A retrograde urethrogram (RUG) is a specialized, live X-ray scan (fluoroscopy) used to check the male urethra. The urethra is the tube that carries urine from your bladder out of your body. If you have trouble urinating, a RUG helps your doctor see if the tube is blocked, narrowed (strictured), or injured.
During the scan, a liquid dye (contrast) is gently injected into the opening of your urethra. X-ray images are taken as the dye flows upward. This highlights the shape of the tube on the screen and clearly shows any narrow areas.
Common Indications for a Retrograde Urethrogram (RUG)
- Investigating difficulty urinating or a weak urine stream.
- Checking for narrowing (urethral strictures) caused by past infections or catheter use.
- Evaluating the urethra for injury after pelvic trauma or a fall.
- Assessing the urethra before or after reconstructive surgery.
- Investigating blood in the urine or chronic urinary tract infections.
What exactly does a retrograde urethrogram (RUG) show?
The scan shows the entire path of your urethra up to the entrance of your bladder. It highlights the exact location, length, and severity of any narrow sections (strictures) or tears in the tube.
How should I prepare for a retrograde urethrogram (RUG)?
No special diet or fasting is required. You can eat and drink normally. You will be asked to empty your bladder completely just before the procedure starts.
Do I need to stop taking medication?
No. Continue taking all your prescribed medications as usual. If you have any allergies—especially to contrast dye or iodine—inform your referring doctor and the scan team beforehand.
What happens when I arrive for my scan?
You will change into a clean hospital gown. The radiographer will guide you to the fluoroscopy room and ask you to lie down on a motorized X-ray table. The area around the tip of your penis will be cleaned with a sterile antiseptic solution to prevent infection.
How is the procedure performed?
You will lie on your back. The doctor will insert a small, soft catheter a very short distance into the tip of your penis. A tiny balloon on the catheter tip may be gently inflated to keep it in place. The doctor will then slowly inject the contrast dye through the catheter. You may feel a cooling sensation as the liquid flows. The radiographer will take X-ray images from different angles as the dye fills your urethra.
How long does a retrograde urethrogram (RUG) take?
The entire procedure takes about 20 to 30 minutes. Most of this time is spent preparing and positioning you for the scan.
Is there any discomfort?
Yes. You will feel a stretching sensation or pressure in your urethra as the catheter is inserted and the contrast dye is injected. While it can be uncomfortable and cause a mild urge to urinate, it is usually not painful. The team will work slowly and carefully to minimize any discomfort.
Are there risks?
Yes, but they are minimal. There is a small risk of a urinary tract infection or mild bleeding (seen as pink urine) for a day or two. There is also a very small risk of a mild allergic reaction to the contrast dye. The procedure uses a low dose of radiation, similar to a few months of natural background radiation.
Can children have this scan?
Yes. Children can have this scan safely if requested by a specialist, such as a pediatric urologist. Smaller, softer catheters are used to ensure their comfort.
Can I have this scan if I am pregnant?
Pregnancy Precaution
Tell your doctor or radiographer if you are pregnant or think you might be. While RUG is almost exclusively performed on male patients, any X-ray scan of the pelvis is avoided during pregnancy because the radiation can harm a developing baby.
When will I get my results?
The radiologist will study the X-ray images during the procedure. A written report and the images will be sent to your referring doctor or handed to you within a few hours.
What if the scan finds something?
If the scan shows a stricture or tear, your referring doctor (usually a urologist) will discuss treatment options. These may include a simple procedure to stretch the narrow area (dilation) or reconstructive surgery.
What are the important limitations and safety checks?
Fluoroscopy shows movement or anatomy during a specific examination, but it does not guarantee a diagnosis or exclude every abnormality. Image quality and interpretation can be limited by positioning, movement, body size, retained contrast, overlying structures, incomplete filling, or the patient's ability to complete the study. Further endoscopy, ultrasound, CT, MRI, laboratory testing, or tissue sampling may still be needed.
Fluoroscopy uses ionising radiation. Dose varies with the body area, examination complexity, equipment, patient size, and imaging time; the team should use the lowest exposure that still answers the clinical question. Tell the team before the examination if you are or may be pregnant. Pregnancy does not create a universal ban: the referrer and imaging team should decide whether to defer, modify, or proceed when the expected benefit outweighs the risk.
Contrast and preparation are procedure-specific. Barium, water-soluble iodinated contrast, intravenous contrast, and contrast placed into a joint, bladder, uterus, duct, or fistula have different risks. Tell the team about prior reactions, swallowing or aspiration problems, suspected perforation, kidney or thyroid disease, diabetes, medicines, and recent contrast studies. Do not fast, stop medicines, interrupt breastfeeding, or take bowel preparation or antibiotics based only on a general webpage; follow the center's written instructions.
Questions to ask the fluoroscopy team
- What exact question should this examination answer, and is a radiation-free or non-invasive alternative suitable?
- Which contrast route and agent will be used, and what preparation, pregnancy, breastfeeding, allergy, kidney, diabetes, or medicine instructions apply to me?
- Will a catheter, internal examination, sedation, or pain relief be needed, and may I stop the procedure if I am uncomfortable?
- What symptoms require urgent help afterward, when will the signed report be ready, and who will explain the result?
Sources and further reading
- RadiologyInfo.org: Fluoroscopy
- American College of Radiology: Manual on Contrast Media
- RadiologyInfo.org: Radiation safety for children
Conclusion
A retrograde urethrogram can define urethral injury or narrowing but may underestimate or fail to traverse a severe lesion and does not assess every cause of urinary symptoms. Report significant pain during the study and follow the team's catheter and aftercare advice.