Owen Arthurs MBBChir, PhD, Presenter: Nothing to Disclose

Andrea D Edwards MSC, Abstract Co-Author: Nothing to Disclose

Ilse Joubert, Abstract Co-Author: Nothing to Disclose

Martin John Graves, Abstract Co-Author: Nothing to Disclose

Patricia Ai Khoon Set MBBS, Abstract Co-Author: Nothing to Disclose

David John Lomas MD, Abstract Co-Author: Nothing to Disclose

The current diagnostic standard for vesico-ureteric reflux (VUR) remains the Micturating Cystourethrogram (MCUG), using X-ray fluoroscopy, despite ionizing radiation exposure, and the need to move the child into different positions. In this study, we evaluate the feasibility of performing interactive MR voiding cystourethrography, which allows real-time control of contrast and slice location in unsedated infants.

Standard X-ray MCUG images were obtained following Urografin® administration via urethral catheter. Interactive MR was performed using an in-house developed pulse sequence that allows real-time switching between interactive fast spoiled gradient echo (FSPGR) and single shot fast spin echo (SSFSE) based pulse sequences. This provides real-time control over slice location and imaging parameters. The interactive FSPGR and SSFSE images were used to monitor bladder filling with dilute Gadovist® (Gadobutrol). Interactive sagittal FSPGR imaging was obtained during voiding to assess the posterior urethra, and to evaluate vesico-uretric reflux during all phases of the examination. No sedation or anaesthesia was used.

10 children (mean age 1.9 months) underwent conventional MCUG, followed by iMRVC. Every case of reflux identified with MCUG was identified by iMRVC. Across 20 renal units, there was excellent agreement between the appearances of the bladder and urethra, and 85% concordance (17/20) according to the severity of reflux (Figure 1: MCUG (left) and iMRVC (right) imaging of high grade VUR). In this population, iMRVC gave a sensitivity of 100%, specificity of 78%, PPV of 66.6% and NPV of 100%. In 2 / 10 cases, MR gave additional information over that of MCUG.

iMRVC is feasible in unsedated infants. iMRVC allowed selection of image plane and contrast to delineate the renal tract anatomy, monitor bladder filling and voiding, the posterior urethra and detect vesicoureteric reflux in a single procedure. The technique avoids ionizing radiation and postural alterations.

iMRVC has the potential to replace conventional X-ray based MCUG. A larger evaluation of diagnostic performance is required.

Arthurs, O, Edwards, A, Joubert, I, Graves, M, Set, P, Lomas, D, Interactive Real-time MR Voiding Cysto-Urethrography (iMRVC) for Vesico-Ureteric Reflux in Unsedated Infants.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9004022.html