Neuroimaging (dual-energy CT)

Last revised by Daniel J Bell on 3 Apr 2023

Dual-energy CT has a number of clinical applications in neuroimaging particularly in the realm of material composition and virtual non-contrast imaging.

Contrast staining of the brain parenchyma post iodinated contrast can lead to interpretation issues, especially when the density of contrast is similar to that of blood. Virtual non-contrast imaging is an accurate 1 method in differentiating intracranial hemorrhage from iodinated contrast staining following interventional procedures such as endovascular clot retrieval.

Using iodine quantification one can measure the amount of iodine leak within a core and the penumbra of hemorrhagic contusions after contrast-enhanced whole-body CT 2

Conventionally removing bone in was either a manual process or a threshold related algorithm (that often subsequently involves a manual process). Using three material differentiation, dual-energy CT scans can be post-processed to remove bone which is particularly advantageous in both angiography and venography 3. It is not perfect and has been found to overestimate stenosis when there is calcification close to the skull, additionally the presence of blooming artefact caused by calcifications can lead to artefacts in the post-processing too 3.

Using monoenergetic image reconstruction one can change the energy levels depending on the region of interest, for example using 75 keV at the posterior fossa to reduce beam hardening artefact 4.

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