Retrograde Urethrogram

  • Retrograde urethrogram (RUG) is a diagnostic procedure that employs contrast dye to X-ray the urethra(1). X-rays are used to monitor the flow of the dye back down the urethra and into the bladder.
  • Suppose the doctor concludes that the urine incontinence is not due to the normal prostate enlargement seen in older men. In that case, the physician may suggest that the patient undergo a retrograde urethrogram procedure(2).
  • A urethrogram requires no special preparation(3). However, it is best to treat any urinary tract infection before surgery. Surgery is feasible even though the patient is still undergoing therapy.

What Is Retrograde Urethrogram?

Urethrography is the radiographic examination of the urethra using iodinated contrast media. It is a standard procedure among men(4).

Retrograde urethrogram (RUG) is a technique that uses contrast dye to X-ray the urethra(5). The one operating the X-rays can monitor the passage of the dye back down the urethra and into the bladder.

The RUG analyzes the anterior urethra most effectively(6). The anterior urethra is the section of the urethra between the penis and the beginning of the posterior urethra. The anterior urethra is like a tube or hose that only transports urine. It has nothing to do with leakage.

A radiologist, radiographer, and sometimes a nurse perform urethrograms.

Generally, a radiologist reviews the patients’ images and offers a written report to the physician(7). A radiologist can also communicate with the patients throughout the examination.

Why Would the Physician Recommend RUG?

The doctor may recommend a retrograde urethrogram operation if the urine incontinence is not due to the typical enlargement of the prostate found in older men(8). 

A bladder catheter, injury, prostate surgery, or an infection may have occurred in the past. Any of these occurrences can cause urethral narrowing(9).

A specialist doctor may perform a urethrogram as an emergency procedure if a suspected urethral injury occurs. 

Urologists, usually working in a hospital’s radiology unit or department of urology, can recommend patients for urethrograms(10). 

Suppose the patients are having difficulty passing their urine. In that case, their primary care physician may refer them for RUG before visiting a urologist.

How Retrograde Urethrogram Works

Urethrogram is conducted by inserting the tip of a Foley catheter into the urethral opening, followed by the instillation of 50 milliliters of contrast under low pressure(11). A simple X-ray is then taken of the region. 

A healthy urethra should have a smooth linear shape and a full bladder. Meanwhile, a damaged urethra may have an uneven shape, cease abruptly without bladder filling, or have contrast extravasation into adjacent tissues. 

If the study is normal, the Foley catheter may be advanced. In the event of an abnormal examination, suprapubic catheterization may be administered.

RUG/ASU vs. VCUG/MCU

A RUG/ASU (retrograde urethrography and ascending urethrography) is performed to see anterior urethra abnormalities. At the same time, a VCUG/MCU  (voiding cystourethrogram and micturating cystourethrography) is used to view posterior urethra abnormalities(12).

In addition, a VCUG/MCU may help detect bladder abnormalities and vesicoureteric reflux. Oftentimes, the bladder is not the primary focus of the test, as with a cystogram (VUR).

A RUG/ASU procedure should be a priority for conditions involving urethral trauma. A VCUG/MCU should not be done initially since attempting to blindly insert a Foley catheter into the bladder in a trauma setting may result in further iatrogenic urethral damage.

Assessment Methodology (RUG/ASU)

The following steps show how the assessment method for RUG/ASA works(13). 

Usually, the one who performs the assessment retracts the foreskin and wipes the tip of the penis with Betadine (povidone-iodine) or antiseptic. They then inject a little dose of topical local anesthetic like lidocaine gel into the urethra using a syringe. 

The patient may constrict the sphincter muscle during the surgery, leading to a stricture diagnosis. Hence, using a local anesthetic, in this case, may help relax the sphincter.   

However, some physicians advise against using lidocaine gel because of the formation of an insufficient seal.

On the other hand, the patient should be positioned at an angle to see the complete length of the membranous urethra. The practitioner will then place the tip of the metallic adaptor into the urethral orifice and attach the contrast-filled syringe to it. 

Alternatively, they will place the tip of a Foley catheter in the navicular fossa and inflate the balloon using sterile water until a seal is formed. The physician will take care not to cause the patient pain or damage the distal urethra.

Once a significant portion of the contrast has been injected, they will inject the contrast and image and take spot photos.

Urethral Diseases

The urethra is the tube that allows urine to exit the body(14). The urethra is a long tube that passes through the penis of male patients. It also transports sperm in men. In females, the urethra is short and slightly above the vagina. 

Problems with the urethra may be due to age, sickness, or trauma(15). 

Common urethral diseases are the following:

1. Urethral Cancer

Cancer of the urethra is a disorder in which malignant (cancer) cells originate in the urethra‘s tissues(16).

The urethra is the conduit that transports urine from the bladder to the outside of the body. On the other hand, the female urethra is about 1.5 inches long and directly above the vagina. 

Men’s urethras are around 8 inches long and pass through the prostate gland and penis before exiting the body. In males, the urethra also transports sperm.

These signs and symptoms, along with others, may be caused by urethral cancer or other illnesses(17). There may be no symptoms present in the early stage. However, individuals with any of the following conditions must consult a doctor:

  • Problems initiating the urine flow
  • Discharge from the urethra
  • Blood in the urine or bleeding from the urethra
  • Weak or intermittent (stop-and-go) urine flow
  • Urinating often, particularly at night
  • Incontinence
  • Swelling or thickening of the perineum or penis
  • Painless lump or swelling in the groin

2. Urethral Stricture Disease

The urethra is the channel through which urine exits the body(18). This tube can constrict when a man urinates, creating difficulties and pain. This disorder is known as urethral stricture. In some instances, a urethral stricture may need immediate medical care.

Men with a stricture may experience increased urinary pain and a slowed urine stream(19). This stricture can gradually grow and lead to pushing or straining to urinate. The condition appears without warning, requiring rapid treatment.

The most noticeable symptom of urethral stricture is a weakened urine system. Examples of symptoms include(20):

  • Urinating with difficulty
  • Urinary system infection
  • Prostatitis
  • Pain during urinating

Meanwhile, there are patients referred for strictures in the bulbar urethra. It is the urethral stricture in the portion of the urethra under the scrotum far from the tip of the penis(21). 

Some patients previously had balloon imaging and acquired a separate stricture when the catheter was inflated at the tip of their penis. Thus, there is a need for the repair of both strictures. 

The first step in identifying urethral stricture or developing an efficient treatment strategy for urethral stricture is obtaining the patient’s complete medical history(22). 

The “history” consists of the patient’s account of his urinary symptoms. The medical history describes any past therapy and general information, such as medical conditions, previous surgeries, urethral dilatation or urethrotomy, urethroplasty procedures, and allergies. 

It is very uncommon for patients to have had past dilations, incisions, or open surgery for urethral stricture failure(23).

Note that during the thorough physical exam, one must pay close attention to the penile skin and urethral aperture(24). This procedure is done when a male is uncircumcised with normal skin or is circumcised with some skin redundancy (extra skin). 

The urethral aperture (urethral meatus) is also significant. Meatal stenosis is a constriction of the urethral at the penis’ tip. Meatal stenosis refers to the constriction of the urethra at the tip of the penis. 

The condition may be a diagnosis of Lichen Sclerosis, also known as Balanitis Xerotica Obliterans, if there is an accompanying white color change of the urethral tip opening, mainly when abnormalities of the skin of the penis are present. 

3. Urethritis

Urethritis is an inflammation of the urethra(25). Infection is often the reason.

Non-gonococcal urethritis (NGU) refers to urethritis that is not caused by the sexually transmitted infection gonorrhea.

NGU symptoms in males include:

  • White or hazy discharge from the penis tip
  • Burning or painful sensation when urinating
  • Irritable and uncomfortable penis tip

Normal Anatomy

The Journal of Practical Medical Imaging and Management explained the normal anatomy of the male urethra(26). 

The length of the male urethra from the external meatus to the urine bladder varies between 17 and 24cm (reported mean 22 2.4cm).

The urogenital diaphragm separates the posterior and anterior parts of the urethra. Approximately 16cm in length, the anterior urethra runs from the external meatus to the urogenital diaphragm. It is separated into a proximal bulbous segment and a distal penile segment. 

Fossa navicularis refers to most aspects of the anterior urethra; its length is roughly 1 to 1.5cm. Within the urogenital diaphragm, Cowper’s glands drain into the proximal bulbous region. The periurethral Littré glands are situated in the penile urethra and the distal bulbous urethra‘s dorsal surface.

The posterior urethra extends about 5cm from the urogenital diaphragm to the urine bladder. A proximal prostatic section and a distal membranous segment are subdivided. The verumontanum, found in the posterior wall of the prostatic urethra, is 1cm long.

Ejaculatory ducts surround the prostatic utricle on both sides, while the internal urethral sphincter found inside the distal prostatic urethra extends from the bladder neck to the verumontanum. 

Meanwhile, the extrinsic sphincter originates from the levator ani complex and encircles the urethra.

Indications

Indications for RUG include trauma, abnormalities of the lower urinary system, urethral masses, and postoperative assessment(27). 

The most prevalent symptom is trauma, which, upon physical examination, often manifests as blood in the mobile prostate gland or urethral meatus in cases of urethral disruption.   

Lower urinary tract structural diseases requiring RUG include urethral strictures, urethral diverticulum, and urethral fistula, which may manifest as urinary urgency, a weak urine stream, and poor bladder emptying. 

Meanwhile, other possible urethral injuries (performed before Foley Catheter placement) are the following(28): 

  • Inability to void
  • Hematoma of the perineal or scrotal region
  • High riding prostate
  • Pelvic fracture

Preparation 

Typically, no extra preparation is necessary for a urethrogram(29). Any urinary tract infection should be treated before the surgery. However, the procedure can be performed in rare instances while the patient is still undergoing therapy.

The radiology practice or the hospital radiology department where the operation will be performed will provide the patients with any necessary preparatory instructions.

For the patient’s safety and comfort, they will be requested to change into an examination gown so that the clothes do not interfere with the images(30).

Patients can consume food and liquids before and after the treatment(31). If the patients are on regular medication or have diabetes and are on insulin, they must continue with the usual diet and treatment.

If patients are on blood-thinning medicine (such as Warfarin, Aspirin, or Clopidogrel), are allergic to iodine, or are pregnant, they must inform their doctor.

Tests and Procedures

Inside radiology briefly explains how the tests and procedures for urethrogram work(32).

The radiologist (certified and specialized physician) who will be doing the examination will explain the process to the patients.

Typically, the patients will be asked to empty their bladder before disrobing, wearing a gown, and lying down on an X-ray table called a fluoroscopy table. The procedure will be in the radiology or X-ray department or radiology practice. 

The radiologist will examine the bladder and urethra during the procedure using a big camera and a screen placed above the patient’s table.

The lower body will be covered with sterile drapes, and the penis and groin will be cleansed with an antiseptic solution. The radiologist will do the operation while wearing sterile gloves.

The majority of radiologists will perform the procedure by inserting a catheter (a thin plastic, silicone, or rubber tube) directly into the area of the penis where urine is expelled. A tiny balloon will be inflated to secure the catheter and prevent the contrast medium from escaping the penis. The majority of patients will suffer pain during catheter insertion and balloon inflation.

A contrast medium is administered softly via the catheter. A contrast medium, also known as contrast (or X-ray dye, despite being a colorless fluid), is a fluid that creates a shadow on an X-ray image. 

The urethra is filled with this fluid, and X-ray images are captured using a camera. These scans will reveal whether the urethra is constricted and show its location and severity.

Then, this portion of the examination only detects narrowings in the middle and lower urethra. Although the exam in the middle and lower urethra is enough, it may be essential to capture images of the upper urethra while voiding. 

There may be a need to extract the initial catheter and inject a local anesthetic jelly into the urethra. Then, it would lubricate and numb the urethra and facilitate the insertion of a catheter into the bladder.

After the catheter has been inserted into the bladder, the contrast will be injected into the bladder. When the catheter becomes so full that patients must urinate, it will be removed. As needed, images of the bladder will be captured at this phase.

If the urethra is severely constricted, it is not feasible or safe to insert the catheter into the bladder. The first study often provides sufficient information for the urologist if this is the case.

Lastly, the X-ray table will be progressively tilted to bring the patients to a standing posture, and a urine collection container will be provided. More images of the bladder and urethra will be obtained to determine how effectively the bladder empties and reveal any urethral narrowings.

Risks

Here are the possible risks that come with urethrogram(33). 

Although an injury to the urethra is uncommon, it is more frequent when the urethrogram is performed. The reason is that the urethral lining is often ripped before the treatment, allowing the catheter to flow through the torn region outside of the urethra.

In an emergency, a urethrogram performed with the catheter inserted to the end of the penis should reveal urethral rips and prevent additional harm that may be caused by inserting the catheter into the bladder. 

If the urethra is already injured, attempting to put a catheter into the bladder may worsen the damage. A catheter may also perforate the urethra through the tear. 

An injury may happen when the urethra is constricted. It may also be difficult to pass the catheter beyond the constriction.

Also, a urethrogram rarely causes urethral injury if the urethra is not already torn or severely constricted before the procedure starts.

Urine contamination is also relatively uncommon since sterile procedures are used. Initial soreness or stinging is expected after the test. If the patients have an infection, passing pee will accompany a burning feeling. 

If this persists for more than 36 hours, individuals should see a physician, who can prescribe antibiotics. 

Additionally, patients should see their doctor if they feel the urge to urinate often and pass urine more than 36 hours after the treatment or if they develop a fever or chills after the procedure. 

Suppose the patients get a fever (temperature more than 38°C). In that case, they must contact their general practitioner immediately and have their urine tested for infection.

Also, hypersensitivity to contrast media may pose a possible risk. Although it is uncommon for a contrast not to be injected directly into a blood artery, it may occur. 

Suppose the patients have ever had an allergic response to iodine-containing contrast. In that case, they must inform the radiologist before the treatment. Patients should also inform the hospital or radiology clinic of their visit. 

Doctors can recommend corticosteroids (steroids) to their patients a day before the treatment, or these practitioners may choose not to do the procedure.

Meanwhile, BMJ Journals reported a rare complication of retrograde urethrogram(34).

A 53-year-old man arrived with severe urine retention, for whom suprapubic catheterization was done after several unsuccessful per-urethral catheterization efforts. 

A retrograde urethrogram indicated an anterior urethral stricture and extensive intravasation. At the same time, a cavernosogram and spongiogram revealed a deep penis dorsal vein and pelvic vasculature. 

After taking the RUG, the patient got high-grade fever, chills, rigidity, tachycardia, and hypotension (septicaemia). He was treated with intravenous broad-spectrum antibiotics and inotropes and had an excision and primary anastomosis of the anterior urethral stricture three weeks later.

Side Effects

Urethrograms are safe diagnostic procedures(35). The risk of urinary tract infection is minimized by performing the surgery in sterile conditions and adhering to stringent infection control procedures.

There is a slight chance of an allergic response if X-ray contrast is provided(36). One out of one thousand injections result in a moderate allergic reaction, including rashes, hives, or sneezing. 

More severe symptoms include breathing troubles(37). Severe life-threatening side effects are uncommon (1 in 170,000).

Various diagnostic procedures can identify urethral issues(38). Among them are urine tests, x-rays, and an inspection of the urethra with a cystoscope. Treatment relies on the underlying source of the issue. Doctors can prescribe medications and recommend surgery in extreme circumstances. 

Expected Results

The duration of the procedure will be between 30 and 60 minutes. The time required will depend on(39):

  • Reasons for the procedure
  • If the radiologist has trouble inserting the catheter when the urethra is relatively narrow
  • If the patients have trouble passing pee once the bladder is full

Meanwhile, the time required for the physician to get a written report on the test or treatment will vary based on the following factors(40):

  • The intricacy of the test or operation
  • The urgency with which the doctor needs the findings
  • If the patients have had prior X-rays or other medical imaging that has to be compared with the current test or treatment (this is usually the case if the progression of a disease or condition is under evaluation)
  • If the doctor must provide additional information before the test or treatment can be interpreted by the radiologist
  • How the report is communicated to the physician (i.e., phone, email, fax, or mail)

Patients must feel free to ask the private practice, clinic, or hospital when the doctor will get the written report.

Abnormal Results 

Abnormal findings may indicate:

  • Lacerations
  • Tumors
  • Valves, known as “posterior urethral valves”
  • Strictures
  • Congenital abnormalities
  • Fistulas or false passages

Sample Case Studies

Urinary tract injuries may result from blunt trauma, penetrating trauma, urology operations, or spontaneous occurrence(41). 

Up to 15% of pelvic fractures are accompanied by bladder damage. About 11% of men and 6% of women get urethral injuries with a urinary tract infection. Retrograde urethrography and cystography rule out a partial urethral rupture, a complete urethral rupture, or a bladder rupture in trauma patients.

Following the discovery of a pelvic fracture, the lower genitourinary tract must be examined to rule out concomitant damage. There is a significant prevalence of simultaneous bladder trauma in patients with disruption of the pubic symphysis, pubic rami, or vertically unstable pelvic fracture.

An isolated acetabulum, femur, or iliac crest fracture is associated with minimal bladder damage or rupture risk.

Unfortunately, the absence of a pelvic fracture does not exclude bladder or urethral damage.

Blood at the urethral meatus, failure to void, swelling or ecchymosis of the perineum or penis, a boggy prostate, and a high-riding prostate indicate genitourinary tract damage. 

According to the traditional view, urethral catheterization should be avoided if a bladder and urethra damage is suspected view. Following this instruction, a retrograde urethrogram and cystogram must be conducted before urethral catheterization to rule out any injuries. 

A preliminary investigation reveals that blind urethral catheterization may be safe despite the risk of harm. However, more extensive studies are necessary.

  1. Diagnostic Fluoroscopy – Urology – Retrograde Urethrogram
    https://drjones.com.au/x-ray-diagnostic-fluoroscopy-urology-retrograde-urethrogram
  2. Urethrogram
    https://www.insideradiology.com.au/urethrogram/
  3. Ibid.
  4. Urethrography
    https://radiopaedia.org/articles/urethrography?lang=us
  5. Diagnostic Fluoroscopy – Urology – Retrograde Urethrogram
    https://drjones.com.au/x-ray-diagnostic-fluoroscopy-urology-retrograde-urethrogram
  6. Urethral Stricture Diagnostic Evaluation
    https://www.centerforreconstructiveurology.org/urethral-stricture/diagnosis/
  7. Diagnostic Fluoroscopy – Urology – Retrograde Urethrogram
    https://drjones.com.au/x-ray-diagnostic-fluoroscopy-urology-retrograde-urethrogram
  8. Urethrogram
    https://www.insideradiology.com.au/urethrogram/
  9. Ibid.
  10. Ibid.
  11. Urethrography
    https://www.sciencedirect.com/topics/medicine-and-dentistry/urethrography
  12. Urethrography
    https://radiopaedia.org/articles/urethrography
  13. Ibid.
  14. Urethral Disorders
    https://medlineplus.gov/urethraldisorders.html
  15. Ibid.
  16. Urethral Cancer Treatment (PDQ®)–Patient Version
    https://www.cancer.gov/types/urethral/patient/urethral-treatment-pdq
  17. Urethral Cancer Treatment (PDQ®)–Patient Version
    https://www.cancer.gov/types/urethral/patient/urethral-treatment-pdq#
  18. Urethral Stricture in Men
    https://my.clevelandclinic.org/health/diseases/15537-urethral-stricture-in-men
  19. Ibid.
  20. Ibid.
  21. Urethral Stricture Diagnostic Evaluation
    https://www.insideradiology.com.au/urethrogram/
  22. Urethral Stricture evaluation starts with history and physical exam
    https://www.centerforreconstructiveurology.org/urethral-stricture/diagnosis/
  23. Ibid.
  24. Ibid.
  25. Non-gonococcal urethritis
    https://www.nhs.uk/conditions/non-gonococcal-urethritis/
  26. Post-traumatic Retrograde Urethrography: A Review of Acute Findings and Chronic Complications
    https://www.appliedradiology.com/articles/post-traumatic-retrograde-urethrography-a-review-of-acute-findings-and-chronic-complications
  27. Ibid.
  28. Retrograde Urethrogram
    https://fpnotebook.com/mobile/uro/Rad/RtrgrdUrthrgrm.htm
  29. Urethrogram
    https://www.insideradiology.com.au/urethrogram/
  30. Diagnostic Fluoroscopy – Urology – Retrograde Urethrogram
    https://drjones.com.au/x-ray-diagnostic-fluoroscopy-urology-retrograde-urethrogram
  31. Ibid.
  32. Urethrogram
    https://www.insideradiology.com.au/urethrogram/
  33. Ibid.
  34. Urethro-venous intravasation: a rare complication of retrograde urethrogram
    https://casereports.bmj.com/content/2016/bcr-2016-215206
  35. Diagnostic Fluoroscopy – Urology – Retrograde Urethrogram
    https://drjones.com.au/x-ray-diagnostic-fluoroscopy-urology-retrograde-urethrogram
  36. Ibid.
  37. Ibid.
  38. Urethral Disorders
    https://medlineplus.gov/urethraldisorders.html
  39. Urethrogram
    https://www.insideradiology.com.au/urethrogram/
  40. Urethrogram
    https://www.insideradiology.com.au/urethrogram/
  41. Chapter 145. Retrograde Urethrography and Cystography
    https://accessemergencymedicine.mhmedical.com/content.aspx?sectionid=45343791&bookid=683
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