|Year : 2002 | Volume
| Issue : 2 | Page : 140-142
Posterior urethral valves: Transperineal ultrasonography - a diagnostic tool: Pictorial essay
Dhiraj Nandi Chowdhury, Sankar Prasad Kabiraj, Anup Kumar Kundu
Department of Surgery and Radiology, North Bengal Medical College & Hospital, Siliguri, India
Anup Kumar Kundu
4, P.C. Sarkar Sarani, Hakimpara, Siliguri (W.B.) - 734 401
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Posterior urethral valves (PUV) is a singular structure, often incorrectly referred as plural, an obstructive uropathy in male infants and neonates. This congenital abnormnality is diagnosed by non-invasive investigation - perineal ultrasonography.
Keywords: PUV; MCU; USG; Transperineal.
|How to cite this article:|
Chowdhury DN, Kabiraj SP, Kundu AK. Posterior urethral valves: Transperineal ultrasonography - a diagnostic tool: Pictorial essay. Indian J Urol 2002;18:140-2
|How to cite this URL:|
Chowdhury DN, Kabiraj SP, Kundu AK. Posterior urethral valves: Transperineal ultrasonography - a diagnostic tool: Pictorial essay. Indian J Urol [serial online] 2002 [cited 2020 Apr 4];18:140-2. Available from: http://www.indianjurol.com/text.asp?2002/18/2/140/37615
| Introduction|| |
Valvular obstruction of the posterior urethra is the most common cause of lower urinary tract obstruction in male infants. Males with PUV represent about 10% of neonates with a significant uropathy.  With the advances in diagnosis and management the mortality of the sick and affected infants is reduced. Definitive confirmation of the urethral obstruction is attained with a Micturating Cysto-Urethrogram (MCU). The use of ultrasonography for the last 25 years in evaluation of neonatal genitourinary tract, including the evaluation of posterior urethral valves has further enhanced the ability of the sonologist to make a timely and accurate diagnosis. We took the help of transperineal ultrasonography (USG) to improve our diagnostic capability.
| Materials and Methods|| |
19 male patients (aged between I day to 13 years), who were suspected to have posterior urethral valves were studied with routine renal tract ultrasonography, performed through fluid-filled bladder, as well as through the perineum in both transverse and longitudinal orientations. All these patients presented with voiding urinary symptoms, urinary tract infections, dribbling of urine, enuresis, renal failure and abnormal urinary stream at birth. Clinically almost all of them had palpable urinary bladder with or without palpable kidneys. Seven of them were already catheterised. The cases were examined with real-time sector and linear scanner using 7.5 mHz transducer. The kidney and bladder areas were first examined in both longitudinal and transverse planes to note the presence or absence of pelvic, calyceal or proximal ureteral dilatation or peritoneal fluid (urinary ascites). The ultrasound examination of full bladders were done to note distal ureteral dilatation and bladder wall (including the trigone) hypertrophy (when the thickness is more than 4-5 mm).  An inferior angulation, through the fluid-filled bladder, was used to enhance the possibility of imaging a dilated posterior urethra. This was followed by transperineal scan by putting the transducer and coupling gel on the perineum between the scrotum and anus directed towards the bladder neck. The transperineal views were obtained in the transverse plane with cranio-caudal angulation and in the longitudinal plane in midline and with parasagittal angulation. The catheters were taken out during ultrasonography.
We sought to image the posterior urethra and note whether it was dilated and if a posterior urethral valves could be imaged within it. All the cases later had MCU, IVU followed by urethro-cystoscopy.
| Results|| |
PUV was diagnosed in 14 of the 19 patients by transperineal ultrasonography. The transverse and longitudinal views showed dilated posterior urethra and areas of soft tissue echogenicity in the periphery of the dilatation. In 5 patients USG suggested a diagnosis of PUV by a thick walled urinary bladder and dilated posterior urethra [Figure - 1] and in 4 children only dilated posterior urethra [Figure - 2]a, b, c. In 5 cases, USG diagnosed PUV by demonstrating an area of linear echogenicity [Figure - 3], which is a valuable confirmatory evidence within the dilated posterior urethra at transperineal examination.  9 of the 14 children had pelvicalyceal dilatation, bilaterally dilated ureters and large bladders [Figure - 4]. One patient had increased renal parenchymal echogenicity with loss of cortico-medullary differentiation, suggesting CRF.
In all these patients identified at USG as PUV, the diagnosis was confirmed by MCU. The valves were endoscopically confirmed and fulgurated in 10 cases. 1 patient died of chronic renal failure. One child of one-day age developed severe septicemia following MCU. 2 patients attended with enuresis, refused operation and were lost to follow-up.
| Discussion|| |
MCU is the "gold standard" for the diagnosis of PUV. It is an invasive investigation. PUV, the obstructive uropathy, is usually associated with urosepsis and we lost a baby due to septicemia following MCU. Non-invasive ultrasound scanning of the perineum, urinary bladder and kidneys (which will show hydronephrotic changes and/or increased renal cortical echogenicity  ) may demonstrate "dilated and elongated posterior urethra"  of PUV, allowing the differentiation of PUV from neurogenic bladder outlet obstruction or stricture urethra. Cremin and Aarason' described dilated posterior urethra for diagnosis of PUV by trans-perineal ultrasonography. Cohen et al  imaged a linear area of echogenicity within dilated posterior urethra by same method and believed it to be PUV which was also observed by others. ,, Antenatally PUV may also be diagnosed by USG. 
So we conclude that transperineal USG has not yet replaced MCU for diagnosis of PUV but it is a practical proposition where urinary tract infection contradicts the performance of micturating cystourethrogram.
| References|| |
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]
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