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Ultrasound in Reconstructive Urology

Ultrasound images tissue in real time without ionizing radiation. It assesses bladder emptying, upper-tract dilatation, anterior urethral anatomy and selected pelvic-floor problems.[1][5][7] Its usefulness depends on the clinical question, technique and operator.

Bladder ultrasound measures PVR, renal ultrasound follows upper-tract dilatation according to symptoms and risk, and sonourethrography or pelvic-floor ultrasound is added when the extra anatomy can change the evaluation.[1][5][8]

1. Overview: Why Ultrasound in Reconstructive Urology?​

The retrograde urethrogram (RUG) shows the contrast-filled lumen. It does not show the periurethral tissue, so it cannot show spongiofibrosis, the fibrous replacement of the corpus spongiosum in stricture disease. Sonourethrography (SUG) distends the urethra with saline and images the lumen and surrounding spongiosum together.[1][2][16]

ExaminationMain reconstructive questionCompanion
Bladder ultrasound/PVRIs emptying incomplete?Voided volume, symptoms, repeat measurement when needed
Renal ultrasoundIs there collecting-system dilatation or parenchymal change?Clinical history, renal function, comparison imaging
Sonourethrogram (SUG)What are the anterior stricture's length and surrounding appearance?RUG/VCUG and operative findings
Pelvic-floor ultrasoundIs there a specific support, levator or implant-related question?Examination and symptom correlation
Penile duplex / endoanal ultrasoundSelected vascular or anal-sphincter assessmentDedicated specialist protocols

RUG and SUG differ in what each shows:

FeatureRUGSUG
LumenDirect contrast opacificationGood when distension is adequate
Periurethral tissue and spongiofibrosisNot shownShown as distensibility and echogenicity change
Stricture lengthUnderestimates bulbar length in comparative seriesCloser to operative length in comparative series
Radiation and iodinated contrastYesNone (saline distension)
Posterior urethraAssessed with VCUGNot adequately imaged
Operator dependenceModerateHigh; requires specific training

2. Sonourethrogram (SUG): Overview and Indications​

SUG depicts the distended anterior urethra and adjacent tissues. It identifies stricture site, number and caliber, and it shows calculi, diverticula and false passages.[3] Spongiofibrosis appears as loss of urethral distensibility during saline instillation, and posterior shadowing has been described in severe post-traumatic strictures. In complex or reoperative anterior strictures, sonographic staging also shows calculi, urethral hair, false passages and stent encrustation.[4] The EAU describes SUG as a three-dimensional, outpatient, radiation-free assessment of location, length and associated spongiofibrosis.[1]

Length is the main practical gain:

  • In the original 17-patient series, SUG length was consistently closer to the open-urethroplasty measurement than RUG length in the 7 patients compared.[2]
  • In 101 patients (123 paired studies), the penile-urethra correlation with operative length was similar for the two tests (0.91 vs 0.98). In the bulb, SUG correlated better (0.69 for RUG, 0.89 for SUG). SUG indicated a different reconstructive procedure from the RUG-based plan in 16%.[3]
  • In 67 men with bulbar strictures of 25 mm or less on RUG, sonographic measurements were frequently twice the RUG length. SUG changed the chosen procedure in 15 of 41 men (37%) whose RUG length was 11 to 25 mm, to flap or graft procedures. It changed nothing in the 26 men with strictures of 10 mm or less, all of whom had excision and end-to-end anastomosis.[14]
  • In 52 men with anterior strictures, mean length was 2.0 cm on RUG, 3.8 cm on SUG and 3.5 cm at surgery.[15]
  • The EAU summarizes that the preoperative SUG findings changed a RUG-based surgical plan in 31% of cases.[1]

SUG is an adjunct that requires expertise and is not required before every urethroplasty.[1][4]

  • complex or reoperative strictures, including prior failed dilation, urethrotomy or urethroplasty;
  • bulbar strictures of intermediate length on RUG, where excision versus substitution is undecided;
  • suspected calculus, false passage, diverticulum or periurethral pathology;
  • a clinical picture (symptoms, flow rate, cystoscopy) that suggests a longer or more severe stricture than RUG shows.

In a 67-man bulbar reconstruction series, SUG did not change the planned repair in the 26 men whose RUG stricture length was 10 mm or less.[14] SUG is used more often in lichen sclerosus and post-hypospadias strictures because these are usually complex, although the cited series do not test that indication separately.

The main domain is anterior disease. For nearly obliterative stenosis or PFUI, combined RUG and VCUG and selected endoscopy or MRI remain necessary because conventional SUG assesses the posterior urethra poorly.[1][2]

3. SUG: Equipment​

Use equipment suited to superficial urethral imaging: a high-frequency linear transducer (7.5 MHz or higher is typical), B-mode imaging and a trained operator. A curved low-frequency abdominal probe lacks the resolution to separate the layers of the urethral wall for penile imaging. The study also needs an aseptic method of gentle urethral distension and a way to document longitudinal and transverse images. Color or power Doppler is an optional adjunct. Probe selection and distal versus bulbar windows depend on the target segment.[2][4][16]

Set-ups described in practice use sterile saline or 2% lidocaine jelly, which also provides local anesthesia, for urethral distension,[36][37][41] and either a Foley catheter with the balloon inflated in the fossa navicularis to keep saline from leaking at the meatus[41] or a penile clamp to retain the jelly.[37] A three-patient SUG technique report used approximately 20 to 30 mL of 2% lidocaine jelly as the distension medium.[36] For adult male urethral anesthesia, the 2025 Xylocaine label specifies about 15 mL initially, up to 15 mL more if needed, a maximum of 600 mg in 12 hours, and contraindications including amide-anesthetic hypersensitivity and infected or severely traumatized mucosa.[37] Sterile saline can be instilled retrogradely through a catheter-tip syringe at the meatus[2][4] or using a 60 mL syringe through a Foley catheter[41]. Sterile gloves, a transducer cover and acoustic gel complete the sterile field.[2][4]

4. SUG: Technique​

Acquisition principles​

SUG evaluates the anterior urethra during retrograde fluid distension. The EAU notes that distension requires intraurethral anesthesia.[1] The steps below are a commonly described sequence and should be adapted to the local trained-service protocol for anesthesia, sterile preparation and meatal sealing.[2][4]

  1. The patient lies supine with the penis stretched along the lower abdomen. This aligns the penile urethra for a longitudinal scan. The scrotum is retracted to expose the perineum for bulbar imaging.
  2. The catheter tip or clamp seals the meatus.
  3. Sterile saline is injected slowly and continuously while scanning. Under-distension leaves the walls collapsed and falsely echogenic; excessive probe pressure can also create an apparent stricture.[38]
  4. Injection stops if the patient has pain or the resistance is high. The purpose is imaging, not dilation.

Catheter size, balloon volume, injection pressure and total volume are not fixed by the literature. Some strictures pass only a small volume.[1][4]

Penile urethra. The probe sits on the ventral penile surface. The longitudinal view shows the tubular urethra with a continuous mucosal line, and irregularity, narrowing or hyperechogenicity marks a stricture. The transverse view shows the corpus spongiosum around the lumen, and fibrosis appears as asymmetric or circumferential echogenicity in place of normal spongiosum.[2][4]

Bulbar urethra. The bulbar urethra curves into the perineum and is not seen from the ventral penile surface. The probe is placed in the midline perineum between the posterior scrotum and the anus and angled anterosuperiorly. A slightly parasagittal orientation often gives the best longitudinal view. McAninch and colleagues also described a transscrotal approach.[2][4] The proximal bulbar urethra near the perineal body can be difficult to image.[1]

Reporting checklist​

ParameterHow it is describedUse
Segment, number and length of narrowingsLongitudinal scan, proximal to distal extent of the abnormal segmentRepair selection (excision versus onlay or substitution)
Luminal distensibility and caliberTransverse scan at the narrowest pointSeverity
Surrounding echogenicity and depthTransverse scan, from mucosa toward the tunica albugineaExtent of spongiofibrosis
Calculus or calcificationEchogenic focus, often with acoustic shadowingAssociated finding reported separately from stricture severity.[4]
Extension beyond the spongiosumAbnormal tissue crossing the tunica albugineaComplex reconstruction
False passage, diverticulum, stone, hair, stent or implantDirect visualizationAssociated findings
Proximal extentRelation to the perineal body and membranous urethraNeed for perineal access

Describe measurement conditions and any disagreement with RUG. Measure the abnormal segment, not only the narrowed lumen. Some surgeons add a margin to the imaging length when planning the incision or graft. That practice is not validated, so the imaging measurement is not automatically increased by a fixed distance to set graft length or resection margins.[3][4]

5. Normal Ultrasound Anatomy of the Urethra​

Fluid distension outlines the lumen within the corpus spongiosum. The layers are recognized by echogenicity:

StructureEchogenicityAppearance
Urethral mucosaHyperechoicThin bright line around the distended lumen
Distended lumenAnechoicSmooth fluid-filled channel of consistent caliber
Corpus spongiosumIntermediate, homogeneousUniform tissue around the urethra
Tunica albugineaHyperechoicThin bright line at the outer margin of the spongiosum
Corpora cavernosaIntermediatePaired bodies dorsal and lateral to the spongiosum, separated by the septum
Bulbospongiosus and ischiocavernosus (perineal view)IntermediateMuscle layers around the bulb

Focal or diffuse hyperechogenicity in the spongiosum, an irregular mucosal line or a narrowed lumen indicates disease. Appearance varies with scan plane and acquisition conditions, and the fossa navicularis is naturally more fibrous, so comparison with adjacent urethra helps interpretation.[2][4]

The operative assessment of tissue and reconstructive feasibility remains necessary.[3]

6. Spongiofibrosis: Descriptive Assessment​

The literature supports sonographic staging but does not validate a depth-to-operation algorithm.[2][3][4]

The direct evidence is limited. Nash and colleagues found SUG unreliable at predicting the depth of spongiofibrosis against full-depth biopsies in 36 patients. In 52 men, Gupta and colleagues reported SUG accuracy for spongiofibrosis of 42%, 56% and 83% for mild, moderate and severe degrees. The EAU states that the clinical relevance of assessing spongiofibrosis preoperatively remains to be established, and it describes sonourethrography with real-time elastography as a qualitative and quantitative option under investigation.[3][15][1]

See the urethral stricture pathway for treatment selection.

7. Evidence: SUG vs. RUG​

Primary studyDesign and sampleWhat it supportsWhat it does not establish
McAninch et al., 1988Preliminary series: 17 patients; operative length comparison in 7, full-depth biopsy in 5[2]Feasibility and closer length agreement than RUG; classification of spongiofibrosis by distensibilityPopulation-wide accuracy or definitive fibrosis grading
Nash et al., 1995123 paired examinations in 101 patients with 110 stricturesBetter length correlation in the bulbar subgroup; detection of calculi, diverticula and false passagesReliable histological fibrosis depth; superiority in every segment
Morey and McAninch, 199767 men with bulbar strictures of 25 mm or less on RUGSonographic length often about twice RUG length; procedure changed in 37% of intermediate-length strictures[14]Improved outcomes after the changed procedure
Gupta et al., 200652 men with anterior strictures, compared with operative findingsMean length 2.0 (RUG), 3.8 (SUG) and 3.5 cm (surgery); modest spongiofibrosis accuracyReliable grading of mild or moderate fibrosis

These studies support complementary imaging in selected patients. RUG length differences varied across these cohorts; improved clinical outcomes after SUG-driven changes were not established.[2][3][14][15] RUG maps the anterior urethra for reconstruction; VCUG adds the proximal and posterior urethra when a nearly obliterative stricture, stenosis or pelvic fracture injury limits retrograde filling, and SUG can add anterior periurethral detail.[1]

8. SUG: Limitations​

LimitationDetail
Operator dependenceSUG needs specialized training in ultrasound and is not in widespread use.[1]
Bulbar segmentThe EAU lists lower sensitivity for detecting bulbar strictures. The proximal bulbar urethra is hard to image, particularly through the perineum in larger patients.[1][3]
Posterior urethraMembranous and prostatic segments are not adequately imaged. PFUI needs RUG and VCUG, with selected endoscopy or MRI.[2][1]
DistensionIt requires intraurethral anesthesia, and patients who cannot tolerate adequate volume give limited images.[1]
Fibrosis depthNot reliable against biopsy in the largest available comparison.[3]

9. Renal Ultrasound​

Indications and report​

Renal ultrasound is a radiation-free initial imaging option when upper-tract dilatation or parenchymal change is relevant to obstruction, reconstruction or a surveillance plan.[7] Typical reconstructive settings are:

  • baseline assessment when stricture or bladder outlet obstruction raises concern for upper-tract injury, or when neurogenic bladder risk is not yet established;[8]
  • follow-up after urinary diversion, pyeloplasty or ureteral reconstruction;
  • new or worsening dilatation after urethroplasty or reimplantation;
  • transplant ureteral anastomosis.

The examination scans in supine and decubitus positions through different acoustic windows, using a low-frequency curvilinear probe. Report laterality, extent of calyceal or pelvic dilatation, visible ureteral change, cortical thickness, parenchymal appearance and relevant bladder findings. Compare prior studies and document conditions that may affect interpretation, such as bladder fullness.[7] In a series of 665 adult volunteers, median renal length was 11.2 cm on the left and 10.9 cm on the right, decreasing with age largely because of parenchymal thinning; renal length correlated best with body height and, among the 94 volunteers measured in both positions, did not differ significantly between supine and prone measurement.[23] A marked discrepancy in longitudinal length between the two kidneys, or focal parenchymal thinning, is a reason to look for asymmetric obstruction, reflux nephropathy or renovascular disease rather than an incidental finding.

In a 52-woman obstetric-gynecologic feasibility study, transvaginal color Doppler showed intermittent ureteral jets into the bladder bilaterally in women with two functional ureters and on the functional side in three women with one functional kidney or ureter; the authors proposed its use when ureteral integrity is questioned after surgery.[24] The clinical value of demonstrating jets has been questioned, and a survey of urologists and radiologists found them divided on its relevance; accurately confirming absence of a jet, rather than merely a missed frame, may require continuous observation for up to 10 minutes.[35] After percutaneous nephrolithotomy, small studies have used microbubble contrast through a nephrostomy tube to assess ureteral patency without radiation. Its performance after ureteral reconstruction or in other nephrostomy populations remains unestablished.[25][26]

Hydronephrosis is not synonymous with obstruction​

Dilatation may persist after a successful repair, and its importance depends on the clinical setting.[7] The Society for Fetal Urology system grades postnatal hydronephrosis. It is qualitative and was developed for infants: grade 0 is normal; grade 1 is renal pelvic dilatation only; grade 2 adds some calyces; grade 3 involves all calyces with normal parenchyma; grade 4 adds parenchymal thinning.[17] It does not define adult anteroposterior pelvic-diameter cutoffs, and no universal adult diameter table should be applied. If a formal grade is reported, the report names the system and its intended population.

Ultrasound cannot measure differential function or drainage. When the unresolved issue is drainage or split function, MAG3 answers it. When anatomy or cause remains unclear, CT urography or MRU may help. The ACR lists ultrasound with Doppler, CT urography, MR urography and MAG3 as viable initial studies in symptomatic patients with hydronephrosis of unknown cause. Escalation depends on symptoms, renal function, prior surgery and change over time, not on ultrasound grade alone.[7]

Risk-based follow-up​

For adult NLUTD with stable urinary signs and symptoms, the AUA/SUFU guideline (Statements 13 to 15) recommends no surveillance upper-tract imaging in low-risk patients, imaging every 1 to 2 years in moderate-risk patients and annual imaging in high-risk patients . New symptoms, infections, stones or renal deterioration prompt reassessment. The EAU strongly recommends regular upper-tract assessment in high-risk neurogenic patients and describes ultrasound approximately every six months in this group.[8]

Renal artery duplex needs a vascular question and a laboratory-validated protocol. In 313 patients (606 arteries) compared with angiography, a peak systolic velocity of 180 cm/s or more with a renal-to-aortic ratio of 3.5 or more detected 60% or greater stenosis with sensitivity 72% and specificity 81%, and the best single cutoffs were 285 cm/s and 3.7.[21] The authors advised validation in each vascular laboratory.[7][21]

Bladder ultrasound and PVR​

For women with non-neurogenic LUTS, the EAU recommends PVR measurement at initial assessment and ultrasound as the measurement method because of its favorable risk-benefit profile.[5] NICE also prefers a bladder scan to catheterization in women with suspected voiding dysfunction or recurrent UTI.[5][6] Timing and voided volume are recorded from a representative void where practical. In women, the EAU identifies no consensus threshold for a significant PVR and recommends reporting bladder voiding efficiency, VV/(VV + PVR) × 100, as an additional parameter .[5]

NICE advises against imaging in routine assessment of uncomplicated female urinary incontinence and against ultrasound other than for residual urine.[6]

A 2013 narrative review reported greater bladder-wall thickness in women with urodynamic detrusor overactivity than in women with stress incontinence, with proposed transvaginal cutoffs of about 5.0 to 6.5 mm that varied by technique and study.[33] A 2026 meta-analysis selected eight studies, pooled six transvaginal studies, and found no significant overall thickness difference between women with and without detrusor overactivity.[39]

Bladder ultrasound can show a diverticulum, although a narrow neck may be difficult to delineate transabdominally; transrectal imaging can help, and color Doppler may show to-and-fro urine flow across the neck.[40]

10. Pelvic Floor Ultrasound (Transperineal / Translabial)​

Selective clinical use​

Transperineal (translabial) ultrasound shows levator morphology, bladder-neck mobility and pelvic-organ descent in real time through the perineum. It is used for selected support, levator, or sling and mesh questions. Routine imaging to document clinically demonstrable prolapse is unnecessary. When imaging is useful, ultrasound and dynamic MRI provide different views, and performance depends on technique and expertise.[6][11]

A curved-array transducer (about 3.5 to 8 MHz) is placed on the perineum with the patient in dorsal lithotomy or supine. Three- and four-dimensional volumes are needed for levator assessment. Acquisitions are usually made at rest, on maximal Valsalva and on pelvic-floor contraction, with bladder filling adjusted to the question.[9][10]

One example protocol images the bladder at about 150 mL during urodynamic filling and again near capacity when vesicoureteral reflux is in question, with dynamic translabial images then obtained standing at rest and with Valsalva or cough, bladder-neck descent measured relative to the inferior pubic symphysis, and PVR measured at the end of the study. For prolapse imaging, at least 200 mL in the bladder with static images followed by rest and Valsalva views has been described. Excessive transducer pressure can distort anatomy or obscure prolapse.[30]

Hiatus and levator injury​

The methods and maneuver are stated when hiatal dimensions are reported. Dietz and colleagues proposed a Valsalva hiatal area above 25 cm² as "ballooning" in a retrospective tertiary-clinic dataset of 544 women. For symptomatic prolapse, that cutoff had sensitivity 0.55 and specificity 0.77, and the area under the ROC curve for Valsalva hiatal area was 0.71.[9]

Levator avulsion (detachment of the pubovisceral muscle from the pelvic sidewall) is assessed on three-dimensional or tomographic translabial images by inspecting the muscle insertion in serial slices. In a prospective series of 61 nulliparous women, 50 were seen postpartum; among them, avulsion was found in 14 of 39 women (36%) after vaginal delivery and was associated with stress incontinence 3 months postpartum.[18] In 262 women referred with lower urinary tract dysfunction or prolapse, 19% had avulsion (unilateral or bilateral), and defect score was higher in women with prolapse symptoms and associated with cystocele but not with incontinence.[18][10] Report side, extent, method and uncertainty.[10] One tomographic-ultrasound method requires all three central slices of the minimal hiatal plane to be abnormal to diagnose complete avulsion; in a 764-woman urogynecological cohort, this finding was present in 30% of patients and was significantly associated with symptoms and signs of prolapse, while lesser (partial) trauma was not.[34]

Mobility and posterior compartment​

Bladder-neck position relative to the symphysis, descent on Valsalva, and funneling of the proximal urethra can be documented. In the posterior compartment, ultrasound can show rectal herniation or intussusception on Valsalva and can separate an enterocele (echogenic bowel content that moves) from a rectocele.[11] An image of rectal bulging needs correlation with bowel symptoms and examination. A universal 10-mm bladder-neck or rectocele threshold is not an adequate basis for surgery.[5][6][11]

FeatureTransperineal ultrasoundDynamic pelvic MRI
Real-time dynamic imagingYes, including 4DLimited by acquisition time
Levator avulsionWell shown on 3D/4DWell shown
Multi-compartment and apical assessmentLimitedBetter
Fascial planesLimitedBetter
Patient tolerance and costWell tolerated, low costLonger study, higher cost
Operator dependenceHighModerate

For clinically suspected prolapse that requires imaging, the ACR rates MR defecography as Usually Appropriate and transperineal ultrasound as May Be Appropriate; ultrasound can provide real-time dynamic and levator assessment.[11]

Mesh and sling evaluation​

The implant type and operation history are provided with the request. Ultrasound can locate accessible sling or mesh material and assess its relation to adjacent structures. Polypropylene is echogenic, and synthetic mesh can be hard to separate from scar on MRI.[6][11] Two studies quantify performance:

  • In 100 women with lower urinary tract symptoms after mesh or sling surgery, combined translabial and transvaginal ultrasound flagged mesh within 1 mm of the bladder or urethra as highly suspect for exposure; against cystourethroscopy, sensitivity was 100%, specificity 98% to 100% and negative predictive value 100%.[19] Exposure was uncommon (3%), and positive predictive value was 33% to 50% for the urethra.[19] The authors proposed screening use, but only three exposures occurred in this cohort.[19]
  • In 124 women with suspected mesh complications after midurethral sling (12% with erosion into the urethra or bladder at surgery), translabial ultrasound had sensitivity 53% and specificity 100% when only intraluminal mesh counted, and sensitivity 93% and specificity 72% when intramural mesh also counted. Cystourethroscopy had sensitivity 67%.[20]

When new voiding dysfunction, elevated PVR, worsened urgency or pain follows sling placement, dynamic transperineal ultrasound can characterize the sling in relation to the urethra. In two retrospective analyses of women with lower urinary tract symptoms after midurethral sling placement, a sling that remained C-shaped at rest and during Valsalva was associated with higher detrusor pressure at maximum flow than slings that were parallel to the urethra at rest, including those that became C-shaped only during Valsalva; the persistent C shape also predicted high-pressure voiding in the models.[27][28] In 126 of 141 women with complete data after suburethral sling surgery (median follow-up, 36 months), a larger sling-pubis gap on Valsalva correlated with lower detrusor pressure at maximum flow and a higher likelihood of urodynamic stress incontinence.[29]

In 36 women after anterior Prolift implantation, mean midline mesh length was 90.3 mm at implantation, 57.1 mm on day 4 ultrasound, and 48.3 mm at 3 to 5 months; the authors attributed much of the initial difference to folding and considered the later approximately 15% decrease possible shrinkage or retraction.[31] A longitudinal study of 40 women after one anterior transobturator mesh found no reduction in measured length or width over 59.6 woman-years.[32]

Transperineal ultrasound can show the suburethral sling and anterior or posterior sacrocolpopexy mesh, but views of retropubic, obturator, apical and cranial components are limited. For subacute or chronic postsurgical complications, the ACR rates MR defecography, dynamic pelvic MRI and pelvic MRI without and with IV contrast as Usually Appropriate, and transperineal ultrasound as May Be Appropriate.[11] No modality excludes every complication. Clinical examination evaluates vaginal exposure, and suspected urinary tract exposure requires endoscopy. See Mesh Complications & Removal for evaluation and management.[6][11]

11. Endoanal Ultrasound​

Dedicated endoanal ultrasound assesses anal-sphincter anatomy in selected patients with fecal incontinence, prior obstetric sphincter injury or a repair complication. The external sphincter appears as a hyperechoic ring and the internal sphincter as a hypoechoic ring inside it. Defects appear as discontinuity or thinning and are recorded by clock-face position and arc. Interpret anatomy alongside symptoms, examination and, where available and indicated, anorectal physiology.[13]

In specialist follow-up after obstetric anal sphincter injury, the 2026 IUGA guideline describes endoanal ultrasound for residual structural defects and anorectal manometry for sphincter function at least six weeks postpartum, when available and indicated, to help counsel about a subsequent birth.[13] Where unavailable, appropriately performed transperineal ultrasound can serve as a screening alternative, with suspected defects referred for endoanal confirmation.[13]

12. Doppler Ultrasound: Penile Duplex​

Penile duplex is a selected second-level test for suspected vasculogenic ED when the result can change management. The usual protocol images both cavernosal arteries at the penile base with a high-frequency linear probe, records baseline velocities, gives an intracavernosal vasoactive agent (alprostadil or a papaverine-based mixture) and repeats measurements at intervals over 20 to 30 minutes. Response depends on adequate pharmacological stimulation, timing, technique and anxiety, and an abnormal study can be falsely positive.[12][22]

Protocols and criteria vary. In a review of published studies, 39% defined a normal peak systolic velocity as 30 cm/s or more and 57% used an end-diastolic velocity of 5 cm/s or less as normal, and no consensus criteria exist.[22] Reduced peak systolic velocity may suggest impaired arterial inflow; persistently raised end-diastolic velocity after adequate pharmacologic relaxation and arterial inflow may suggest veno-occlusive dysfunction, interpreted with the protocol's stated thresholds.[12][22]

Use the dedicated penile Doppler article for acquisition and interpretation. There is no general requirement for duplex before every urethroplasty. Baseline erectile and ejaculatory function is documented with a validated tool before male urethral stricture surgery ; duplex is considered when suspected vasculogenic erectile dysfunction may change management.[1][12]

13. Practical Pearls​

  • State the question. Residual urine, upper-tract change, stricture anatomy, levator morphology and an implant complication each need a different examination.
  • State the conditions. Voided volume and timing for PVR, distension for SUG and the maneuver for pelvic-floor imaging make measurements interpretable.
  • Use the transperineal window for the bulb. The bulbar urethra is not seen from the ventral penile surface, and a bulbar stricture imaged only from the penis is underestimated or missed.[2][4]
  • Order SUG when the plan can change. The gain is largest for bulbar strictures of intermediate length and for complex or reoperative disease.[14]
  • Keep observation separate from treatment. Fibrosis appearance, collecting-system dilatation and hiatal enlargement need clinical context.
  • Escalate for uncertainty that matters. The next test is chosen to answer the unresolved question. Renal ultrasound is morphological and cannot quantify split function or drainage.[1][5][7][9]

14. References​

1. European Association of Urology. Urethral Strictures Guidelines: Diagnostic Evaluation. 2026. Official guideline.

2. McAninch JW, Laing FC, Jeffrey RB Jr. Sonourethrography in the evaluation of urethral strictures: a preliminary report. J Urol. 1988;139(2):294-297. doi:10.1016/s0022-5347(17)42391-3

3. Nash PA, McAninch JW, Bruce JE, Hanks DK. Sono-urethrography in the evaluation of anterior urethral strictures. J Urol. 1995;154(1):72-76. PMID 7776459

4. Morey AF, McAninch JW. Sonographic staging of anterior urethral strictures. J Urol. 2000;163(4):1070-1075. PMID 10737469

5. European Association of Urology. Non-neurogenic Female LUTS Guidelines: Diagnosis. 2026. Official guideline.

6. NICE. Urinary Incontinence and Pelvic Organ Prolapse in Women: Management (NG123). Recommendations on PVR, imaging, prolapse, and mesh complications. Official recommendations. Accessed September 11, 2026.

7. Whitworth P 3rd, Courtney KG, Oto A, et al. ACR Appropriateness Criteria: Hydronephrosis on Prior Imaging-Unknown Cause. J Am Coll Radiol. 2024;21(6S):S144-S167. doi:10.1016/j.jacr.2024.02.020

8. American Urological Association/SUFU. Adult Neurogenic Lower Urinary Tract Dysfunction Guideline. 2021. Risk-stratified surveillance statements 13 to 15. Official guideline; European Association of Urology. Neuro-Urology Guidelines. 2026. Follow-up recommendations.

9. Dietz HP, Shek C, De Leon J, Steensma AB. Ballooning of the levator hiatus. Ultrasound Obstet Gynecol. 2008;31(6):676-680. doi:10.1002/uog.5355

10. Dietz HP. Quantification of major morphological abnormalities of the levator ani. Ultrasound Obstet Gynecol. 2007;29(3):329-334. doi:10.1002/uog.3951

11. American College of Radiology. ACR Appropriateness Criteria: Pelvic Floor Dysfunction in Females. Revised 2021. Official narrative and scenario-specific ratings.

12. European Association of Urology. Guidelines on Sexual and Reproductive Health, Limited Update March 2026, sections 5.5.3 (erectile dysfunction) and 8.2.2 (Peyronie's disease). ED guideline; curvature guideline.

13. Sultan AH, Okeahialam NA, De Leeuw J, et al. IUGA International Guidelines on Obstetric Anal Sphincter Injuries. Int Urogynecol J. 2026;37(8):2223-2280. doi:10.1007/s00192-026-06642-3

14. Morey AF, McAninch JW. Role of preoperative sonourethrography in bulbar urethral reconstruction. J Urol. 1997;158(4):1376-1379. PMID 9302124

15. Gupta N, Dubey D, Mandhani A, et al. Urethral stricture assessment: a prospective study evaluating urethral ultrasonography and conventional radiological studies. BJU Int. 2006;98(1):149-153. doi:10.1111/j.1464-410X.2006.06234.x

16. Pavlica P, Barozzi L, Menchi I. Imaging of male urethra. Eur Radiol. 2003;13(7):1583-1596. doi:10.1007/s00330-002-1758-7

17. Fernbach SK, Maizels M, Conway JJ. Ultrasound grading of hydronephrosis: introduction to the system used by the Society for Fetal Urology. Pediatr Radiol. 1993;23(6):478-480. PMID 8255658

18. Dietz HP, Lanzarone V. Levator trauma after vaginal delivery. Obstet Gynecol. 2005;106(4):707-712. doi:10.1097/01.AOG.0000178779.62181.01

19. Frigerio M, Barba M, Marino G, et al. Pelvic floor ultrasound evaluation in the diagnosis of exposure of synthetic implanted materials in the lower urinary tract. Int J Gynaecol Obstet. 2023;163(3):834-839. doi:10.1002/ijgo.14933

20. Viragh KA, Cohen SA, Shen L, et al. Translabial US: preoperative detection of midurethral sling erosion in stress urinary incontinence. Radiology. 2018;289(3):721-727. doi:10.1148/radiol.2018180786

21. AbuRahma AF, Srivastava M, Mousa AY, et al. Critical analysis of renal duplex ultrasound parameters in detecting significant renal artery stenosis. J Vasc Surg. 2012;56(4):1052-1059. doi:10.1016/j.jvs.2012.03.036

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