Learning objectives
To describe the basic technical principles of dual energy CT (DECT).
To explain the most important vascular applications.
To highlight the advantages of DECT in angiographic studies.
Background
X-Rays physics:
Dual energy CT is a technique based on the attenuation of photons from different x-ray spectra transmitted through the body.
Multiple dataset are acquired using different enery spectra.
The attenuation of a single voxel depends on the material composition in terms of atomic number Z and electron density and on the energy of the x-ray beam.
Due to photoelectric interactions,
the attenuation increases at lower energies, especially in elements with higher atomic number such as iodine and calcium.
The attenuation value at two...
Findings and procedure details
Case:
82 years old male,
abdominal aortic aneurysm CT study,
80 ml of contrast medium was administrated with IDR of 1,48 gl/s.
Technical parameters are reported in figure 1.
At 86 keV, ROI in abdominal aorta demonstrates a contrast enhancement of 272 HU(Fig.
1).
At same IDR,
by decreasing KeV,
an initial increased contrast enhancement is
obtained,
up until 1255 HU of density by choosing very low KeV (40 KeV) to improve imaging quality (Fig.
2).
Case:
63 years old female,
oncological history; performed an...
Conclusion
Usually patients with diffuse vascular disease benefit of DECT.
Hence,
oncological patients may be an adequate target of study because of difficult venous accesses,
low tolerance of high flows injections.
Furthermore reducing iodine concentration decreases the risk of contrast-induced nephropathy (CIN),
useful in all patients with renal impairment.
In DECT acquisition the basal scan can be avoid with post processing image (virtual non unenhanced imaging),
thus reducing the radiation dose without losing data.
Moreover this would also allow a time reduction,especially in the emergency.
It...
References
- Marin D.; Boll D.; Mileto A.; Nelson R.
(2014); State of the art: Dual-energy CT of the abdomen.
Radiology 2014 May; 271(2):327-42.
- Kwang Nam Jin,
Chung W.
et Al.(2017) Dual Energy computed tomography angiography: virtual calcified plaque subtraction in a vasular phantom Acta Radiologica,
95–103.
- Chung,
R.,
& Morgan,
R.
(2012).
Dual-Energy CT: Vascular Applications,
(November).
- Fukui,
R.,
& Tate,
E.
(2016).
Dual-Energy Spectral CT : Various Clinical Vascular Applications 1,
1215–1232.
- Thorsten R.
C.
J.
(2012).
Dual-Energy CT :...