Room: Exhibit Hall | Forum 5
Purpose: This work investigates the accuracy of iodine concentration within a head and abdomen phantom and the size-specific calibration curves needed to accurately correlate image value (HU) from dual-spiral and split-filter dual-energy CT (DECT) iodine-enhancement images to iodine concentration (mg I/ml).
Methods: The head and abdomen Gammex Multi-Energy CT Phantom was imaged using the Siemens SOMATOM Definition Edge dual-spiral and split-filter DECT modalities. The phantoms were imaged with solid iodine inserts of nominal concentrations ranging from 2-15 mg I/ml. Iodine concentrations were determined using Siemens’ integrated imaging software, Syngo.via and were compared to the nominal concentrations. Iodine-enhancement images were reconstructed in Syngo.via and a correlation between iodine-enhancement image value and iodine concentration was established for each DECT scan and phantom size. Iodine concentrations determined using a single average calibration curve were compared to iodine concentrations determined from phantom size-specific calibration curves.
Results: Iodine concentrations determined in Syngo.via in the head phantom differed from the nominal concentrations (range, -4 to 5% for dual-spiral; -5 to 20% for split-filter). Iodine concentrations determined in Syngo.via in the abdomen phantom also differed from the nominal concentrations (range, -9 to -2% for dual-spiral; -20 to -2% for split-filter). For the same iodine inserts, iodine-enhancement image values in the abdomen phantom differed from values in the head phantom (range, -22 to -14% for dual-spiral; -36 to -5% for split-filter). Size-specific calibration curves increased the accuracy of iodine quantification from iodine-enhancement images to within 3% in the abdomen for dual-spiral and 12% for split-filter.
Conclusion: For the iodine concentrations investigated, the use of size-specific calibration curves increased the accuracy of iodine quantification for both dual-spiral and split-filter DECT compared to a single average calibration curve and Syngo.via. Therefore, to accurately correlate iodine-enhancement image value to iodine concentration, a size-specific calibration is needed.
Not Applicable / None Entered.
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