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Use of Magnetic Field and Radio Frequency
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Introduction
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Magnetism
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Magnetic Fields
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MRI and Nuclei
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Atoms
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Hydrogen Nuclei
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Precessing Nuclei
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Net Magnetization
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Larmour Equation
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Radio Frequency (RF)
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RF
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Resonance
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Dephasing
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Induction
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Faraday's Law of Induction
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Free Induction Decay (FID)
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FID
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Amplitude
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Image Resolution
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Spatial Resolution
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Example
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Image Contrast
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Factors Affecting Image Contrast
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Relaxation Recovery - T1 Weighting
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T1 Relaxation
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Relaxation Dephasing - T2 Weighting
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T2 Relaxation
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Image Weighting
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Dominant Internal Factor
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Pulse Sequence
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Overview
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Example
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Saturation
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Overview
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Example
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Proton Density
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Overview
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Example
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Inversion Recovery
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Overview
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Example
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T2 and T2*
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True T2 Relaxation vs. T2*
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Spin Echo Overview
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Example
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Time Repetition (TR) and Time Echo (TE)
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TR vs. TE
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Creating T1, T2 and Proton Density Images
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TR and TE Effects
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Partial Saturation vs. Spin Echo
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Example
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Transitional Images
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Overview
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Gradient Coils
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Overview
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X, Y and Z Gradient Coils
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Bandwidth
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Spatial Encoding
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Overview
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Phase and Frequency Encoding
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Example
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Spatial Resolution
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Overview
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Signal to Noise Ratio (SNR)
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Factors that Affect SNR
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Effects of Changing Factors
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Imaging Trade-offs
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References
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References
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