A Pseudo Non-Cartesian Pulse Sequence For Hyperpolarized Xenon-129 Gas MRI of Rodent Lungs At Low Magnetic Field Strength

Background: Early diagnosis of radiation-induced lung injury (RILI) following radiation therapy is critical for prevention of permanent lung damage. Pulmonary imaging using magnetic resonance imaging (MRI) of the apparent diffusion coefficient (ADC) of hyperpolarized xenon (129Xe) gas shows promise for early measurement of RILI. Methods: An ultra-short echo time imaging sequence based on a pseudo-Cartesian k-space trajectory, known as Sectoral, is implemented at low magnetic field (0.07 T) for efficient use of the non-renewable magnetization of hyperpolarized 129Xe gas. A pilot study was performed to demonstrate the feasibility of ADC mapping using the Sectoral sequence on healthy and 2-weeks post irradiated rats. Results: A significant (p \u3c 0.05) correlation between mean ADC values from Sectoral ADC maps and the mean linear intercept (Lm), as a measure of interalveolar wall distance, from histological sections of the lungs was observed (p = 0.0061) and a significant (p \u3c 0.05) separation between healthy and irradiated lungs was observed with full width at half maximum ADC (p = 0.0317). Conclusion: Sectoral MRI with 129Xe is feasible in rats. Decreases in ADC were measured following lung irradiations which correlate with Lm

The Influence of Impaired Functioning of Brain Structures on the Ability to Read Emotions and Showing Empathy by People with Autism

Mental states are difficult to understand for people with autism, of course, they need close emotional relationships and refer such contacts, and feel compassion, but sometimes they appear only incidentally, in a unique, social hardship for reading, understanding and acceptance. In the following text, in simple and short way are traced some of the selected concepts of psychological and neurobiological, trying to find some answers to the questions posed at the same time trying to understand the behavior of my patients.Udostępnienie publikacji Wydawnictwa Uniwersytetu Łódzkiego finansowane w ramach projektu „Doskonałość naukowa kluczem do doskonałości kształcenia”. Projekt realizowany jest ze środków Europejskiego Funduszu Społecznego w ramach Programu Operacyjnego Wiedza Edukacja Rozwój; nr umowy: POWER.03.05.00-00-Z092/17-00

\u3csup\u3e1\u3c/sup\u3eH MR spectroscopy of the motor cortex immediately following transcranial direct current stimulation at 7 Tesla

Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that may modulate cortical excitability, metabolite concentration, and human behaviour. The supplementary motor area (SMA) has been largely ignored as a potential target for tDCS neurorehabilitation but is an important region in motor compensation after brain injury with strong efferent connections to the primary motor cortex (M1). The objective of this work was to measure tissue metabolite changes in the human motor cortex immediately following tDCS. We hypothesized that bihemispheric tDCS would change levels of metabolites involved in neuromodulation including N-acetylaspartate (NAA), glutamate (Glu), and creatine (tCr). In this single-blind, randomized, cross-over study, fifteen healthy adults aged 21–60 participated in two 7T MRI sessions, to identify changes in metabolite concentrations by magnetic resonance spectroscopy. Immediately after 20 minutes of tDCS, there were no significant changes in metabolite levels or metabolite ratios comparing tDCS to sham. However there was a trend toward increased NAA/tCr concentration (p = 0.08) in M1 under the stimulating cathode. There was a strong, positive correlation between the change in the absolute concentration of NAA and the change in the absolute concentration of tCr (p\u3c0.001) suggesting an effect of tDCS. Both NAA and creatine are important markers of neurometabolism. Our findings provide novel insight into the modulation of neural metabolites in the motor cortex immediately following application of bihemispheric tDCS

Electric field probe for time-domain monitoring of radio frequency exposure during development and evaluation of MRI-conditional medical devices at 3 T

This paper presents the design and validation of a tuned time-domain electric field probe for mapping of radio frequency (RF) exposures used during testing of magnetic resonance imaging (MRI) conditional medical devices. The probes were 5 and 10 mm short dipole antenna, developed as a tradeoff between spatial resolution, linearity, and sensitivity. The probes were tuned and matched at a center frequency of 127.6 MHz, which corresponds to the RF frequency for 3T MRI scanners. To improve the accuracy and sensitivity, an RF low noise amplifier with high gain and very low noise figure was developed, followed by distributed λ/4 baluns along a triaxial cable to reduce the electric field pickup in the MRI environment. The probe was fabricated on a double-sided printed circuit board, FR4 thickness of 1.57 mm and a copper thickness of 35μm. Theoretical analysis was performed to calculate the exposed electric field from the real-time receive signals. To verify the probe performance finite-difference time-domain method simulations were compared to the actual measured electric fields. Developed probe was tested in a commercially available 3T RF exposure system to determine the probe dynamic range and linearity

Reliable RF B/E-Field Probes for Time-Domain Monitoring of em Exposure during Medical Device Testing

This paper presents electric and magnetic probes to measure radio frequency (RF) electric and magnetic fields for measuring the time-varying RF fields used in magnetic resonance imaging (MRI). A small single loop (2 cm) and short dipole antenna (2 cm) were developed to monitor the near field magnetic and electric exposure during the medical device testing. Theoretical analysis for each designed probe was performed to convert the real time receive signals to the exposed electric and magnetic field. Probes in this paper were tuned and matched at center frequency of 127.6 MHz for 3T MRI scanners to improve the accuracy and sensitivity. Different cables were designed to reduce the E-field pick up and achieving the most accurate measurement setup. Probes were fabricated on a single sided printed circuit board, FR4 of thickness 1.57 mm and a copper thickness of 35μm. The measured S-parameters of the magnetic and electric field probes show less than-44 and-45 dB return loss at 127.6-MHz center frequency of the RF Birdcage

1H MR spectroscopy of the motor cortex immediately following transcranial direct current stimulation at 7 Tesla.

Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that may modulate cortical excitability, metabolite concentration, and human behaviour. The supplementary motor area (SMA) has been largely ignored as a potential target for tDCS neurorehabilitation but is an important region in motor compensation after brain injury with strong efferent connections to the primary motor cortex (M1). The objective of this work was to measure tissue metabolite changes in the human motor cortex immediately following tDCS. We hypothesized that bihemispheric tDCS would change levels of metabolites involved in neuromodulation including N-acetylaspartate (NAA), glutamate (Glu), and creatine (tCr). In this single-blind, randomized, cross-over study, fifteen healthy adults aged 21-60 participated in two 7T MRI sessions, to identify changes in metabolite concentrations by magnetic resonance spectroscopy. Immediately after 20 minutes of tDCS, there were no significant changes in metabolite levels or metabolite ratios comparing tDCS to sham. However there was a trend toward increased NAA/tCr concentration (p = 0.08) in M1 under the stimulating cathode. There was a strong, positive correlation between the change in the absolute concentration of NAA and the change in the absolute concentration of tCr (p<0.001) suggesting an effect of tDCS. Both NAA and creatine are important markers of neurometabolism. Our findings provide novel insight into the modulation of neural metabolites in the motor cortex immediately following application of bihemispheric tDCS