RGU or Retrograde Urethrography is a radiologic procedure to assess urethra and bladder base. In this procedure, a dye is injected through the urethra and X-Ray pictures are taken.

MCU or Micturating Cystourethrography is a radiologic procedure which is used to assess the act of micturition and thereby, to assess the function and structure of the urinary bladder and urethra. This procedure involves the introduction of dye into the urinary bladder while the patient is asked to micturate/urinate.