There are 2 inseparable and complimentary technical advantages of dual-energy computed tomography (CT) imaging of the thoracic aorta. One advantage stems from the simultaneous availability of low and high peak kilovoltage (kVp) spectra data and, in particular, the benefits conferred by the improved conspicuity of iodinated contrast media at lower kVp CT imaging. This, in turn, permits improved aortic visualization or, alternatively, reduction in the volume or rate of contrast administration. Image noise at low kilovoltage does not appear to be a significant issue, with the backup availability of simultaneously acquired high kVp images a distinct advantage over single, low kVp imaging techniques. The second advantage of dual-energy CT imaging stems from the potential to calculate material-specific images derived mathematically from the simultaneous availability of attenuation measurements at 2 distinct energies. These material-specific data sets include virtual noncontrast images, virtual contrast, or “bone-subtracted” angiographic-like images. These techniques may confer significant advantages in the evaluation of patients with aortic disease, improving interpretation and reducing reconstruction time, while potentially reducing the need for, and associated radiation burden of, precontrast or postcontrast multiphasic imaging.
*Department of Radiology, Division of Thoracic Imaging, New York University Medical Center, New York
†St George's Hospital NHS Trust, London, UK
Reprints: Ioannis Vlahos, BSc, MBBS MRCP, FRCR, Department of Radiology, NYU Langone Medical Center, 560 First Avenue, IRM-236, New York, NY 10016 (e-mail: firstname.lastname@example.org).
Disclosures: Ioannis Vlahos: recipient of a fellow support grant from Bayer HealthCare, consultant for Siemens Medical Solutions, consultant for GE Healthcare; Myrna C.B. Godoy: prior recipient of a Bayer HealthCare fellow grant support; David P. Naidich: consultant for Siemens Medical Systems.