How far does B-ultrasound hold urine?

Do urinary B-ultrasound and gynecological B-ultrasound, need to hold urine, urine to bladder is very Peng Long, gently pressed by hand did not show urinary incontinence symptoms, this degree is the best. Because the more sufficient urine hold, bladder mucosa stretch of the more obvious, so do bladder B-ultrasound examination observation of the bladder wall more clear analysis. Do gynecological B-ultrasound examination because the bladder in front of the uterus, bladder filling, can prevent residual gas in the bladder, and affect gynecological B-ultrasound detection results. For an ultrasound, the patient needs to start holding urine before the examination.