Abstract
PURPOSE To investigate iodine dose concentration required for adequate hepatic parenchymal enhancement on fast-kilovoltage-switching dual-energy computed tomography (DECT) of the abdomen based on patient body weight. MATERIALS AND METHODS The protocol of this prospective study was approved by the local Institutional Review Board and written informed consent for study participation was obtained from all patients. The study cohort of 204 consecutive patients who underwent whole body single-source DECT to screen for tumor metastases and/or recurrence after surgical resection of malignant tumors were randomly assigned to one of three protocols according to the iodine dose (400, 500, and 600 mgI/kg). For each case, two radiologists quantitatively and qualitatively reviewed three energy levels (65, 70, and 75 kilo electron volt [keV]) of the portal venous phase virtual monochromatic images (VMIs). CT numbers of the liver and the qualitative hepatic parenchymal enhancement were compared among the VMIs with the three protocols and three energy levels. RESULTS Hepatic enhancement (ΔHU > 50HU) was achieved at 65 keV with 400, 500, and 600 mgI/kg, at 70 keV with 500 and 600 mgI/kg, and at 75 keV with 600 mgI/kg. The hepatic parenchymal enhancement was graded as sufficient hepatic enhancement in 97%, 100%, and 99% at 65 keV with 400, 500, and 600 mgI/kg, 88% and 97% at 70 keV with 500 and 600 mgI/kg, and 84% at 75 keV with 600 mgI/kg, respectively. CONCLUSION The iodine dose can be reduced to 400 mgI/kg at 65 keV or 500 mgI/kg at 70 keV in DECT without compromising hepatic parenchymal enhancement.
