I am 59 yrs old, having incomplete evacuation of urine, increased frequency, urgency and slow urination for last 5 yrs. I use to do USG KUB, urine routine and culture all normal for 5 yrs. now I have done USG, it shows urinary bladder wall appears mildly thickened and irregular and post void urine is 63 cc. prostate is normal 19 cc. urine routine & culture, PSA normal, CA-125 negative. what may be the cause and further investigation should be done.Pl advise me