Michael Riccabona

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

We present here a few basic proposals for algorithms and procedures for imaging the paediatric genitourinary tract based on initial discussion at a paediatric uroradiology symposium and proposals of the ESUR Paediatric Uroradiologic Guidelines Subcommittee. These recommendations were developed in the light of new knowledge that might influence existing guidelines. Regional, individual and local flexibility and variability should be preserved in order to make these recommendations applicable throughout Europe. They should help standardize dedicated imaging not only in terms of a quality measure to ensure state-of-the-art patient care, but also in forming a common basis for multi-institutional research. There is an urgent need for these guidelines in order to advance our understanding of the subject and to gain evidence and improve imaging efficacy. Our session worked towards establishing an agreement on imaging indications in common paediatric urological conditions, respecting the ALARA principle, and patient safety and care, and taking into account state of the art knowledge and efficacy aspects. We started the task with a reassessment of (1) imaging in urinary tract infection in infants and children, (2) postnatal imaging in mild-to-moderate neonatal hydronephrosis, (3) how to perform voiding cystourethrography, and (4) procedural recommendations for paediatric urosonography. This list is incomplete, and future recommendations will be developed, discussed and presented at forthcoming meetings.

Distance and volume measurement using three-dimensional ultrasonography.

The purpose of this study was to assess the accuracy of distance and volume measurements obtained by three‐dimensional ultrasonography. A tissue‐mimicking phantom was scanned using a prototype three‐dimensional sonographic imaging system to verify distance measurements. Measurements were taken from the reconstructed three‐dimensional sonographic data and compared to the real distances. Volume measurements were obtained by scanning 30 balloons of various shapes, sized 23 ml to 2400 ml. Each balloon was scanned twice in two orientations; three different masks were accomplished for each volume. Each volume measurement of 180 three‐dimensional sonographic measurements was compared to conventional two‐dimensional ultrasonographic volume estimates and to the actual, measured balloon size. Distance measurements had a mean error of 0.02 +/‐ 3.65% (range, ‐4.27 to 7.18%). Two‐dimensional sonographic volume estimates using traditional scanner based methods had a mean error of 13.7 +/‐ 10.1%. Three‐dimensional sonographic volume measurements had a mean error of 2.2 +/‐ 2.9% for regular and irregular objects over the entire range of volumes. The masking required 10 to 30 min. The field of view varied from 10 to 24 cm with a mean object depth of 9.8 cm. Three‐dimensional ultrasonographic methods can provide accurate volume measurements of regular and irregular objects and offer improved accuracy compared to traditional two‐dimensional methods.

In vivo three-dimensional sonographic measurement of organ volume: validation in the urinary bladder.

The purpose of this study was to assess the accuracy of in vivo measurement of organ volume using 3DUS and compare the results to 2D sonographic methods using the urinary bladder as the target organ and voided urine volume for validation. Fifty normal volunteers were studied. 2D volume measurements were based on length, width, and depth data and assumed a regular geometric model. 3D volume measurements were based on masked slices with the voxels integrated over the entire bladder. Voided urine volumes ranged from 35 ml to 701 ml. Residual urine volume was present in 48% of the subjects and ranged from 1% to 14% of the voided volume. 2D volume estimates for all 50 subjects had a mean absolute value of the error of 27.5% +/‐ 17.8%. 3D volume measurements had a mean absolute value of the error of 4.3% +/‐ 3.7% (transverse) and 5.6% +/‐ 3.8% (longitudinal). 3DUS provided more accurate volume measurements than 2DUS, particularly for irregularly shaped organs.

Activation of the clotting system during extracorporeal membrane oxygenation in term newborn infants

OBJECTIVES To determine the degree of clotting activation that occurs with the usual anticoagulation regimen with systemic heparinization. METHODS To allow a standardized comparison of the patients, this study focused on the first 48 hours of extracorporeal membrane oxygenation (ECMO) in term newborn infants. The ECMO perfusion circuit consisted of a roller pump, silicone membrane lungs, and silicone rubber tubing. Coagulation was controlled routinely by measuring prothrombin time, fibrinogen, antithrombin III, and reptilase time. Platelet counts, activated clotting time, and heparin concentration were controlled regularly. The following specific activation markers of the clotting system were measured: prothrombin activation fragment 1 + 2(F1+2), thrombin-antithrombin III complexes, and D-dimer. Measurements were done before the start of ECMO, after 5 minutes, and at hours 1, 2, 3, 4, 6, 12, 24 and 48. RESULTS All seven term infants had excessively high levels of clotting activation markers within the first 2 hours of ECMO: F1+2, 11.6(+/- O.9) nmol/L (mean +/- SEM); thrombin-antithrombin, 920(+/- 2.2) microg/L; D-dimer, 15.522(+/- 3.689) ng/L. During the next 46 hours of ECMO, F1+2 and thrombin-antithrombin III complexes decreased from those high values, whereas D-dimer did not. The increase of activation markers was accompanied by low fibrinogen, low platelet counts. and prolongation of reptilase time. CONCLUSIONS These findings fit the pattern of consumptive coagulopathy during neonatal ECMO, especially in the first 24 hours.

Imaging recommendations in paediatric uroradiology

The imaging and procedural recommendations as elaborated by the ESPR Paediatric Uroradiology Taskforce and the ESUR Paediatric Uroradiology Working Group were presented and discussed at the first uroradiology panel held during the ESPR Annual Congress in Barcelona in 2007. These recommendations were published in this journal [1] and have gained wide acceptance throughout Europe and beyond. A few imaging algorithms have been newly proposed by group members, partially completing the existing recommendations, and further important recommendations have been added. The imaging algorithm for prenatally diagnosed hydronephrosis (HN) has been supplemented by a statement on imaging neonates with fetally diagnosed high-grade HN and suspected posterior urethral valves (PUV). Recommendations referring to imaging children with suspected obstructive uropathy, the imaging algorithm for childhood haematuria, and the imaging algorithm for children with suspected urolithiasis have been formulated. The aim was again to reduce invasive and unnecessary investigations wherever possible without running the risk of missing potentially damaging conditions and increasing patient morbidity. As with the existing algorithms, the new proposals are consensus-based recommendations since little Pediatr Radiol (2009) 39:891–898 DOI 10.1007/s00247-009-1233-6

Three dimensional ultrasound: display modalities in the fetal spine and thorax

PURPOSE To evaluate the display modalities of three dimensional ultrasound (3D US) in the prenatal assessment of the fetal spine and thorax. METHOD Twenty prenatal spine examinations (mean gestational age: 21 weeks, 15 normal findings, five pathological cases) were performed with a commercially available 3D US device. The visualization of fetal spine and rib anatomy and pathology by 3D US display was evaluated using various rendering methods and the optimal method was determined in regard to comprehensive diagnostic display. RESULTS Demonstration of continuity of both the spine and the ribs could be achieved by 3D US. Visualization of clavicles, scapula and iliac bone was possible on rendered images. CONCLUSION 3D US offers an additional diagnostic tool for prenatal assessment of the fetal spine and ribs; it provides a continuous demonstration of curved or tortuous structures in the rendered image. It improves comprehension of complex anatomy by providing a simultaneous display of all orthogonal sectional planes.

Potential applications of three-dimensional ultrasound in the pediatric urinary tract: pictorial demonstration based on preliminary results

The aim of this study was to describe the potential of three-dimensional ultrasound (3DUS) in the urinary tract of neonates, infants, and children. The potential applications are illustrated based on our experience in 80 patients using two different 3DUS techniques. Various disease entities throughout the neonatal and pediatric age have been evaluated. The potential of 3DUS is discussed based on comparison with conventional 2DUS or other imaging (as clinically indicated), focused on the potentially improved renal parenchymal volume assessment. In our experience, 3DUS is feasible in neonates, infants, and children without sedation. It reduces imaging time, improves demonstration of complex anatomy and allows for evaluation of anatomy/pathology in any plane. The 3DUS improves volume assessment and follow-up comparison by offering an improved standardization and documentation. Rendered views of the dilated collecting system enable a comprehensive demonstration of hydronephrosis similar to intravenous urography or MR urography images. Additionally, 3DUS offers an ideal tool for training and education. Yet, limitations have to be acknowledged: areas inaccessible for 2DUS; poor quality of the original 2DUS acquisition; limited resolution; patient motion and breathing; cardiac pulsation creating artifacts and misregistration; equipment cost; lack of 3D DICOM standards creating problems with data storage; as well as system-inherent technical limitations. Nevertheless, the 3DUS holds the potential to become a valuable additional imaging tool for sonographic evaluation of the pediatric urinary tract.

Potential of modern sonographic techniques in paediatric uroradiology

OBJECTIVE To describe the potential of modern sonographic techniques in paediatric uroradiology. METHOD Ultrasound (US)-now being the primary imaging tool-has revolutionised imaging diagnostic in the urinary tract. Constant developments and technical refinements have secured the role of US in uroradiology. Colour Doppler Sonography (CDS) and innovative applications such as the transperineal approach or application of m-mode US to the urinary tract have helped to develop US from just a basic tool to a sophisticated and respected method. The ongoing introduction of new and even more sophisticated methods further enhance the sonographic potential, which shall be demonstrated by a more detailed discussion of these methods. RESULTS Harmonic imaging, extended field of view US, amplitude coded CDS, echo-enhanced US, and three-dimensional US as the most recent new sonographic techniques are successfully applicable to paediatric urinary tract disease. They improve sonographic diagnosis in many conditions, such as detection of vesico-ureteral reflux, renal parenchymal volume assessment, comprehensive visualisation of hydronephrosis and complex pathology, evaluation of renal perfusional disturbances or defects, superior documentation with improved comparability for follow-up, or simply by offering clearer tissue delineation and differentiation. CONCLUSION Modern US techniques are successfully applicable to neonates, infants, and children, further boosting the value of US in the paediatric urinary tract. However, as handling became more sophisticated, and artefacts have to be considered, modern urosonography became not only a more powerful, but also a more demanding method, with the need for expert knowledge and dedicated training.

Cystography in infants and children: a critical appraisal of the many forms with special regard to voiding cystourethrography.

Abstract. The aim of this study was to describe and discuss the various forms of cystography and their clinical value. Conventional fluoroscopic voiding cystourethrography (VCU), radionuclide cystography and the various sonographic cystographic approaches, including echo-enhanced cystosonography (EECS), are described. Their indications, potential, benefit and setbacks/restrictions are discussed with regard to the literature and the constantly changing clinical demand. With the introduction of EECS a new and reliable tool has been established to be useful for follow-up and screening for vesico-ureteral reflux (VUR); however, with the growing importance of functional disturbances a reliable method to evaluate both function and anatomy/VUR as offered by modified VCU is mandatory, and thus VCU remains to play a major part in evaluating children with urinary tract infection, suspected VUR, hydronephrosis or functional bladder disturbances. While EECS offers a new method for certain indications, such as follow-up examinations in VUR or screening, VCU remains an irreplaceable tool for evaluating anatomy (particularly the male urethra) and bladder function (if performed using the modified technique).

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.