What is diffusion on an 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.

What causes restricted diffusion on MRI?

The pathophysiologic basis of restricted diffusion in the vast majority of cases results from failure of energy-dependent adenosine triphosphate production in cell membranes resulting in intracellular cytotoxic edema, usually implying cell death.

What is diffusion gradient MRI?

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 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 is diffusion imaging 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 is apparent diffusion coefficient on an MRI?

Apparent diffusion coefficient (ADC) is a measure of the magnitude of diffusion (of water molecules) within tissue, and is commonly clinically calculated using MRI with diffusion-weighted imaging (DWI) 1.

What is diffusion weighted imaging used for?

Diffusion weighted imaging (DWI) is a method of signal contrast generation based on the differences in Brownian motion. DWI is a method to evaluate the molecular function and micro-architecture of the human body.

What does diffusion tensor imaging measure?

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.

When did diffusion-weighted imaging of the breast begin?

Evaluation of breast images acquired with sensitization to the diffusion of water molecules has the potential to play an adjunct role in the assessment of breast tissue. Diffusion-weighted imaging was initially applied in the clinical setting in the mid-1990s for the diagnosis of acute stroke.

When do you use diffusion weighted MR imaging?

Diffusion-weighted imaging is used to visualize the degree of water molecule diffusion at in vivo MR imaging.

How is magnetic resonance imaging used to diagnose bone marrow?

Summary. MR imaging is useful in evaluating the bone marrow, with high sensitivity in diagnosing marrow disease. The T1 relaxation times within the marrow reflect the tissue types within the imaging voxels, particularly marrow fat, and are also affected by the relative amount of extracellular fluid present in the tissue.

How is fat suppression used in magnetic resonance imaging?

In the majority of cases, spin echo sequences with T1 weighting and T2 weighting are sufficient to evaluate the marrow. Fat suppression is commonly used with the T2 weighted images to enhance conspicuity of the marrow signal abnormality.

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