Introduction: Dual-energy computed tomography (DECT) reduces metal artifact volume (MAV) by calculating
virtual monoenergetic computed tomography (VMCT) scans. Different energies influence
densities of iodinated contrast media (iCM) and bone. This triangle—bone and iCM density
and MAV—is mandatory for CT arthrography with joint-related metallic implants (JRMIs).
We investigated the energy-related influence on different dilutions of iCM, MAV, and
bone density in an experimental setting.
Material and Methods: A phantom was built with a titanium metal plate, a piece of bovine long bone, and
probes (1 mL) of 0.9% saline solution and six different dilutions of iCM (400 mg/mL,
300 mg/mL, 200 mg/mL, 100 mg/mL, 50 mg/mL, and 25 mg/mL iodine content). All contents
were embedded in 0.5% gelatin.
DECT was performed on a 64-slice CT scanner (Siemens, Sensation 64) with two sequential
scans (80 keV and 140 keV) and calculated to VMCT (40, 50, 70, 100, 120, 140, and
190 keV).
MAV, iCM to bone contrast to noise ratio (iCM-b-CNR), and density were measured digitally
for all probes. Optimized iCM-b-CNR, density differences, and reduction of MAV were
correlated considering different VMCT energy levels.
Results: The iCM with iodine contents of 200, 300 and 400 mg/mL and titanium plate were on
the upper border of measurable density (3,000 HU) at any energy level. Bone density
decrease with rising energy levels was parallel to 100 mg/mL iodine content. The iCM-b-CNR
was optimal at VMCT of 120 to 190 keV. MAV optimum was achieved with VCMT of 120 to
190 keV.
Conclusion: The phantom study suggests iCM with 200 mg/mL iodine content, VAM of 120 keV considering
iCM-b-CNR and MAV, with regard to CT arthrography with JRMI.
