The value of MR urography that uses HASTE sequences to reveal urinary tract disorders

OBJECTIVE. Breath-hold MR urography using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences was evaluated as a noninvasive alternative to excretory urography in healthy volunteers and in patients with disorders of the urinary tract. SUBJECTS AND METHODS. Twenty healthy volunteers and 45 patients with disorders of the urinary tract underwent HASTE MR urography on a 1.5-T MR imaging unit. Imaging time was 2 sec for single-thick-slice (20- to 60-mm slice thickness) technique and 10-18 sec for multislice technique. In the latter, images were postprocessed with maximum-intensity-projection technique and visualized in an arbitrary plane. Obstruction and its level were determined solely by excretory urography in eight patients, by excretory urography, with other imaging techniques (CT, retrograde pyelography, or sonography) in 27 patients, and by sonography alone in the 20 normal volunteers, seven pregnant women, and three patients who were allergic to iodinated contrast media. We evaluated whether HASTE MR urograms showed obstruction, showed the level of obstruction, and showed the cause of obstruction. RESULTS. In all 20 healthy volunteers and all 45 patients, the upper, middle, and lower group of renal calices and the pelvis were clearly revealed by HASTE MR urography. In patients whose urinary tracts were seen on excretory urography (n = 31), the accuracy of HASTE MR urography in revealing urinary tract dilatation and level of obstruction completely correlated with that of excretory urography, although functional information about the obstructed collecting system was not obtained. However, MR urography revealed nonfunctioning urinary tracts that were invisible on excretory urography (n = 6). In patients with extrinsic obstruction (n = 27), MR urography also revealed the obstructing lesions. Small stones within the ureter were more clearly seen on single-shot or source images. With HASTE MR urography, hydronephrosis in pregnant women (n = 7) was clearly shown. CONCLUSION. HASTE MR urography can be used as an alternative to excretory urography to obtain high-quality images of the dilated urinary tract and adjacent abnormalities. HASTE MR urography allows rapid acquisition of images, thus overcoming the drawbacks of earlier MR urography techniques.