Search results for "magneettitutkimus"

Neuroanatomical substrate of noise sensitivity.

2018

Recent functional studies suggest that noise sensitivity, a trait describing attitudes towards noise and predicting noise annoyance, is associated with altered processing in the central auditory system. In the present work, we examined whether noise sensitivity could be related to the structural anatomy of auditory and limbic brain areas. Anatomical MR brain images of 80 subjects were parcellated with FreeSurfer to measure grey matter volume, cortical thickness, cortical area and folding index of anatomical structures in the temporal lobe and insular cortex. The grey matter volume of amygdala and hippocampus was measured as well. According to our findings, noise sensitivity is associated wi…

Synthesis, Stability and Relaxivity of TEEPO-Met: An Organic Radical as a Potential Tumour Targeting Contrast Agent for Magnetic Resonance Imaging

2018

Cancer is a widespread and life-threatening disease and its early-stage diagnosis is vital. One of the most effective, non-invasive tools in medical diagnostics is magnetic resonance imaging (MRI) with the aid of contrast agents. Contrast agents that are currently in clinical use contain metals, causing some restrictions in their use. Also, these contrast agents are mainly non-specific without any tissue targeting capabilities. Subsequently, the interest has notably increased in the research of organic, metal-free contrast agents. This study presents a new, stable organic radical, TEEPO-Met, where a radical moiety 2,2,6,6-tetraethylpiperidinoxide (TEEPO) is attached to an amino acid, methio…

Association between radiography-based subchondral bone structure and MRI-based cartilage composition in postmenopausal women with mild osteoarthritis

2016

Summary Objective Our aim was to investigate the relation between radiograph-based subchondral bone structure and cartilage composition assessed with delayed gadolinium enhanced magnetic resonance imaging of cartilage (dGEMRIC) and T 2 relaxation time. Design Ninety-three postmenopausal women (Kellgren–Lawrence grade 0: n  = 13, 1: n  = 26, 2: n  = 54) were included. Radiograph-based bone structure was assessed using entropy of the Laplacian-based image ( E Lap ) and local binary patterns ( E LBP ), homogeneity indices of the local angles (HI Angles,mean , HI Angles,Perp , HI Angles,Paral ), and horizontal (FD Hor ) and vertical fractal dimensions (FD Ver ). Mean dGEMRIC index and T 2 relax…

Alaraajojen luun mineraalipitoisuuden ja polven nivelruston väliset yhteydet postmenopausaalisilla naisilla

2011

Tämän poikkileikkaustutkimuksen tarkoituksena oli selvittää luuston (reisiluun kaula, lanneranka L2-L4) mineraalitiheysarvojen ja polven nivelruston (reisiluu, sääriluu) eheyttä kuvaavien dGEMRIC-arvojen välistä yhteyttä postmenopausaalisilla naisilla. Tutkimukseen rekrytoitiin 82 naista (keskimääräiseltä iältään 57,7 vuotta, SD 4,2) lehti-ilmoituksen perusteella. Sisäänottokriteerinä oli rtg:llä arvioidun Kellgren-Lawrence-luokituksen (K/L) mukaan ensimmäisen (K/L1) tai toisen (K/L2) asteen lievä polven nivelrikko. Reisiluun kaulan ja lannerangan (L2–L4) BMC-arvot mitattiin DXA-laitteistolla. Tutkimushenkilöillä ei ollut osteoporoosia, jonka kynnysarvona käytettiin T-arvoa >2,5. Tibian ja …

Aerobic fitness, but not physical activity, is associated with grey matter volume in adolescents.

2019

Higher levels of aerobic fitness and physical activity are linked to beneficial effects on brain health, especially in older adults. The generalizability of these earlier results to young individuals is not straightforward, because physiological responses (such as cardiovascular responses) to exercise may depend on age. Earlier studies have mostly focused on the effects of either physical activity or aerobic fitness on the brain. Yet, while physical activity indicates the amount of activity, aerobic fitness is an adaptive state or attribute that an individual has or achieves. Here, by measuring both physical activity and aerobic fitness in the same study, we aimed to differentiate the assoc…

Brain, cognition and physically active lifestyle in healthy ageing

2018

Normal ageing is accompanied by profound changes in brain structure and declines in the automatic processing of sensory stimuli, which in turn lead to altered cognitive performance. However, behaviour and lifestyle factors, such as physical activity, may help to maintain the brain’s structural connectivity and function, as well as cognitive functioning in old age. Study I examined the effects of age on the brain’s capability to detect changes in somatosensory stimuli by recording event-related potentials (ERPs) in response to electrical stimulation of different fingers in young and older adults. The results of Study I show that somatosensory mismatch response (sMMR) was attenuated in amplit…

Examining stability of independent component analysis based on coefficient and component matrices for voxel-based morphometry of structural magnetic …

2018

Independent component analysis (ICA) on group-level voxel-based morphometry (VBM) produces the coefficient matrix and the component matrix. The former contains variability among multiple subjects for further statistical analysis, and the latter reveals spatial maps common for all subjects. ICA algorithms converge to local optimization points in practice and the mostly applied stability investigation approach examines the stability of the extracted components. We found that the practically stable components do not guarantee to produce the practically stable coefficients of ICA decomposition for the further statistical analysis. Consequently, we proposed a novel approach including two steps: …

Cluster priors in the Bayesian modelling of fMRI data

2001

Use of deeper plantar flexor muscles in low torque isometric and concentric plantar flexion tasks

2016

Coordination of a task such as plantar flexion might seem simple, but is in reality achieved through the activation of several muscles—muscles that play an important role in locomotion and posture control. These can be divided in to two groups, superficial and deep plantar flexors. It has been shown that although people usually produce certain well learned movements very similarly, some variability in the coordination might occur. This is also the case with the ankle plantar flexors as shown by Finni et al. (2006) and Masood et al (2014). Purpose of the study was to examine whether some individuals use their deeper plantar flexors to a greater extent than others and to see whether the relat…

Anxiety reduction with music and tempo synchronization on magnetic resonance imaging patients

2017

Anxiety and claustrophobic reactions in MRI examinations cause unintentional movements, and such motion artifacts lead to interpretation problems. Furthermore, requested anesthesia makes the process costly. A total of 60 outpatients were examined in the Diagnostic Centre of Pécs, Hungary, to test whether synchronizing recorded music to the gradient pulsation of the MRI device can improve the sedative effect of the music. The patients were assigned to three groups: a nonmusic (control), an original tempo (random) and a synchronized music (synchronous) group. Results showed a significantly decreased state anxiety level after the MRI examination in the random and synchronous groups as compared…