Utility of Cine MR Urography of the Urinary Tract and Comparison with Static MR Urography

PURPOSE: MR urography using heavily T2-weighted images can depict the urinary tract without the need for contrast medium. However, this technique has potential problems with regard to evaluating the non-dilated ureter. We compared the efficacy of cine MR urography (C-MRU) with static MR urography (S-MRU). MATERIALS AND METHODS: Twenty-two patients with suspected upper urinary tract disease underwent C-MRU. The final clinical diagnosis was compared with the diagnosis made using S-MRU and C-MRU, respectively. The sequence used was single-shot fast spin echo with a slice thickness of 50 mm, FOV of 45 cm, and 256x256 matrix. MR urography was obtained sequentially by 6 to 10 repetitions of single-shot scans with intermittent breath holding. S-MRU was used in the initial phase of this sequence, while C-MRU was used for the entire sequence. A final diagnosis was made based on 1) existence of stenosis, 2) rate of certainty of existence of stenosis, 3) etiology of stenosis. RESULTS: No statistically significant difference was observed between S-MRU and C-MRU, except in certainty of existence of stenosis, where C-MRU (average rate: 2.82 +/- 0.39) was significantly superior to S-MRU (2.41 +/- 0.73). CONCLUSION: C-MRU can improve the certainty of existence of urinary stenosis, and may be useful in excluding suspected stenoses in normal or undilated ureters.