A retrograde urethrogram is a roentenographic demonstration of the renal pelvis and ureter by the retrograde injection of radio-opaque material through the ureters.
ANATOMY OF URETHRA
•The urethra is the vessel responsible for transporting urine from the bladder to an external opening in the perineum.
• lined by stratified columnar epithelium, which is protected from the corrosive urine by mucus secreting glands.
•Male urethra is 18-20 cms long
•Extends from bladder neck till the meatal opening at penis
•It has three named region:
•Approximately 3 cm in length.
•Begins as a continuation of the bladder neck and passes through the prostate gland.
•It is the widest and most dilatable portion of the urethra.
•Approximately 1 cm in length
•Passes through the pelvic floor and deep perineal pouch.
•It is the narrowest and least dilatable portion of the urethra
•From the bulb and corpus spongium of the penis, ending at the external urethral orifice(meatus)/
•begins at bladder neck and passes inferiorly through the perineal membrane and mascular pelvic floor.
•4-5 cms in length
•Narrowest & least distensible at meatus.
•This forms the spinning top configuration of urethra on normal MCU.
•The distal end of the urethra is marked by the presence of two mucous glands that lie either side of the urethra – Skene’s glands.
•Absent or unsatisfactory visualisation of the collecting system on IVU
•Unexplained hematuria, when the ureters have not been visualised by IVU.
•Evaluating persistent intrauretral or intrapelvic filling defect.
• Demonstrating the exact site of ureteral fistula
•Acute urinary tract infection
•allergic to iodinated contrast media
•Ionic contrast media can be used safely unless there is any specific contraindication like known hypersensitivity etc.
•The strength of contrast media should be 150-200mg I/ml.
•Contrast media should not be too dense as it will obscure small lesions in the ureters and the pelvis.
•Bowel preparation with cathartics is not routinely performed.
•Full length supine AP abdomen before the examination is started.
•With ureteric catheter in situ.The patient is transferred to the radiology department.
•Urine is aspired and under flouroscopic control contrast medium is slowly injected.
•About 3-5 ml is usually enough to fill the pelvis. Injection should be terminated before this if the patient complains of pain or fullness.
•Normal retrograde urethrogram (RGU):
•If the radiopaque contrast is injected properly, the entire anterior and posterior urethra should be filled with contrast and seen to jet into the bladder neck. The verumontanum is seen as an ovoid filling defect in the posterior urethra
•The distal end of the verumontanum marks the proximal boundary of the membranous urethra and constitutes the urethra that passes through the urogenital diaphragm.
1. supine PA film of the kidney.
2.both 35* anterior oblique of the kidney,low kvp 67-75 is used to visualise calculi and contrast medium.
3.If some pelvic-ureteric junction obstruction is there, the CM in the pelvis is aspirated.
•Prophylaxis antibiotic may be used
•Chemical pyelitis- if there is statis of contrast medium.
•extravasation due to over distention of pelvis
•introdcution to infection
•mucosal damage to the ureter
•perforation of the ureter of pelvis by the catheter