Lajos Rudolf Kozák

Semmelweis University | SOTE · Department of Neuroradiology

Citation: Strelnikov, D.; Alijanpourotaghsara, A.; Piroska, M.; Szalontai, L.; Forgo, B.; Jokkel, Z.; Persely, A.; Hernyes, A.; Kozak, L.R.; Szabo, A.; et al. Heritability of Subcortical Grey Matter Structures. Medicina 2022, 58, 1687. https:// Abstract: Background and Objectives: Subcortical grey matter structures play essential roles in cognitive...

Introduction: White matter hyperintensities (WMH) indicate white matter brain lesions in magnetic resonance imaging (MRI), which can be used as a marker for brain aging and cerebrovascular and neurodegenerative disorders. Twin studies revealed substantial but not uniform WMH heritability in elderly twins. The objective of our study was to investiga...

Purpose We assessed diffusion tensor imaging (DTI) metric changes of the corpus callosum and cingulum correlated to postprocedural ischemic lesion load (ILL) and cognitive performance in transcatheter aortic valve replacement (TAVR). Methods TAVR subjects had DTI post-TAVR (≤ 8 days) and at 6 months (78 participants, males 56%, age 78.8 years ± 6....

Background Previous studies suggested a circadian variation of migraine attack onset, although, with contradictory results – possibly because of the existence of migraine subgroups with different circadian attack onset peaks. Migraine is primarily a brain disorder, and if the diversity in daily distribution of migraine attack onset reflects an impo...

Several factors can contribute to the development and chronification of migraines, including stress, which is undoubtedly a major trigger. Beyond pharmacotherapy, other treatment methods also exist, including behavioral techniques aiming at reducing patients’ stress response. However, the exact brain mechanisms underlying the efficacy of such metho...

Previous studies targeting inter-individual differences in pain processing in migraine mainly focused on the perception of pain. Our main aim was to disentangle pain anticipation and perception using a classical fear conditioning task, and investigate how migraine frequency and pre-scan cortisol-to-dehydroepiandrosterone sulfate (DHEA-S) ratio as a...

A 76-year-old man with hypertension underwent elective carotid computed tomography (CT) angiography to evaluate a previously known asymptomatic right carotid stenosis. Before the examination, the patient had no neurological symptoms. During scanning, he developed head and gaze deviation to the right, and on physical examination immediately afterwar...

Background: Merkel cell carcinoma (MCC) is a rare primary neuroendocrine cutaneous tumor, rarely metastasizing to the brain. Chronic lymphoid leukemia (CLL) is a disease predisposing to MCC. According to previous reports, headache and focal neurological deficits suggest disease progression to the brain. We present a patient with MCC whose seizure...

Background Schizophrenia (SZ) is a complex disorder characterized by a range of behavioral and cognitive symptoms as well as structural and functional alterations in multiple cortical and subcortical structures. SZ is associated with reduced functional network connectivity involving core regions such as the anterior cingulate cortex (ACC) and the t...

A szerzők jelen tanulmányukban a fogyasztói etnocentrizmus idegi korrelációit vizsgálták 16 fő önkéntes részvételével, block-design fMRI-paradigma alkalmazásával. Az inger bemutatása (vagyis a stimulációs blokkok fő hatása) megmutatta a várt erős kétoldali occipitalis, occipito-temporális és alacsonyabb temporális lebeny aktivitást, amely összhangb...

Background and purpose: 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...

Abstract Background Identification of early signs of hypoxic ischemic encephalopathy (HIE) with magnetic resonance imaging (MRI) has proven of prognostic significance. Yet, the importance of intracranial hemorrhage (ICH), being present concomitantly had not been investigated yet, despite the known influence of hypothermia on hemostasis. We aimed to...

Background: The anterior cingulate cortex (ACC) is a key structure of the pain processing network. Several structural and functional alterations of this brain area have been found in migraine. In addition, altered serotonergic neurotransmission has been repeatedly implicated in the pathophysiology of migraine, although the exact mechanism is not k...

Background: The initial effects of selective serotonin reuptake inhibitors (SSRIs) in the human living brain are poorly understood. We carried out a 3T resting state fMRI study with pharmacological challenge to determine the brain activation changes over time following different dosages of citalopram. Methods: During the study, 7.5 mg i.v. cital...

Quantitative MRI methods have recently gained extensive interest and are seeing substantial developments; however, their application in single patient vs control group comparisons is often limited by inherent statistical difficulties. One such application is detecting malformations of cortical development (MCDs) behind drug resistant epilepsies, a...

The dysfunctions of the mesolimbic cortical reward circuit have been proposed to contribute to migraine pain. Although supporting empirical evidence was mainly found in connection with primary rewards or in chronic migraine where the pain experience is (almost) constant. Our goal however was to investigate the neural correlates of secondary reward/...

Previous studies have demonstrated that migraine is associated with enhanced perception and altered cerebral processing of sensory stimuli. More recently, it has been suggested that this sensory hypersensitivity might reflect a more general enhanced response to aversive emotional stimuli. Using functional magnetic resonance imaging and emotional fa...

Background: Unilateral weakness of an upper extremity is most frequently caused by traumatic nerve injury or compression neuropathy. In rare cases, lesion of the central nervous system may result in syndromes suggesting peripheral nerve damage by the initial examination. Pseudoperipheral hand palsy is the best known of these, most frequently cause...

Rumination – as a stable tendency to focus repetitively on feelings related to distress – represents a transdiagnostic risk factor. Theories suggest altered emotional information processing as the key mechanism of rumination. However, studies on the anticipation processes in relation to rumination are scarce, even though expectation in this process...

Abstract Background Neonatal hypoxic-ischemic encephalopathy (HIE) commonly leads to neurodevelopmental impairment, raising the need for prognostic tools which may guide future therapies in time. Prognostic value of proton MR spectroscopy (H-MRS) between 1 and 46 days of age has been extensively studied; however, the reproducibility and generalizab...

Background: Anatomic variants of the circle of Willis (CW) are commonly observed in healthy subjects. Genetic and environmental factors influencing these variants remain unclear. Our aim was to assess the genetic and environmental background affecting variant CW phenotypes. Methods: A total of 122 adult healthy twins from the Hungarian Twin Regi...

Background and purpose: To develop an evidence-based, standardized structured reporting (SR) method for brain MRI examinations in neonatal hypoxic-ischemic encephalopathy (HIE) suitable both for clinical and research use. Methods: SR template development was based on comprehensive review of the pertinent literature with the basic sections and su...

Background Schizophrenia has a negative effect on the activity of the temporal and prefrontal cortices in the processing of emotional facial expressions. However no previous research focused on the evaluation of mixed emotions in schizophrenia, albeit they are frequently expressed in everyday situations and negative emotions are frequently expresse...

Mild cognitive impairment (MCI) gained a lot of interest recently, especially that the conversion rate to Alzheimer Disease (AD) in the amnestic subtype (aMCI) is higher than in the non-amnestic subtype (naMCI). We aimed to determine whether and how diffusion-weighted MRI (DWI) using the diffusion tensor model (DTI) can differentiate MCI subtypes f...

Introduction and aim In order to investigate and map the precise epileptic mechanism(network) and seizure onset zone during the planning of epilepsy surgery we use more and more complex imaging and electrophysiological studies. The analysis and evaluation of the ever growing datasets needs such a complex platform which can integrate the spatial inf...

Generally, the interpretation of functional MRI (fMRI) activation maps continues to rely on assessing their relationship to anatomical structures, mostly in a qualitative and often subjective way. Recently, the existence of persistent and stable brain networks of functional nature has been revealed; in particular these so-called intrinsic connectiv...

Former studies suggest that the core features of psychopathy, namely the callous-unemotional (CU) traits are associated with emotional dysfunction characterized by atypical processing of other people's distress. Using a dimensional approach to CU traits, the current study aims to test neural activity during performance of a facial expression recogn...

Cumulative evidence suggests that trait rumination can be defined as an abstract information processing mode, which leads people to constantly anticipate the likely impact of present events on future events and experiences. A previous study with remitted depressed patients suggested that enhanced rumination tendencies distort brain mechanisms of an...

Background Although migraine is one of the most investigated neurologic disorders, we do not have a perfect neuroimaging biomarker for its pathophysiology. One option to improve our knowledge is to study resting-state functional connectivity in and out of headache pain. However, our understanding of the functional connectivity changes during sponta...

Since the publication of the book titled “Neuroophtalmology” in 1996, the development of CT and MRI and PET techniques are the most relevant to follow up in neuroradiology. The reason is that these modalities, as well as their advanced imaging methods are widely available. Therefore the structure of this chapter will follow technical considerations...

Purpose: Resting state functional MRI (rs-fMRI) examinations are gaining importance in clinical practice as they are quick, easy to perform, do not require patient cooperation, and automated processing pipelines lead to results with minimal user interaction. Still, the lack of a widely accepted processing pipeline makes comparison of results cumber...

Objective: We used functional MRI (fMRI) and a left-lateralizing verbal and a right-lateralizing visual-spatial working memory (WM) paradigm to investigate the effects of levetiracetam (LEV) on cognitive network activations in patients with drug-resistant temporal lobe epilepsy (TLE). Methods: In a retrospective study, we compared task-related f...

We report the palliative embolization and functional imaging follow-up of a recurrent shoulder plasmacytoma. The multiple myeloma patient complained of severe pain and discomfort, while he could not tolerate further chemotherapy. The left shoulder lesion had earlier received a high dose of irradiation. Thus, the well-vascularized lesion was emboliz...

The role of cortical connectivity in brain function and pathology is increasingly being recognized. While in vivo magnetic resonance imaging studies have provided important insights into anatomical and functional connectivity, these methodologies are limited in their ability to detect electrophysiological activity and the causal relationships that...

Gender identity disorder (GID) refers to transsexual individuals who feel that their assigned biological gender is incongruent with their gender identity and this cannot be explained by any physical intersex condition. There is growing scientific interest in the last decades in studying the neuroanatomy and brain functions of transsexual individual...

Diffusion weighted magnetic resonance imaging is increasingly being used for neonatal and young pediatric subjects. Our purpose was to investigate a) whether cardiac triggering was needed to reduce variability of diffusion (tensor) imaging data, b) how pulsation artifacts affect the fitted diffusion tensor when triggering is not used and c) the fea...

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 betwe...

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 a...

It has been proposed that enhanced activity in the human motion complex (hMT⁺/V5) underlies the perception of illusory motion. Recent studies, however, have argued that in the case of motion aftereffect (MAE) this increase is due to visual selective attention rather than to the perception of MAE itself. It has also been reported that no net increas...

Visual attentional selection enhances the neural response to relevant features and suppresses the response to competing irrelevant features. Feature-based enhancement is known to operate across the visual field, and here we use fMRI in human observers to determine if attentional suppression is restricted to the currently attended spatial location o...

Training on a visual task leads to increased perceptual and neural responses to visual features that were attended during training as well as decreased responses to neglected distractor features. However, the time course of these attention-based modulations of neural sensitivity for visual features has not been investigated before. Here we measured...

After adaptation to transparent stimuli moving in different directions, the motion aftereffect (MAE) is perceived in a single direction. This phenomenon has been explained by postulating that direction-selective neurons in an initial stage (identified with V1) excite neurons in a second stage (MT) which have similar direction tuning, and inhibit th...

Hypothermia is often induced to reduce brain injury in newborns, following perinatal hypoxic-ischaemic events, and in adults following traumatic brain injury, stroke or cardiac arrest. We aimed to devise a method, based on diffusion-weighted MRI, to measure non-invasively the temperature of the cerebrospinal fluid in the lateral ventricles. The wel...

Activity in the human motion complex (hMT(+)/V5) is related to the perception of motion, be it either real surface motion or an illusion of motion such as apparent motion (AM) or motion aftereffect (MAE). It is a long-lasting debate whether illusory motion-related activations in hMT(+) represent the motion itself or attention to it. We have asked w...

A part of patients with the therapy resistant epilepsy can be cured by surgical interventions. The more concordant the presurgical evaluation data, the better prognosis the patient has postoperatively. In case of discordant examination data, multimodal evaluation or case-specific decision might be successful. We report on a five-year-old boy with b...

When learning to master a visual task in a cluttered natural environment, it is important to optimize the processing of task-relevant information and to efficiently filter out distractors. However, the mechanisms that suppress task-irrelevant information are not well understood. Here we show that training leads to a selective increase in motion coh...

Functional magnetic resonance imaging examinations became an integral part of epilepsy surgery workup. In the pediatric population these examinations are usually carried out in full anesthesia, however in some forms of epilepsy, e.g. electrical status epilepticus in sleep, anesthesia could jeopardize the success of the examination. Here, we show on...

To study how central visual motion integration and segmentation processes are influenced by the congruence or incongruence of peripheral contextual moving surrounds and to determine their clinical relevance. Nine subjects participated in experiments 1 and 2 (12-second blocks containing 2-second static fixation and 10-second surface plaid movement)...

Purpose: Our goal was to assess the utility of functional magnetic resonance imaging (fMRI) in simultaneous mapping of perceptual and neural visual field deficits, and in the assessment of neural plasticity processes underlying spontaneous and medication-induced visual field recovery.Methods: Neural function of two patients with predominantly unila...

To quantify chromatic dysfunction in Best disease to reassess the classic categorization of macular chromatic damage and to investigate psychophysical and clinical correlations. Color-contrast discrimination was measured using 2 different psychophysical strategies in age-matched control (n = 41) and patient (n = 34) eyes. The first strategy measure...

To use a new methodological approach, based on luminance noise, to assess without bias the relative damage of blue-yellow and red-green pathways in ocular hypertension and glaucoma and to correlate obtained measurements with clinical markers of disease progression. A psychophysical procedure modified from Cambridge color test was used to assess col...

This review first gives an overview on the concept of fractal geometry with definitions and explanations of the most fundamental properties of fractal structures and processes like self-similarity, power law scaling relationship, scale invariance, scaling range and fractal dimensions. Having laid down the grounds of the basics in terminology and ma...