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Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device in clinical use by the early 1980s. The early MRI...
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When protons A and X are coupled, their nuclear spin energy levels are slightly modified. This is because the energy required to excite proton A to a spin state parallel to proton X is slightly different from the energy required for it to become anti-parallel to spin X. Consequently, there are two possible excitation frequencies for A (A1 and A2), depending on the spin state of X, and vice versa. The mutual nature of coupling implies that the difference between frequencies A1 and A2, indicated...
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Diffusion Imaging in the Rat Cervical Spinal Cord
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Apparent propagator anisotropy from single-shell diffusion MRI acquisitions.

Santiago Aja-Fernández1, Antonio Tristán-Vega1, Derek K Jones2

  • 1Laboratorio de Procesado de Imagen, Universidad de Valladolid, Valladolid, Spain.

Magnetic Resonance in Medicine
|December 14, 2020
PubMed
Summary
This summary is machine-generated.

Apparent propagator anisotropy (APA) offers enhanced white matter insights over fractional anisotropy (FA) using single-shell diffusion MRI data. This new metric provides greater reliability in detecting pathologies with faster computation, making it ideal for clinical adoption.

Keywords:
EAPHARDIdiffusion MRImicrostructurepropagator anisotropy

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Area of Science:

  • Diffusion MRI
  • Neuroimaging
  • Biophysics

Background:

  • Fractional anisotropy (FA) is a standard diffusion MRI metric.
  • Ensemble averaged propagator anisotropy (PA) offers more information than FA but requires extensive data and long processing times.
  • This limits the widespread clinical adoption of PA.

Purpose of the Study:

  • Introduce apparent propagator anisotropy (APA) as a novel diffusion MRI metric.
  • Develop an APA estimation method using single-shell data.
  • Compare APA's performance against FA and PA.

Main Methods:

  • APA was estimated from single-shell diffusion MRI data.
  • The study utilized publicly available datasets of healthy and diseased subjects.
  • APA was compared with FA and PA regarding structural information and processing time.

Main Results:

  • APA showed strong correlation with PA in healthy subjects.
  • APA identified statistically significant differences in white matter pathologies with higher reliability than FA.
  • APA computation is significantly faster than PA, comparable to FA.

Conclusions:

  • APA provides more relevant white matter information than FA.
  • APA requires no additional data acquisition demands.
  • APA is a promising metric for integration into existing diffusion MRI analysis pipelines.