What Is the b-Value in Diffusion-Weighted MRI? A Physics Primer for Trainees

The b-value sets diffusion weighting in DWI MRI, changing sensitivity to water motion. Higher b-values increase diffusion sensitivity but lower SNR. Essential for DWI interpretation and radiology physics exams — part of a 100-question high-yield series.

• Defines b-value (s/mm²) and explains how it determines the degree of diffusion weighting, affecting image contrast and signal intensity.
• Intended for radiology trainees preparing for board and certificate exams; question 15 of a 100-question high-yield physics series.

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