Separation of bone from iodine- and gadolinium-based contrast agents using dual energy CT

ABSTRACT This study aims to evaluate the separability of bone from iodine- and gadolinium-based intravenous contrastagents using dual energy CT techniques in a phantom. The phantom was prepared containing varying concen-trations of iodine-based contrast, gadolinium-based contrast, and calcium hydroxyapatite (to simulate bone).Thirteen iodine concentrations from 0.1 to 12 mg/mL, twelve gadolinium concentrations from 0.72 to 34.42mg/mL, and four calcium concentrations from 0 to 200 mg/mL were used. These phantoms were scanned ona dual source CT using two die rent source spectra, producing one set of data at 80 kVp and another at 140kVp. On each resulting image, the mean HU was measured at every concentration level for iodine, gadolin-ium, and calcium, and plotted on a graph of HU value at 80 versus 140 kVp. Linear regression was used toproduce a best-“t line for each material. These lines were compared to test for a die rence of slopes betweencalcium and iodine as well as between calcium and gadolinium. Each material exhibited a linear relationshipbetween the HU values at 140 and 80 kVp ( R