Josef Vymazal

• Head of Department at Na Homolce Hospital

High grade glioma (HGG) is the most common primary brain tumour; we aimed to evaluate T2 relaxivity and diffusion tensor imaging (DTI) metrics in the prediction of progression-free survival. Seventy-two non-recurrent HGG subjects (IDH: MUT=10, Unknown=20) followed at our institution after surgery and combined chemo-radiotherapy were included. All d...

Gadolinium-based contrast agents (GBCA) were introduced with high expectations for favorable efficacy, low nephrotoxicity, and minimal allergic-like reactions. Nephrogenic systemic fibrosis and proven gadolinium retention in the body including the brain has led to the restriction of linear GBCAs and a more prudent approach regarding GBCA indication...

BACKGROUND Tumor Treating Fields (TTFields) are electric fields that disrupt processes critical for cancer cell viability and tumor progression by a multi-modal mechanism of action. TTFields therapy is FDA-approved for newly diagnosed glioblastoma (ndGBM) based on results from the randomized, phase 3 EF-14 study (NCT00916409). We assessed the overa...

BACKGROUND Tumor Treating Fields (TTFields) are electric fields that disrupt processes critical for cancer cell viability and tumor progression by a multi-modal mechanism of action. TTFields therapy is FDA-approved for newly diagnosed glioblastoma (ndGBM) based on results from the randomized, phase 3 EF-14 study (NCT00916409). We assessed the overa...

Purpose Tumor Treating Fields (TTFields) therapy, an electric field-based cancer treatment, became FDA-approved for patients with newly diagnosed glioblastoma (GBM) in 2015 based on the randomized controlled EF-14 study. Subsequent approvals worldwide and increased adoption over time have raised the question of whether a consistent survival benefit...

2059 Background: Tumor Treating Fields (TTFields) are electric fields that exert forces on cancer cells, disrupting processes critical for cancer cell viability and tumor progression. TTFields therapy became an FDA-approved treatment option for patients with newly diagnosed glioblastoma (GBM) in 2015 on the basis of the randomized controlled EF-14...

In functional magnetic imaging (fMRI) in Parkinson’s disease (PD), a paradigm consisting of blocks of finger tapping and rest along with a corresponding general linear model (GLM) is often used to assess motor activity. However, this method has three limitations: (i) Due to the strong magnetic field and the confined environment of the cylindrical b...

Introduction The prognosis of glioblastoma remains unfavorable. TTFields utilize low intensity electric fields (frequency 150–300 kHz) that disrupt cellular processes critical for cancer cell viability and tumor progression. TTFields are delivered via transducer arrays placed on the patients’ scalp. Methods: Between the years 2004 and 2022, 55 pati...

Despite considerable progress in the management of many malignant tumors, the prognosis of the most malignant primary brain tumor, GBM, remains unfavorable. TTFields utilize low intensity electric fields with intermediate frequency (100–500 kHz) that act as an antimitotic, selectively inhibiting growth of rapidly dividing tumor cells by disrupting...

Glioblastoma (GBM) is the most common and aggressive primary brain tumour; we aimed to evaluate T2 relaxivity in their follow. Fifty-one newly diagnosed GBM followed at our department after surgery and combined chemo-radiotherapy were included (> 180 days progression-free survival [PFS] as determined by RANO, ≥ 3 MRI examinations in the PFS interva...

In functional magnetic imaging (fMRI) in Parkinson's disease (PD), a paradigm consisting of blocks of finger tapping and rest along with a corresponding general linear model (GLM) is often used to assess motor activity. However, this method has three limitations: (i) Due to the Strong magnetic field and the confined environment of the cylindrical b...

Introduction: We aimed to evaluate T2 relaxation times in the follow-up of patients with glioblastoma (GBM), the most common and aggressive primary brain tumor with nearly universal recurrence following standard therapy. Methods: In this partially retrospective study, 53 patients (mean age 45.05 years ± 12.6) with non-recurrent GBM followed at our...

Background Neonates and young children require efficacious magnetic resonance imaging (MRI) examinations but are potentially more susceptible to the short- and long-term adverse effects of gadolinium-based contrast agents due to the immaturity of their body functions. Objective To evaluate the acute safety and diagnostic efficacy of gadoteridol (P...

Background Concerns over gadolinium (Gd) retention encourage the use of lower Gd doses. However, lower Gd doses may compromise imaging performance. Higher relaxivity gadobenate may be suited to reduced dose protocols. Purpose To compare 0.05 mmol/kg and 0.1 mmol/kg gadobenate in patients undergoing enhanced MRI of the central nervous system (CNS)....

The back cover image is based on the Original Article Quantification of artifacts during cardiac magnetic resonance in patients with leadless Micra pacemakers by Pavel Hála et al., https://doi.org/10.1111/jce.14988.

A series of 3 patients (35-60 years old) with bleeding distal aneurysm not associated with AVM who underwent radiosurgery by gamma knife are reported. One isocentre centralized over the aneurysm was used; peripheral dose 24-28.8 Gy was applied. Control angiography 20-36 months after gamma knife surgery (GKS) demonstrated obliteration of both the an...

Introduction When cardiac magnetic resonance (MR) is performed after previous leadless transcatheter pacemaker implantation, an image distortion has to be expected in the heart region and evaluation of myocardial tissue can be affected. In this clinical prospective study, we aim to assess the extent and impact of this artifact on individual ventric...

PURPOSE Glioblastoma multiforme (GBM) is the most common and malignant primary intracranial tumor and traditionally has a median survival of only 10 to 14 months, with only 3 to 5% of patients surviving more than three years. Recurrence (RGBM) is nearly universal, and further decreases the median survival to only 5 to 7 months with optimal therapy....

BACKGROUND Tumor treating fields (TTFields; 200 kHz) have shown significant prolonged survival in newly diagnosed (ndGBM). TTFields are anti-mitotic, low intensity, intermediate frequency alternating electric fields. The applied fields disrupt the mitotic spindle, microtubule assembly and the segregation of intracellular organelles during cell divi...

Gadolinium deposition in the brain following administration of gadolinium-based contrast agents (GBCAs) has led to health concerns. We show that some clinical GBCAs form Gd ³⁺ -ferritin nanoparticles at (sub)nanomolar concentrations of...

Introduction: Glioblastoma multiforme (GBM) is the most common malignant primary intracranial tumor and traditionally has a median survival of only 10 to 14 months, with only 3 to 5% of patients surviving more than three years. Recurrence is nearly universal, and further decreases the median survival to only 5 to 7 months with optimal therapy. Tumo...

Levodopa is the first-line treatment for Parkinson’s disease, although the precise mechanisms mediating its efficacy remain elusive. We aimed to elucidate treatment effects of levodopa on brain activity during execution of fine movements and to compare them with deep brain stimulation of the subthalamic nuclei. We studied 32 patients with Parkinson...

Introduction Glioblastoma (GBM) is the most common malignant primary brain tumor, and methods to improve the early detection of disease progression and evaluate treatment response are highly desirable. We therefore explored changes in whole-brain apparent diffusion coefficient (ADC) values with respect to survival (progression-free [PFS], overall [...

Level of Evidence: 1 Technical Efficacy: Stage 5

Emotional and cognitive impairments in Parkinson's disease (PD) are prevalent, hamper interpersonal relations and reduce quality of life. It is however unclear to what extent these domains interplay in PD-related deficits and how they are influenced by dopaminergic availability. This study examined the effect of cognitive impairment and dopaminergi...

Purpose Stereotactic radiosurgery is one of the treatment options for prolactinomas, the most commonly used being Gamma Knife Radiosurgery (GKRS). GKRS is indicated mainly in the treatment of dopamine agonist (DA)-resistant prolactinomas. In our study, we report on our experience in treating prolactinoma patients by GKRS. Methods Twenty-eight pati...

Levodopa has been the mainstay of symptomatic therapy for Parkinson’s disease (PD) for the last five decades. However, it is associated with the development of motor fluctuations and dyskinesia, in particular after several years of treatment. The aim of this study was to shed light on the acute brain functional reorganization in response to a singl...

We aimed at testing the potential of biomarkers in predicting individual patient response to dopaminergic therapy for Parkinson's disease. Treatment efficacy was assessed in 30 Parkinson's disease patients as motor symptoms improvement from unmedicated to medicated state as assessed by the Unified Parkinson's Disease Rating Scale score III. Patient...

OBJECTIVE The aim of this study was to compare 3 different methods to assess the geometrical distortion of two 1.5-T and one 3-T magnetic resonance (MR) scanners and to evaluate co-registration accuracy. The overall uncertainty of each particular method was also evaluated.METHODS Three different MR phantoms were used: 2 commercial CIRS skull phanto...

INTRODUCTION Based on the positive results of our pilot study that evaluated MR diffusion tensor imaging characteristics in the white matter of 13 subjects with glioblastoma, we aimed to evaluate the prognostic value of diffusion restriction in a new, larger cohort of glioblastoma patients. METHODS Thirty-five subjects diagnosed with glioblastoma...

The effects of dopaminergic therapy for Parkinson's disease (PD) on the brain functional architecture are still unclear. We investigated this topic in 31 PD patients (disease duration: 11.2 ± (SD) 3.6 years) who underwent clinical and MRI assessments under chronic dopaminergic treatment (duration: 8.3 ± (SD) 4.4 years) and after its withdrawal. Thi...

Background Based on the positive results of our pilot study that evaluated MR diffusion tensor imaging characteristics in the white matter of 13 subjects with glioblastoma, we aimed to evaluate the prognostic value of diffusion restriction in a new, larger cohort of glioblastoma patients. Material and Methods Thirty-five subjects diagnosed with gl...

Introduction: Quantitative MR parameters, including those derived from diffusion imaging, may advance knowledge on the biological characteristics of gliomas in both diagnostic and treatment settings. We evaluated quantitative diffusion differences that could be detected in glioblastoma patients treated with standard therapy plus TTFields (Optune) v...

Two minimally-invasive techniques in the spinal region are introduced: vertebroplasty and epiduroscopy. Vertebroplasty is mostly used in the treatment of osteoporotic vertebral body fractures, as well as in the palliative treatment of spinal metastases or symptomatic hemangiomas. It is usually performed under fluoroscopic, and often also CT control...

Characterization of the subject's motion inside the MR scanner using the maximum framewise displacement (FD) and the maximum FD with disregarding 5% of the largest values (Max95) obtained by the SPM's translational motion parameters.

Individual STN DBS parameters and positions of the active (−) contact with respect to the lateral wall of the third ventricle (x-coordinate) and the mid-commissural point (y-, z-coordinate) within the STN. Bipolar mode was used for stimulation with a reference in contact 3(+) of the 3389 electrode (Medtronic, MN) in all patients.

Characterization of the subject's motion inside the MR scanner using the mean framewise displacement (FD) and movements with FD > 2 mm obtained by the SPM's translational motion parameters.

Levodopa and, later, deep brain stimulation (DBS) have become the mainstays of therapy for motor symptoms associated with Parkinson's disease (PD). Although these therapeutic options lead to similar clinical outcomes, the neural mechanisms underlying their efficacy are different. Therefore, investigating the differential effects of DBS and levodopa...

INTRODUCTION Quantitative MR parameters, including those derived from diffusion imaging, may advance our knowledge regarding the biological characteristics of gliomas both in diagnostic and treatment settings. We evaluated whether any quantitative diffusion differences could be detected in glioblastoma patients treated with standard therapy plus TT...

INTRODUCTION Glioblastoma (GBM) is the most common and malignant primary intracranial tumor and traditionally has a median survival of only 10 to 14 months, with only 3 to 5% of patients surviving more than three years. Recurrence (RGBM) is nearly universal, and further decreases the median survival to only 5 to 7 months with optimal therapy. METH...

Objective: The aim of the present study was to investigate if prospective memory (PM) is impaired in idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD). RBD is a parasomnia characterized by dream enactment and by REM sleep without muscle atonia. iRBD is considered as the initial stage of neurodegeneration with pathological storage o...

Depression, anxiety and apathy are distinct neuropsychiatric symptoms that highly overlap in Parkinson's disease (PD). It remains unknown whether each symptom is uniquely associated with a functional network dysfunction. Here, we examined whether individual differences in each neuropsychiatric symptom predict functional connectivity patterns in PD...

Introduction: Glioblastoma multiforme (GBM) is the most common and malignant primary intracranial tumor and traditionally has a median survival of only 10 to 14 months, with only 3 to 5% of patients surviving more than three years. Recurrence (RGBM) is nearly universal, and further decreases the median survival to only 5 to 7 months with optimal th...

Although essential tremor (ET) is the most common movement disorder, there is little knowledge about the pathophysiological mechanisms of this disease. Therefore, we explored brain connectivity based on slow spontaneous fluctuations of blood oxygenation level dependent (BOLD) signal in patients with essential tremor (ET). A cohort of 19 ET patients...

Scientific Reports 7 : Article number: 43743 10.1038/srep43743 ; published online: 08 March 2017 ; updated: 10 April 2017 This Article contains errors in the Acknowledgements section.

We describe an analysis method that characterizes the correlation between coupled time-series functions by their frequencies and phases. It provides a unified framework for simultaneous assessment of frequency and latency of a coupled time-series. The analysis is demonstrated on resting-state functional MRI data of 34 healthy subjects. Interactions...

The review article describes individual MR contrast agents on the basis of gadolinium chelates, it focuses on their physic-chemical properties and clinical use. The paper emphasizes schematic division of the contrast agents to linear and cyclic chelates because the situation in vivo is more complex. The paper focuses further on nephrogenic systemic...

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor with nearly universal progression despite aggressive first-line therapy. The Optune device represents an innovative treatment option for patients with recurrent GBM, which utilizes alternating electric fields at an intermediate frequency of 200 kHz, or Tumor Treating Fie...

Introduction Deep brain stimulation (DBS) of the globus pallidus interna (GPi) is widely used in treatment of pharmacoresistant dystonic syndromes. In our study, we analyzed functional connectivity change derived from resting state fMRI in two conditions: with the DBS chronically switched on (ON condition) and two hours after switching the DBS off...

Purpose Multiple system atrophy (MSA) is a rare neurodegenerative disease that remains poorly understood, and the diagnosis of MSA continues to be challenging. We endeavored to improve the diagnostic process and understanding of in vivo characteristics of MSA by diffusion tensor imaging (DTI). Materials and methods Twenty MSA subjects, ten parkins...

Objective Anxiety is a common symptom of Parkinson’s disease (PD) negatively influencing quality of life. To identify brain regions associated with this symptom we compared resting brain connectivity to subjective assessment of anxiety. Participants and methods Using the resting state-fMRI (3T, TR = 2s, 300 scans) we analysed spontaneous signal fl...

Background: Cognitive decline, Parkinsonism and depression are frequent accompaniments of aging. Prevalence of these disorders rises together with age. Among residents of assisted living facilities there is presumption of higher occurrence of these disorders. Objective: To obtain a direct estimate of the prevalence of dementia, Parkinsonism and dep...

Background/objectives: The treatment of large arteriovenous malformations (AVMs) presents a challenge and the effectiveness of radiosurgery decreases with increasing treatment volume. Here, we analyzed and compared single-session treatment for AVMs >15 cm3 with staged treatment, when the volume of a large AVM was divided into 2 or more compartment...

Huntington's disease (HD) is an inherited neurodegenerative disorder with progressive impairment of motor, behavioral and cognitive functions. The clinical features of HD are closely related to the degeneration of the basal ganglia, predominantly the striatum. The main striatal output structure, the globus pallidus, strongly accumulates metalloprot...

This paper is open-access, please download it from europace site ! Our aim was to evaluate the potential for safely imaging patients with a new type of implantable cardioverter-defibrillator called the subcutaneous implantable cardioverter-defibrillator (S-ICD) in a 1.5 T magnetic resonance imaging (MRI) scanner. With the increasing number of pati...

Background and purpose: Gadobutrol (Gadavist) and gadoteridol (ProHance) have similar macrocyclic molecular structures, but gadobutrol is formulated at a 2-fold higher (1 mol/L versus 0.5 mol/L) concentration. We sought to determine whether this difference impacts morphologic contrast-enhanced MR imaging. Materials and methods: Two hundred twent...

The accumulation of iron in the brain is a common physiological process. However, alterations in the deposition of iron or other paramagnetic substances are associated with various diseases. In the present study, the deposition of paramagnetic substances in patients with brain tumours was evaluated using T2 relaxometry. A total of 23 patients with...

Considering the functional organization of the subthalamic nucleus (STN), we hypothesized that subthalamic deep brain stimulation (STN-DBS) in Parkinson's disease might have a differential impact on the hypothalamic-pituitary-adrenal axis in relation to the position of active stimulating contact within the STN. In addition, we searched for any STN-...

Object: Glomus tumors usually display indolent behavior, and the effectiveness of radiation in stopping their growth can be assessed after long-term follow-up. Currently only midterm results of radiosurgery are available, so the authors included patients treated by Gamma Knife at least 10 years ago in this study to obtain a perspective of long-ter...

Figure 1. (A) Scheme representing the different compartments in the model and the rate constants associated with the interactions between them. [L] = Latent/Nondividing cells; [R] = Replicating/Dividing cells; [D] = Dead cells; [C] = Cells cleared from tumor by physiological mechanisms. TTFields were modeled as effecting K3. (B) Results of kinetic...

Introduction It has been hypothesised that changes of iron content in the brain may be involved in the pathogenesis of Huntington’s disease (HD). The aim of our study was to detect whether the deposits of iron change during the disease progression. Subjects and methods To ascertain the hypothesis, we re-investigated 13 right-handed HD patients (mea...

Purpose: To characterize the relationship between superparamagnetic ferritin-bound iron and diffusion tensor scalars in vitro, and validate the results in vivo. Materials and methods: The in vitro model consisted of a series of 40-mL 1.1% agarose gels doped with ferritin covering and exceeding those concentrations normally found within healthy h...

Please, download PDF directly using this link: http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0071431&representation=PDF Fractional anisotropy (FA) is the most commonly used quantitative measure of diffusion in the brain. Changes in FA have been reported in many neurological disorders, but the implementat...

Bland Altman plots comparing fractional anisotropy (FA) acquired in sequences with 12 and 30 motion probing gradient directions. FA values are multiplied by 100 BG, basal ganglia; GM, gray matter; CC, corpus callosum; cROI, circular region of interest. (TIFF)

Prediction intervals and correlation coefficients between fractional anisotropy (FA) in 12 and 30 motion probing gradient directions (MPG). Group, group of the region of interest (ROI); Pred.Low, Pred.Upp – lower border and upper border, respectively of the 95% prediction interval for the difference between FA in 12 and 30 MPGs; Cor, Cor.PValue – c...

Comments on Bland Altman plots comparing fractional anisotropy acquired in sequences with 12 and 30 motion probing gradient directions. (DOC)

Natalizumab (monoclonal antibody) is currently indicated as a second line treatment for relapse-remitting multiple sclerosis (RRMS). Serious and potential fatal side effect of this treatment is progressive multifocal leukoencefalopathy (PML), which belongs to rare brain infections caused by JC virus (JCV). There is a progressive inflammation of the...

Purpose: Radiosurgery of cavernomas should prevent rebleeding, growth of the lesion, and deterioration of clinical symptoms. However, there is no direct diagnostic tool to verify the endpoints of treatment. At present, the positive effects of radiosurgery are identified by clinical observation and analysis of imaging changes on magnetic resonance i...

To tackle the heterogeneity of Parkinson's disease symptoms, most functional imaging studies tend to select a uniform group of subjects. We hypothesize that more profound considerations are needed to account for intra/inter-subject clinical variability and possibly for differing pathophysiological processes. Twelve patients were investigated using...

Electrode implantation into the subthalamic nucleus for deep brain stimulation in Parkinson's disease (PD) is associated with a temporary motor improvement occurring prior to neurostimulation. We studied this phenomenon by functional magnetic resonance imaging (fMRI) when considering the Unified Parkinson's Disease Rating Scale (UPDRS-III) and coll...

Individual description of the PD patient's group (N = 12). ID – patient's identification number; age – age of patient at surgery in years; G – gender: male (M); DD – duration of the PD in years; LD – duration of the levodopa treatment in years; MC – duration of motor complications in years; UPDRS-III in sessions 1–4: First number refers to OFF cond...

Glioblastoma multiforme (GBM) is the most common and malignant primary intracranial tumor, and has a median survival of only 10 to 14 months with only 3 to 5% of patients surviving more than three years. Recurrence (RGBM) is nearly universal, and further decreases the median survival to only five to seven months with optimal therapy. Tumortreating...

Background: Cerebrovascular disease represents a major source of global mortality and morbidity. Imaging examinations play a critical role in the management of stroke patients, from establishing the initial diagnosis to determining and guiding further treatment. Methods: In this article, current CT and MRI methods employed in the management of s...

Backround Huntington's disease (HD) is an inherited autosomal dominant neurodegenerative disorder with progressive impairment of motor and cognitive functions and behavioural abnormalities. The clinical features of HD are closely related to the degeneration of the basal ganglia, predominantly the striatum. The main striatal output structure, the gl...

A prospective quantitative MR study of brain tumours was performed to show the potential of combining different MR techniques to distinguish various disease processes in routine clinical practice. Twenty-three patients with various intracranial tumours before treatment (diagnosis confirmed by a biopsy) and 59 healthy subjects were examined on a 3-T...

The aim of our study was to assess changes in body-weight in relation to active electrode contact position in the subthalamic nucleus. Regular body weight measurements were done in 20 patients with advanced Parkinson's disease within a period of 18 months after implantation. T1-weighted (1.5T) magnetic resonance images were used to determine electr...

Gadobenate dimeglumine has proved advantageous compared with other gadolinium-based contrast agents for contrast-enhanced brain MR imaging. Gadobutrol is a more highly concentrated agent (1.0 mol/L). This study intraindividually compared 0.1-mmol/kg doses of these agents for qualitative and quantitative evaluation of brain tumors. Adult patients wi...

Background Parkinson's disease (PD) patients are deficient in time estimation. This deficit improves after dopamine (DA) treatment and it has been associated with decreased internal timekeeper speed, disruption of executive function and memory retrieval dysfunction.Methodology/findingsThe aim of the present study was to explore the neurophysiologic...

PURPOSE As the prevalence of implanted cardiac devices and indications for MRI concurrently increase, a growing need for MR-conditional devices has become apparent. MR-conditional (MR-C) cardiac pacemaker systems (CPS) are specific pacemaker/lead combinations determined to be safe at 1.5T under specific conditions. The first such system, the EnRhyt...

PURPOSE The aim of our study was to evaluate diffusion changes in main subtypes of Multiple System Atrophy (MSA): MSA-P (Parkinsonian) and MSA-C (cerebellar). We compared MSA patients to healthy subjects as well as MSA-C to MSA-P using TBSS. METHOD AND MATERIALS Patients with probable MSA-P (n=7, 1 Male, 6 Female, 58.8Y±5SD), MSA-C (n=10, 6 male,...

Patients with writer's cramp (WC) were studied for differences in cortical activation during movements likely to induce WC (complex movements) and movements which rarely lead to dystonia (simple movements). Eleven WC patients (10F, 1M, mean age 41.5 ± (SD)7.2 years) and eleven age matched controls were examined for Blood oxygenation-level dependent...

Supplementary motor area (SMA) was suggested to have a dominant role in the temporal control of behavior by many neuroimaging studies. The aim of this study was to support this hypothesis by influencing time estimates with theta burst transcranial magnetic stimulation (TMS) over the SMA. Nineteen healthy volunteers with a mean age 25.9±3 (SD) years...

To evaluate the potential of quantitative MR techniques [voxel-based morphometry (VBM), T2-relaxometry, mean diffusivity (MD), fractional anisotropy (FA)] in the diagnostics of amyotrophic lateral sclerosis (ALS). Thirty-three ALS patients and thirty age- and sex-matched healthy volunteers were included in the cross-sectional study. T1WI, T2WI and...