b-value
A parameter in diffusion MRI that determines the strength and duration of diffusion-weighting gradients.
Full Definition
The b-value is a fundamental parameter in diffusion-weighted imaging that quantifies the amount of diffusion weighting applied to the MRI pulse sequence. Measured in s/mm², the b-value depends on the strength, duration, and timing of diffusion gradients. Higher b-values provide greater sensitivity to diffusion but lower signal-to-noise ratio. Typical clinical DWI uses b-values around 1000 s/mm², while DTI often employs multiple b-values. The choice of b-value affects image contrast and the ability to detect different types of tissue pathology.
Usage
Usage note: Always include units (s/mm²) when specifying values; hyphenate when used as adjective
In Context
- "Diffusion images were acquired with b-values of 0 and 1000 s/mm² for ADC map calculation." — Stroke imaging protocol
- "The high b-value images at 3000 s/mm² enhanced the visibility of small ischemic lesions." — Advanced diffusion imaging study