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Clinical Neuroscience

JANUARY 30, 2020

[Correction of the physiological artefacts at pre-surgical clinical functional MR]

KISS Máté, GÁL Andor Viktor, KOZÁK Lajos Rudolf, MARTOS János, NAGY Zoltán

[Introduction/aim of the study - Pre-surgical functional MRI (fMRI) is an important modality of examinations before brain surgery. There are several artefacts (e.g. motion, susceptibility) which may hinder the evaluation of fMRI data. Physiological artefacts (breathing, pulsation) also affect the sensitivity and specificity of anatomical localization. The aim of this study is to demonstrate the efficiency of physiological artefact identification and removal methods for presurgical evaluation. Materials and methods - Siemens Magnetom Verio 3T MRI scanner was used to collect data. The physiological parameters (breathing, pulse) were recorded with the MRI system’s built-in devices. Data from fourteen patients - with primary brain tumour - were evaluated with SPM12 utilizing the RETROICOR/RVHR tool to detect and decrease the effect of physiological artefacts. We compared the statistical maps obtained with and without the physiological correction using the Jaccard similarity coefficient, and ROI analyses. Results - Significant differences were found in the mean ROI values (p<0.0016) and the extensions of eloquent activations (p<0.0013), when using the physiological correction (RETORICOR/RVHR) based on convolution method. On the other hand, no significant differences were found between the ROIs’ standard deviations (F=0.28). The RETROICOR/ RVHR method helps to define the precise localisation of eloquent areas (p<0.009). The number of irrelevant (non-significant) voxels were increased (p<0.001). Conclusions - Minimising of physiological artefacts in fMRI data calculations, the (RETROICOR/RVHR) method based on convolution has been successfully adapted. This algorithm could be helpful before neurosurgical intervention. The activity pattern became more reliable. ]

Clinical Neuroscience

SEPTEMBER 30, 2016

[Functional magnetic resonance imaging studies in pain research]

ÉDES Andrea Edit, JUHÁSZ Gabriella

[Functional imaging studies opened a new way to understand the neural activity underlying pain perception and the pathomechanism of chronic pain syndromes. In the last twenty years several results of functional magnetic resonance imaging (fMRI) studies have been published about examining the different aspects of complex pain experience. The aim of these studies is to understand the functioning of the pain control system, the so-called pain matrix, activated by acute nociceptive stimulus. Another important field of pain research is the investigation of neuronal processes underlying chronic pain, since the pathomechanism of this is still unclear. Our review aims to provide insight into the methods of pain research using fMRI and the achievements of the last few years.]

Clinical Oncology

MAY 10, 2015

[Diagnosis and therapy of childhood brain tumors – an update]

GARAMI Miklós

[Childhood cancers are rare disorders. The average annual age-standardized incidence is 149/1000000 (0-14 yrs). Diagnosis of childhood brain tumors, despite the specifi c localization and advanced imaging techniques can cause diffi culties. In recent years, due to better early recognition, number of surgically removable brain tumors is increasing. Early detection of the disease (clinical knowledge), use of modern imaging (fMRI) techniques and detection of characteristic molecular lesions allow up-to-date diagnosis and successful treatments. These approaches provide the basis for risk-adapted personalized treatment options]

Clinical Neuroscience

SEPTEMBER 30, 2015

Anxiety management and functional magnetic resonance imaging - should it be a priority?

VANDULEK Csaba, DONKÓ Tamás, ILLÉS Anikó, EMRI Miklós, OPPOSITS Gábor, REPA Imre, KOVÁCS Árpád

Background and purpose - Studies have shown that a high proportion of patients undergoing MRI examinations experience anxiety and distress which may compromise image quality and successful data acquisition. Research on fMRI related anxiety is limited as to date, therefore, the purpose of this study was to assess the changes in anxiety as well as to examine its interactions with the implementation of a dedicated patient preparation phase prior to the examination. Methods - An fMRI examination consisting of six paradigms was performed on nine female and nine male healthy volunteers. Prior to the examination, the volunteers were subject to an extensive patient preparation phase including the professional support of a psychologist. The volunteers were subject to the State Trait Anxiety Inventory (STAI) pre and post fMRI. Blood pressure and heart rate were also measured pre and post fMRI examination. Results - A high level of trait and state anxiety was observed (STAI-T: 41.67±8.96; STAI-S: 34.78±9.79) prior to the examination. The level of state anxiety decreased significantly following the examination (STAI-S: 28.83±4.99, p<0.01). Correlation between the volunteers level of anxiety prior to the fMRI scan and the volume of the activation areas was observed in the finger-tapping (r=0.656; 0.561) and word generation (r=0.471) paradigms. Conclusion - The results of this study support the contribution of a supportive patient preparation phase inclusive of professional guidance to help reduce the volunteers’ level of distress and anxiety. These results encourage the study to be extended to clinical patients.

Clinical Neuroscience

MAY 30, 2015

Altered BOLD response within the core face-processing network in congenital prosopagnosia

NÉMETH Kornél, ZIMMER Márta, NAGY Krisztina, BANKÓ Éva, VIDNYÁNSZKY Zoltán, VAKLI Pál, KOVÁCS Gyula

Background and purpose - Congenital prosopagnosia is a life-long disorder of face perception. To study the neural backgrounds of congenital prosopagnosia we measured the blood oxygen level-dependent response of congenital prosopagnosic participants, using functional magnetic resonance imaging. Methods - We tested three persons of the family (father, daughter and son), having symptoms of congenital prosopagnosia, as well as healthy controls, using combined neuropsychological and functional magnetic resonance imaging methods. To reveal the neural correlates of the impairments, blood oxygen level-dependent responses within the occipito-temporal cortex were measured to faces and nonsense object images in a block-design experiment. Results - Neuropsychological tests demonstrated significant impairments of face perception/recognition in each subject. We found that the activity of the fusiform and occipital face areas as well as of the lateral occipital cortex was significantly reduced in congenital prosopagnosic participants when compared to controls. Analysis of the hemodynamic response function revealed a lower peak response, but also a significantly faster and stronger decay of the blood oxygen level-dependent response in the occipito-temporal areas in congenital prosopagnosic participants when compared to controls. Conclusion - Our results emphasize the dysfunction of the core face processing system, as well as the lateral occipital complex, in congenital prosopagnosia. Further, the functional impairment of these areas is signalled best by the altered hemodynamic response function, showing abnormally low initial peak and stronger and faster decay in the later parts of the blood oxygen level-dependent response.

Clinical Neuroscience

SEPTEMBER 30, 2012

[Role of the intraoperative electrical brain stimulation in conserving the speech and language function in neurosurgical operations of awake patients]

ERÕSS Loránd, FEKETE Gábor, ENTZ László, FABÓ Dániel, BORBÉLY Csaba, KOZÁK Lajos Rudolf, ANDREJKOVICS Mónika, CZIRJÁK Sándor, FEDORCSÁK Imre, NOVÁK László, BOGNÁR László

[Aim of the study - To summarize the results gained with awake craniotomies, which were performed in either low grade glioma patients or epilepsy surgical patients whose tumor or epileptogenic zone, was in the vicinity of eloquent, mostly language, cortices. Patient selection and methods - In our retrospective study we selected 16 patients who were operated awake between 1999-2011 at the Neurosurgical Department of MÁV Kórház Budapest, or at the National Institute of Neurosciences in Budapest, or at the Neurosurgical Department of the University of Debrecen in Debrecen. In the presurgical evaluation if it was possible we performed functional magnetic resonance imaging, tractography and detailed neuropsychological testing. At the National Institute of Neurosciences all patients were operated with the aid of MR guided neuronavigation. Results - Anesthesia was carried out without complications in all of the 16 cases. Monitoring of sleep deepness has significantly contributed to the safety of anesthesia during the superficial anesthezied states of the operation. The intraoperative neuropsychological tasks used for testing language were sensitive enough to judge the little disturbances in speech during stimulation. Stimulation evoked seizures could be adequately managed during surgery and did not influence the outcome of the procedures. The use of neuronavigation helped significantly by planning the optimal place for the craniotomy and by intraoperative orientation. Conclusions - Awake craniotomies require well practiced surgical teams, which requires the cooperation of neuro-anesthesiologits, neurosurgeons, neuropsychologist and electrophysiologists. It has two goals, first to reduce the time of surgery to minimize surgical complications, secondly the detailed intraoperative mapping of cognitive and motor functions to avoid any neurological deficit. The intraoperative anatomical data provided by the neuronavigation and the functional data provided by awake intraoperative stimulation of the patient together serve the safety of the patient which is essential in the neurologically minimal invasive neurosurgical approach of the 21st century.]

Clinical Neuroscience

SEPTEMBER 23, 2011

[Functional magnetic resonance imaging for cortical mapping in epilepsy]

KOZÁK Lajos Rudolf, TÓTH Vivien, BARSI Péter, RUDAS Gábor

[It is not only the total curative resection of pathological tissue or the minimization of symptoms to be considered in epilepsy surgery or other neurosurgical procedures, it is equally desirable to maintain the best possible quality of life. Cortical mapping methods can help achieve this goal by delineating eloquent areas, i.e. brain regions that are vital for providing an acceptable quality of life, albeit not prone to compensatory reorganization. These areas include among others the Broca and Wernicke regions for speech, the primary motor, sensory and visual cortices. Functional MRI gained importance in the last decade as a non-invasive clinical cortical mapping technique. This method is capable of localizing cortical areas selectively activated by a given task condition. Thus, selecting appropriate tasks can help mapping eloquent brain regions. Using functional MRI provides information that is complementary to other mapping methods. Moreover, it can replace invasive methods such as the Wada test. Here, we explain the background of functional MRI, compare it to other clinical mapping methods, explain the intricacies of paradigm selection, and show the limitations of the technique while also pointing out alternative uses.]

Clinical Neuroscience

JANUARY 22, 2008

[Functional magnetic resonance imaging in neurology (in English language)]

AUER Tibor, SCHWARCZ Attila, HORVÁTH Réka A., BARSI Péter, JANSZKY József

[The present contribution discusses the clinical use of functional MRI (fMRI) and its role in the most common neurological diseases. FMRI was found a reliable and reproducible examination tool resulting in a wide distribution of fMRI methods in presurgical evaluation of epilepsy in determining the relationship of eloquent areas and the epileptic focus. Preliminary data suggest that fMRI using memory paradigms can predict the postoperative memory decline in epilepsy surgery by determining whether a reorganization of memory functions took place. Speech-activated fMRI became the most used tool in determining hemispheric dominance. Visual and senso-motor cortex can also be routinely investigated by fMRI which helps in decision on epilepsy surgery. FMRI combined with EEG is a new diagnostic tool in epilepsy and sleep disorders. FMRI can identify the penumbra after stroke and can provide an additional information on metabolic state of the threatened brain tissue. FMRI has a predictive role in poststroke recovery. In relapsing-remitting MS an adaptive reorganization can be demonstrated by fMRI affecting the visual, motor, and memory systems, despite preserved functional performance. Much more extensive reorganization can be demonstrated in secondary progressive MS. These findings suggest that the different stages of MS are related to different stages of the reorganization and MS becomes progressive when there is no more reserve capacity in the brain for reorganization. FMRI offers the capability of detecting early functional hemodynamic alterations in Alzheimer’s disease before morphological changes. FMRI can be a valuable tool to test and monitor treatment efficacy in AD. FMRI can also provide information about the mechanisms of different therapeutic approaches in Parkinson disorder including drug treatment and deep brain stimulation.]

Clinical Neuroscience

NOVEMBER 30, 2007

[DIFFUSION TENSOR AND FUNCTIONAL MR IMAGING OF SEVERE TRAUMATIC BRAIN INJURY AT LOW MAGNETIC FIELD]

AUER Tibor, SCHWARCZ Attila, EZER Erzsébet, CZEITER Endre, ARADI Mihály, HUDVÁGNER Sándor, JANSZKY József, BÜKI András, DÓCZI Tamás

[Aim of the study - Presentation of diffusion tensor imaging (DTI) performed at low magnetic field (1 Tesla) in the algorithm of work-up of a patient suffering from severe traumatic brain injury (TBI). Method - DTI and functional MRI (fMRI) were applied at 1 Tesla for visualization of neural pathways and examination of sensory functions of a patient with severe TBI. DTI-measurement was also performed on a healthy patient for comparison. Results - DTI acquired at low magnetic field yielded appropriate visualization of neural pathways. DTI confirmed the results of the clinical and fMRI examinations in the patient suffering from severe TBI. Conclusion - An optimized DTI can be useful in the examination of patients with TBI, moreover, it may also help in the establishment of diagnoses of other central nervous system diseases affecting neuronal pathways. The presented results suggest that DTI of appropriate quality can be performed at low magnetic field.]

Clinical Neuroscience

MARCH 25, 2009

[Plasticity of brain lateralization in epilepsy: fMRI studies]

KALMÁR Zsuzsanna, WOERMANN Friedrich, SCHWARCZ Attila, JANSZKY József

[Aims - This review is a summary of four studies investigating the effect of epileptic disturbance and other functional factors on the brain lateralization. Methods - Patients were investigated by functional MRI by using visual, sensorimotor, memory, and speech paradigms. Results - 1. Malformations of cortical development localized within speech centers induce contralateral speech reorganization in only 50% of cases. 2. Epileptic disturbance can induce a reorganization in language lateralization independent of the effect of lesion. 3. Bilateral epileptic activity can prevent a reorganization of memory functions contralateral to the seizure onset region. 4. Injury of the right upper limb can induce a left-to-right shift of language lateralization. Conclusions - Our results may have implication during neurorehabilitation process and neurosurgical interventions. Participation of malformations of cortical development in cognitive functions should keep in mind during surgery. Reorganization of speech- and memory functions should also be considered during operations of central nervous system.]