Magnetic Resonance Urology (MRU) is a non-invasive urological test that uses water in the urine as a natural contrast agent for “imaging” purposes. Urine contains a large amount of water and has a long T2 relaxation time, while the tissue surrounding the urinary tract has a short T2 relaxation. By using heavy T2-weighted imaging, the signal of water in the urinary tract can be highlighted and the signal of surrounding tissues can be suppressed. The obtained raw images are then subjected to post-processing, maximum density projection, 3D reconstruction and multi-angle rotation to obtain MRU images. MRU has obvious advantages in displaying urethral malformations and obstructive lesions; the display of obstructive lesions has the following characteristics: First, it shows clearly the water in the urethra above the obstruction, and for the dilated water caused by tumor or enlarged lymph node compression, it not only shows the site of obstruction and the degree of water, but also shows the location of the tumor and its shape and size. Secondly, the display of ureteral stenosis or stone can be judged according to the morphology of the obstruction site, and stones are generally cup-shaped stenosis with low or no signal. However, the display of stones is much less effective than that of CTU. It is especially important to emphasize that MRU has a high value for the assessment of the part and degree of urinary tract obstruction, but the judgment of the nature of obstruction needs to be combined with routine MRU plain scan and enhancement, therefore, routine urinary tract scan must be perfected before MRU is done. Drink 500-1000 ml of water 2 hours before the MRU examination to keep the entire urinary tract in a state of filling. The examination is done with a feeling of urination in the bladder. Diuretics are sometimes needed before the examination to facilitate the display of the renal pelvis and ureter.