Kidney volume normative values in Central European children aged 0-19 years: a multicenter study.

BACKGROUND AND OBJECITVES: The currently available kidney volume normative values in children are restricted to small populations from single-centre studies not assessing kidney function and including none or only a small number of adolescents. This study aimed to obtain ultrasound-based kidney volume normative values derived from a large European White/Caucasian paediatric population with normal kidney function. METHODS: After recruitment of 1427 children aged 0-19 years, 1396 individuals with no history of kidney disease and normal estimated glomerular filtration rate were selected for the sonographic evaluation of kidney volume. Kidney volume was correlated with age, height, weight, body surface area and body mass index. Kidney volume curves and tables related to anthropometric parameters were generated using the LMS method. Kidney volume predictors were evaluated using multivariate regression analysis with collinearity checks. RESULTS: No clinically significant differences in kidney volume in relation to height were found between males and females, between supine and prone position and between left and right kidneys. Males had, however, larger age-related kidney volumes than females in most age categories. For the prediction of kidney volume, the highest coefficient correlation was observed for body surface area (r = 0.94), followed by weight (r = 0.92), height (r = 0.91), age (r = 0.91), and body mass index (r = 0.67; p < 0.001 for all). CONCLUSIONS: This study presents LMS-percentile curves and tables for kidney volume which can be used as reference values for children aged 0-19 years.

Kidney length normative values - new percentiles by age and body surface area in Central European children and adolescents.

BACKGROUND: Kidney size evaluation is an essential examination in pediatric nephrology. While body length/height is the best predictor of kidney length, age-based and body surface area (BSA)-based normative values may be useful in clinical practice or research. This study aimed to establish ultrasound-based kidney length lambda-mu-sigma (LMS) percentiles by age and BSA in healthy children. METHODS: In 1758 Polish and Lithuanian children (868 boys, 49%) aged 0-19 years, kidney length was measured using ultrasonography. In all participants, anthropometric measurements were taken and kidney function was evaluated based on serum creatinine concentration. Participants with chronic or kidney diseases, abnormal kidney function, or pathologies in sonographic examination were excluded from the analysis. RESULTS: Kidney length (median kidney length) increased progressively from infancy to the age of 18 years, from 60.1 to 114.2 mm in males, and from 57.3 to 105.2 mm in females. A gradual increase of kidney length (50th percentile) in relation to BSA (from 46.1 mm in infants with a BSA of 0-1.2 m2 to 118.3 mm in adolescents with a BSA of 2.6-2.8 m2) was also observed. LMS percentiles by age (stratified by sex) and BSA were determined and presented as graphs and tables of percentiles and LMS parameters by 1-year age intervals and 0.2 m2 of BSA, respectively. CONCLUSIONS: We present the first age- and BSA-based kidney length LMS normative values based on the largest pediatric cohort to date, which can be used in both clinical practice and research studies. A higher resolution version of the Graphical abstract is available as Supplementary information.

Kidney length normative values in children aged 0-19 years - a multicenter study.

BACKGROUND: Currently used pediatric kidney length normative values are based on small single-center studies, do not include kidney function assessment, and focus mostly on newborns and infants. We aimed to develop ultrasound-based kidney length normative values derived from a large group of European Caucasian children with normal kidney function. METHODS: Out of 1,782 children aged 0-19 years, 1,758 individuals with no present or past kidney disease and normal estimated glomerular filtration rate had sonographic assessment of kidney length. The results were correlated with anthropometric parameters and estimated glomerular filtration rate. Kidney length was correlated with age, height, body surface area, and body mass index. Height-related kidney length curves and table were generated using the LMS method. Multivariate regression analysis with collinearity checks was used to evaluate kidney length predictors. RESULTS: There was no significant difference in kidney size in relation to height between boys and girls. We found significant (p < 0.001), but clinically unimportant (Cohen's D effect size = 0.04 and 0.06) differences between prone vs. supine position (mean paired difference = 0.64 mm, 95% CI = 0.49-0.77) and left vs. right kidneys (mean paired difference = 1.03 mm, 95% CI = 0.83-1.21), respectively. For kidney length prediction, the highest coefficient correlation was observed with height (adjusted R2 = 0.87, p < 0.0001). CONCLUSIONS: We present height-related LMS-percentile curves and tables of kidney length which may serve as normative values for kidney length in children from birth to 19 years of age. The most significant predictor of kidney length was statural height.

The role of modern diagnostic imaging in diagnosing and differentiating kidney diseases in children.

Urinary tract diseases are in the group of the most commonly diagnosed medical conditions in pediatric patients. Many diseases with different etiologies are accompanied by pain, fever, hematuria, or urinary tract dysfunction. Those most common ones in children are urinary tract infections and congenital malformation. They can also represent tumors or changes caused by systemic diseases. Clinical tests and even more often additional imaging studies are required to make a proper diagnosis of urinary tract diseases. Just a few decades ago urography, cystography or voiding cystourethrography were the main methods in diagnostic imaging of the urinary tract. Today's imaging methods supported by digital radiographic and fluoroscopy systems, high sensitivity detectors with quantum detection, advanced algorithms eliminating motion artifacts, modern medical imaging monitors with a resolution of three or even eight megapixels significantly differ from conventional radiographic methods. The methods that are currently usually performed are: computed tomography, magnetic resonance imaging, isotopic methods and ultrasonography using elastography and new solutions in Doppler imaging. Modern techniques are currently focused on reducing radiation exposure with better imaging capabilities. The development of these techniques became an essential diagnostic aid in nephrological and urological practice. The aim of this paper is to present the latest solutions that are currently used in the diagnostic imaging of urinary tract diseases.

Interleukin 18 and neutrophil-gelatinase associated lipocalin in assessment of the risk of contrast-induced nephropathy in children.

The aim of the study was to determine the usefulness of interleukin 18 (IL-18) and neutrophil-gelatinase associated lipocalin (NGAL) in the risk assessment of contrast nephropathy in children. The study included patients among whom radiological examinations were performed using intravascular contrast agent. The material consisted of 33 children (19 girls, 14 boys) aged 6.37 ±5.41 years. 20/33 (61%) of patients had hydronephrosis, 9/33 (27%) had other urinary tract defects referred as "no hydronephrosis" and 4/33 (12%) had urolithiasis. NGAL determination was performed with the use of Human Lipocalin-2 / NGAL Immunoassay. To determine the concentration of human IL-18 an ELISA Kit (MBL International Corporation) was used. There were no statistically significant differences in the concentrations of NGAL and IL-18 in serum determined before the procedure, and after the administration of contrast agent. Concentrations of NGAL and IL-18 were determined in urine three times: before the procedure, 2-4 hours after administration of the contrast agent, and 48 hours after the performed procedure. The analysis showed that the concentration of IL-18 and NGAL in urine did not differ significantly in three consecutive preformed measurements. The study has also found no statistically significant differences between serum creatinine before and 48 hours after injection of contrast. Implementation of new biomarkers such as NGAL and IL-18 expands the possibilities of renal function assessment in children undergoing radiological procedures using contrast agents. In examined children with normal or slightly impaired renal function they did not demonstrate the risk of contrast nephropathy.