Spinal dysraphism at MR urography: Initial experience

PURPOSE: To prospectively evaluate the role of magnetic resonance (MR) urog raphy in the radiologic assessment of patients with spinal dysraphism. MATERIALS AND METHODS: Fourteen patients with spinal dysraphism were referr ed for MR urography with half-fourier rapid acquisition with relaxation enh ancement (RARE) (repetition time msec/echo time msec = 11.9/95) and RARE (2 ,800/1,100) sequences on a 1.5-T MR machine. Six patients did not tolerate MR urography owing to claustrophobia (n = 4) or flexion deformities (n = 2) , giving a final success rate of 57% (eight patients). Two patients had a s ingle kidney tone after nephrectomy, one with a crossed-fused ectopic kidne y). Images were jointly assessed by two radiologists and compared with excr etory urographic studies. The signal intensity ratio and contrast-to-noise ratio were also calculated. RESULTS: Visualization of the kidneys, pelvicaliceal system, and ureters wa s better with half-fourier RARE than with RARE imaging, whereas visualizati on of the bladder was comparable with both sequences. The mean signal inten sity ratios for half-Fourier RARE and RARE sequences, respectively, were 16 .2 +/- 3.65 and 19.2 +/- 3.65 (P =.58, factorial analysis of variance model ), whereas the mean contrast-to-noise ratios were 55.4 +/- 5.16 and 47.8 +/ - 5.16 (P =.34). Cortical scarring was depicted more clearly at MR urograph y than at excretory urography, whereas a renal calculus seen at excretory u rography was not detected at MR urography. CONCLUSION: MR urography was feasible in 57% of patients with spinal dysrap hism and is a safe, accurate method of evaluating the upper urinary tract.