Objectified kidney ultrasound echogenicity and size metrics as potential predictors for kidney function in children.

BACKGROUND: Kidney echogenicity is typically determined subjectively but may have a quantifiable relationship to kidney function. Similarly, kidney length has been shown to correlate with kidney function. This study sought to quantify echogenicity using readily available software. Secondarily, we aimed to evaluate the correlation between quantified echogenicity and kidney length to the estimated glomerular filtration rate (eGFR) in children with acute kidney injury (AKI) and chronic kidney disease (CKD). METHODS: In a single-center retrospective observational study, echogenicity index (EI) was determined using a ratio of right kidney to liver mean pixel density. The kidney length ratio (KLR) was determined by the actual to predicted lengths of both kidneys. Both variables were correlated to eGFR using correlation analyses and predictive capacity was determined with receiver operating characteristic curve (ROC) analysis. RESULTS: Of 94 subjects, 46% (43/94) had AKI, 28% (26/95) had CKD and 26% (25/95) were controls. The higher the EI the lower the eGFR (r = - 0.46, p < 0.0001). EI between 1.0 and 1.1 predicted an eGFR < 90 ml/min/1.73m2 with an AUC of 0.71-0.78 while an EI between 1.1 and 1.2 predicted an eGFR < 60 ml/min/1.73m2 with AUC of 0.75-0.80. Overall, the larger the KLR the lower the eGFR (r = - 0.25, p 0.018). CONCLUSION: We have developed an accessible methodology to quantify kidney echogenicity. Overall, there was an inverse correlation between EI and eGFR in pediatric CKD and AKI. However, these correlations did not persist within subgroups which could be due to small sample size and heterogeneity of etiologies. Overall, KLR had a weaker correlation to eGFR, compared to EI. Despite these correlations, both EI and KLR had "fair" to "good" performance as a biomarker for an eGFR < 60 ml/min/1.73m2.

Use of lacosamide for focal epilepsy in a child with kidney failure undergoing peritoneal dialysis.

BACKGROUND: Lacosamide (LCM) has become commonly used for focal onset seizures due to its high tolerability and low drug interactions. Unlike patients on hemodialysis (HD), pharmacokinetic data and dosing recommendations for patients undergoing peritoneal dialysis (PD) are scant. CASE REPORT: A 2-year-old girl with end-stage kidney disease undergoing PD suffered prolonged focal onset seizures. The patient had congenital anomalies of the kidney and urinary tract associated with branchio-oto-renal syndrome due to an EYA1 gene mutation. She also had neurological sequelae from post-resuscitation encephalopathy at the age of one month. Antiseizure medication with few drug interactions, less impact on the neurodevelopmental state and possibility of intravenous administration was preferred. LCM met those criteria and was carefully administered. Although the patient had recurrent prolonged seizures during the titration periods, LCM could be continued without any apparent side effects. The blood levels of LCM increased linearly to the optimal level. We confirmed excretion of LCM in the PD fluid. Kidney transplantation was done three months after and her seizures were well controlled. CONCLUSIONS: LCM might be a promising option for patients undergoing PD. Due to the lower removal efficacy in PD compared with in HD, close attention should be paid to possible drug excess.

Reference values for urinary protein, albumin, beta 2-microglobulin, and the alpha 1-microglobulin-to-creatinine ratio in Japanese children.

BACKGROUND: The importance of the ratio of creatinine to urinary protein, albumin, and low-molecular weight protein as a urinary marker in chronic kidney disease patients is widely recognized. However, no reference values have hitherto been established for these markers in Japanese children. The present study aimed to establish the reference values for these urinary markers in Japanese children. METHODS: The first morning urine was randomly collected from 1712 pupils aged ≥ 3 to < 18 years during school and kindergarten mass urinary screenings. The upper limit of the reference values was set at the 97.5th percentile of the creatinine ratio per marker. RESULTS: The urinary protein-to-creatinine ratio (PCR), urinary albumin-to-creatinine ratio (ACR), urinary beta 2-microglobulin-to-creatinine ratio (BMCR), and urinary alpha 1-microglobulin-to-creatinine ratio (AMCR) showed an age-related decrease at the 50th percentile reflecting an age-related increase in urinary creatinine. The appropriate reference value for the PCR and ACR was 0.12 g/gCr and 35 mg/gCr, respectively, in the entire cohort. The appropriate reference value for the BMCR was 0.5 µg /mgCr for age ≥ 3 to < 6 years and 0.35 µg/mgCr for age 6 years or older. The appropriate reference value for the AMCR was 5.0 µg/mgCr for age ≥ 3 to < 6 years and 3.5 µg /mgCr for age 6 years or older. CONCLUSION: The present study was the first to determine appropriate reference values for the PCR, ACR, BMCR, and AMCR based on an analysis of the first morning urine samples of a large number of children.

Obstructed Hemivagina with Ipsilateral Renal Agenesis: A Challenging Case Report and a Management Flow Chart.

We present here a case of complex uterine anomaly-obstructed hemivagina with ipsilateral renal agenesis (OHVIRA), also known as Herlyn-Werner-Wunderlich syndrome in a 13-year-old girl with a history of recurrent urinary tract infections (rUTI). In the emergency room, a trans-abdominal sonography revealed an ovarian cyst and renal agenesis, without any suspicion of vaginal obstruction. This led to a delay in the diagnosis of this uncommon anomaly. Finally, MRI findings confirmed the presence of OHVIRA syndrome. As the congenital anomalies of the kidney and urinary tract (CAKUT) are present in almost one third of cases associated with genital malformations, urologists should carefully screen patients with rUTI. The patient underwent simultaneous laparoscopy and vaginoscopy, which was in our opinion the most appropriate therapeutic decision. In this article, we are also going to discuss the role of laparoscopy in the management of OHVIRA syndrome, as well as other surgical techniques described in the literature.

Bi-allelic pathogenic variants in ITGA8 cause slowly progressive renal disease of unknown etiology.

Integrin Subunit Alpha 8 gene (ITGA8) encodes an integrin chain that is known to be critical in the early stage of the kidney development. Bi-allelic pathogenic variants in ITGA8 are associated with bilateral renal agenesis, as well as anomalies involving urogenital system. Here, we report two unrelated patients presenting with slowly progressing chronic kidney disease associated with bilateral renal hypodysplasia carrying homozygous loss of function variants in the ITGA8 gene. These results broaden the clinical and genotypic spectrum of ITGA8 defects, revealing the high and unexpected degree of phenotypic heterogeneity of this autosomal recessive disease. Our study emphasizes the usefulness of Next-Generation Sequencing in unraveling the genetic cause of chronic kidney disease of unknown etiology, and raises the question of genetic modifiers involved in the variation of the phenotypes associated with autosomal recessive ITGA8 pathogenic variants.

Prenatal diagnosis and molecular cytogenetic analyses of a paternal inherited deletion of 1q23.3 encompassing PBX1 gene.

BACKGROUND: Patients with deletions involving the long arm of chromosome 1 are rare. The PBX1 gene is located on chromosome 1q23.3. PBX1 encodes a transcription factor which promotes protein-protein interaction and plays a crucial role in several developmental processes. PBX1 haploinsufficiency had been reported to lead syndromic congenital anomalies of kidney and urinary tract (CAKUT) in humans. CASE PRESENTATION: In this research, a 24-year-old woman (gravida 1, para 0) underwent amniocentesis at 22 weeks' gestation because of a horseshoe kidney of the fetus on prenatal ultrasound. RESULTS: Chromosomal microarray analysis (CMA) from this family revealed a 1.14 Mb paternal inherited deletion on chromosome 1q23.3, spanning from position 163,620,000 to 164,760,000 (hg19). Trio whole-exome sequencing (WES) showed heterozygous deletions in exons 1-2 of the PBX1 in fetal and paternal samples. At the 3-year follow-up, the baby did not have an abnormal phenotype except a horseshoe kidney. CONCLUSION: We provide a detailed description of the phenotype in a family with paternal inherited deletion of 1q23.3 encompassing exons 1-2 of the PBX1 gene. Combination of karyotype analysis, CMA, WES, prenatal ultrasound and genetic counseling is helpful for the prenatal diagnosis of chromosomal microdeletions/microduplications.

Nephrological and urological symptoms in patients with Robinow syndrome - a report of two cases.

Robinow syndrome is a rare congenital syndrome described in 1969 by Meinhard Robinow. The genetic background is heterogeneous - mutations of DVLI1, DVLI3, WNT5A genes (mild, autosomal dominant inheritance) or ROR2 gene (severe, autosomal recessive inheritance) are responsible for the syndrome. The syndrome is characterized by facial dysmorphism, skeletal defects, short stature, cardiovascular and urinary system abnormalities. CASE REPORT: We report nephrological and urological problems in two 4-year-old male patients with Robinow syndrome. The first patient has a horseshoe kidney located mainly on the right side, right vesicoureteral reflux grade II, dysfunctional voiding, buried penis, and retractile testicles. The second patient has recurrent urinary tract infections; diagnostic findings include left kidney duplication, grade II left vesicoureteral reflux, large posterior urethral diverticulum, dysfunctional voiding, buried penis, glanular hypospadias, and bilateral cryptorchidism. CONCLUSIONS: Patients with Robinow syndrome require multidisciplinary care, including nephrology-urology care. Nephrological and urological manifestations in children with Robinow syndrome are diverse, and urinary tract defects may be atypical and complex.

Deep-learning segmentation of ultrasound images for automated calculation of the hydronephrosis area to renal parenchyma ratio.

PURPOSE: We investigated the feasibility of measuring the hydronephrosis area to renal parenchyma (HARP) ratio from ultrasound images using a deep-learning network. MATERIALS AND METHODS: The coronal renal ultrasound images of 195 pediatric and adolescent patients who underwent pyeloplasty to repair ureteropelvic junction obstruction were retrospectively reviewed. After excluding cases without a representative longitudinal renal image, we used a dataset of 168 images for deep-learning segmentation. Ten novel networks, such as combinations of DeepLabV3+ and UNet++, were assessed for their ability to calculate hydronephrosis and kidney areas, and the ensemble method was applied for further improvement. By dividing the image set into four, cross-validation was conducted, and the segmentation performance of the deep-learning network was evaluated using sensitivity, specificity, and dice similarity coefficients by comparison with the manually traced area. RESULTS: All 10 networks and ensemble methods showed good visual correlation with the manually traced kidney and hydronephrosis areas. The dice similarity coefficient of the 10-model ensemble was 0.9108 on average, and the best 5-model ensemble had a dice similarity coefficient of 0.9113 on average. We included patients with severe hydronephrosis who underwent renal ultrasonography at a single institution; thus, external validation of our algorithm in a heterogeneous ultrasonography examination setup with a diverse set of instruments is recommended. CONCLUSIONS: Deep-learning-based calculation of the HARP ratio is feasible and showed high accuracy for imaging of the severity of hydronephrosis using ultrasonography. This algorithm can help physicians make more accurate and reproducible diagnoses of hydronephrosis using ultrasonography.

De novo PBX1 variant in a patient with glaucoma, kidney anomalies, and developmental delay: An expansion of the CAKUTHED phenotype.

An infant was referred for evaluation of congenital glaucoma and corneal clouding. In addition, he had a pelvic kidney, hypotonia, patent ductus arteriosus, abnormal pinnae, and developmental delay. Exome sequencing identified a previously unpublished de novo single nucleotide insertion in PBX1 c.400dupG (NM_002585.3), predicted to cause a frameshift resulting in a truncated protein with loss of function (p.Ala134Glyfs*65). Identification of this loss of function variant supports the diagnosis of congenital anomalies of the kidney and urinary tract syndrome with or without hearing loss, abnormal ears, or developmental delay (CAKUTHED). Here, we propose glaucoma as an extra-renal manifestation associated with PBX1-related disease due to the relationship of PBX1 with MEIS1, MEIS2, and FOXC1 transcription factors associated with eye development.

Maternal occupational exposure to endocrine-disrupting chemicals and urogenital anomalies in the offspring.

STUDY QUESTION: Is there an association between maternal occupational exposure to endocrine-disrupting chemicals (EDCs) early in pregnancy and subgroups of congenital anomalies of kidney and urinary tract (CAKUT), and hypospadias? SUMMARY ANSWER: Exposure to specific EDCs can increase the risk of CAKUT and no association with hypospadias was observed. WHAT IS KNOWN ALREADY: Previous studies showed an association between maternal occupational exposure to EDCs and hypospadias. However, little is known about the effect of these chemicals on the development of CAKUT, especially subgroups of urinary tract anomalies. STUDY DESIGN, SIZE, DURATION: For this case-control study, cases with urogenital anomalies from the European Concerted Action on Congenital Anomalies and Twins Northern Netherlands (Eurocat NNL) registry and non-malformed controls from the Lifelines children cohort (living in the same catchment region as Eurocat NNL) born between 1997 and 2013 were selected. This study included 530 cases with CAKUT, 364 cases with hypospadias, 7 cases with both a urinary tract anomaly and hypospadias and 5602 non-malformed controls. Cases with a genetic or chromosomal anomaly were excluded, and to avoid genetic correlation, we also excluded cases in which a sibling with the same defect was included. PARTICIPANTS/MATERIALS, SETTING, METHODS: Information on maternal occupation held early in pregnancy was collected via self-administered questionnaires. Job titles were translated into occupational exposure to EDCs using a job-exposure matrix (JEM). Adjusted odds ratios (aORs) and 95% CIs were estimated to assess the association between maternal occupational exposure to EDCs (and to specific types of EDCs) and CAKUT and hypospadias. MAIN RESULTS AND THE ROLE OF CHANCE: For CAKUT and hypospadias, 23.1% and 22.9% of the cases were exposed to EDCs, respectively, whereas 19.8% of the controls were exposed. We found an association between maternal occupational exposure to organic solvents/alkylphenolic compounds and CAKUT (aOR 1.41, 95% CI 1.01-1.97) that became stronger when combinations of urinary tract anomalies co-occurred with other defects (aOR 7.51, 95% CI 2.41-23.43). An association was also observed for exposure to phthalates/benzophenones/parabens/siloxanes and CAKUT (aOR 1.56, 95% CI 1.06-2.29), specifically urinary collecting system anomalies (aOR 1.62, 95% CI 1.03-2.54) and combinations of urinary tract anomalies (aOR 2.90, 95% CI 1.09-7.71). We observed no association between EDC exposure and hypospadias. LIMITATIONS, REASONS FOR CAUTION: The different study designs of Eurocat NNL and Lifelines could have introduced differential information bias. Also, exposure misclassification could be an issue: it is possible that the actual exposure differed from the exposure estimated by the JEM. In addition, women could also have been exposed to other exposures not included in the analysis, which could have resulted in residual confounding by co-exposures. WIDER IMPLICATIONS OF THE FINDINGS: Women, their healthcare providers, and their employers need to be aware that occupational exposure to specific EDCs early in pregnancy may be associated with CAKUT in their offspring. An occupational hygienist should be consulted in order to take exposure to those specific EDCs into consideration when risk assessments are carried out at the workplace. STUDY FUNDING/COMPETING INTEREST(S): N.S. was paid by the Graduate School of Medical Sciences (MD/PhD programme), University Medical Center Groningen (UMCG), Groningen, the Netherlands. Eurocat Northern Netherlands is funded by the Dutch Ministry of Health, Welfare and Sports. The Lifelines Biobank initiative has been made possible by subsidy from the Dutch Ministry of Health, Welfare and Sport, the Dutch Ministry of Economic Affairs, the University Medical Center Groningen (UMCG the Netherlands), University Groningen and the Northern Provinces of the Netherlands. The authors report no conflict of interest. TRIAL REGISTRATION NO: N/A.

Pelvic Renal Ectopia: Unusual Position Abnormality.

Pelvic renal ectopia is a congenital anomaly secondary to poor renal migration to the lower back. Usually, these pathologies are of asymptomatic course, therefore its finding is usually fortuitous during radiological examinations for other causes or in work-up of the infrequent symptomatic cases characterized by the occurrence of recurrent infections or symptoms of obstructive uropathy. The objective of this report is to present a case of a 37-year-old female with the unusual manifestation of left pelvic renal ectopia. She was intervened for acute lithiasic cholecystitis, and radiologic techniques diagnosed left pelvic renal ectopia. An updated review of the literature is performed. Despite the anomaly, the patient's renal function tests were normal, so only cholecystectomy was performed without complications.

Urinary biomarkers as point-of-care tests for predicting progressive deterioration of kidney function in congenital anomalies of kidney and urinary tract: trefoil family factors (TFFs) as the emerging biomarkers.

BACKGROUND: Children with congenital anomalies of kidney and urinary tract (CAKUT) are at high risk of progressive deterioration of kidney function and further developing stage 5 chronic kidney disease (CKD 5), even after a successful surgery. This prospective study was designed to determine whether urinary biomarkers can predict progressive deterioration of kidney function in children with CAKUT. METHODS: The study included 50 consecutive children, aged < 14 years, who were diagnosed with congenital uropathies (PUV, VUR, and PUJO) and 20 age-matched controls. Examination of four urinary biomarkers, i.e., trefoil family factors (TFF) 1 and 3, neutrophil gelatinase-associated lipocalin (NGAL) and microalbuminuria (MALB) was done at the beginning of follow-up. Kidney function was assessed, at the beginning and after 12-months of follow-up, by technetium-99m diethylene triamine pentaacetic acid (DTPA) and technetium-99m dimercaptosuccinic acid (DMSA) scans. Progressive deterioration in the kidney function was defined as a fall in the GFR from ≥ 60 to < 60 ml/min/1.73 m2 on comparing the baseline and latest DTPA scans; and/or new-onset cortical scar/scars or increase in the size of previous scar/scars on serial DMSA scans. Group 1 and group 2 included children without and with progressive functional deterioration respectively. RESULTS: The median (IQR) age of children with CAKUT and controls was 3 (1.5-5) and 2.3 (1.2-3.6) years, respectively, and showed no significant difference (p = 0.29). Median concentrations of TFF1, TFF3, NGAL, and microalbumin in patients were 44.5, 176.5, 281.2, and 15.5 mcg/gCr, respectively, and were significantly elevated as compared to controls (p < 0.05). Children belonging to group 2 had significantly higher concentration of biomarkers as compared to those in group 1. TFF3 was found have the highest AUC (0.9198) on ROC curve for predicting progressive functional deterioration. CONCLUSION: Urinary TFFs, NGAL, and microalbumin significantly correlate with progressive deterioration of kidney function in children harboring CAKUT. TFF3, with the strongest prediction of functional deterioration, is an emerging peptide showing sufficient potential to be included in the biomarker panel. Graphical abstract.

PAX2 Mutation-Related Renal Hypodysplasia: Review of the Literature and Three Case Reports.

Paired box 2 (PAX2)-related disorder is an autosomal dominant genetic disorder associated with kidney and eye abnormalities and can result in end stage renal disease (ESRD). Despite reported low prevalence of PAX2 mutations, the prevalence of PAX2 related disorders may have been underestimated in past studies. With improved genetic sequencing techniques, more genetic abnormalities are being detected than ever before. Here, we report three patients from two families with PAX2 mutations identified within 1 year. Two patients were adults with chronic kidney disease and were followed for decades without correct diagnoses, including one with ESRD who had even undergone kidney transplant. The third patient was a neonate in whom PAX2-related disorder manifested as oligohydramnios, coloboma, and renal failure that progressed to ESRD within 1 year after birth. The phenotypes of PAX2 gene mutation were shown to be highly variable, even within the same family. Early detection promoted genetic counseling and guided clinical management. The appropriate time point for genetic study is an important issue. Clinicians must be more alert for PAX2 mutation when facing patients with congenital kidney and urinary tract anomalies, chronic kidney disease of unknown etiology, involvement of multiple systems, and/or a family history of renal disease.

Long-term outcome of transplant ureterostomy in children: A National Review.

BACKGROUND: CAKUT are the most common cause of end-stage renal failure in children (Pediatr Nephrol. 24, 2009, 1719). Many children with CAKUT have poor urinary drainage which can compromise post-transplant outcome. Identifying safe ways to manage anatomical abnormalities and provide effective urinary drainage is key to transplant success. Much debate exists regarding optimum urinary diversion techniques. The definitive formation of a continent urinary diversion is always preferable but may not always be possible. We explore the role of ureterostomy formation at transplantation in a complex pediatric group. METHODS: We report six pediatric patients who had ureterostomy formation at the time of transplantation at the National Paediatric Transplant Centre in Dublin, Ireland. We compared renal function and burden of urinary tract infection to a group with alternative urinary diversion procedures and a group with normal bladders over a 5-year period. RESULTS: There was no demonstrable difference in estimated glomerular filtration rate between the groups at 5-year follow-up. The overall burden of UTI was low and similar in frequency between the three groups. CONCLUSIONS: Ureterostomy formation is a safe and effective option for temporary urinary diversion in children with complex abdominal anatomy facilitating transplantation; it is, however, important to consider the implications and risk of ureterostomy for definitive surgery after transplantation.

Against the Odds: Management of Ureteral Calculus in Patient With Crossed Fused Renal Ectopia.

Crossed fused renal ectopia (CFRE) is a rare congenital abnormality of the urinary tract where the kidneys are fused on one side, while the ureter of the ectopic kidney crosses the midline with the normal entrance in the bladder on the contralateral side. Congenital anomalies are associated with a stone formation whose management represents a real challenge. To our knowledge, we report the second case of CFRE associated with ureteral stone, which has been successfully resolved with Extracorporeal Shockwave Lithotripsy (ESWL) and the first of its kind where a sufficient degree of stone disintegration has been achieved after a single session with a complete stone clearance during the follow-up. Radiological examination showed an inferior type of CFRE with stone in the proximal part of the ureter of the upper kidney. ESWL is an acceptable and effective treatment option in CFRE patients due to the minimally invasive approach, potentially high stone-free rate, and rare complications.

Targeted Exome Sequencing Provided Comprehensive Genetic Diagnosis of Congenital Anomalies of the Kidney and Urinary Tract.

Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of chronic kidney disease in children. The search for genetic causes of CAKUT has led to genetic diagnosis in approximately 5-20 % of CAKUT patients from Western countries. In this study, genetic causes of CAKUT in Korean children were sought using targeted exome sequencing (TES) of 60 genes reported to cause CAKUT in human or murine models. We identified genetic causes in 13.8% of the 94 recruited patients. Pathogenic single nucleotide variants of five known disease-causing genes, HNF1B, PAX2, EYA1, UPK3A, and FRAS1 were found in 7 cases. Pathogenic copy number variations of 6 patients were found in HNF1B, EYA1, and CHD1L. Genetic abnormality types did not significantly differ according to CAKUT phenotypes. Patients with pathogenic variants of targeted genes had syndromic features more frequently than those without (p < 0.001). This is the first genetic analysis study of Korean patients with CAKUT. Only one-seventh of patients were found to have pathogenic mutations in known CAKUT-related genes, indicating that there are more CAKUT-causing genes or environmental factors to discover.

A case of bilateral pelvic kidneys.

A rare case of bilateral pelvic kidneys detected incidentally on computed tomography.

A Predictive Model of Postnatal Surgical Intervention in Children With Prenatally Detected Congenital Anomalies of the Kidney and Urinary Tract.

The aim of this study was to identify predictive factors and develop a model to assess individualized risk of postnatal surgical intervention in patients with antenatal hydronephrosis. This is a retrospective cohort study of 694 infants with prenatally detected congenital anomalies of kidney and urinary tract with a median follow-up time of 37 months. The main event of interest was postnatal surgical intervention. A predictive model was developed using Cox model with internal validation by bootstrap technique. Of 694 patients, 164 (24%) infants underwent surgical intervention in a median age of 7.8 months. Predictors of the surgical intervention in the model were: baseline glomerular filtration rate, associated hydronephrosis, presence of renal damage and the severity of renal pelvic dilatation. The optimism corrected c statistic for the model was 0.84 (95%CI, 0.82-0.87). The predictive model may contribute to identify infants at high risk for surgical intervention. Further studies are necessary to validate the model in patients from other settings.

Influence of diuretic (furosemide) on contrast medium distribution in computed tomography urography of high-grade hydronephrosis in children.

INTRODUCTION: Diuretics improve visualization of the urinary tract in computed tomography urography in adults, as well as in magnetic resonance urography in adults and children. Also, diuretics can help to diagnose upper urinary tract obstruction in intravenous urography, ultrasonography or dynamic scintigraphy. However, there are still missing data on evaluation of furosemide usefulness in computed tomography urography examinations in children with suspected congenital anomalies of the urinary tracts.The aim of this study was to compare the homogeneity of contrast medium distribution in high-grade hydronephrosis in pediatric computed tomography urographies performed with and without use of diuretic (furosemide). MATERIALS AND METHOD: We have restrospectively analyzed computed tomography urography image series performed in the Department of Pediatric Radiology, in children with suspected congenital anomalies of the kidney and the urinary tract. Kidney units with high-grade hydronephrosis were divided in two groups: non-furosemide (n = 25) and furosemide (n = 28) group, where diuretic in dose 1 mg/kg, with maximum 20 mg, was administered intravenously 3-5 min before contrast medium administration. Subjective image quality and diagnostic confidence were evaluated by two independent radiologists and compared between study groups. RESULTS: There were no significant differences in subjective image quality and diagnostic confidence between furosemide and non-furosemide groups. CONCLUSIONS: Addition of furosemide to computed tomography urography does not improve homogeneity of contrast medium distribution in hydronephrotic kidneys in children.

Computed tomography urography with iterative reconstruction algorithm in congenital urinary tract abnormalities in children - association of radiation dose with image quality.

PURPOSE: To assess the extent to which a radiation dose can be lowered without compromising image quality and diagnostic confidence in congenital urinary tract abnormalities in children by using a CT scanner with an iterative reconstruction algorithm. MATERIAL AND METHODS: 120 CT urography image series were analysed retrospectively. Image series were divided into four study groups depending on effective radiation dose (group 1: 0.8-2 mSv; group 2: 2-4 mSv; group 3: 4-6 mSv; group 4: 6-11 mSv). Objective and subjective image quality were investigated. In objective analysis, measurements of attenuation and standard deviation (SD) in five regions of interest (ROIs) were performed in 109 excretory image series, and image noise was evaluated. In subjective analysis, two independent radiologists evaluated 138 kidney units for subjective image quality and diagnostic confidence. RESULTS: There were no significant differences in image noise in objective evaluation between the following study groups: 2 vs. 3 and 3 vs. 4 in all ROIs (with the only exception in spleen SD measurement between study groups 2 vs. 3), while there was significantly more image noise in group 2 in comparison to group 4. For all other ROIs in all study groups, there was more image noise on lower dose images. There were no significant differences in pairwise comparisons between study groups in subjective image quality. Diagnostic confidence was not significantly different between all study groups. CONCLUSIONS: Low-dose CT urography can be a valuable method in congenital urinary tract abnormalities in children. Despite poorer image quality, diagnostic confidence is not significantly compromised in examinations performed with lower radiation doses.