Imaging recommendations in paediatric uroradiology. Minutes of the ESPR uroradiology task force session on childhood obstructive uropathy, high-grade fetal hydronephrosis, childhood haematuria, and urolithiasis in childhood. ESPR Annual Congress, Edinburgh, UK, June 2008

Multi-detector CT in the paediatric urinary tract

The use of paediatric multi-slice CT (MSCT) is rapidly increasing worldwide. As technology advances its application in paediatric care is constantly expanding with an increasing need for radiation dose control and appropriate utilization. Recommendations on how and when to use CT for assessment of the paediatric urinary tract appear to be an important issue. Therefore the European Society of Paediatric Radiology (ESPR) uroradiology task force and European Society of Urogenital Radiology (ESUR) paediatric working groups created a proposal for performing renal CT in children that has recently been published. The objective of this paper is to discuss paediatric urinary tract CT (uro-CT) in more detail and depth. The specific aim is not only to offer general recommendations on clinical indications and optimization processes of paediatric CT examination, but also to address various childhood characteristics and phenomena that facilitate understanding the different approach and use of uro-CT in children compared to adults. According to ALARA principles, paediatric uro-CT should only be considered for selected indications provided high-level comprehensive US is not conclusive and alternative non-ionizing techniques such as MR are not available or appropriate. Optimization of paediatric uro-CT protocols (considering lower age-adapted kV and mAs) is mandatory, and the number of phases and acquisition series should be kept as few as possible.

CT in children--dose protection and general considerations when planning a CT in a child

Today CT represents about 10% of all ionizing radiation based imaging modalities, but delivers more than 50% of the total collective dose for diagnostic imaging. Compared to adults the radiation sensitivity of children is considerable higher than in adults. Additionally children differ from adults--factors like body size, mass, density, proportions as well as metabolism have to be mentioned. Children grow and mature--all this components have to be mapped in examination protocols by Pediatric Radiology. The total dose of a CT examination depends on the settings of several factors such as the scout view, the scan length, exposure settings including automated exposure control, type of scanning (single slice, helical, volume mode), slice thickness, pitch values as well as on image reconstruction parameters. If intravenous contrast media injection is needed bolus tracking or timing represents another source of radiation. The aim of the paper is to present and discuss all aspects of defining a pediatric age and query adapted CT protocol particularly concerning all dose relevant factors in pediatric CT and their adjustment in children. Moreover hints are given concerning optimization of intravenous contrast media injection as well as special (low dose) imaging protocols.

MR imaging of the abdomen and pelvis in infants, children, and adolescents

Recent developments in magnetic resonance (MR) imaging have profoundly changed the investigation of abdominal and pelvic disease in pediatrics. Motion reduction techniques, such periodically rotated overlapping parallel lines with enhanced reconstruction, or PROPELLER, have resulted in reliable imaging with quiet breathing. Faster imaging sequences minimize artifact and allow for more efficient studies. Diffusion-weighted imaging has become increasingly important in the evaluation of neoplastic disease, depicting disease with increased cellularity and helping to differentiate benign from malignant masses. MR enterography helps visualize intra- and extraluminal bowel pathologic conditions. MR cholangiopancreatography can depict congenital and acquired causes of pancreatic and biliary abnormalities. MR urography is an effective technique for a one-stop-shop evaluation of structural urinary tract abnormality and renal function. Three-dimensional acquisitions allow volumetric display of structures from multiple angles. Specialized techniques allow quantification of iron and fat in the viscera in children with hemolytic anemia and obesity, respectively. This article covers current techniques and strategies to perform and optimize MR imaging of the abdomen and pelvis in infants, children, and adolescents and describes important practical applications.

ESPR uroradiology task force and ESUR paediatric working group: imaging recommendations in paediatric uroradiology, part IV: Minutes of the ESPR uroradiology task force mini-symposium on imaging in childhood renal hypertension and imaging of renal trauma in children

Two new recommendations of the European Society of Radiology task force and the European Society of Uroradiology workgroup on paediatric uroradiology are presented. One deals with diagnostic imaging in children after trauma to the urinary tract-renal trauma, in particular. The other concerns the evaluation of suspected renal hypertension. Available data in the paediatric literature are either unsatisfactory or controversial for both of these clinical settings. Therefore, the following consensus-based proposals aim at outlining effective imaging algorithms to reduce invasive imaging procedures while optimising diagnostic accuracy. The objective of following a more uniform imaging approach is to facilitate future meta-analysis as well as multicentre and other more evidence-based studies. The practise in paediatric radiology is typically based on local availability and on the limitations of professional expertise and equipment, balanced against the perceived needs of the individual child. Although this is unlikely to change in the near future, it does not release the physicians in charge of diagnostic imaging from their responsibility in choosing and providing state-of-the-art imaging and management protocols that are adapted specifically for use in children.

[Imaging evaluation of renal function: principles and limitations]

The kidney performs multiple functions. Glomerular filtration is the most studied of these functions. In clinical practice, the surgical indication for patients with unilateral uropathy is frequently based on the split renal function as demonstrated by scintigraphy. MRI is not yet validated as a technique but nonetheless offers an interesting non-radiating alternative to achieve both morphological and functional renal evaluation. Recent pulse sequences such as diffusion, arterial spin labeling, and blood oxygenation dependent imaging may also provide additional information. CT and US remain of limited value for the evaluation of renal function.

Pediatric uroradiology: state of the art

Recent years have witnessed major strides in imaging modalities, including US and contrast-enhanced voiding urosonography, fluoroscopy, CT and MRI, and these have significantly impacted paediatric uroradiology. The trend is towards reduced or no radiation exposure and combined morphological and functional imaging. This review presents the currently available and recommended modalities in modern paediatric uroradiology practice.

ESPR uroradiology task force and ESUR paediatric working group: imaging and procedural recommendations in paediatric uroradiology, part III. Minutes of the ESPR uroradiology task force minisymposium on intravenous urography, uro-CT and MR-urography in childhood

The ESPR working groups have addressed intravenous urography (IVU), uro-CT and MR-urography (MRU) in childhood as the last in the series of recommendations for paediatric uroradiology. The aim of this process was again to standardise paediatric uroradiologic imaging and to reduce invasiveness and radiation dose. As for the existing recommendations, the new proposals are consensus-based because evidence is lacking, use and indications have changed, or approaches on how to perform the examination in children differ in the literature (MRU). As in the previous recommendations, a thorough review of the literature and existing guidelines and recommendations has been performed. The proposals were discussed within the group and with non-member experts and colleagues from other partner disciplines. These recommendations aim to serve as a quality measure in order to standardise the procedures and thus grant comparable good quality results throughout different institutions.

Obstructive diseases of the urinary tract in children: lessons from the last 15 years

Imaging urinary tract obstruction is a common query in paediatric uroradiology. With the advent of a more conservative treatment approach, the task of imaging today is to distinguish as early as possible those kidneys that do not require surgery, from those that will deteriorate and lose function and/or growth potential and thus benefit from surgery. At present, in spite of significant advancements in imaging and the introduction of diuretic paediatric MR-urography, there is still no reliable a-priori pro-futuro assessment. Thus, repeated follow-up imaging is often necessary for monitoring. Imaging usually starts with US; the major additional complementary and more function-oriented tools are diuretic renal scintigraphy and MR-urography. The frequency and timing as well as the detailed protocol vary within institutions, partly because of differences in the criteria that are used for indicating surgery. Intra-venous urography (IVU) for obstruction has practically vanished apart from for a few exceptions, and the "Whitaker" test is today seldom performed, being reserved for complicated cases.

MR urography in children. Part 1: how we do the F0 technique

MR urography (MRU) has been widely accepted as a substitute to intravenous urography for investigating children with a dilated urinary tract after preliminary assessment by US and voiding cystourethrography. Hydronephrosis is by far the main indication for MRU because upper tract dilatation is a frequent condition in infants and children. Recent advances in technology have allowed MR to go beyond morphology and to assess renal function parameters such as split renal function and drainage. In this article we report our routine practice of the F0 MRU technique. The main advantages of our protocol are no requirement for general anaesthesia, no bladder catheterization, use of low-dose gadolinium-based contrast agent (0.05-0.1 mmol/kg) and total acquisition time of 30 min or less.

[Imaging studies in infants and children with dilatation of the upper urinary tract]

Prenatally or postnatally diagnosed dilatation of the upper urinary tract initiates postnatal investigations, including sonography, dynamic renography (MAG 3) and optional voiding cystourethrography. The first ultrasound examination should be performed 3-5 days after birth and in urgent cases 10-12 h after delivery of the baby. Dynamic renography (MAG 3) is the standard diagnostic investigation and permits simultaneous assessment of renal perfusion and drainage. MRI combines excellent anatomical detail with functional information, without exposure to radiation but needs general anaesthesia in infants and younger children. Intravenous urography is no longer performed routinely in children with a dilated upper urinary tract. The combination of ultrasound and MAG 3 produces the necessary anatomical and functional information to follow the degree of obstruction and to decide between surgical intervention or a conservative follow-up.