I used to be very prone to UTIs until I began drinking two full glasses of water during the evening, taking a cranberry capsule with the water and getting up at least once during the night to urinate and empty my bladder. Good luck with your MRI. It is certainly important to find a solution to your fecal problem. I do find that at age 75 I don’t always feel when I need to defecate so I have developed the habit of thinking about it and that seems to help me go at the right time.