Friday 7 October 2011

Artifact on MRI Diffusion

Diffusion has limited value as far as brain parenchyma near base of skull is concerned like temporal lobe near mastoid and sometimes frontal lobes near roof of orbit, bright signal here may be mistaken for restricted diffusion to suggest an infarct or may obscure pathology.

This is a susceptibility artifact caused by field inhomogeneities at the air-bone interface of the temporal bone.
Usually bilateral and often symmetrical.
Can be reduced with the use of parallel imaging techniques.
Additional MRI techniques, such as sensitivity encoding echo-planer and single-shot turbo spin echo imaging, have been shown to greatly enhance the quality of DWI images by reducing the blurring artifacts at the temporal bone.

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