European Journal of Radiology 82 (2013) e112–e119 Contents lists available at SciVerse ScienceDirect European Journal of Radiology journa l h o me pa ge: www.elsevier.com/locate/ejrad Interactive magnetic resonance imaging for paediatric vesicoureteric reflux (VUR) Owen J. Arthurs ∗ , Andrea D. Edwards, Ilse Joubert, Martin J. Graves, Pat A.K. Set, David J. Lomas Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK a r t i c l e i n f o Article history: Received 12 June 2012 Received in revised form 25 September 2012 Accepted 31 October 2012 Keywords: Vesicoureteric reflux Vesicoureteral reflux Magnetic resonance imaging Paediatric Micturating cystourethrogram a b s t r a c t Objectives: The current gold standard for diagnosing vesicoureteric reflux in unsedated infants is the X- ray-based Micturating CystoUrethroGram (MCUG). The aim of this study was to assess the diagnostic performance of interactive MRI for voiding cysto-urethrography (iMRVC). Methods: 25 infants underwent conventional MCUG followed by iMRVC. In iMRVC, patients were exam- ined using a real-time MR technique, which allows interactive control of image contrast and imaging plane location, before, during and after micturition. Images were assessed for presence and grade of VUR. Parental feedback on both procedures was evaluated. Results: iMRVC gave a sensitivity of 100%, specificity of 90.5% (95% CI: 81.6–99.4%), PPV of 66.7% and NPV of 100% in this population. There was 88% concordance (44/50 renal units) according to the presence of VUR between the two methods, with iMRVC up-grading VUR in 6 units (12%). There was very good agreement regarding VUR grade: Kappa = 0.66 ± 0.11 (95% CI 0.43–0.88). 60% of parents preferred the MRI, but did not score the two tests differently. Conclusion: Interactive MRI allows dynamic imaging of the whole urinary tract without ionising radiation exposure. iMRVC gives comparable results to the MCUG, and is acceptable to parents. © 2012 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Vesicoureteric reflux (VUR) is the abnormal passage of urine from the bladder upwards into the ureter or renal pelvis, and may be associated with congenital renal dysplasia in newborns. VUR is more commonly identified in infants undergoing investigations for urinary tract malformations, urinary tract infections (UTIs) and pyelonephritis [1], and the combination of high grade VUR and UTI may lead to renal damage and its sequelae, with treatment primarily aimed at preserving renal function [2,3]. Although the optimal treatment of VUR remains controversial, infants continue Abbreviations: ce-VUS, contrast-enhanced voiding urosonography; DAP, dose- area product; DRC, direct radionuclide cystography; ED, effective dose; FIESTA, fast imaging employing steady state acquisition; FSPGR, fast radio-frequency spoiled gradient echo; iMRVC, interactive magnetic resonance voiding cystourethrogra- phy; IRC, indirect radionuclide cystography; IV, intravenous; MCUG, micturating cystourethrogram; MR, magnetic resonance; NPV, negative predictive value; PPV, positive predictive value; RTGS, real-time gradient and spin echo; SSFSE, single shot fast spin echo; UTI, urinary tract infection; VUR, vesicoureteric reflux. ∗ Corresponding author at: Department of Radiology, Box 219, Addenbrooke’s Hospital, Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 0QQ, UK. Tel.: +44 0 1223 336890; fax: +44 0 1223 330915. E-mail address: oja20@cam.ac.uk (O.J. Arthurs). to be investigated for VUR with a Micturating CystoUrethroGram (MCUG) considered the gold standard investigation [4,5]. MCUG involves bladder catheterisation, contrast medium instil- lation and intermittent X-ray fluoroscopic observation until micturition, with postural changes to allow imaging of the entire urinary tract [6]. MCUG reproducibility depends on the severity or grade of reflux, with only high grade VUR being diagnosed with 100% reliability [7]. As many of the infants imaged are normal, and MCUG carries a significant radiation burden partic- ularly to the paediatric (and especially female) gonads, the test is no longer routinely recommended following uncomplicated UTI in all European countries [8–10]. Other imaging techniques have been evaluated for VUR in infants (radionuclide cystog- raphy and contrast-enhanced voiding urosonography (ce-VUS) methods), although none give simultaneous imaging of the entire urinary system from kidney to urethra. Magnetic resonance imag- ing (MRI) presents an non-ionising radiation based alternative, although early attempts to demonstrate VUR with conventional MRI sequences typically required intravenous (IV) or oral seda- tion, IV fluids, IV diuretics or gadolinium, and were complicated by delays in switching between imaging sequences and locations [11–13]. In order to address these issues, we have developed an interac- tive imaging capability using a range of fast pulse sequences that 0720-048X/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ejrad.2012.10.024