|Year : 2019 | Volume
| Issue : 2 | Page : 83-88
Sonourethrography in evaluation of anterior urethral abnormalities and comparison with retrograde urethrogram
C Anil1, B Vijayalakshmi Devi1, AY Lakshmi1, N Anil Kumar2, N Rukmangada3
1 Department of Radiodiagnosis, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
2 Department of Urology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
3 Department of Pathology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
|Date of Web Publication||11-Nov-2019|
B Vijayalakshmi Devi
Professor, Department of Radiodiagnosis, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Background: Sonourethrography (SUG) offers important technical advantages over conventional retrograde urethrography (RGU) by estimating the length of strictures, degree of spongiofibrosis which could be more informative in making decisions about management. The present study is intended to evaluate the role of SUG in investigating anterior urethral abnormalities and comparison of SUG with RGU and per-operative (PER-OP) findings.
Methods: All 31 patients had undergone RGU first and then followed by SUG. The findings of both examinations were tabulated and compared with per-operative findings.
Results: Total number of pathologies detected in RGU, SUG and PER-OP are 45, 53 and 53, respectively. In detecting strictures, the overall sensitivity is 97% and 100%, specificity 50% and 66%, positive predictive value 94% and 97%, negative predictive value 66.6% and 100%, accuracy is 92% and 97% and Cohen's Kappa is 0.53 and 0.78 for RGU and SUG, respectively. The mean length of stricture calculated on SUG was closer to that of surgery when compared with RGU. The percentage sensitivity and accuracy of SUG in detecting spongiofibrosis is 94.7%. The accuracy of RGU and SUG in detecting urethritis is 47% and 94%.
Conclusions: SUG gives more accurate information about stricture length and periurethral fibrosis, thus is more useful to determine the suitable operative procedure.
Keywords: Anterior urethral abnormalities, retrograde urethrography, sonourethrography
|How to cite this article:|
Anil C, Devi B V, Lakshmi A Y, Kumar N A, Rukmangada N. Sonourethrography in evaluation of anterior urethral abnormalities and comparison with retrograde urethrogram. J Clin Sci Res 2019;8:83-8
|How to cite this URL:|
Anil C, Devi B V, Lakshmi A Y, Kumar N A, Rukmangada N. Sonourethrography in evaluation of anterior urethral abnormalities and comparison with retrograde urethrogram. J Clin Sci Res [serial online] 2019 [cited 2019 Dec 16];8:83-8. Available from: http://www.jcsr.co.in/text.asp?2019/8/2/83/270756
| Introduction|| |
As urethra is the final pathway of the lower urinary tract, various diseases affect urethra. It is subjected to various infections resulting in urethritis. It is the common site of strictures either due to infections, trauma or iatrogenic. Congenital anomalies, though rare can still be encountered. Urethral stricture is one of the important causes of bladder outflow obstruction and becomes one of the important workloads of the urological centres in developing countries retrograde urethrography (RGU) is a conventional and standard radiographic technique in imaging of male urethra and for the planning of urethral reconstruction., Although RGU is gold standard imaging inherit limitations persist. Limitations include it produces static images, variation in penile stretch, urethral distension and patient positioning.,, Furthermore, extravasation of contrast into other areas of penis occurs in addition to venous and lymphatic intravasation, leading to sepsis and hypersensitivity., To overcome the constraints of conventional radiography technique, In 1988, McAninch et al. reported a new technique for imaging male urethra with high-resolution ultrasound and has evaluated complex urethral strictures more precisely. Since then it has been routinely used to evaluate anterior urethral strictures. They are being used to study the urethral mucosa and periurethral spongy tissue which can be involved in urethral pathologies such as strictures, diverticula, trauma and tumours.,
As a three-dimensional study, sonourethrography (SUG) offers important technical advantages by estimating the length of strictures, degree of spongiofibrosis which could be more informative in making decisions about management., A significant reduction in the incidence of recurrent strictures may be obtained by selecting patients for treatment based on SUG findings. The present study evaluated the role of SUG in investigating anterior urethral abnormalities and compared it with RGU and per-operative findings.
| Material And Methods|| |
The study was performed in our institute from June 2012 to 2014. After taking informed consent and institutional ethical board approval, all the selected patients by defined criteria have undergone retrograde urethrogram first and then followed by SUG. Retrograde urethrogram was performed by inflating 10 F Foley's bulb (according to the meatal size) with 2 mL of normal saline in fossa navicularis. Then, 20 mL urograffin (60%, ionic) is injected through Foley's catheter, and X-ray films were taken in an appropriate position. SUG was performed in Siemens Sonoline G40 machine using 7.5 MHz linear array transducer. After cleaning the penis and perineum with antiseptic solution, the penis is extended over the lower abdomen, and ultrasound gel is applied on the ventral surface. About 20–100 mL of normal saline is infused through catheter after taking care to exclude air bubbles. The penile urethra is visualised up to penoscrotal junction with multiple longitudinal and transverse scans by placing transducer on ventral penile surface. Subsequently, the transducer is repositioned to visualise proximal penile and distal bulbar urethra with transscrotal approach. Transperineal scans are performed to visualise proximal bulbar urethra. The findings of RGU were recorded on conventional radiographs and digital radiographs. The findings of sonourethrogram were recorded in the memory disc of the sonography unit. The findings of both examinations were tabulated and compared with per-operative findings (gold standard). The findings of the study were then subjected to statistical tests of significance. Statistical Package for Social Sciences (SPSS) version 20 was used for calculations. The findings of both examinations were analysed in terms of sensitivities, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, pathology detection rates and Cohen's Kappa values.
| Results|| |
The total number of cases included in the study was 31 from June 2012 to May 2014. The age range was 20–81 years with a median age being 52 years. Total number of pathologies detected in RGU, SUG and per-operative are 45, 53 and 53, respectively [Table 1].
Of 31 patients, in RGU, 28 patients showed 34 strictures [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]. Out of them, 6 (21%) patients had double strictures, and 22 (79%) patients had single stricture. In RGU, the most common location of the strictures is bulbar urethra (20 pts), penile strictures (11 pts) and penobulbar (3 pts) strictures. Whereas in SUG, 29 patients showed 34 strictures. Out of them, 5 (30%) patients had double strictures and 24 (70%) patients showed single stricture. One patient who had double strictures in RGU showed only single stricture in SUG (false stricture). Another patient who does not have stricture in RGU shows single stricture in SUG and per-operative. Whereas peroperatively, out of 31 patients, 26 showed only strictures, 1 patient has both stricture and diverticula, 1 patient showed no stricture, 5 patients showed double strictures and 23 patients had single stricture.
|Figure 1: A 28-year-old patient showing long segment stricture in peno-bulbar region in retrograde urethrography (a). Sonourethrography of the same patient showing stricture (b)|
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|Figure 2: A 76-year-old patient showing bulbar diverticulum in retrograde urethrography (a). Sonourethrography of the same patient shows diverticulum (b)|
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|Figure 3: (a) A 10-year-old patient showing penile diverticulum (black arrow) in retrograde urethrography. (b) The same patient in sonourethrography shows diverticulum|
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|Figure 4: A 60-year-old patient showing multiple strictures involving bulbar and penile urethra in retrograde urethrography (a). The same patient showing strictures in sonourethrography, this patient has no increase in periurethral echogenicity (b)|
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|Figure 5: Patient showing stricture in bulbar urethra (arrow) with periurethral echogenicity (spongiofibrosis)|
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The overall sensitivity, specificity, PPV, NPV and accuracy of both RGU and SUG in detecting strictures were shown in [Table 2]. However, in terms of stricture length, variation noted among RGU, SUG and per-operative findings. The length of stricture measured on SUG was slightly more than the length measured on RGU. The mean lengths of strictures on RGU, SUG and surgery were 13.76 mm, 16.78 mm and 18.43 mm, respectively [Table 3]. The mean length calculated on SUG was closer to that of surgery when compared with RGU.
|Table 2: Anterior urethral stricture detection on sonourethrography, retrograde urethrography|
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|Table 3: Mean length of stricture on per-operative, retrograde urethrography and sonourethrography|
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The sensitivity and accuracy of RGU in predicting correct stricture lengths between 1 and 4 cm are 81% and 81%, whereas in SUG it is 100% and 96%.
Spongiofibrosis was noticed in 18 cases by SUG and in 19 cases by peroperatively. The percentage sensitivity and accuracy of SUG in detecting spongiofibrosis is 94.7%.
Urethritis was seen in 8, 16 and 17 cases of RGU, SUG and peroperatively. The accuracy of RGU and SUG in detecting urethritis is 47% and 94%. RGU and SUG are equally sensitive in detecting periurethral extravasation. The sensitivity of RGU and SUG is 100% in diagnosing diverticulum.
There was no situation where RGU picked up a lesion and ultrasound did not. Our results showed SUG has detected more number of anterior urethral pathologies when compared with retrograde urethrogram.
| Discussion|| |
Various urethral pathologies affect anterior urethra, especially strictures are a common malady that affect male anterior urethra. Imaging has an important role to play in the study of the diseases of the male urethra since it can detect pathology not visible on urethroscopy.
Mean age of the patients in the study is 49 years. Peak prevalence of strictures is at 40–45 years of age and is very rare below 9 years.
In our study, the most common cause of stricture is infection (18 out of 28 cases), trauma due to catheterisation in 3 patients, and the remaining cases were idiopathic. These observations are similar to that documented in earlier,,, wherein they stated that in developing countries, infection studies is the predominant cause of stricture unlike the developed world where trauma is predominate.
In our study, we categorised stricture length as short segment strictures which are <25 mm in length and long segment strictures which are more than 25 mm in length. This classification is modification of classifications,, Earlier investigators, using standard radiographic imaging alone, proposed that only strictures 1 cm or less be selected for excision therapy., Since sonographic measurements are often longer than the actual length, new ultrasonic criteria proposed indicated resection and end-to-end anastomosis for adult bulbar stricture measuring up to 25 mm. The accurate estimation of stricture length is important, as it is one of the factors that determine the suitable operative procedure.
We found about 27 strictures were short segment and 7 strictures were long segment and 5 patients has multiple strictures in SUG. Similar findings were reported in author study.
In our study, one patient who was normal in RUG showed stricture in SUG. Similar findings were reported in author study.
In our study, retrograde urethrogram showed one false stricture which was not seen in SUG and peroperatively. Similar findings were reported in author study. Reflex contraction of the pelvic muscle due to forceful injection of contrast may lead to a false-positive diagnosis of stricture.
We noticed the discrepancy in stricture length measured by RUG and SUG techniques in our study. Majority of times stricture length was more in sonourethrographic measurements. Similar results were noted in author study which also found out that in most cases the stricture appeared shorter on radiographic study than on SUG. This was particularly true for proximal penile, bulbopenile and bulbar urethral strictures. The reason could be due to variations in patient positioning and penile traction during the injection of a contrast medium can greatly alter the radiographic appearance of stenotic areas. RGU is done while keeping the patient in a steep oblique position, and the bulbar urethra typically lies in an oblique position relative to the axis of the X-ray beam, resulting in a shorter appearance of strictures at the bulbar urethra. Better pathology detection rates were demonstrated with SUG in the present study as in another study.
In our study, SUG has detected spongiofibrosis in 18 cases out of 28 (64.2%). These results were similar to other studies,, where sonography revealed periurethral fibrosis in 34 (56.7%) stricture patients. Periurethral fibrosis (spongiofibrosis) is a critical determinant of appropriate therapy and ultimate prognosis. Excessive fibrosis is said to be responsible for high recurrence rates.
The advantage of SUG here is the determination of true stricture length and luminal diameter preoperatively, which guides whether to go for excision or tissue transfer. In our study for the estimation of stricture length in between 1 and 4 cm, the sensitivity and accuracy of RGU were 81% each whereas for SUG were 100% and 96%. These findings are similar to these documented in another study. In our study, we found that mean length of strictures in SUG was closer to that of surgery. Similar findings were seen in a prospective study, where the mean length on SUG was closer to that at surgery. From the above findings, we found that the diagnostic values are better for SUG than retrograde urethrogram and that SUG is quite competent and sensitive in picking up of the lesions. In fact, it is better than conventional radiographic RGU in determining accurate stricture length.
A major drawback with SUG is its limited ability to evaluate the posterior urethra. Another significant limitation is interobserver variation that lies within all ultrasonographic studies.
From the present study, both RGU and SUG are equally sensitive in the detection of anterior urethral abnormalities. However, for further characterisation of strictures in terms of length, SUG has greater sensitivity when compared with RGU. In addition, SUG has lower incidence of complications. SUG gives more accurate information about periurethral fibrosis associated with strictures and other abnormalities thus is more useful when determining the type of operative procedure suitable for patients with pathologies, especially strictures localised to the anterior urethra.
Considering all the advantages of SUG, we recommend the routine use of the SUG in addition to RGU for the evaluation of anterior urethral abnormalities, SUG is preferred over RUG in determining accurate stricture length measurement and other diagnosing urethral abnormalities.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3]