What is B value in diffusion MRI?

The b-value is a factor that reflects the strength and timing of the gradients used to generate diffusion-weighted images. The higher the b-value, the stronger the diffusion effects.

What does diffusion weighted imaging measure?

Diffusion-weighted imaging (DWI) is a form of MR imaging based upon measuring the random Brownian motion of water molecules within a voxel of tissue. In general simplified terms, highly cellular tissues or those with cellular swelling exhibit lower diffusion coefficients.

What is diffusion weighted MRI used for?

Diffusion-weighted images are very useful to diagnose vascular strokes in the brain. It is also used more and more in the staging of non-small-cell lung cancer, where it is a serious candidate to replace positron emission tomography as the ‘gold standard’ for this type of disease.

How is the b-value related to diffusion?

The b-value is a factor that reflects the strength and timing of the gradients used to generate diffusion-weighted images. The higher the b-value, the stronger the diffusion effects. S = S oe −bD. The term e −bD thus behaves very much like the T2-weighting term e −TE/T2 found in many other pulse sequences.

How to increase the visibility of diffusion weighted imaging?

However, the lesions are well-visualized on the b = 1600 s/mm2 DW image (arrow; c,f) given the greater strength of diffusion weighting and decreased T2 shine-through effect. One approach to increase tumor visibility is to use a short TE (≤90ms) in order to decrease the T2 weighting and thus reduce the T2 shine-through effect.

What does the b value of a MRI mean?

The b-value is a factor that reflects the strength and timing of the gradients used to generate diffusion-weighted images. The higher the b -value, the stronger the diffusion effects.

Why are diffusion weighted images used for prostate cancer?

Diffusion-weighted images with a high b value (b≥800s/mm 2) are routinely acquired in order to increase the conspicuity of tumor foci within the prostate. Higher b values provide greater contrast between tissues based on differences in the extent of signal attenuation of water molecules.