Iodine quantification and detectability thresholds among major dual-energy CT platforms

To estimate the minimum detectable iodine concentration on multiple dual-energy CT (DECT) platforms. A phantom containing iodine concentrations ranging from 0 to 10 mg ml was scanned with five dual-energy platforms (two rapid kilo volt switching (r-kVs), one dual source (DS), one sequential acquisition and one split-filter). Serial dilutions of 300 mg ml iodinated contrast material were used to generate concentrations below 2 mg ml . Iodine density and virtual monoenergetic images were reviewed by three radiologists to determine the minimum visually detectable iodine concentration. Contrast-to-noise ratios (CNRs) were calculated. 1 mg mL (~0.8 mg mL corrected) was the minimum visually detectable concentration among the platforms and could be seen by all readers on the third-generation r-kVs and DS platforms. At low concentrations, CNR for monoenergetic images was highest on the DS platform and lowest in the sequential acquisition and split-filter platforms. The results of this study corroborate previous estimates of iodine detection limits at DECT and provide a comparison for the performance of different DECT platforms at low iodine concentrations .