Objective: The purpose of this study is to evaluate the diagnostic performance of split-bolus portal venous phase dual-energy CT (DECT) urography in patients with hematuria.
Materials and methods: True unenhanced and split-bolus portal venous phase contrast-enhanced weighted-average images were obtained in 171 patients with hematuria. Virtual unenhanced and iodine-overlay images were reconstructed from contrast-enhanced 80-kVp and tin-filtered 140-kVp scans. Images were independently reviewed by two radiologists who were blinded to the final diagnoses in two separate reading sessions: virtual unenhanced and iodine-overlay images (single phase) in the first session and true unenhanced and contrast-enhanced weighted-average images (dual phase) in the second session (mean ± SD, 52 ± 8 days later). Sensitivity, specificity, and accuracy of mass detection were calculated from the data of both reading sessions. The number of calculi detected on virtual unenhanced images was compared with the number detected on true unenhanced images. The difference in radiation dose between the single- and dual-phase protocols was calculated. The statistical significance was determined by ANOVA.
Results: The sensitivity, specificity, and accuracy were 98.7%, 98.9%, and 98.8%, respectively, for the single-phase approach to malignant mass detection and 98.7%, 97.9%, and 98.3%, respectively, for the dual-phase approach (p > 0.05 for all comparisons). The overall sensitivity of stone detection was 86.7% (39/45) for virtual unenhanced images. Omitting the unenhanced scan reduced the mean radiation dose from 15.4 to 6.7 mSv.
Conclusion: The diagnostic performance of both the single- and dual-phase approaches of portal venous phase split-bolus DECT urography is equally good in patients with hematuria, and single-phase acquisition has the added benefit of radiation reduction.
Keywords: dual-energy CT; hematuria; urinary neoplasms; urography; virtual unenhanced imaging.