Use of Dynamic Magnetic Resonance of the Urethra in Surgical Planning of Vesicourethral Anastomotic Stenosis Urethroplasty.

OBJECTIVE

To evaluate the impact of dynamic Magnetic Resonance of the Urethra (d-MRU) on postoperative results and their agreement with intraoperative findings in patients with urethral stricture after radical prostatectomy.

METHODS

Forty-eight male patients (mean age 65.2 ± 8.1 years) with vesicourethral anastomotic stenosis (VUAS) after radical prostatectomy confirmed by cystoscopy were evaluated using dynamic MRU and cystourethrography (CUG). They were divided into two groups: d-MRU and CUG. Patients in the d-MRU group were evaluated using a new MRI protocol: urethral filling with lidocaine gel and distal urethral obstruction with sterile gas tourniquet; MR urethrography including axial T1-weighted images, coronal space, sagittal T2-weighted, axial T2-weighted, sagittal maximum intensity projection (MIP) with urographic effect, voiding sagittal MIP, and T1-weighted with fat saturation (T1 fat-sat) before and after gadolinium enhancement. Dynamic imaging acquisition with motion images was performed during voiding.

RESULTS

No significant difference in restenosis rates was observed between the D-MRI and UCG groups (5.6% vs. 16.7%, respectively; p = 0.261), but a significant difference in vascular preservation (94.4% vs. 63.3%, p=0.016). We found consistent dynamic MRU and intraoperative measurements of VUAS. Intraclass correlation coefficients showed satisfactory to excellent levels of agreement between the two imaging modalities and a strong correlation of dynamic MRU and intraoperative findings. Additionally, the Bland-Altman analysis revealed an agreement bias close to zero.

CONCLUSIONS

Dynamic MRU is a safe and appropriate evaluation method that can provide guidance for surgical treatment planning in patients with VUAS after radical prostatectomy.