Urinary system pathologies determined in dual energy CT urography

Purpose: To determine the benefits and limitations of Dual Energy CT compared to single-energy CT in patients with DECT urography using the split-bolus method Materials and Methods: 98 patients who underwent DECT urography between July 2017 and October 2017 at Inonu University Medical Faculty Radiology Department were evaluated. In the analysis of the images, two radiologists analyzed the virtual non-contrasted images obtained from the combined nephrogenic-excretory phase using the '' Liver VNC '' algorithm of Syngo.Via Dual Energy software and then the true non-contrasted images independently of each other. The true non-contrast images were accepted as the gold standard for stone detection. In addition, both radiologists determined complicated cysts with consensus. They assessed the postcontrast and precontrast density differences (postcontrast-precontrast) and contrast enhancement of these cysts on the iodine map. Findings: 83 different stones were detected in 26 of the 98 patients included in the study. 2 stones were excluded from study. Sensitivities of virtual non-contrast images in detecting urinary system stones were 66.7% (54 of 81 stones) and 65.4% (53 of 81 stones) according to the first and second radiologists respectively. 15 complicated cysts were detected in 98 patients included in the study. According to the measurement of the density values, none of these cysts showed contrast enhancement(postcontrast-precontrast <20). According to iodine map images, there was no enhancement in 14 of 15 cysts; only 1 cyst showed minimal contrast enhancement. Result: With DECT urography, virtual non-contrasted images obtained from combined nephrogenic-excretory phase can detect urinary system stones but due to some limitations and technical features, all stones can not be detected like in true non-contrast images. Although different studies are needed, iodine map images are helpful in excluding contrast enhancement of complicated cysts. As a result, if CT urography is performed with dual energy, it can provide additional information about patients. Keywords: Dual Energy Computed Tomography, Urinary System Stones, Complicated Kidney Cysts