It is best to hold your urine to keep your bladder full when examining both kidneys. If the patient has kidney stones, when doing ultrasound, it will show single or multiple strong echogenic light clusters in the collecting system within the kidney, these strong echogenic light clusters are of different sizes, some of them are double kidney stones and some are single kidney stones. If the stone is discharged down the ureter, the patient’s pain is very obvious, and may be accompanied by vomiting, urinary urgency, frequent urination, and blood in the urine. If the stone is embedded in the ureter, hydronephrosis and dilatation of the ureter may occur, and a strong light mass may be displayed in the ureter. If the stone is discharged into the bladder, there can be a strong light mass shown in the bladder, and the strong light mass can move with the change of body position, which needs to hold urine to make the bladder filled up for easy observation. When an ultrasound is done in the hospital, checking the urinary system would include both kidneys, the ureters and the bladder. It costs the same as doing a single kidney or both kidneys, so patients try to hold their urine to allow the doctor to do more tests.