Accuracy of iodine quantification in dual-layer spectral CT: Influence of iterative reconstruction, patient habitus and tube parameters

• DOI: 10.1016/j.ejrad.2018.03.009
• Publication Date: 2018-03-08T13:31:02Z
• Authors: Andreas P. Sauter; Felix K. Kopp; Daniela Münzel; Julia Dangelmaier; Martin Renz; Bernhard Renger; Rickmer Braren; Alexander A. Fing...; Ernst J. Rummeny; Peter B. Noël
• Keywords: 03 medical and health sciences; 0302 clinical medicine; Phantoms, Imaging; Abdomen; Image Processing, Computer-Assisted; Humans; Reproducibility of Results; Radiation Dosage; Tomography, X-Ray Computed; Algorithms; Iodine

Evaluation of the influence of iterative reconstruction, tube settings and patient habitus on the accuracy of iodine quantification with dual-layer spectral CT (DL-CT).A CT abdomen phantom with different extension rings and four iodine inserts (1, 2, 5 and 10 mg/ml) was scanned on a DL-CT. The phantom was scanned with tube-voltages of 120 and 140 kVp and CTDIvol of 2.5, 5, 10 and 20 mGy. Reconstructions were performed for eight levels of iterative reconstruction (i0-i7). Diagnostic dose levels are classified depending on patient-size and radiation dose.Measurements of iodine concentration showed accurate and reliable results. Taking all CTDIvol-levels into account, the mean absolute percentage difference (MAPD) showed less accuracy for low CTDIvol-levels (2.5 mGy: 34.72%) than for high CTDIvol-levels (20 mGy: 5.89%). At diagnostic dose levels, accurate quantification of iodine was possible (MAPD 3.38%). Level of iterative reconstruction did not significantly influence iodine measurements. Iodine quantification worked more accurately at a tube voltage of 140 kVp. Phantom size had a considerable effect only at low-dose-levels; at diagnostic dose levels the effect of phantom size decreased (MAPD <5% for all phantom sizes).With DL-CT, even low iodine concentrations can be accurately quantified. Accuracies are higher when diagnostic radiation doses are employed.