ABSTRACT
The dual energy CT (DECT) technology has been recently employed in the form of two X-ray sources of different energies to enhance the contrast between adjacent structures. Its use in the cardiac arena has been widely highlighted due to the higher temporal resolution. However, it may also be used in the craniocervical and peripheral vasculature for better differentiation between contrast-enhanced vascular lumina and calcified plaques, in the characterisation of ureteric stones, and in the evaluation of hepatic lesions. The objective of this paper is to revisit DECT physics, review the literature and discuss its use in CT neuroangiography with case illustrations from our institution, and impact on dose savings.
Dual energy CT (DECT) technology, initially introduced in the 1970s, failed to make an impact due to its technical limitation.1-3 It was recently reintroduced in the novel form of two separate X-ray sources and their respective detector sets, placed orthogonal to one another. The most highlighted application of this technological innovation is in coronary CT angiography (CTA). In this context, it would be more accurate to term it as dual source CT technology, since the two X-ray tubes operate at the same energy. Two X-ray tubes operating in sync at the same energy translates into higher temporal resolution, which is clearly advantageous in securing non-motion degraded images in the setting of an elevated heart rate.4 In contrast, the application of DECT in neuro, pulmonary and peripheral angiography, characterisation of hepatic lesions, and ureteric stone detection is based on the simultaneous use of the two X-ray tubes at different energies.5-9
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