscopic and diffusion measurements. Evaluation of repeatability and reproducibility in white matter in the parieto-occipital region, in the hippocampus and in gray matter in the frontal lobe did not show significant differences in accuracy of measurements on 1.5T and 3T scanners, but showed a significant increase of signal-to-noise ratio on 3T As a part of the thesis a program KORELACE has been developed. The program enables the evaluation of spectroscopic and diffusion data on the "pixel-by-pixel" basis in individual subjects. The existence of a statistically significant inverse correlation between the concentrations of choline and the diffusion trace values has been proven in glioblastoma, but no significant correlation has been found in a healthy tissue in volunteers. The correlation can be used to characterize borders of brain tumors and to identify the healthy tissue. Simulations confirmed the influence of...
|
|
|
Fluorine nuclear relaxation times in chelates with lanthanides
Bobrova, Yulia ; Římal, Václav (advisor) ; Wagnerová, Dita (referee)
Contrast agents containing fluorine have great prospects for magnetic resonance imaging in medicine. Low representation of fluorine in human body and the suitable magnetic properties of its nucleus 19 F, provide great sensitivity. The slow relaxation of 19 F, can be shortened by using paramagnetic complexes.In this thesis, transversal and longitudinal 19 F relaxation times of chelates with different paramagnetic lanthanides (Ce, Yb,Tm, Dy, Ho) were measured in two different magnetic fields: 4,7 and 11,7 T. Their values meet the expected assumptions. Furthermore, the values are compared with Bloch-Redfield- Wangsness theory.While Ho, Tm, and Dy reduce fluorine nuclear relaxation times to milliseconds, which is too short for MRI, relaxation rates of Ce a Yb reach approximately 100ms. Such relaxation rates can be considered as optimal for imaging methods. On the basis of our results it is possible to find suitable candidates for fluorine contrast media and optimize the measurement sequence settings in further research or in clinical use.
|
|
|
Measurement of liver metabolic profile using MR spectroscopy
Vratislavská, Hana ; Wagnerová, Dita (advisor) ; Šoltésová, Mária (referee)
This bachelor thesis deals with application of MR spectroscopy for determination of metabolite signal intensities and chemical changes in human liver. Measurements were performed in a magnetic field with induction 3T using proton and dual proton/phosphorus surface coils. First we did experiments with three chemical solutions. Then we measured MR spectrums of 28 healthy volunteers who were divided into four groups by gender and body mass index (BMI). During measurements with phantoms we found out dual coil range and inappropriateness of adiabatic pulses usage. Also we realized that it would be necessary to use buffer solutions. During measurements with healthy volunteers we found out that it is necessary to narmalize signal intensities by water or total phosphate, however, it would not be necessary to use correction factors for groups comparison with different sex and BMI.
|
|
|
Correlation between in vivo quantitative MR parameters in various tissues (MR spectroscopic imaging, MR diffusometry, MR relaxometry)
Wagnerová, Dita ; Hájek, Milan (advisor) ; Krššák, Martin (referee) ; Mechl, Marek (referee)
Coregistration of MR spectroscopic (SI), diffusion (DTI), relaxation images and their subsequent correlations based on pixel-by-pixel quantitative analysis have the potential to distinguish between pathological states and healthy tissue and therefore can help assessing brain pathology extent. Patients with brain tumours and temporal lobe epilepsy (TLE) were involved in the study to validate the use of this method in clinical practice. 30 patients with a new diagnosed brain lesion, 22 patients with a treated tumour (diagnosis assessed by histology or by radiological follow-up), 20 TLE patients and 59 healthy subjects were examined on a 3T system. The measurement protocol consisted of T2-weighted MR images, SI, DTI and T2 relaxometry. Correlations were analysed with the CORIMA programme with automatic identification of pixels in the normal tissue according to control data. Brain lesions: Specific correlation patterns between metabolites, MD and T2 relaxation times (T2) were found for a given lesion localisation and tumour type. The patterns depend on different tissue states involved in the examined area. Recurrent tumours exhibited the same patterns as untreated ones but with changed parameter values caused by therapy. Metabolic values did not correlate with MD and T2 in radiation necrosis. TLE: MR...
|
|
|
Metabolic profile of human brain in vivo in MR image and spectrum
Wagnerová, Dita ; Hájek, Milan (advisor) ; Lang, Jan (referee)
Magnetic resonance imaging and spectroscopic imaging have proven to be useful to monitor a metabolism in the human brain. The thesis is concerned to repeatability and reproducibility of spectroscopic data measured on 1.5T and 3T scanners and to the development of a new method enabling the separation of pathologic and healthy tissues in patients with brain tumor using the combination of MR spectroscopic and diffusion measurements. Evaluation of repeatability and reproducibility in white matter in the parieto-occipital region, in the hippocampus and in gray matter in the frontal lobe did not show significant differences in accuracy of measurements on 1.5T and 3T scanners, but showed a significant increase of signal-to-noise ratio on 3T As a part of the thesis a program KORELACE has been developed. The program enables the evaluation of spectroscopic and diffusion data on the "pixel-by-pixel" basis in individual subjects. The existence of a statistically significant inverse correlation between the concentrations of choline and the diffusion trace values has been proven in glioblastoma, but no significant correlation has been found in a healthy tissue in volunteers. The correlation can be used to characterize borders of brain tumors and to identify the healthy tissue. Simulations confirmed the influence of...
|
guest ::
RSS feed.