Imaging recommendations in paediatric uroradiology: minutes of the ESPR workgroup session on urinary tract infection, fetal hydronephrosis, urinary tract ultrasonography and voiding cystourethrography, Barcelona, Spain, June 2007

Paediatric uroradiology is one of the mainstays of daily paediatric imaging practice. The number of infants and children submitted for assessment of the urinary tract has grown significantly, since fetal US screening has become routine. This has resulted in an increasing number of babies being evaluated for prenatally detected “hydronephrosis” (HN). When studying these children and observing their further course, new knowledge and insight has been gained that sheds new light on the accepted traditional imaging algorithms. In particular, neonatal vesicoureteral reflux (VUR) is now thought to be often a transitory condition that in up to 80% of patients diminishes or disappears spontaneously, even in those with high-grade VUR. We also learned that VUR itself does not impair renal function after the fetal period. High-grade neonatal VUR (mostly in boys) is often associated with prenatally developed renal dysplasia associated with high-grade HN (Fig. 1), whereas most other forms of primary or congenital VUR are not necessarily associated with renal damage or long-term sequelae. As therapeutic concepts are changing and even the necessity and usefulness of long-term antibiotic prophylaxis is being discussed and new surgical options such as cystoscopic subureteric injection are now available, the impact of imaging results on patient management is changing and indications for various procedures need to be reassessed.

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Traditionally, VUR has been considered the major risk factor for urinary tract infection (UTI) and renal damage, with potentially severe long-term sequelae such as hypertension and impaired renal function. It has been shown that UTI and renal scarring occur without VUR and that, even in patients with VUR, UTI does not necessarily cause renal damage and scarring, while about half the patients with renal scarring do not have or never had VUR. On the other hand, we know that the incidence of renal involvement and potential scarring after UTI is significantly higher in those patients with medium-to-high-grade VUR, and that the diagnosis of VUR may be missed. Thus new strategies are being developed, focusing more on preserving renal parenchyma than on VUR detection and management, with increasing interest in bladder function. Several other factors determine the risk of renal damage, such as the time of diagnosis and onset of treatment, the virulence of the bacteria, bacterial resistance to various antibiotics, immunological competence of the urothelium, intravesical pressure, and genetic and some anatomic predispositions (e.g. compound papillae or underlying urinary tract malformation). For these reasons imaging strategies in UTI are changing. They range from exhaustive imaging workup to not performing any imaging at all. We evaluated the various arguments carefully and recommend limiting and possibly avoiding invasive investigations, especially procedures that use ionizing radiation, for economic reasons, as well as to improve patient care. On the other hand, there are benefits deriving from the traditional imaging protocols that should be preserved. Although there is no conclusive evidence that traditional imaging significantly impacts long-term patient outcome, there is also no certainty that these studies can be abandoned without endangering the patients’ health and long-term outcome.

Additionally, the technique and scope of imaging procedures have evolved. By using modern X-ray equipment and following the ALARA principle with careful coning and elimination of unnecessary radiation (e.g. grid, large field-of-view, etc voiding cystourethrography; VCUG) may be performed with a large dose reduction. Ultrasonographic resolution and colour Doppler techniques have been markedly improved and new US techniques have been introduced. Ultrasonography has developed from a roughly orienting initial study to a powerful diagnostic tool. Finally, new imaging methods have been introduced and have become commonly used in paediatric imaging, such as US contrast media, magnetic resonance urography (MRU) and multidetector CT (MDCT). All this needs to be considered in relation to imaging algorithms and standard recommendations on how the various imaging modalities should be applied and how the various conditions should be best approached.

Increasing efforts throughout the medical community to standardize diagnostic imaging to ensure proper patient management, increasing acceptance of quality assurance measures, and growing economic pressure, particularly on paediatric radiology, have led to the development of many recommendations and guidelines in many countries and scientific organizations as well as by various health-care providers. The existence of too many different guidelines leads to irritation, puts pressure on organizations and institutions, and renders comparison of scientific and outcome-oriented studies difficult.

Under these circumstances and based on new insights and newly gained knowledge, and incorporating the outcomes of new therapeutic strategies, efforts have been made to unify recommendations and, at the same time, to consider economic needs and to focus on efficacy (without putting at risk true health-care achievements from earlier improvements). In order to facilitate general acceptance throughout the European countries the following discussion was taken up by two European societies, the ESUR (European Society of Uroradiology) and the ESPR (European Society of Paediatric Radiology), in an attempt to create at least a basic consensus statement for the most common and important conditions in paediatric uroradiology. This will allow flexibility and local adaptation without risking quality, and also provide the various institutions with arguments for maintaining a necessary basic level of health care and education in the face of economic pressure.