Indication Dual Energy CTA Aorta

Aortic aneurisms are a common pathology, with the potential risk of rupture. To characterize the aneurysm and for differential diagnosis CTA is performed. Dual Energy improves the aortic examination by higher image quality of CT angiography (CTA).

MSCT – first line modality for aortic pathologies in the ER

In imaging of the aorta multislice spiral CT (MSCT) has replaced digital subtraction angiography (DSA) in the assessment of the aorta in the emergency room and mostly in routine practice.
The main benefits of MSCT compared to DSA are:

• Minimally invasive
• Without potential complications of bleeding or discomfort after invention
• Visualization of the aorta beyond the vessel wall
• Also showing e.g. intramural thrombi or periaortic infections

In most of the cases the complete aorta from the aortic root to the inguinal arteries should be imaged to rule out distal aortic dissections. MSCT offers scanning of the whole area within a few seconds. It additionally allows

• quick 3D reconstruction (volume rendering technique: VRT)
• multiplanar reformats (MPR) or
• maximum intensity projections (MiP)

in any direction with the same image quality as the axial images.

DSCT for excellent imaging of the aorta

The University of Aachen uses the latest technical development for the imaging of the aorta. The DSCT further increased spatial and temporal resolution of aortic examinations. Facilitating the use of two different tube voltages allows direct bone removal for direct visualization of the aorta and branching vessels.

In this respect, optimal contrast bolus timing is essential to achieve high quality images with optimal contrast enhancement of the aorta. Using Dual Energy, an optimal bolus administration is prerequisite for high quality CTA. Therefore, at the University of Aachen, large bore i.v. lines are placed.

Virtual non-contrast reconstruction with Dual Energy

The examination should start with a non-enhanced scan for the whole scan field to be able to rule out intramural haematoma and to allow for differentiation of calcifications from bleeding. We think that in future, a virtual non-contrast reconstruction based on Dual Energy may take place of the initial non-contrast scan.
A late phase scan is recommended especially after endovascular stent placement to rule out endoleakage.

Authors: Marco Das, Andreas H. Mahnken, Joachim E. Wildberger
See corresponding procotol:  Protocol CT Angiography Aorta
See corresponding cases: Prothesis infection after surgical abdominal aortic prosthesis, Abdominal aortic aneurysm and interventional stent placement