Kidney size estimation in Korean children with Technesium-99m dimercaptosuccinic acid scintigraphy

Types of Parenchymal Changes Diagnosed on DMSA Scans of Kidneys Affected by Different Grades of Vesicoureteral Reflux

Background

Renal parenchymal damage and scarring usually is associated with urinary tract infection (UTI), whereas the impact of vesicoureteral reflux (VUR) on the kidneys is unclear. We aimed to compare kidneys with all grades of VUR (grades Io-V) and those without VUR by using direct radionuclide cystography, voiding cystourethrography, and findings from ^99mTc-DMSA scintigraphy (DMSA scan).

Material/Methods

The present analysis included 253 renal ureteral units (RUU) from 129 children with VUR and recurrent UTI and children with a single febrile UTI associated with abnormal ultrasonographic findings. The 6 grades of VUR (Io, I, II, III, IV, and V) and 35 RUUs without VUR were divided into 4 groups: 1. Non-dilated VUR (grades Io-II); 2. Mildly dilated VUR (grade III); 3. Dilated VUR (grades IV–V); and 4. The control group.

Results

DMSA scanning showed significant differences between the groups with non-dilated VUR, grade III VUR, grades IV–V VUR, and the control group in kidney width (χ²=30.5; P<0.001); position and shape (χ²=30.6; P<0.001); intensity of activity (χ²=38.1; P<0.001); distribution of activity (χ²=34.5; P<0.001); and existence of scars (χ²=16; P<0.001). The probability of abnormalities on DMSA scans increased with the VUR grade. However, inside the groups of dilated and non-dilated VUR we found no significant statistical differences between those characteristics.

Conclusions

Our results indicate that kidneys without VUR or with non-dilated lateral VUR and dilated VUR on the contralateral side represent 2 different categories of parenchymal changes.

Ultrasonographic length of morphologically-normal kidneys in children presented to a premier tertiary healthcare setting of Sri Lanka

Background

Accurate prediction of reference ranges of renal lengths facilitates clinical decision making. Currently a single renal-length-reference chart is used for both kidneys, which is solely based on the age of the child without adjusting for anthropometrics.

Objective of the study is to assess the length of morphologically-normal kidneys ultrasonically and to build models to predict the renal lengths of children presenting at the Radiology Department of Lady Ridgeway Hospital for Children.

Methods

A descriptive cross sectional study was done among 424 children with 233 males and 191 females at the study setting. Study population included children undergoing abdominal ultrasound scans for indications not related to renal disease. Children with a family history of renal diseases or with morphologically-abnormal kidneys were excluded. Bipolar-lengths of kidneys, gender and anthropometrics were documented. Having tested for assumptions, Wilcoxon-signed rank test, Mann-Whitney U test and multiple linear regression were used.

Results

The mean (SD) bipor-length of right and left kidneys were 6.83 (1.43) and 7.05 (1.36) respectively (p < 0.001). Age, height and weight were significantly correlated with the renal lengths (p < 0.05). Until 16 months, there was a significant difference between the renal lengths between males and females (P < 0.05). Yet the association with gender was not significant from 17 months and in overall. Until 16 months, the best linear-regression equation (p < 0.001) for the left kidney was; 3.827 +  0.019(length in centimeters) +  0.141(weight in kilograms) - 0.023(age in months) - 0.347(for male sex). For the right kidney, it was; 3.888 + 0.020(length or height) + 0.121(weight) - 0.037(age) - 0.372 (for male sex). The respective R squares were 59.2 and 53.5% with VIF (Variance-Inflation-Factor) ranging from 1.06 to 2.08. From 17 months, best equation for left kidney (p < 0.001) was; 5.651+ 0.022(age) + 0.01(BMI). For right kidney it was; 5.336 + 0.022(age) + 0.012(BMI). The R squares were 62.5 and 66.1% with VIF being 1.

Conclusions

The established models explain more variability for children above 17 months. Both renal lengths are affected significant by the body’s’ anthropometric parameters. For each kidney, separate normograms of renal lengths which are local-context-specific must be prepared. Further research must be promoted.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1377-z) contains supplementary material, which is available to authorized users.

Birth weight influences the kidney size and function of Bangladeshi children

Early-life conditions influence organ growth patterns and their functions, as well as subsequent risk for non-communicable chronic diseases in later life. A limited number of studies have determined that in Bangladesh, kidney size relates to its function among children as a consequence of the maternal and postnatal conditions. The present study objectives were to determine early-life conditions in relation to childhood kidney size and to compare their influences on kidney function. The study was embedded in a population-based prospective cohort of 1067 full-term singleton live births followed from fetal life onward. Kidney volume was measured by ultrasound in children at the age of 4.5 years (range 45-64 months), and the estimated glomerular filtration rate (eGFR) was assessed at the age of 9 years (range 96-116 months). The mean (s.d.) kidney volume of children at 4.5 years was 64.2 (11.3) cm3, with a significant mean difference observed between low birth weight and normal birth weight children (P<0.001). The multivariable model showed, changes in status from low birth weight to normal birth weight children, with kidney volume increases of 2.92 cm3/m2, after adjusting for the child's age, sex, maternal age and early pregnancy body mass index, and socio-economic index variables. One-unit change in kidney volume (cm3/m2) improved the eGFR to 0.18 ml/min/1.73 m2. The eGFR in low birth weight children was 5.44 ml/min/1.73 m2 less than that in normal birth weight children after adjustments. Low birth weight leads to adverse effects on kidney size and function in children.

Measurement and Estimation of Renal Size by Computed Tomography in Korean Children

Adequate organ growth is an important aspect of growth evaluation in children. Renal size is an important indicator of adequate renal growth; computed tomography (CT) can closely estimate actual kidney size. However, insufficient data are available on normal renal size as measured by CT. This study aimed to evaluate the relationships of anthropometric indices with renal length and volume measured by CT in Korean pediatric patients. Renal length and volume were measured using CT images in 272 pediatric patients (age < 18 years) without renal disease. Data for anthropometric indices-including height, weight, and body surface area (BSA)-were obtained using medical records. Using the equation for an ellipsoid, renal volume was calculated in cubic centimeters. Height showed greatest correlation with renal length on stepwise multiple linear regression analysis; BSA showed the strongest significant correlation with renal volume. The mean renal size for each age group and height group was determined; it showed a tendency to increase with age and height. This is the first Korean study to report the relationship between body indices and renal size measured by CT. These results can serve as normative standards for assessing adequate renal growth.

Sonographic Growth Charts for Kidney Length in Normal Korean Children: a Prospective Observational Study

Kidney length is the most useful parameter for clinical measurement of kidney size, and is useful to distinguish acute kidney injury from chronic kidney disease. In this prospective observational study of 437 normal children aged between 0 and < 13 years, kidney length was measured using sonography. There were good correlations between kidney length and somatic values, including age, weight, height, and body surface area. The rapid growth of height during the first 2 years of life was intimately associated with a similar increase in kidney length, suggesting that height should be considered an important factor correlating with kidney length. Based on our findings, the following regression equation for the reference values of bilateral kidney length for Korean children was obtained: kidney length of the right kidney (cm) = 0.051 × height (cm) + 2.102; kidney length of the left kidney (cm) = 0.051 × height (cm) + 2.280. This equation may aid in the diagnosis of various kidney disorders.