Achille Mileto MD, Presenter: Nothing to Disclose

Rendon C. Nelson MD, Abstract Co-Author: Consultant, General Electric Company Consultant, Nemoto Kyorindo Co, Ltd Consultant, VoxelMetrix, LLC Research support, Bracco Group Research support, Becton, Dickinson and Company Speakers Bureau, Siemens AG Royalties, Wolters Kluwer nv

Ehsan Samei PhD, Abstract Co-Author: Research Grant, Siemens AG Research Grant, General Electric Company Research Grant, Carestream Health, Inc

Tracy Anne Jaffe MD, Abstract Co-Author: Nothing to Disclose

Erik K. Paulson MD, Abstract Co-Author: Nothing to Disclose

Daniele Marin MD, Abstract Co-Author: Nothing to Disclose

To investigate, in a phantom experiment and a clinical study, the impact of dual energy MDCT with virtual monochromatic imaging on renal cysts pseudoenhancement.

Four renal compartments inserted into torso phantoms were filled with both saline and iodinated solutions to simulate the noncontrast state and three different levels of renal parenchymal enhancement (+140, +180, and +240 HU). Saline-filled spheres simulating renal cysts (15-mm, 18-mm) were serially suspended in the renal compartments and imaged with both dual-energy MDCT and single-energy MDCT at four polychromatic energy levels (80, 100, 120, and 140 kVp). Twenty-eight patients (mean age, 66±10 years; mean BMI, 31.3±6.2 kg/m2) with 34 renal cysts underwent dual-energy MDCT. Virtual monochromatic images were reconstructed at energy levels ranging from 40 to 140 keV at 10 keV increments.

In the phantom experiment, all polychromatic datasets demonstrated pseudoenhancement in all investigated conditions, which was inversely proportional to cyst size (P <0.0001), proportional to depth of intraparenchymal location (P =0.0001), and proportional to the renal background attenuation level (P <0.0001). Virtual monochromatic images at energy levels ranging from 80 to 140 keV did not show pseudoenhancement, with the lowest attenuation increase (mean, 6.1±1.6 HU; range, 1.6-7.7 HU) at 80 keV. In patients, pseudoenhancement did not occurr on virtual monochromatic images at energy levels ranging from 90 to 140 keV. Patient’s body size had a significant proportionate effect (P =0.0070) on the optimal monochromatic energy level.

Dual energy MDCT with reconstruction of optimal energy virtual monochromatic images can overcome renal cyst pseudoenhancement.

Optimal energy virtual monochromatic images may enable the unequivocal diagnosis of simple renal cysts, eliminating the need of additional work-up.

Mileto, A, Nelson, R, Samei, E, Jaffe, T, Paulson, E, Marin, D, Dual Energy MDCT in Renal Cysts: Effect of Virtual Monochromatic Imaging on Pseudoenhancement in an In-Vitro and In-Vivo Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14011796.html