Abstract:Objective: To study the MRI manifestations of renopelvic carcinoma and to evaluate the diagnostic value of MRI. Methods: Thirteen surgically and pathologically proved cases of renopelvic carcinoma were examined with MRI pre-operation. All the cases were scanned with T1WI, T2WI, STIR and FIESTA sequences on axial and/or coronal position. Enhancing scans were performed in 6 cases. Two patients received MRU scan. Results: In these 13 cases, the size of lesions were between 0.6cm×0.8cm to 3.5cm×4.0cm on MRI. The lesions were limited mass in renal pelvis with clear borderline in 9 cases. In the other 4 cases, the lesions showed invasive growth and adjacent renal parenchyma was involved. Hydronephrosis and renal cysts were showed in 3 cases and 4 cases respectively. The lesions belonged to Ⅰ~Ⅱ stage(n=7), Ⅲ stage(n=3) and Ⅳ stage(n=3) by MRI staging. On T1WI, the lesions presented as homogeneous hypointense signal masses in 7 cases, heterogeneous signal intensity in 2 cases, isointense signal intensity in 4 cases. On T2WI, the lesions presented as homogeneous hyperintense signal in 6 cases, inhomogeneous hyperintense signal in 2 cases and isointense signal intensity in 5 cases. Homogeneous enhancement was presented in 4 cases, while inhomogeneous enhancement in 2 cases in cortical phase. Intensity of enhancement was mildly raised in 5 cases in parenchymal and pyelographic phases. There were no abnormal manifestations on MRU. The cases belonged to Ⅰ stage(n=0), Ⅱ stage(n=6), Ⅲ stage(n=4) and Ⅳ stage(n=3) by histopathology staging. All the cases were transitional cell carcinoma. Conclusion: Renopelvic carcinoma can be detected accurately by MRI. Coronal MRI is helpful for diagnosis. MRU is an alternative method and not essential in fact.