Magnetic resonance imaging procedure for pelvic fracture urethral injuries and recto urethral fistulas: A simplified protocol

Abstract

Objective:The urethral gap in pelvic fracture urethral injury (PFUI) is traditionally assessed using voiding cystourethrogram (VCUG) and retrograde urethrogram (RGU). Magnetic resonance imaging (MRI) is performed in complex cases. We assessed the refined "Joshi" MRI protocol to evaluate complex urethral defects after PFUI. Material and methods:A prospective study was conducted at our center from January 2018 to January 2020, involving patients aged >18 years with PFUI, suitable for MRI, and those who gave consent to perform standard RGU, VCUG, and MRI using standard and "Joshi" protocol. Forty men were included in the study. Distance between urethral/prostatic stumps was measured. Image quality was scored by four radiologists and four urologists. The surgical approach and type of PFUI repair were noted. We also established the need for inferior pubectomy by assessing the position of the posterior urethra (membranous) in relation to a horizontal line drawn from the lower edge of the pubic bone anteriorly to the rectum posteriorly in a sagittal image. Results:The mean age was 30 years (SD, 5.25; range, 21-43), and the time from injury to imaging was 4 months (3-10 months); 40% of the men underwent crural separation, 57.5%, inferior pubectomy, and 2.5%, crural rerouting. There was a difference of 0.3 to 1.1 cm in the urethral gap measurements between MR images using the standard versus "Joshi" technique. MRI identified complex injuries such as rectourethral fistula, the need for inferior pubectomy, and the orientation of the posterior urethra. Urologists' and radiologists' satisfaction scores for the MR images were satisfactory to excellent. If the posterior urethra was over the defined mark, there was a 100% likelihood of inferior pubectomy (23/40 patients).Conclusion: MR image acquisition using the "Joshi" protocol provided high-quality anatomical information in PFUI cases to assist with surgical planning.

Role of magnetic resonance imaging in the management of male pelvic fracture urethral injury

“…Joshi et al . reported that compared with conventional MRI, using the aforementioned Joshi protocol resulted in a urethral gap length that was 0.3–1.1 cm shorter, improving consistency with urethrography results 17 …”

“…2c). The most dreaded complication of DAU is rectal injury 17 . Knowing the positional relationship between the rectum and the urethra based on MRI before urethroplasty might help prevent rectal injury.…”

“…Although MRI might not be necessary for the preoperative evaluation of every case, information obtained from it can be beneficial for inexperienced surgeons. MRI is also useful in the management of complex PFUIs, such as after a failed previous urethroplasty, rectourethral fistula or a long gap 17,50 . The appropriate use of MRI and its cost‐effectiveness require confirmation in future studies.…”

“…Joshi et al reported a "Joshi protocol," which is MR urethrography using a mixture of sterile saline and lignocaine jelly combined with a selective alphablocker administration on the day before the examination to efficiently open the bladder neck. 17 In both conventional MRI and MR urethrography for evaluation of the urethra, the imaging protocol for MRI itself requires high-resolution thin-slice imaging with a small FOV and sufficient imaging time to avoid a degraded signal-to-noise ratio. For this reason, MRI at 3.0 T or 1.5 T is recommended.…”

“…19 Joshi et al reported that compared with conventional MRI, using the aforementioned Joshi protocol resulted in a urethral gap length that was 0.3-1.1 cm shorter, improving consistency with urethrography results. 17 In PFUI, the posterior urethra is displaced not only vertically, but also laterally; however, it is difficult to evaluate lateral displacement using conventional urethrography. The degree of lateral urethral displacement can easily be estimated in the cor view (Fig.…”