![]() ![]() ![]() Ninety directions typically require upwards of 20 additional minutes in the MR scanner, therefore, it may not be suitable for routine clinical practice. DTI MR settings can measure the diffusion of water along an axon in many directions, 6, 9, 33, and 90 directions are typical parameters used, with 33 directions and above increasing confidence in the accuracy. When a voxel contains scalar values constituting a vector, it is known as a tensor, which is where DTI received its name and explains the additional information provided through DTI. Significant reduction of diffusion anisotropy was also detected when diffusion tensor results from the patients were compared with those of the controls.”ĭWI uses volume elements (voxels) as a statistical method for data collection. Such differences were not observed in the control subjects. “This study included five patients with mild traumatic brain injury (three men and two women) and ten volunteers with no known neurological disorders (five men and five women).” This study reported abnormalities in the patients with a mild brain injury that were absent in the control subjects or the uninvolved sides of the injured patients' brains: “Patients displayed a significant reduction of diffusion anisotropy in several regions compared with the homologous ones in the contralateral hemisphere. ![]() The latter measures movement of water along axons, analogous to the straws in a glass of water.Īs early as May of 2002, medical literature reported that DTI showed abnormalities in patients who suffered from mild brain trauma as compared to normal control subjects. Water molecules will diffuse differently through space depending on the tissue type, components, structure, architecture, and integrity these principles allow clinically significant imaging to occur, particularly the DTI. The greater the anisotropy the more directional and linear the diffusion of water molecules. Anisotropy is when there is a directionality in the diffusion of water present, and the movement of water is no longer random (such as water movement along straws placed in a glass). Isotropy is defined as uniformity in all directions and when applied to water molecules, isotropy occurs when the diffusion of water is entirely uninhibited (such as water movement in a glass of water). Random thermal motion, also known as Brownian motion, is water molecular diffusion in three-dimensional space. DTI does not require contrast and is available on almost all modern MR scanners with relatively quick scan times for this sequence. The first application of DWI to the human brain was performed in 1986 and since has become the gold standard for detecting acute stroke. DTI is a variant of diffusion-weighted imaging (DWI) which utilizes a tissue water diffusion rate for image production. Specifically, diffusion tensor imaging (DTI) has become increasingly studied and utilized in recent years and has become incorporated by many radiologists into routine clinical practice with most research performed on traumatic brain injury. Advanced magnetic resonance (MR) neuroimaging modalities are becoming more available and useful as their value in the diagnosis and prognosis of central nervous system diseases is more fully understood and studied. ![]()
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