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Functional and structural connectivity of human neocortex in epileptosurgery
Šulc, Vlastimil ; Hořínek, Daniel (advisor) ; Doležalová, Irena (referee) ; Tintěra, Jaroslav (referee)
1 ABSTRACT The presented dissertation deals with prognostic factors influencing a favorable postoperative outcome in patients undergoing surgical treatment of epilepsy and the possibilities of improving the methods used in the localization of epileptogenic lesions. This work is based on the results of four published studies. The first study evaluated the factors influencing the long-term outcomes of epilepsy surgery in MRI-negative (nonlesional) extratemporal lobe epilepsy (nETLE). The aim of the study was to evaluate the benefit of non-invasive diagnostic tests and their relationship with a favorable surgical outcome in a group nETLE patients. Univariate analysis showed that localized interictal epileptiform discharges (IEDs) on the scalp EEG were associated with a favorable surgical outcome. Diagnostic difficulty in this group of patients is highlighted by the fact that, although 9 of 24 patients undergoing surgery had a favorable outcome, and only nine of 85 patients with nETLE achieved such a favorable outcome. The second work evaluated the benefit of SPECT (Single Photon Emission Tomography) statistical processing over traditional subtraction methods in patients with MRI-negative temporal lobe epilepsy (nTLE) and MRI-negative extratemporal epilepsy (nETLE). 49 consecutive patients who underwent...
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Validity of primary motor area localization with fMRI versus electric cortical stimulation: A comparative study.
Bartoš, Robert ; Petrovický, Pavel (advisor) ; Zvěřina, Jaroslav (referee) ; Tintěra, Jaroslav (referee)
During my postgraduate studies, I have been working on the problems of surgery on eloquently located intrinsic brain tumors in a wider context. Towards the end of my research work, the technically challenging insular glioma surgery became the main topic. ln general, the radicality of the resection is an acceptable favourable prognostic factor even in low grade gliomas. However, for a safe resection to be possible, a mere knowledge of anatomy is not sufficient. In cases, where a suspicion of an eloquent tumor location arises, careful consideration should be made regarding the the position and the relationship of the functional cortex to the tumor. This consideration can be aided by the use of functional magnetic resonance results. ln our study, functional magnetic resonance was reliable in 83% of patients operated on a tumor in the central motor area (15/18). The distances between the fMRI activated cluster and the ECS targets were within the range of 5mm (error inherent for target-Iocalizing accuracy of neuronavigation system) in 20/26 of our measurements. The spread of the BOLD activation volume is significantly lower during more restrictive corrected thresholding P<0.05c. In all patients with this fMRI threshold, the concordance with the ECS result was absolute. If the volume of the gained corrected fMRI...
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Functional and structural connectivity of human neocortex in epileptosurgery
Šulc, Vlastimil ; Hořínek, Daniel (advisor) ; Doležalová, Irena (referee) ; Tintěra, Jaroslav (referee)
1 ABSTRACT The presented dissertation deals with prognostic factors influencing a favorable postoperative outcome in patients undergoing surgical treatment of epilepsy and the possibilities of improving the methods used in the localization of epileptogenic lesions. This work is based on the results of four published studies. The first study evaluated the factors influencing the long-term outcomes of epilepsy surgery in MRI-negative (nonlesional) extratemporal lobe epilepsy (nETLE). The aim of the study was to evaluate the benefit of non-invasive diagnostic tests and their relationship with a favorable surgical outcome in a group nETLE patients. Univariate analysis showed that localized interictal epileptiform discharges (IEDs) on the scalp EEG were associated with a favorable surgical outcome. Diagnostic difficulty in this group of patients is highlighted by the fact that, although 9 of 24 patients undergoing surgery had a favorable outcome, and only nine of 85 patients with nETLE achieved such a favorable outcome. The second work evaluated the benefit of SPECT (Single Photon Emission Tomography) statistical processing over traditional subtraction methods in patients with MRI-negative temporal lobe epilepsy (nTLE) and MRI-negative extratemporal epilepsy (nETLE). 49 consecutive patients who underwent...
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Validity of primary motor area localization with fMRI versus electric cortical stimulation: A comparative study.
Bartoš, Robert ; Petrovický, Pavel (advisor) ; Zvěřina, Jaroslav (referee) ; Tintěra, Jaroslav (referee)
During my postgraduate studies, I have been working on the problems of surgery on eloquently located intrinsic brain tumors in a wider context. Towards the end of my research work, the technically challenging insular glioma surgery became the main topic. ln general, the radicality of the resection is an acceptable favourable prognostic factor even in low grade gliomas. However, for a safe resection to be possible, a mere knowledge of anatomy is not sufficient. In cases, where a suspicion of an eloquent tumor location arises, careful consideration should be made regarding the the position and the relationship of the functional cortex to the tumor. This consideration can be aided by the use of functional magnetic resonance results. ln our study, functional magnetic resonance was reliable in 83% of patients operated on a tumor in the central motor area (15/18). The distances between the fMRI activated cluster and the ECS targets were within the range of 5mm (error inherent for target-Iocalizing accuracy of neuronavigation system) in 20/26 of our measurements. The spread of the BOLD activation volume is significantly lower during more restrictive corrected thresholding P<0.05c. In all patients with this fMRI threshold, the concordance with the ECS result was absolute. If the volume of the gained corrected fMRI...
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Source localization for EEG patterns relevant to motor imagery BCI control
Bobrov, P. ; Frolov, A. ; Húsek, Dušan ; Tintěra, J.
This work concerns spatial localization of sources of EEG patterns the most specific for control of the motor imagery based BCI. In our previous work we have shown that performance of Bayesian BCI classifier can be drastically improved by extraction of the most relevant independent components of the EEG signal. This paper presents the results of spatial localization of electrical brain activity sources which activity is reflected by the extracted components. The localization was performed by solving the inverse problem in EEG source localization, using individual finite-element head models. The sources were located in central sulcus (Brodmann area 3a), in the superior regions of post- and precentral gyri, and supplementary motor cortex.
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