Urethral Resistive Index (URI) as a non-invasive test for urethral blockage

Urethral Resistive Index (URI): A New Uroflowmetric Parameter in the Non-Invasive Diagnosis of Urethral Obstruction

This project tests a new, painless urine-flow measure called the Urethral Resistive Index (URI) to see if it can detect urethral strictures in men.

Quick facts

• Study type: Observational
• Enrollment: 60 (estimated)
• Ages: 18 Years to 80 Years
• Sex: Male
• Sponsor: Ankara City Hospital Bilkent (other)
• Locations: 1 site (Ankara, Universiteler)
• Trial ID: NCT07403786 on ClinicalTrials.gov

What this trial studies

This is a prospective, cross-sectional observational diagnostic accuracy project enrolling 60 men (30 with suspected urethral stricture and 30 healthy controls). Each participant performs two non-invasive uroflowmetry tests: a standard natural voiding and a forced void using the Valsalva maneuver, and the URI is calculated as Qmax_forced divided by Qmax_normal. The stricture group includes men scheduled for urethral surgery with intraoperative confirmation, while controls are age-matched healthy volunteers without lower urinary tract symptoms. Diagnostic performance will be analyzed using ROC curves to determine AUC and an optimal cutoff value for URI at Ankara Bilkent City Hospital.

Who should consider this trial

Good fit: Men aged 18–80 with suspected urethral stricture scheduled for confirmatory surgery or healthy male volunteers without lower urinary tract symptoms are ideal candidates.

Not a fit: Patients with voided volumes under 150 mL, obstruction from other causes (e.g., BPH), neurogenic bladder, or severe comorbidities are unlikely to benefit or may be excluded.

Why it matters

Potential benefit: If successful, the URI could offer a quick, painless screening test that reduces the need for invasive procedures to confirm urethral strictures.

How similar studies have performed: The use of forced uroflowmetry concepts has precedent, but the URI parameter itself is novel and largely untested in clinical populations.

Eligibility criteria

Inclusion Criteria:

* Male participants aged between 18 and 80 years.
* For the Stricture Group: Patients scheduled for surgery (urethroplasty or internal urethrotomy) due to suspected urethral stricture, where the diagnosis is confirmed intraoperatively.
* For the Control Group: Healthy male volunteers without any lower urinary tract symptoms.
* Voluntary signing of the Informed Consent Form.

Exclusion Criteria:

* Voiding volume less than 150 mL.
* Causes of obstruction other than stricture, such as Benign Prostatic Hyperplasia (BPH).
* Diagnosis of neurogenic bladder dysfunction or a history of neurological disease affecting bladder function.
* Presence of severe comorbidities.

Where this trial is running

Ankara, Universiteler

• Ankara Bilkent City Hospital — Ankara, Universiteler, Turkey (Türkiye) (RECRUITING)

Study contacts

• Study coordinator: Yusuf Gökkurt

Conditions: Urethral Stricture