![]() Whilst the anatomy of the olfactory structure has previously been investigated using dissection microsurgery, the use of magnetic resonance tractography makes it possible to visualize the complicated olfactory system non-invasively. However, neither the anatomy of the olfactory pathway nor its development in child populations have been studied in depth. The olfactory sense plays an important role in everyday life. Tractography is a non-invasive technique that is already used as a tool that permits surgical planning in brain tumors. Lastly, if the direction of the diffusion is from the posterior to the anterior part, it is assigned a green color. If the direction is from bottom to top, it is assigned a blue color. If the direction of the diffusion is from left to right, it is assigned a red color. It is possible to obtain 3D maps of brain WM using the DTI technique called tractography, in which a coded color map is overlaid on the images, the color showing the privileged direction of water molecule diffusion. ADC reflects the average magnitude of molecular displacement by diffusion the higher the ADC value, the more isotropic the medium. FA reflects the directionality of molecular displacement by diffusion and varies between "0" (isotropic diffusion) and "1" (infinite anisotropic diffusion). ![]() The two main parameters derived from DTI data are the apparent diffusion coefficient (ADC) and the fractional anisotropy (FA). This directional dependence of diffusivity is called anisotropy. The diffusion parameters that can be obtained are therefore modulated by the tissue barriers. Within the brain WM, water molecules tend to dissipate more freely along the direction of the axonal fascicles than across them. Myelin consists of concentric layers of lipids and proteins that isolate the axon while providing mechanical and biochemical support. This signal is reinforced by myelin and other biological processes, which accumulate around the axons as brain development takes place. The main function of axons is to drive electrical signals between neurons. White matter consists mainly of densely clustered nerve fibers, each cluster is comprised of an axon extending from the neuron body with a long, narrow cylindrical geometry and surrounded by myelin. These functional networks can be modulated by brain white matter (WM) tissues. The movement of water molecules is dependent on both the microscopic and macroscopic restrictions of the tissue.īrain functions require efficient communication networks between different regions of the brain and between the brain and the rest of the body. ĭTI relies on the Brownian motion of water molecules within tissue. We have used the magnetic resonance technique known as diffusion tensor imaging (DTI), a relatively new modality of MRI which provides information on the degree and directionality of water diffusion in tissues and on microstructural brain development. MRI uses non-ionizing radiation, which makes it a fairly safe technique for which no negative effects on tissues have been demonstrated. Magnetic resonance imaging (MRI) is a powerful tool capable of visualizing the anatomy of tissues in vivo non-invasively. The results of DTI show white matter maturation as a function of age, and this could be used to characterize changes in white matter density and its organization. The DTI technique is a powerful tool for obtaining the complete structure of white matter associated with the olfactory system which allows connections between different areas of the brain to be explored. ![]() A sufficiently significant correlation of the generalized FA values was not found over the white matter tracts of the olfactory system. Generalized diffusion parameters such as Fractional Anisotropy (FA) and Apparent Diffusion Coefficient (ADC) of the total tracts of white matter were correlated with age using a Pearson correlation.Ī significant negative correlation between ADC values and age was obtained. The study was conducted with the consent of their parents. ĭiffusion tensor imaging was performed in fifty-one volunteer children, aged 6-16 years. The intrinsic trajectories of the olfactory pathway that can be identified using the diffusion-weighted magnetic resonance technique provide an important anatomical reference for the evaluation of clinical disorders commonly associated with the olfactory system in the brains of pediatric patients. Diffusion tensor imaging allows virtual dissections of functional white matter tracts in the human brain in vivo using regions of interest (ROI). One of the techniques of Nuclear Magnetic Resonance is Diffusion Tensor Imaging, which measures the speed of diffusion of extracellular water molecules found in tissues. To characterize white matter tracts of the olfactory system and evaluate differences in diffusion parameters as a function of age in healthy children. ![]()
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