Search Results (4)

The aims of this study were to assess the common anomalies in the MRI examinations of the heads of soldiers as well as to compare the relative concentration of magnetic resonance spectroscopy (MRS) metabolites in the brains of soldiers with those of healthy age-matched controls. Overall, 54 professional male soldiers were included in the study group and 46 healthy, age-matched males were in the control group. The relative values of N-acetylaspartate (NAA), choline (Cho), and myoinositol (mI) to creatine (Cr) were assessed. The mean relative concentrations of metabolites were compared between the study and the control group, separately for the frontal and occipital lobes, as well as between the right and left hemispheres within the study group only. The most frequent findings in the head MRI of the soldiers were: asymmetric lateral ventricles and dilated perivascular spaces, enlargement of the subarachnoid spaces, and the presence of cavum septum pellucidum and cavum vergae; the high frequency of sinus disease should also be noted. In the frontal lobes, the mI/Cr ratio was significantly higher (p = 0.005), while the NAA/Cr ratio was lower (p = 0.001), in the group of soldiers (vs. the study group). In the occipital lobes, the NAA/Cr ratio was significantly lower (p = 0.005) in the military personnel and there was a tendency to a higher mI/Cr ratio in the soldiers’ occipital lobes (p = 0.056) (vs. the study group). Comparing the metabolites between the left and right hemispheres in soldiers preferring a right shooting position, a significantly higher mI/Cr (p < 0.001) ratio was observed in the right frontal lobe (vs. the left) and a markedly lower NAA/Cr (p = 0.003) in the right occipital lobe (vs. the left). These changes are associated with astrogliosis and neuronal loss, presumably secondary to repetitive mild traumatic brain injury. Full article

The asymmetric development of the cerebellum has been reported in several mammalian species. The current study quantitatively characterized cerebellar asymmetry and sexual dimorphism in cynomolgus macaques using magnetic resonance (MR) imaging-based volumetry. Three-dimensional T₁W MR images at 7-tesla were acquired ex vivo from fixed adult male (n = 5) and female (n = 5) monkey brains. Five transverse domains of the cerebellar cortex, known as cerebellar compartmentation defined by the zebrin II/aldolase expression pattern, were segmented on MR images, and the left and right sides of their volumes were calculated. Asymmetry quotient (AQ) analysis revealed significant left-lateralization at the population level in the central zone posterior to the cerebellar transverse domains, which included lobule VII of the vermis with the crura I and II of ansiform lobules, in males but not females. Next, the volume of the cerebellar hemispherical lobules was calculated. Population-level leftward asymmetry was revealed in the crus II regions in males using AQ analysis. The AQ values of the other hemispherical lobules showed no left/right side differences at the population level in either sex. The present findings suggest a sexually dimorphic asymmetric aspect of the cerebellum in cynomolgus macaques, characterized by a leftward lateralization of the crus II region in males, but no left/right bias in females. Full article

A hemispherical resonator gyroscope (HRG) has been implemented by using a consumer wineglass as the resonator and 3 × 3 optical interferometers as the detectors. The poorness of the off-the-shelf wineglass as the resonator can be overcome by the high performance of the optical interferometer. The effects of asymmetries in stiffness and absorption of the resonator are analyzed theoretically and confirmed experimentally. We prove that the trace of the amplitude ratio of two n = 2 fundamental resonant modes of the resonator follows a straight line in a complex plane. By utilizing the straightness of the ratio and the high performance of the optical interferometer, we extract four real constant parameters characterizing the HRG system. Experimentally, by using a resonator having an average resonance frequency of 444 Hz and Q value of 1477.2, it was possible to measure the Coriolis force at the level of industrial grade. The bias stability was measured as small as 2.093°/h. Full article

The brain is the most complex organ in the human body and it is divided into two hemispheres—left and right. The left hemisphere is responsible for control of the right side of our body, whereas the right hemisphere is responsible for control of the left side of our body. Brain image segmentation from different neuroimaging modalities is one of the important parts of clinical diagnostic tools. Neuroimaging based digital imagery generally contain noise, inhomogeneity, aliasing artifacts, and orientational deviations. Therefore, accurate segmentation of brain images is a very difficult task. However, the development of accurate segmentation of brain images is very important and crucial for a correct diagnosis of any brain related diseases. One of the fundamental segmentation tasks is to identify and segment inter-hemispheric fissure/mid-sagittal planes, which separate the two hemispheres of the brain. Moreover, the symmetric/asymmetric analyses of left and right hemispheres of brain structures are important for radiologists to analyze diseases such as Alzheimer’s, autism, schizophrenia, lesions and epilepsy. Therefore, in this paper, we have analyzed the existing computational techniques used to find brain symmetric/asymmetric analysis in different neuroimaging techniques such as the magnetic resonance (MR), computed tomography (CT), positron emission tomography (PET), single-photon emission computed tomography (SPECT), which are utilized for detecting various brain related disorders. Full article