When the urethra is studied with instillation of contrast into the distal/anterior urethra it has been referred to as:
- retrograde urethrography (RUG)
- ascending urethrography (ASU)
When the posterior urethra is studied during micturition, this has been referred to as:
- voiding cystourethrography (VCUG)
- descending urethrography
- micturating urethrography
- pelvic trauma in the emergency department (retrograde only)
- diminished urinary stream
- urethral strictures
- urethral diverticula
- urethral obstruction
- suspected urethral foreign bodies
- urethral mucosal tumors
- suspected urethral fistula
Examination technique (RUG/ASU)
- retract the foreskin and clean the tip of the penis with Betadine or antiseptic solution
- inject a small amount of topical local anesthetic (e.g. lidocaine gel) into the urethra with a syringe
- local anesthetic helps to relax the sphincter as the patient may contract it during the procedure thus leading to a diagnosis of a stricture
- some advocate against the use of lidocaine gel on the basis that an inadequate seal is formed
- the patient position should be oblique to visualize the full length of the urethra
- place the tip of the metallic adaptor into the urethral orifice and attach the contrast loaded syringe to it
- an alternative is to place a Foley catheter tip in the navicular fossa and gently inflate the balloon with sterile water until a seal is formed making sure not to cause the patient pain or damage the distal urethra
- inject the contrast and image as soon as a major part of the contrast has been injected, taking spot images when appropriate
Ideal images demonstrate the entire length of the urethra with contrast beginning to fill the bladder.
RUG/ASU vs VCUG/MCU
Generally, a RUG/ASU is carried out to visualize anterior urethral abnormalities and a VCUG/MCU for posterior urethral abnormalities.
Additionally, although the bladder is not generally the main target of the exam, as with a cystogram, a VCUG/MCU may be useful in the detection of bladder abnormalities and vesicoureteric reflux (VUR).
In a trauma situation, a RUG/ASU should be performed first. A VCUG/MCU should not be performed first because blindly trying to introduce a Foley catheter into the bladder in a trauma setting may lead to additional iatrogenic urethral damage.
- 1. Gillenwater JY, Grayhack JT, Howards SS et-al. Adult and Pediatric Urology. Lippincott Williams & Wilkins. (2002) ISBN:0781732204. Read it at Google Books - Find it at Amazon
- 2. Lebowitz RL. Pseudostricture of the urethra: urinal artefact on urethrography. AJR Am J Roentgenol. 1978;130 (3): 570-1. doi:10.2214/ajr.130.3.570 - Pubmed citation
- 3. ALMER PE. URETHROGRAPHY IN THE MALE AND SUPRAPUBIC CYSTOGRAPHY. Br J Radiol. 1964;37 (443): 867-70. doi:10.1259/0007-1285-37-443-867 - Pubmed citation