CT urine holding needs to drink water 30~60 minutes in advance, it is recommended to consult the examining doctor. Generally in the examination of urological diseases or gynecological pelvic diseases, especially when checking the bladder, prostate, etc., the doctor will instruct the patient to drink water to hold urine, the purpose of which is to make the bladder full, so as to facilitate the examination to observe the internal organs more clearly, such as bladder tumors, adenomas of the bladder, etc., which can be observed clearly, and also has a certain degree of help in the observation of the pelvis for women, and the prostate gland for men. Generally drinking water can be done 30~60 minutes before the examination, when most of the water ingested has been absorbed and the bladder is basically full, which is favorable for observation and will not cause discomfort due to overfilling. Before the examination, the doctor will be instructed, you can also take the initiative to consult the doctor whether you need to hold urine, according to the doctor’s instructions can be implemented, relax your mind, do not be too nervous.