Urothelial tumors of the upper urinary tract (renal pelvis and ureters) are rare: the most common of these are Transitional Cell Carcinomas (TCC), usually localized in the bladder (75% of cases), whereas only 7-10% arise in the renal pelvis and 2,5-5% in the ureter. Multicentricity is not infrequent and synchronous or metachronous tumors have been reported to develop in 11-13% of patients with upper urinary tract cancer and 2-4% of those with bladder cancer. The presence of additional lesions can change patient management. Clinically these tumors may present with hematuria or flank pain, but sometimes there are no specific clinical findings. Radiological studies play an important role in tumor detection and staging and in follow up. The diagnosis is usually performed by IVU and US, while CT is generally employed in the staging. Our purpose was to verify the role of Spiral CT with Multiplanar Reconstructions (MPRs) in the evaluation of ureteral tumors.Nine patients with ureteral neoplasms were examined with a single detector spiral-CT, using the following parameters: 120 kV, 200 mA; 5 mm collimation, pitch 1.4, slice reconstruction every 5 mm; image acquisition 2-5 minutes after injection of 120 cc of contrast medium (300 mgI/ml). All the exams were transferred to a separate workstation to obtain curvilinear MPRs.Spiral CT on the axial plane visualized 4 urothelial tumors as concentric ureteral wall thickening; 3 as intraluminal soft tissue masses, with involvement of almost the entire urinary tract, as far as the bladder in 1 case. In other 2 patients there were synchronous lesions which presented both patterns (wall thickening and intraluminal mass). In all cases the lesions exhibited moderate enhancement after c.m. injection. Medium- to high-grade hydronephrosis above the tumors was always present. On MPRs both ureteral involvement and dilated, urine-filled upper urinary tract were clearly represented on coronal and sagittal oblique planes; these images allowed to visualize the craniocaudal extension of short or long lesions, and to detect multicentricity.The radiological diagnosis of ureteral tumors is usually performed by IVU, US and CT. IVU allows to visualize the tumors as filling defects or irregular narrowing of the ureteral lumen. IVU however is unable to show the real extent of the tumor in obstructive disease or in nonfunctioning kidney. US visualizes the lesion as an echoic mass in the lumen, although it is sometimes difficult to differentiate neoplastic lesions from other filling defects and to visualize the entire ureteral tract. CT is generally employed in the staging of ureteral tumors. CT findings are usually very useful for distinguishing ureteral neoplasms from other filling defects based on their attenuation and enhancement characteristics. Spiral CT with MPRs allows to obtain panoramic views of the urinary tract; these images are more effective than those of IVU, because of their capability to show the longitudinal extension of the lesion and the presence of multicentric tumors. Furthermore with MPRs it is possible to visualize the ureteral tract distal to the lesion, overcoming the limitations of IVU in nonfunctioning kidney or obstructive disease.Spiral CT with MPRs is useful in the evaluation of ureteral tumors as it is capable of visualizing the whole extension of the lesion and the presence or absence of multicentric lesions, which can change patient management.