Because of the different attenuations of tissues at
different energy levels, dual-energy CT offers tissue differentiation
and characterization, reduction of artifacts, and remodeling
of contrast-to-noise ratio (CNR) and signal-to-noise
ratio (SNR), hereby creating newopportunities and insights in
CT imaging. The applications for dual-energy imaging in
neuroradiology are various and still expanding. Automated
bone removal is used in CT angiography and CT venography
of the intracranial vessels.Monoenergetic reconstructions can
be used in patients with or withoutmetal implants in the brain
and spine to reduce artifacts, improve CNR and SNR, or to
improve iodine conspicuity. Differentiation of iodine and
hemorrhage is used in high-density lesions, after intra-arterial
recanalization in stroke patients or after administration of
contrast media. Detection of underlying (vascular and nonvascular)
pathology and spot sign can be used in patients
presenting with (acute) intracranial hemorrhage.