Comparison of CT Urography and Intravenous Urography in Patients with Hematuria

Lee, Guen Young; Kang, Byung Chul; Hwang, Ji Young

Abstract

PURPOSE
We wanted to compare CT urography (CTU) with using multi-detector row CT (MDCT) and intravenous urography (IVU) for diagnosing the causes of hematuria.
MATERIALS AND METHODS
From January 2003 to March 2004, IVU and CTU were obtained in 48 patients. We evaluated the causes of hematuria in 34 of 48 patients. The IVU images were obtained by the conventional method. The CTU images were routinely obtained before intravenous contrast injection, and at 2 and 5 minutes after intravenous contrast injection. In case of delayed excretion of contrast by the kidneys, the delayed CT scans were obtained at 120 minutes after contrast injection. All the CT images, including the axial and 3D coronal reformatted CTUs with using software as well as conventional IVU images, were reviewed by two radiologists working in consensus. We decided if urinary stone existed or not and we looked for the indirect signs such as hydronephrosis or delayed excretion, etc. We also observed if it was possible to determine the mass, ureteral stricture and enhancement of the ureteral wall, etc. We calculated sensitivity, specificity, positive predictive value and negative predictive value for each modality to diagnose urinary stone. We compared the detection rate according to the phases of CTU.
RESULTS
We confirmed the presence of urinary tract stones in 27 of 34 patients who had undergone both IVU and CTU. We diagnosed ureteritis in 1, transitional cell carcinoma in 5 and acute pyelonephritis in 1 of the remaining 7 patients. The urinary stones were detected in fifteen patients on both IVU and CTU (15/27, 55.6%). We detected the urinary stones on CTU, but not IVU, in twelve patients (12/27, 44.5%). The sensitivity to detect the urinary stones was 100% (27/27) on CTU and 55.6% (12/27) on IVU respectively. The specificity was 100% (7/7) on IVU and CTU, respectively. The positive predictive value was 100% (15/15) on IVU and 100% (27/27) on CTU, respectively. The negative predictive value was 36.8% (7/19) on IVU and 100% (7/7) on CTU. Precontrast CTU demonstrated the urinary stones in all 27 patients (100%, 27/27). On the other hands, urinary stones were detected in 19 patients (19/27, 70.4%) and 8 patients (8/27, 29.6%) at 2 and 5 minutes on CTU, respectively.
CONCLUSION
CTU is superior to IVU to diagnose the causes of hematuria such as urinary tract stone or extrarenal lesion. Precontrast CTU is the most useful modality for the detection of the urinary tract stone of the other enhanced CTUs.