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.

What does diffusion mean in MRI?

Diffusion MRI is a non-invasive technique that can assess the microstructural properties and organization within brain tissue based upon the dispersion of water molecules.

Is diffusion weighted imaging?

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.

Is diffusion tensor imaging the same as diffusion weighted imaging?

(b) For diffusion tensor imaging, diffusion gradients are applied in six directions to fully sample the diffusion tensor in space. Consequently, six individual diffusion-weighted images are generated that are again averaged to render the trace of diffusion or diffusion-weighted image.

How long does a MRI head scan take?

Procedure. An MRI of the brain usually takes 30-45 minutes to perform. Your child will lie on the movable scanning table while the technologist places him or her into position. A special plastic device called a coil may be placed around your child’s head.

What is diffusion in the brain?

Diffusion in the extracellular space (ECS) of the brain is constrained by the volume fraction and the tortuosity and a modified diffusion equation represents the transport behavior of many molecules in the brain. Early diffusion measurements used radiolabeled sucrose and other tracers.

What is DTI imaging used for?

Diffusion Tensor Imaging (DTI) is a technique that detects how water travels along the white matter tracts in the brain (Fig. 2). White-matter tracts connect different parts of the brain and must be protected during surgery.

How is diffusion tensor imaging done?

The analysis of water diffusion is performed by applying magnetic field gradients to generate an image that is sensitized to diffusion in a particular direction. A three-dimensional diffusion model (the tensor) is then estimated by repeating this process in multiple directions.

What is the cause of diffusion?

Diffusion is how smells spread out through the air and how concentrated liquids spread out when placed in water. Diffusion happens on its own when the particles spread out from an area of high concentration , where there are many of them, to areas of low concentration where there are fewer of them.

Why is diffusion-weighted imaging not used in breast imaging?

One reason is that the diagnostic role of diffusion-weighted imaging in breast imaging has not been incorporated into the already established Breast Imaging and Reporting Data System lexicon ( 11 ).

How is the ADC value for diffusion weighted imaging calculated?

The ADC value is a quantitative measurement of diffusion that is calculated on the basis of the attenuation in signal intensity between at least two diffusion-weighted images according to the following equation: where SDW is the attenuated spin-echo signal and SSE is the full spin-echo signal without diffusion attenuation.

Is there a microperfusion effect in the breast?

Microperfusion effect has not been observed at a b value of less than 600 sec/mm 2 in normal fibroglandular breast tissue or in adipose tissue, a finding that is consistent with reports that the mammary gland is not a highly vascular organ ( 15, 16 ).

Which is the most sensitive breast cancer imaging technique?

Contrast material–enhanced breast MR imaging is currently accepted as the most sensitive imaging technique for the diagnosis and staging of breast cancer.