Vascular imaging (dual energy CT)
Dual-energy CT has a variety of clinical applications in vascular imaging, due to the utilization of material decomposition and the ability to reconstruct images at a variety of energy levels.
High kVp CT scans have lower contrast than that of lower kVp due to the K-edge of iodine, giving the lower energy of the dual energy scan an advantage over conventional CT. The attenuation values of large vessels enhanced with iodine are 70% higher at 80 kVp than at 140 kVp 1. In the event of suboptimal contrast injection and or timing, the lower energy set (closer to the K-edge of iodine) can be favored to improve the contrast resolution in various studies from pulmonary angiograms to aortograms 2.
Dual-energy aortogram in surveillance of endovascular aneurysm repair improves detection of endoleaks in fewer acquisitions 1; low kVp scanning can detect subtle leaks, while the virtual non-contrast images replace the unenhanced scan allowing a substantial reduction in radiation burden in patients that require life-long checkups 3,4.
Using lower energy data sets are proven to increase the arterial enhancement of pulmonary angiograms and other contrast studies due to the K-edge of iodine being closer to the lower energy used in a dual energy scanner 5-7.
The 80 kVp image has the potential to improve subsegmental pulmonary artery perfusion and distal pulmonary embolus detection 2. In the setting of suboptimal enhancement of the pulmonary artery, virtual monochromatic reconstructions at lower energy levels can increase vessel enhancement, at the cost of increased noise.
Perfusion blood volume maps can be used to identify the segmental or subsegmental areas of lung affected by a pulmonary embolus. It is important to note that atelectasis, cardiac motion and streak artefact can all cause perfusion defects 10.
- 1. Vlahos I, Godoy MC, Naidich DP. Dual-energy computed tomography imaging of the aorta. J Thorac Imaging. 2010;25 (4): 289-300. doi:10.1097/RTI.0b013e3181dc2b4c - Pubmed citation
- 2. Godoy MC, Heller SL, Naidich DP et-al. Dual-energy MDCT: comparison of pulmonary artery enhancement on dedicated CT pulmonary angiography, routine and low contrast volume studies. Eur J Radiol. 2011;79 (2): e11-7. doi:10.1016/j.ejrad.2009.12.030 - Pubmed citation
- 3. Boll DT, Merkle EM, Paulson EK et-al. Coronary stent patency: dual-energy multidetector CT assessment in a pilot study with anthropomorphic phantom. Radiology. 2008;247 (3): 687-95. doi:10.1148/radiol.2473070849 - Pubmed citation
- 4. Aran S, Daftari Besheli L, Besheli LD et-al. Applications of dual-energy CT in emergency radiology. AJR Am J Roentgenol. 2014;202 (4): W314-24. doi:10.2214/AJR.13.11682 - Pubmed citation
- 5. Lu GM, Wu SY, Yeh BM et-al. Dual-energy computed tomography in pulmonary embolism. Br J Radiol. 2010;83 (992): 707-18. doi:10.1259/bjr/16337436 - Free text at pubmed - Pubmed citation
- 6. Ascenti G, Mazziotti S, Lamberto S, Bottari A, Caloggero S, Racchiusa S, Mileto A, Scribano E. Dual-energy CT for detection of endoleaks after endovascular abdominal aneurysm repair: usefulness of colored iodine overlay. Am J Roentgenol. 2011 Jun;196(6):1408-14. doi: 10.2214/AJR.10.4505.
- 7. Rutherford RA, Pullan BR, Isherwood I. Measurement of effective atomic number and electron density using an EMI scanner. Neuroradiology. 1976;11 (1): 15-21. Pubmed citation
- 8. Boll DT, Merkle EM, Paulson EK et-al. Coronary stent patency: dual-energy multidetector CT assessment in a pilot study with anthropomorphic phantom. Radiology. 2008;247 (3): 687-95. doi:10.1148/radiol.2473070849 - Pubmed citation
- 9. Murphy Andrew, Jeffrey Cheng and Jit Pratap et al. "Dual-Energy Computed Tomography Pulmonary Angiography: Comparison of Vessel Enhancement between Linear Blended and Virtual Monoenergetic Reconstruction Techniques". Journal of Medical Imaging and Radiation Sciences (2018). . doi:10.1016/j.jmir.2018.10.009
- 10. Lu GM, Wu SY, Yeh BM et-al. Dual-energy computed tomography in pulmonary embolism. Br J Radiol. 2010;83 (992): 707-18. doi:10.1259/bjr/16337436 - Free text at pubmed - Pubmed citation
Related Radiopaedia articles
Physics and imaging technology: CT
computed tomography (CT)
- CT technology
- dual energy CT
- CT image reconstruction
- CT image quality
- CT dose
CT contrast medium
- iodinated contrast media
- coronary CT angiography
- patient-based artifacts
- physics-based artifacts
- hardware-based artifacts
- CT safety
- history of CT