Diffusion weighted imaging is a promising method to detect acute pyelonephritis in non-sedated free breathing infants.

INTRODUCTION: Urinary tract infection (UTI) is a common disease in infants. The initial evaluation includes imaging to identify risk factors for permanent renal damage, such as malformation and renal parenchymal involvement of the infection i.e. pyelonephritis. 99mTc-Dimercaptosuccinic acid (DMSA) scintigraphy is a well-established method for detection of pyelonephritis and renal damage, but has limitations in availability, spatial resolution, and detection of congenital malformations. Diffusion weighted magnetic resonance imaging (DWI) has been shown to have a high sensitivity for detection of pyelonephritis in children without the use of invasive procedures, contrast agents or ionizing radiation. How this method performs in young infants during non-sedated free breathing remains, however, to be investigated. OBJECTIVE: To prospectively assess the feasibility and performance of DWI for detection of pyelonephritis in non-sedated free breathing infants. METHODS: 32 children <6 months of age with first-time symptomatic UTI were examined with DWI and DMSA scintigraphy. The DWI examination was performed using a free breathing protocol without the use of sedation. Pyelonephritic lesions were registered for both methods by independent observers. Agreement between DWI and DMSA was evaluated. Consensus diagnosis was determined and compared to the DWI findings. RESULTS: The MRI and DMSA examinations were completed in 25 infants, with a median age of 1.7 (0.7-5.5) months. Focal uptake reductions were detected on the DMSA images in 12 (24%) of the 50 kidneys. The DWI method demonstrated a fair to good agreement with DMSA, k = 0.50 (p < 0.0001). The consensus diagnosis was pyelonephritis in eight (16%) of the 50 kidneys. DWI detected seven of the eight kidneys with pyelonephritis. No false positive findings were detected with DWI compared to consensus diagnosis. DISCUSSION: This study has shown an agreement between DWI and DMSA scintigraphy in the detection of pyelonephritis. Further validation of the performance of DWI, using a consensus diagnosis as a reference, confirmed the potential of the method. This feasibility study included a limited number of patients and the results need to be confirmed in a prospective study of a larger cohort. CONCLUSION: Free breathing DWI is a promising method for detection of pyelonephritic lesions in non-sedated infants.

Renal swelling indicates renal damage in infants with their first urinary tract infection.

AIM: We used ultrasound to evaluate renal swelling as a predictor of acute and permanent renal damage in infants with their first urinary tract infection (UTI). METHODS: The cohort at the Queen Silvia Children's Hospital, Gothenburg, Sweden, comprised 101 infants with their first UTI at a mean age of 3.9 ± 3.0 months. Acute and follow-up ultrasounds were carried out a few days and one month after treatment started, and a 99m technetium dimercaptosuccinic acid (DMSA) scan was carried out after one month and after a year if the first scan was abnormal. RESULTS: The acute ultrasounds showed that renal length and volume, calculated as standard deviation scores (SDS), were 1.39 ± 1.43 SDS and 1.30 ± 1.08 SDS. We found that 52% of the one-month DMSA scans and 25% of the one-year DMSA scans were abnormal. Renal length (p = 0.0026) and initial volume (p = 0.0005) on the ultrasound predicted acute renal damage at the one-month DMSA scan and initial renal length (p = 0.030) predicted permanent renal damage at the one-year DMSA scan. CONCLUSION: Renal swelling was associated with renal damage. Although the diagnostic performance compared with the DMSA scan was weak, renal swelling may help clinicians to make decisions about further investigations and follow-ups of infants with UTIs.

Performing renography in children with antenatally detected pelvi-ureteric junction stenosis: errors, pitfalls, controversies.

The aim of this work is to present to the reader the practical experience of three clinicians having actively participated to the publication of the guidelines on renography in children. The present publication should be considered as a practical guide. We have underlined good practice, obvious errors to avoid, common pitfalls which might be overlooked, some items for which more than one reasonable solution exists and finally a few controversial points, for which there is still no agreement and no solid evidence to resolve these issues. This paper is only focused on the aspects of acquisition and processing and will not cover the clinical aspects, namely the interpretation of the renogram in terms of renal obstruction or, more precisely, in terms of risk of renal deterioration.

Estimation of renal function in children and adolescents with spinal dysraphism.

PURPOSE: In children with spinal dysraphism such as myelomeningocele the relation between muscle mass and body composition varies considerably. Therefore, it is difficult to evaluate the relevance of renal function assessments done with serum creatinine. Since serum cystatin C has been suggested to be independent of body size and composition, this evaluation was compared to chromium(51) edetic acid clearance. MATERIALS AND METHODS: Simultaneous measurements of cystatin C and chromium(51) edetic acid clearance were performed prospectively in 65 patients 2 to 19 years old with spinal dysraphism. RESULTS: Cystatin C values were within the normal range in all patients, while chromium(51) edetic acid clearance was reduced in 10. A significant relation was seen. CONCLUSIONS: Using chromium(51) edetic acid clearance as a gold standard, children with spinal dysraphism and slightly to moderately reduced renal function may remain undiagnosed if cystatin C is used for evaluation.

Does treatment with clean intermittent catheterization in boys with posterior urethral valves affect bladder and renal function?

PURPOSE: In boys with resected posterior urethral valves (PUV) deterioration of renal function is seen during childhood and adolescence, which may partly be caused by bladder dysfunction. We present data on renal and bladder function initially and at followup of boys with PUV in whom the bladder dysfunction has been treated since infancy. MATERIALS AND METHODS: The study included 35 boys with PUV. Bladder regimen, including early toilet training from the age of 1.5 years and detrusor relaxant drugs for the treatment of incontinence from ages 4 to 6 years, was introduced to all patients. A total of 19 boys were started on clean intermittent catheterization (CIC) at a median age of 8 months due to pronounced bladder dysfunction with poor emptying, unsafe pressure levels, high grade reflux and renal impairment. RESULTS: No serious complications of CIC have been seen during followup. Of the 19 boys 2 stopped performing CIC due to noncompliance of the parents at 1 and 3 years, respectively. Initial renal function, measured as median glomerular filtration rate (GFR) in percent of expected for age, was 60% in the CIC group and 90% in the nonCIC group. At followup at a median age of 8 years the CIC group (n = 14, 3 transplanted boys excluded) had an increase in median differential GFR (difference between followup and initial GFR) of 7% (p <0.01), which was similar increase to that of the nonCIC group. In the 2 boys who stopped performing CIC renal function deteriorated with a median differential GFR of -24%. In the CIC group detrusor instability decreased. Poor compliance was seen in 6 of the 19 boys initially and only one remained poorly compliant. In 1 of the boys who stopped performing catheterization a low compliant bladder developed. In all of the other cases bladder capacity increased more than expected for age. CONCLUSIONS: The results suggest that treatment of bladder dysfunction in boys with PUV can counteract the deterioration in renal function seen during childhood but the number of patients in our study is limited.

Renal function 16 to 26 years after the first urinary tract infection in childhood.

OBJECTIVE: To evaluate renal function in a population-based cohort with urographic renal scarring after childhood urinary tract infection (UTI). DESIGN: Follow-up investigation 16 to 26 years after the first recognized UTI. SETTING: Outpatient university clinic for children with UTI serving the local area. PATIENTS: From the original cohort of 1221 consecutive children with first UTI diagnosed during 1970 to 1979, 57 (41 females and 16 males; mean age, 24.5 years) of 68 with nonobstructive renal scarring participated as well as 51 (38 females and 13 males; mean age, 24.9 years) matched subjects without scarring. MAIN OUTCOME MEASURE: Glomerular filtration rate (GFR) measured by chromium 51-EDTA clearance, expressed as milliliters per minute per 1.73 square meters. RESULTS: Median GFR was 99 in both those with and without renal scarring. In patients with unilateral scarring, the total GFR remained unchanged over the years whereas the individual GFR of the scarred kidneys declined significantly from 46 to 39. In 7 patients with bilateral scarring, the GFR declined from 94 to 84 (P = .14); compared with those with unilateral scarring, the GFR was significantly lower at follow-up (P = .007). Median urinary albumin-creatinine ratio was 1.2 and 0.6 mg/mmol in those with scarring and those without, respectively (P = .30). CONCLUSIONS: The GFR 2 decades after the first recognized UTI in childhood was well preserved. However, a significant reduction of individual renal GFR in the unilaterally scarred kidneys indicates that further follow-up is required. Although there were few patients with bilateral scarring, a more serious prognosis can be expected among them.

Imaging of renal scarring.

Children with urinary tract infection should be investigated and followed up, as those with pyelonephritis may develop renal scarring. In this review, after discussing the advantages and disadvantages of various imaging modalities for diagnosis of renal scarring, it is concluded that DMSA scintigraphy and urography can both be used to detect significant renal scarring. With DMSA scintigraphy, small renal lesions (functional uptake defects) not seen at urography will also be detected. The long-term clinical significance of these lesions is, as yet, unknown. A normal DMSA scintigraphy after infection indicates low risk for clinically significant damage. In order to allow acute, reversible lesions to first disappear, a follow-up DMSA examination should not be performed until at least 6 mo after the acute infection. Ultrasonography in isolation cannot be recommended for the diagnosis of renal scarring.

Administered activity of 99Tcm-MAG3 for gamma camera renography in children.

A method of calculating the activity of 99Tcm-MAG3 to be administered to children of different ages has been developed and evaluated. The suggested administered activity schedule is only valid for estimation of split renal function. The activity required to obtain the same count rate over the kidneys for all ages was calculated as a fraction of the activity administered to an adult by using a biokinetic model and taking attenuation effects into account. The activity schedule is based on the age of the child and was tested using renograms from patients of different ages. Statistical noise was added to the smoothed renograms simulating an injected activity corresponding to 45 MBq for an adult. The precision in the determination of split renal function calculated with four different methods was determined for 500 simulated renograms. The precision was approximately the same for all ages, but varied with the method used. The activity to be administered to a very small child is 90% of the adult activity, decreases to less than 50% between 2 and 5 years of age, and then slowly increases to 100% as the child grows to adulthood.

Evaluation of Kock urinary reservoir function in children and adolescents at 3-10 years' follow-up.

The aim of this study was to evaluate Kock reservoir function in children and adolescents operated for congenital urinary incontinence and to determine the complication rate. Reservoir function was investigated in 13 children (age range 10.8-16 years) and 7 adolescents (age range 16-18 years) through enterocystometry, enterocystoscopy and patient history. Patients were followed up for 3-10 years. The follow-up was reported as early (3 months-2 years) and late (2-10 years) postoperative periods. At early follow-up reservoir capacity was high in four patients and normal in the remaining patients. A low reservoir pressure was accompanied by high capacity and compliance. On enterocystometry first sensation for emptying was experienced in 82% of patients at early follow-up and 92% at late follow-up. Reservoir contractions were recorded in 60% of patients at early follow-up and 65% at late follow-up. The contractions were recorded at an average reservoir capacity of 270 ml at early follow-up and 340 ml at late follow-up. The complication rate was high in the child group compared with that in adolescents. Of 13 patients with at least one reservoir complication 10 were from the child group. Nipple dysfunction (angled nipple, prolapsed or stenosed stoma) occurred in 35% of patients, stones in 40% and bleeding during catheterization in 15%. Revision was performed in 38% of the child group and 15% of the adolescents. Reservoir perforation was observed in two patients at 6 and 9 years postoperatively. At late follow-up continence was excellent in 17 of 19 patients and good in 2. We conclude that the Kock reservoir is a good modality for urinary diversion, but the complication incidence is high in the child group (<16 years). Stability of the reservoir in terms of volume and low internal pressures was achieved one year after operation, except in the patients with infrequent reservoir emptying. A time-related increase in the reservoir sensitivity and contractility was reported on enterocystometry. Nipple dysfunction is common during the first two years after surgery, particularly in the child group. Stones may form 3-4 years after surgery. Satisfactory continence was achieved in all patients, although a revisional operation was necessary in some patients in order to obtain permanent continence.

Consensus on renal cortical scintigraphy in children with urinary tract infection. Scientific Committee of Radionuclides in Nephrourology.

A questionnaire related to cortical scintigraphy in children with urinary tract infection was submitted to 30 experts. A wide consensus was reached on several issues related to planar images: 99mTc dimercapto succinic acid (DMSA) appears as the most appropriate tracer for renal imaging; dynamic tracers are considered to be inferior, in particular 99mTc diethylenetriaminepentaacetate, which is not recommended. The general opinion is that DMSA scintigraphy is not feasible with a minimal dose below 15 MBq, whereas the maximum dose should not be higher than 110 MBq. The dose schedule generally is based on body surface area, and sedation is only exceptionally given to children. Images are obtained 2 to 3 hours after injection, preferably with high resolution collimators; pinhole images are used by only half of the experts. Posterior and posterior oblique views are used by most of the experts, and the posterior view is acquired in supine positions. At least 200.000 kcounts or 5 minute acquisition is required for nonzoomed images. As a quality control, experts check the presence of blurred or double outlines on the DMSA images. Color images are not used and experts report on film or directly on the computer screen. As far as normal DMSA images are concerned, most experts agree on several normal variants. Hydronephrosis is not a contraindication for DMSA scintigraphy but constitutes a pitfall. Differential renal function generally is measured, but no consensus is reached whether or not background should be subtracted. Most of the experts consider 45% as the lowest normal value. A consensus is reached on some scintigraphic aspects that are likely to improve and on some others that probably represent persistent sequelae. There is a wide consensus for the systematic use of DMSA scintigraphy for detection of renal sequelae, whereas only 58% of the experts are systematically performing this examination during the acute phase of infection.

Early and late metabolic alterations in children and adolescents with a kock urinary reservoir.

OBJECTIVE: To assess the early and late metabolic effects of urinary diversion in children and adolescents with a Kock urinary reservoir. PATIENTS AND METHODS: Thirteen children (aged 10.8- 16 years) and seven adolescents (aged 16-18 years; 10 girls and 10 boys), underwent surgery for congenital urinary incontinence. They were followed for 3-10 years (mean 6.5), divided into an early (3 months to 2 years) and a late (2-10 years) period, and assessed for renal function and any metabolic effects. RESULTS: At the early and late follow-up, one of 19 and three of 16 patients, respectively, had metabolic acidosis. Hyperchloraemia was present in four of 20 patients at the early and in eight of 18 at the late follow-up. Serum creatinine was increased in four of 20 patients at the early and eight of 18 at the late follow-up. In patients with infrequent reservoir emptying (

Administered activity of 99Tcm-DMSA for kidney scintigraphy in children.

Kidney scintigraphy using 99Tcm-dimercaptosuccinic acid (DMSA) is a common gamma camera investigation in paediatric patients. The present study deals with methods of calculating the activity to be administered to children. Our aim is to find a method of calculation which gives the same count density in the gamma camera images for all ages. Four different methods, based on body weight, height, body surface area and a theoretical model, are compared. The count density in the images of the kidneys was studied retrospectively in 85 patients aged between 3 weeks and 19.5 years. Fourteen young adults aged 22.0-31.9 years were also studied. Two of the calculation methods, based on body surface area and the theoretical model, showed no apparent age dependency (i.e. a constant count density was observed for all ages). The variation between individuals was similar with both methods, but only the body surface area method gave a count density comparable to that for the young adults. As the method based on body surface area is also easy to implement, this method is recommended.

Five-year study of medical or surgical treatment in children with severe vesico-ureteral reflux dimercaptosuccinic acid findings. International Reflux Study Group in Europe.

UNLABELLED: The results of serial dimercaptosuccinic acid (DMSA) imaging over 5 years are reported in 287 children with severe vesico-ureteral reflux entered into the European Branch of the International Reflux Study in Children. The children were randomly allocated to medical (n=147) or surgical (n=140) management and DMSA studies were performed during the follow up period at least 6 months after any urinary tract infection. Abnormal images were classified into four types: (1) large polar hypodensity with normal renal outline; (2) peripheral photon deficient defect(s) in a non-deformed kidney; (3) small renal image with normal contour; and (4) peripheral defect(s) with resultant irregularity of the renal outline. The DMSA findings were abnormal at entry in 235 (82%) with no difference in incidence or severity between the two treatment groups. During follow up, deterioration was observed in 25 medically and 23 surgically treated patients and comprised image deterioration alone in 17, image deterioration with corresponding reduction in differential function in 16 and reduction in relative function without image change in 15, with similar distribution between the two treatment groups. Deterioration was more frequent in children entering the study under the age of 2 years and in those with grade IV rather than grade III reflux. These findings, showing no difference in outcome between children managed surgically or medically, are consistent with the radiological results already published. CONCLUSION: In the International Reflux Study the DMSA scintigraphic data showed no difference in outcome between children managed surgically or medically.