Urethral sonography in the diagnosis of penile and bulbar urethral stenosis

Urethral sonography in the diagnosis of penile and bulbar urethral stenosis

European Journal of Radiolog_v, 14 (1992) 0 1992 Elsevier EURRAD Science Publishers 3 l-36 31 B.V. All rights reserved. 0720-048X/92/$05.00 002...

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European Journal of Radiolog_v, 14 (1992) 0

1992 Elsevier

EURRAD

Science Publishers

3 l-36

31

B.V. All rights reserved. 0720-048X/92/$05.00

0022 1

Urethral sonography in the diagnosis of penile and bulbar urethral stenosis V. GarcibMedina, ‘Department

J.D. Berna, J. Llerena, J. Garcia-Medina and J.L. Genoves

of Radiology, Hospital General, Murcia. Spain, and Department of Radiology. Wniversity of Minnesota, MN, U.S.A.

(Received

Key words: Urethra,

sonography;

16 April 1991; accepted after revision 19 July 1991)

Sonography,

urethra, Urethral

stenosis, bulbar; Urethral

stenosis, penile

Abstract Ultrasound was used in 25 patients for the study of penile (21) and bulbar (4) strictures and for the follow-up of 8 of these patients on whom dural urethroplasty was carried out. There was a good correlation with urethrography. Ultrasound has the added advantages of enabling study of the periurethral tissues without testicular irradiation, and safety and economy of the exploration.

Introduction Retrograde and voiding urethrographies are now the techniques of choice in studying the urethra [ 1,2]. A number of variations, such as double contrast, have been introduced for better identification of intraurethral lesions [ 3,4]. Ultrasound has been used in studying the female urethra [ 51 and the male prostatic urethra [ 61. Its use has also been described for study of the urethra in the fetus [7]. Recently, the use of ultrasound has been described in the study of the male anterior urethra [&lo]. The results of an investigation of penile and bulbar urethral strictures, including follow-up, in a group of patients undergoing urethroplasty are presented. Patients and Methods The study included 25 patients with an age range of 35-60 years. All were evaluated for possible urethral strictures. After diagnostic confirmation by radiographes and cystoscopy, 8 of them underwent dural reconstruction and a 3 month follow-up with ultrasound. Address for reprints: V. Garcia-Medina, M.D., Department of Radiology, Hospital General de Murcia, Avda. Intd Jorge Palacios, 1, 30008 Murcia, Spain.

First, sonographic urethrography was carried out using 7.5 MHz transducers. The penis is placed with its dorsal surface on the ventral wall of the abdomen and the transducer is placed on the ventral surface of the penis. A catheter is inserted through the external meatus, and the glans is lightly constricted in order to avoid reflux. Next, through a syringe connected to the catheter, at least 10 cc of saline solution is introduced. Longitudinal and transversal studies are made. The transducer is then placed upon the scrotum and the perineum in order to study the union of the penile urethra with the bulbar and the bulbar urethra, respectively. Voiding dynamic studies are carried out with the penis in the same position but with a urine bag in place. Transperineal, transscrotal and penile approaches are also realized. In all cases videotape recordings are made. Once the ultrasound diagnosis has been made, the patients undergo a radiographic urethrography and the results are compared. Ultrasonographic anatomy When exploring the urethra by means of longitudinal scans, the corpus cavemosum is seen to be separated from the corpus spongiosum by a hyperechogenic line. This line corresponds to the albugineas, and principally

32

b

a

Fig. 1. (a and b) Undistended penile and bulbar urethra. The hyperechogenic line corresponds to the albugineas spongiosum and the corpus cavernosum are seen above and below the line, respectively.

to those of the corpora cavemosa as these are thicker (Fig. 1a). The sonolucence of the two corpora is similar. In some cases the urethra may appear as a single or double line in the interior of the corpus spongiosum. In the radix penis the corpus spongiosum increases in dimension, backwards and downwards in order to form the bulb (Fig. lb). On introduction of the saline solution, or on voiding, the urethra is distended and adopts the form of a sonolucent tube with hyperechoic walls and with posterior reinforcement that ends at the albuginea (Fig. 2). The sonodensity of the corpus cavemosum does not change. In the transversal scans from the glans towards the bulbar region, three elliptical images are observed; the upper one corresponds to the corpus spongiosum

Fig. 2. Sonolucent

image of the distended urethra.

penile and bulbar

(arrows). The corpus

and the two lower images correspond to the corpus cavernosum. The corpora are seen to be joined at their midpoint at the level of the penile urethra, and further back they separate as the bulb interposes itself (Fig. 3). The albuginea of the corpus cavernosum appears as a hyperechogenic line, but in some cases it can produce a posterior shadow that may be confused with a calcification in Peyronie’s disease. In the transversal scans the lumen can be clearly observed when the urethra is distended. The bulbar urethra can be studied with greater clarity by means of a transperineal approach. With this projection the external sphincter can be observed and its opening and closing can be studied dynamically (Fig. 4).

Fig. 3. Transversal view of the penile urethra. The corpus spongiosum is seen through which the undistended urethra passes (arrow) and below is the corpora cavernosa.

Fig. 4. Transperineal

image of the bulbar urethra with the external sphincter

Fig. 5. (a) Stricture of the penile urethra (arrow). Note the loss of posterior reinforcement left. (b) Radiologic correlation.

(arrows), closed (a) and open (b).

at this level. The tip of the catheter is seen on the

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Fig. 6. Penile stricture (arrow). Example of retrograde

Fig. 7. Stricture of the bulbo-penile

sonourethrography

with its radiologic correlation.

union. Example of sonourethrography

with its radiologic correlation.

Fig. 8. Dural urethroplasty

seen with ultrasound.

The urethroplasty is seen as a hyperechogenic outline is residual.

Results Penile stricture was diagnosed in 24 patients. In all cases the length of the stricture and its caliber were measured, 21 in the penile urethra and 3 in the bulbar. In one patient the stricture was not observed by ultrasound. In some cases of stricture, loss of posterior reinforcement was observed when the lumen was distended (Fig. 5). The retrograde ultrasonographic examination allows the post-stricture region to distend, and the voiding study allows visualization of the pre-stricture region and the capacity of the voiding function of the patient (Figs. 6 and 7). One month after undergoing a dural urethroplasty, 2 of the 8 patients presented a minimal stricture. The dura appears as a fragmented and hyperechogenie line on the ventral wall afthe lumen. On the dorsal wall residual areas of the strictures are seen (Fig. 8). In all cases there is a total correspondence with the radiologic findings, but the evaluation of the length and caliber of the stricture is more precise when ultrasonography is used. In the bulbar region of 4 cases, 3 strictures were diagnosed with ultrasound; one went unnoticed but was seen retrospectively. Discussion Ultrasound urethrography presents clear advantages over radiographic urethrography. In addition to the advantage of the lack of irradiation, it is possible to

line on the ventral wall. The irregular dorsal

obtain a clear image of the lesion itself and of the periurethral tissues [ 91. In our opinion the study system should be: penile approach for the penile urethra, transscrotal approach for the penile and bulbar union, and transperineal approach for the bulbar urethra. Utilization of 10 MHz high-frequency transducers gives a better image than those of 7 and 5 MHz and provides a high definition of the normal and pathological periurethral structures. The urethra distended with liquid has the same flexibility as a vein: it is easily compressed by the transducer. Together with diagnosis and localization of strictures, stones, foreign bodies, disruption after trauma, diverticula and mass [ 111, this technique can be useful in periurethral pathology, fistulas of certain calibers, surgical follow-up such as the cases we present with dura, in the control of interventional urethral procedures such as balloon dilatations and stents, and their follow-up. The prostatic urethra is studied with transrectal transducers. We believe that ultrasound may become a complement to conventional urethrocystography. References Boltuch RL, Lalh AF. A new technique for urethrography. Radiology 1975; 115: 736. McCallum RW. The adult male urethra: normal anatomy, pathology and method of urethrography. Radio1 Clin North Am 1979; 17: 221-224. Wong W, Saito T, Ogawa H. Radiologic detection of prostatic carcinoma by double-contrast retrograde urethrography. J Urol 1975; 114: 746-751.

36 4 Yokoyama M, Watambe K, Iwata H et al. Double-contrast urethrography for visualizing small lesions in the distal urethra. Urology 1982; 19: 440. 5 Hunnigan W Jr, Du Bose TJ. Sonography of the normal female urethra. AJR 1985; 145: 839-841. 6 RiIkin MD. Sonourethrography: technique for evaluation of prostatic urethra. Radiology 1982; 145: 143. 7 Mahony BS, Callen PW, Filly RA. Fetal urethral obstruction: US evaluation. Radiology 1985; 157: 221-224. 8 McAninch JW, Laing FC, Jeffrey RB Jr. Sonourethrography in

the evaluation of urethral strictures: A preliminary report. J Urol 1988; 139: 294-297. 9 Clifford D, Gluck A, Bundy L, Fine C, Laughlin KR, Richie JR. Sonography urethrogram: comparison to roentgenographic techniques in 22 patients. J Urol 1988; 140: 1404-1408. 10 Merkle W, Wagner W. Sonography of the distal male urethra: a new diagnostic procedure for urethral strictures: results of a retrospective study. J Ural 1988; 140: 1409-1411. 11 Benson CB, Doubilet P, Richie JP. Sonography of the male genitale tract. AJR 1989; 153: 705-713.