Sonographic measurement of absolute and relative renal length in adults

Safety and Tolerability of Antimicrobial Agents in the Older Patient

Older patients are at high risk of infections, which often present atypically and are associated with high morbidity and mortality. Antimicrobial treatment in older individuals with infectious diseases represents a clinical challenge, causing an increasing burden on worldwide healthcare systems; immunosenescence and the coexistence of multiple comorbidities determine complex polypharmacy regimens with an increase in drug-drug interactions and spread of multidrug-resistance infections. Aging-induced pharmacokinetic and pharmacodynamic changes can additionally increase the risk of inappropriate drug dosing, with underexposure that is associated with antimicrobial resistance and overexposure that may lead to adverse effects and poor adherence because of low tolerability. These issues need to be considered when starting antimicrobial prescriptions. National and international efforts have been made towards the implementation of antimicrobial stewardship (AMS) interventions to help clinicians improve the appropriateness and safety of antimicrobial prescriptions in both acute and long-term care settings. AMS programs were shown to decrease consumption of antimicrobials and to improve safety in hospitalized patients and older nursing home residents. With the abundance of antimicrobial prescriptions and the recent emergence of multidrug resistant pathogens, an in-depth review of antimicrobial prescriptions in geriatric clinical practice is needed. This review will discuss the special considerations for older individuals needing antimicrobials, including risk factors that shape risk profiles in geriatric populations as well as an evidence-based description of antimicrobial-induced adverse events in this patient population. It will highlight agents of concern for this age group and discuss interventions to mitigate the effects of inappropriate antimicrobial prescribing.

Ultrasound appearance of the kidney among radiology department attendees of a tertiary centre in Malawi

Background: Diagnostic and therapeutic decisions in nephrology in low-resource settings are frequently based on ultrasound assessment of kidney size. An understanding of reference values is critical, particularly given the rise of non-communicable disease and the expanding availability of point-of-care ultrasound. However, there is a paucity of normative data from African populations. We determined estimates of kidney ultrasound measures, including kidney size based on age, sex, and HIV status, among apparently healthy outpatient attendees of Queen Elizabeth Central hospital radiology department, Blantyre, Malawi. Methods: We performed a cross-sectional cohort study of 320 adults attending the radiology department between October 2021 and January 2022. Bilateral kidney ultrasound was performed on all participants using a portable Mindray DP-50 machine and a 5MHz convex probe. The sample was stratified by age, sex, and HIV status. Predictive linear modelling was used to construct reference ranges for kidney size estimating the central 95 percentiles of 252 healthy adults. Exclusion criteria for the healthy sample were known kidney disease, hypertension, diabetes, BMI > 35, heavy alcohol intake, smoking and ultrasonographic abnormalities. Results: There were 162/320 (51%) male participants. The median age was 47 (interquartile range [IQR] 34-59). Among people living with HIV 134/138 (97%) were receiving antiretroviral therapy. Men had larger average kidney sizes: mean 9.68 cm (SD 0.80 cm), compared to 9.46 cm (SD 0.87 cm) in women ( p = 0.01). Average kidney sizes in people living with HIV were not significantly different from those who were HIV-negative, 9.73 cm (SD 0.93 cm) versus 9.58 cm (SD 0.93 cm) ( p = 0.63). Conclusions: This is the first report of the apparently healthy kidney size in Malawi. Predicted kidney size ranges may be used for reference in the clinical assessment of kidney disease in Malawi.

Ultrasound appearance of the kidney among radiology department attendees of a tertiary centre in Malawi

Background: Diagnostic and therapeutic decisions in nephrology in low-resource settings are frequently based on ultrasound assessment of kidney size. An understanding of reference values is critical, particularly given the rise of non-communicable disease and the expanding availability of point-of-care ultrasound. However, there is a paucity of normative data from sub-Saharan Africa (SSA). We determined estimates of kidney ultrasound measures, including kidney size based on age, sex, and HIV status, among apparently healthy outpatient attendees of Queen Elizabeth Central hospital radiology department, Blantyre, Malawi. Methods: We performed a cross-sectional cohort study of 320 adults attending the radiology department between October 2021 and January 2022. Bilateral kidney ultrasound was performed on all participants using a portable Mindray DP-50 machine and a 5MHz convex probe. The sample was stratified by age, sex, and HIV status. Predictive linear modelling was used to construct reference ranges for kidney size estimating the central 95 percentiles of 252 healthy adults. Exclusion criteria for the healthy sample were known kidney disease, hypertension, diabetes, BMI > 35, heavy alcohol intake, smoking and ultrasonographic abnormalities. Results: There were 162/320 (51%) male participants. The median age was 47 (interquartile range [IQR] 34-59). Of those whose HIV status was known and positive, 138/308 (45%), 134/138 (97%) were receiving antiretroviral therapy. Men had larger average kidney sizes: mean 9.68 cm (SD 0.80 cm), compared to 9.46 cm (SD 0.87 cm) in women ( p = 0.01). Average kidney sizes in HIV-positive participants were not significantly different from those who were HIV-negative, 9.73 cm (SD 0.93 cm) versus 9.58 cm (SD 0.93 cm) ( p = 0.63). Conclusions: This is the first report of the apparently healthy kidney size in Malawi. Predicted kidney size ranges may be used for reference in the clinical assessment of kidney disease in Malawi.

Ultrasound Renal Score to Predict the Renal Disease Prognosis in Patients with Diabetic Kidney Disease: An Investigative Study

Renal disease associated with type 2 diabetes mellitus (T2DM) has become the leading cause of chronic kidney disease (CKD). Renal ultrasonography is an imaging examination required in the work-up of renal disease. This study aimed to identify the differences in renal ultrasonographic findings between patients with and without DM, and to evaluate the relationship between renal ultrasound findings and renal prognosis in patients with DM. A total of 252 patients who underwent renal ultrasonography at Chungnam National University Hospital were included. Kidney disease progression was defined as a ≥10% decline in the annual estimated glomerular filtration rate (eGFR), which, in this paper, is referred to as ΔeGFR/year, or the initiation of renal replacement therapy after follow-up. The renal scoring system was evaluated by summing up the following items: the value of renal parenchymal echogenicity (0: normal; 1: mildly increased; and 2: increased) and the shape of the cortical margin (0: normal and 1: irregular; right kidney length/height (RH-0 or 1), mean cortical thickness/renal length/height (CKH-0 or 1), and cortical thickness/parenchymal thickness (CK/PK-0 or 1) based on the median: 0-above median, and 1-below median). Patients with DM had thicker renal PKH than those without, despite having lower eGFRs (0.91 ± 0.15, 0.86 ± 0.14, p = 0.006). In the progression group, the renal scores were significantly higher than those from the non-progression group. In the multivariate logistic regression analysis, the higher renal scores, presence of DM, and younger age were independently predicted for renal disease progression after adjusting for confounding variables, such as the presence of hypertension, serum hemoglobin and albumin levels, and UPCR. In conclusion, patients with high renal scores were significantly associated with renal disease progression. Our results suggest that renal ultrasonography at the time of diagnosis provides useful prognostic information in patients with kidney disease.

Neuroimmunoendocrine Link Between Chronic Kidney Disease and Olfactory Deficits

Chronic kidney disease (CKD) is a multifactorial pathology that progressively leads to the deterioration of metabolic functions and results from deficient glomerular filtration and electrolyte imbalance. Its economic impact on public health is challenging. Mexico has a high prevalence of CKD that is strongly associated with some of the most common metabolic disorders like diabetes and hypertension. The gradual loss of kidney functions provokes an inflammatory state and endocrine alterations affecting several systems. High serum levels of prolactin have been associated with CKD progression, inflammation, and olfactory function. Also, the nutritional status is altered due to impaired renal function. The decrease in calorie and protein intake is often accompanied by malnutrition, which can be severe at advanced stages of the disease. Nutrition and olfactory functioning are closely interconnected, and CKD patients often complain of olfactory deficits, which ultimately can lead to deficient food intake. CKD patients present a wide range of deficits in olfaction like odor discrimination, identification, and detection threshold. The chronic inflammatory status in CKD damages the olfactory epithelium leading to deficiencies in the chemical detection of odor molecules. Additionally, the decline in cognitive functioning impairs the capacity of odor differentiation. It is not clear whether peritoneal dialysis and hemodialysis improve the olfactory deficits, but renal transplants have a strong positive effect. In the present review, we discuss whether the olfactory deficiencies caused by CKD are the result of the induced inflammatory state, the hyperprolactinemia, or a combination of both.

Sex Differences in Renal Function: Participation of Gonadal Hormones and Prolactin

Kidney pathophysiology is influenced by gender. Evidence suggests that kidney damage is more severe in males than in females and that sexual hormones contribute to this. Elevated prolactin concentration is common in renal impairment patients and is associated with an unfavorable prognosis. However, PRL is involved in the osmoregulatory process and promotes endothelial proliferation, dilatation, and permeability in blood vessels. Several proteinases cleavage its structure, forming vasoinhibins. These fragments have antagonistic PRL effects on endothelium and might be associated with renal endothelial dysfunction, but its role in the kidneys has not been enough investigated. Therefore, the purpose of this review is to describe the influence of sexual dimorphism and gonadal hormones on kidney damage, emphasizing the role of the hormone prolactin and its cleavage products, the vasoinhibins.

Low agreement between kidney volume and kidney length z-scores

BACKGROUND

Pediatric nephrologists use kidney length and kidney volume z-scores to longitudinally assess normal nephron endowment. However, most radiologists only report kidney length. Agreement between kidney length and kidney volume z-scores in children has been understudied. This study aims to assess agreement between kidney length and kidney volume z-scores in children.

METHODS

This novel cross-sectional cohort study prospectively followed prematurely born babies from a large specialized prematurity follow-up center. A healthy control group matched the cases by age and sex and was recruited from schools. Children were assessed for kidney length and kidney volumes at age 5 by three independent ultrasonographers. All measurements were performed in triplicate. Detailed anthropometry, blood pressure, and kidney function were also obtained. Age-independent z-scores were calculated for all parameters according to Scholbach and Weitzel and compared using descriptive statistics.

RESULTS

We studied 89 premature patients (median 32 weeks gestational age) and 33 healthy controls (median 38 weeks gestational age). There were 732 determinations of kidney length, width, and thickness. The mean z-score of the right kidney length was 0.65 ± 0.08 (SEM) compared with 0.88 ± 0.08 of the left kidney length (p = 0.0003, two-sided paired t test). The squared correlation coefficient for kidney volume to kidney length was 0.32 (p < 0.0001). Bland and Altman analysis revealed considerable bias with - 1.36 ± 0.76 standard deviations and 95% limits of agreement from - 2.83 to - 0.16.

CONCLUSION

Reporting only kidney length results in significant overestimation of age-independent z-scores. Based on our findings, consideration to measuring all kidney dimensions may be more appropriate.

Sex- and Gender-Based Pharmacological Response to Drugs

In humans, the combination of all sex-specific genetic, epigenetic, and hormonal influences of biologic sex produces different in vivo environments for male and female cells. We dissect how these influences of sex modify the pharmacokinetics and pharmacodynamics of multiple drugs and provide examples for common drugs acting on specific organ systems. We also discuss how gender of physicians and patients may influence the therapeutic response to drugs. We aim to highlight sex as a genetic modifier of the pharmacological response to drugs, which should be considered as a necessary step toward precision medicine that will benefit men and women. SIGNIFICANCE STATEMENT: This study discusses the influences of biologic sex on the pharmacokinetics and pharmacodynamics of drugs and provides examples for common drugs acting on specific organ systems. This study also discusses how gender of physicians and patients influence the therapeutic response to drugs.

Point-of-Care Ultrasound in Acute Care Nephrology

The use of point-of-care ultrasound (POCUS) is rapidly increasing in nephrology. It provides the opportunity to obtain complementary information that is more accurate than the classic physical examination. One can quickly follow the physical examination with a systematic POCUS evaluation of the kidneys, ureter bladder, inferior vena cava, heart, and lungs, which can provide diagnostic information and an accurate assessment of the patient's hemodynamics and volume status. Moreover, because it is safe and relatively easy to perform, it can be performed in a repeated manner as often as necessary so that the physician can reassess the patient's hemodynamics and volume status and adjust their therapy accordingly, permitting a more personalized approach to patient care (rather than blindly following protocols), especially to patients in acute care nephrology. Despite these advantages, nephrologists have been slow to adopt this diagnostic modality, perhaps because of lack of expertise. This review will provide an overview of the most commonly used POCUS examinations performed by nephrologists in the acute care setting. Its aim is to spark interest in in POCUS and to lay the foundation for readers to pursue more advanced training so that POCUS becomes a readily available tool in your diagnostic arsenal.

A Comparability of Renal Length and Volume Measurements in MRI and Ultrasound in Children

Introduction: Despite the significant increase in use of magnetic resonance imaging (MRI) in children, there is still a lack of normal reference values of renal size in this method and reference values are being interpolated from the ultrasound (US) studies. The study provides comparative analysis of agreement in renal length and volume measurements between MRI and ultrasound. Materials and Methods: Ninety-three children with a mean age of 8.0 ± 6.0 years, who had undergone both renal US and MRI exams, were included in the study. Participants were divided into three subgroups; each kidney was considered separately. Group 1 included 106 kidneys without any anomalies. Group 2 comprised 48 kidneys with a dilated collecting system. Group 3 included 32 kidneys with a duplicated collecting system. Measurements were taken in three dimensions, and renal volume was calculated from the ellipsoid formula. Results: We found no significant difference between US and MRI measurements in Group 1 and Group 2. In Group 3, the difference between measurements in both imaging methods was significant. The mean difference varied from 0.05% in Group 1, 2.95% in Group 2, to 4.99% in Group 3. Conclusion: The US and MRI are comparable methods in renal size measurements. The interpolation of sonographic renal length and volume reference values to the MRI in the pediatric population is justified, as there is a strong agreement between both methods. Both methods can be used interchangeably for following up of the renal size changes in the pediatric population.

Reference indices for evaluating kidney dimensions in children using anthropometric measurements

Background

Kidney pathologies often result in change in renal size. Knowledge of normal kidney sizes is important for screening, diagnosis, prognosis and follow-up management of paediatric renal diseases.

Objectives

The aim of this study was to establish the age-, height- and weight-matched kidney dimensions in apparently healthy Nigerian children.

Method

A descriptive, cross-sectional study of right and left kidney parameters (length, width, thickness and volume) of 1315 school-aged Nigerian children was conducted over 8 months. Ages ranged from 5 to 17 years. Parameters were obtained using a General Electric (GE) LOGIC 400CL ultrasound machine. Kidney dimensions were correlated with age, sex and anthropometric measurements.

Results

Normative values for all the kidney parameters for each age, height and weight groups and also gender were established for the study population. The left kidneys were noted to be longer and thicker, and of more volume than the right kidneys. The right kidneys were seen to be wider (p < 0.01). Length of the left kidneys in females was noted to be more than those of the males in the age- and weight-matched categories (p < 0.05). The width of both kidneys was higher in the males in all the categories (p < 0.05). Males showed higher values of thickness and volume in the height category. All the renal parameters significantly correlated with body size indicators, except for body mass index.

Conclusion

This study has established gender-, age-, weight- and height-specific range of values of the kidney parameters of apparently healthy children together with regression models.

Reference values and sex differences in absolute and relative kidney size. A Swiss autopsy study

Background

Men have larger kidneys than women, but it is unclear whether gender remains an independent predictor of kidney size (expressed as weight or length) after correction for body size. We analysed autopsy data to assess whether relative renal length and weight (e.g. corrected for body weight, height or body surface area (BSA)) are also larger in men. Assuming that kidney size is associated with nephron number, opposite findings could partly explain why women are less prone to the development and progression of chronic kidney disease than men.

Methods

All forensic autopsies performed between 2009 and 2015 at the local university hospital of Geneva in individuals of European descent aged ≥18 years without a known history of diabetes and/or kidney disease were examined. Individuals with putrefied or severely injured bodies were excluded. Relative renal weight and length were respectively defined as renal weight divided by body weight or BSA and renal length divided by body height or BSA.

Results

A total of 635 autopsies (68.7% men) were included in the analysis. Left kidneys were on average 8 g heavier and 2 mm longer than right kidneys (both: p < 0.05). Absolute renal weight (165 ± 40 vs 122 ± 29 g) and length (12.0 ± 1.3 vs 11.4 ± 1.1 cm) were higher in men. Relative renal weight was also higher in men, but relative renal length was larger in women. In multivariable regression analysis, body height, body weight, the degree of blood congestion or depletion at autopsy and age were determinants of renal weight, whereas arterial hypertension and smoking were not. Percentile curves of renal weight and length according to sex and body height were constructed.

Conclusion

Absolute and relative renal weights were both smaller in women. This is in line with recent studies stating that nephron numbers are also lower in women. Relative renal length was longer in women, suggesting that female kidneys have a more elongated shape. In comparison with older autopsy studies, renal weight appears to be stable over time.

Sonographically determined kidney measurements are better able to predict histological changes and a low CKD-EPI eGFR when weighted towards cortical echogenicity

BACKGROUND

The renal length and cortical echogenicity have shown correlation to the renal function and histological changes in CKD patients. The aim of this study was to assess the accuracy of crude and composite ultrasound parameters based on kidney measurements and cortical echogenicity to detect renal dysfunction and histological changes.

METHODS

Kidney sonography and biopsy were performed in 112 patients. Histological changes were graded in 0, < 25%, ≥25%, ≤50 and > 50% of the sample. Cortical echogenicity was graded relative to liver or spleen parenchyma: less than, equal to and higher than the liver/spleen. Kidney length, the kidney length/body height ratio (KL/H) and cortical thickness were obtained. Each parameter was multiplied by a cortical echogenicity-weighting arbitrary factor: 1.17, 1 or 0.69 for cortex less than, equal to or higher than the liver, respectively. The GFR was estimated using the CKD-EPI formula. The accuracy of crude and composite parameters to identify patients with a high creatinine, a low GFR and histological changes were evaluated.

RESULTS

The discriminative power of kidney length and cortical thickness for renal dysfunction and histological changes was improved after weighting for cortical echogenicity. However, the best discriminative was the kidney length to height ratio weighted towards renal echogenicity (w-KL/H).

CONCLUSION

w-KL/H exceeded the other parameters as a marker of renal impairment and histological changes in CKD. Calculation of the w-KL/H index may be of help as a non-invasive tool to identify patients with significant renal disease and might be useful to guide therapeutic decisions.

Is There a Gender Difference in Clinical Presentation of Renal Hyperparathyroidism and Outcome after Parathyroidectomy?

Introduction

Gender has been proven to influence the pathophysiology and treatment of numerous diseases, including kidney diseases and hormonal dysfunction like hyperparathyroidism. Thus, higher parathormone levels have been demonstrated in women with end-stage kidney disease, when compared to men.

Objectives

We questioned whether female gender is associated with an increased risk for parathyroid nodular hyperplasia and necessary parathyroidectomy in dialysis patients and assessed demographics as well as outcome data for women and men undergoing parathyroidectomy for renal hyperparathyroidism.

Patients and Methods

One hundred and thirty patients (men = 75, female = 55) with end-stage renal disease on chronic dialysis and advanced secondary hyperparathyroidism who underwent parathyroidectomy between 2008 and 2014 at our center were analyzed retrospectively. Perioperative characteristics and short-term outcome were evaluated with respect to biological gender.

Results

No differences could be demonstrated for patient demography, comorbidities and the perioperative course between males and females. Only preoperative calcium levels were lower in female than in male patients (2.3 ± 0.19 vs. 2.3 ± 0.26, p = 0.04). There were more women, however, with cerebrovascular complications during follow-up (p = 0.04). There was no postoperative mortality, and all complications and comorbidities with exception of cerebrovascular diseases were equally distributed between female and male patients.

Conclusion

Overall, we could not demonstrate many significant differences between male and female patients with end-stage renal diseases, chronic dialysis and operated secondary hyperparathyroidism. Only preoperative electrolyte levels were higher in male than in female patients, and cerebrovascular complications developed more often in females than in males during long-term follow-up.

Ultrasound Assessment of Acute Kidney Injury

Ultrasound assessment of the kidneys in patients with renal impairment has been described in various ways in the critical care, nephrology, and radiology literature, resulting in a somewhat heterogeneous picture of the gray-scale and Doppler ultrasound manifestation of acute kidney injury (AKI). Given that ultrasound assessment can potentially identify reversible causes of AKI or identify underlying chronic kidney disease, it is important for radiologists to be aware of the common etiologies of AKI and the spectrum of ultrasound findings. We review the definition and etiologies of renal injury and introduce the ultrasound SERVeillance framework-assessment of renal size, echogenicity, renal hilum, and vascularity-for the imaging assessment of AKI.

How reliable is renal ultrasound to measure renal length and volume in patients with chronic kidney disease compared with magnetic resonance imaging?

Background

Renal length, volume, and parenchymal thickness are important clinical parameters, yet data concerning the accuracy and reproducibility of ultrasound (US)-based renal length and volume assessment in patients with chronic kidney disease (CKD) are scarce.

Purpose

To establish whether renal length, volume, and parenchymal thickness can be reliably measured with renal US in patients with CKD.

Material and Methods

All participants underwent renal US, immediately followed by 3-T magnetic resonance imaging (MRI). Renal length, width, transverse diameter, and parenchyma thickness were measured with both methods; renal volume was calculated using the ellipsoid formula. A total of 45 patients with CKD (eGFR [mean ± SD] 57.4 ± 4.4 mL/min/1.73 m2) and 46 participants without CKD (eGFR 97.0 ± 2.4 mL/min/1.73 m2) were included.

Results

US-measured renal length correlated strongly with MRI-measured renal length in no-CKD patients (Spearman’s r = 0.83 and 0.85 for the right and left kidney, respectively; P < 0.005) and CKD patients (r = 0.89 and 0.92 for the right and left kidney, respectively; P < 0.005). There was a significant but weaker correlation between MRI- and US-measured right and left renal volume (r = 0.72, P < 0.005) in no-CKD (r = 0.74 and r = 0.72, respectively; for both: P < 0.005) and CKD patients (r = 0.83 and 0.85, P < 0.005). Weak to moderate correlations were found for parenchyma thickness for the right (CKD group: r = 0.29, no-CKD: r = 0.23; for both: P < 0.05) and left kidney (CKD: r = 0.52, no-CKD group: r = 0.37, P < 0.05). Both intra-observer (Pearson’s correlations of 0.82 for the right and 0.89 for the left kidney) and inter-observer (Lin’s correlation coefficient of 0.90 for the right and 0.82 for the left kidney) reproducibility of US-assessed renal length was high.

Conclusions

US-based assessment of renal length in CKD patients is comparable to MRI measures. Both intra- and inter-observer reproducibility of US-assessed renal length in CKD patients are high. Measurements of US renal volume and parenchymal thickness should, however, be interpreted with caution.

Higher NAFLD fibrosis score is associated with impaired eGFR

BACKGROUND/PURPOSE

Chronic kidney disease (CKD) has become a worldwide health problem, leading to high morbidity and mortality, and non-alcoholic fatty liver disease (NAFLD) is considered a risk factor for CKD. The aim of this study was to explore the relationship between NAFLD fibrosis score (NFS) and the estimated glomerular filtration rate (eGFR), and identify possible risk factors related to the NFS among Taiwanese subjects.

METHODS

Subjects were enrolled from the database of the Department of Preventive Medicine of Kaohsiung Municipal Hsiao-Kang Hospital. The eGFR was calculated according to the Taiwanese Modification of Diet in Renal Disease (TMDRD) equation, and the NFS was employed to evaluate the fibrotic level.

RESULTS

In total, 11,376 subjects were enrolled in this study, with a mean age of 52.0 ± 6.81 years, including 4529 (39.8%) males. A fasting sugar level ≥100 mg/dL (OR = 1.70, 95% CI = 1.52-1.87) and an abnormal waist circumference (OR = 1.81, 95% CI = 1.65-1.99) were significant factors associated with NFS (p < 0.05). Trends of a decreasing TMDRD score and an increasing NFS with increasing age were noted (p < 0.05). The NFS was significantly negatively correlated with the TMDRD score (standard coefficients: -0.067, p < 0.001).

CONCLUSION

A higher NFS is associated with an impaired eGFR in Taiwanese subjects. Controlling risk factors, especially fasting sugar level and waist circumference, may be useful in preventing NFS deterioration, which is negatively correlated with the eGFR.

Reference ranges for ultrasonographic renal dimensions as functions of age and body indices: A retrospective observational study in Taiwan

An ethnicity-based reference range for normal renal size is fundamental for ultrasonographic assessment. Herein, we aimed to establish a Chinese renal reference by a large sample size, as well as to elucidate the relationship of renal dimension to age and body indices, with the aid of a comprehensive literature review. Records of 3707 healthy cases were obtained from health evaluation centers of Kaohsiung and Linkuo Chang Gung Memorial Hospitals. As a result, the mean right renal length was 10.62±0.69 cm, left renal length 10.76±0.70 cm, right renal width 4.78±0.75 cm, and left renal width 5.10±0.64 cm. Renal size was well-correlated curvilinearly to age, while linearly to body height, body weight, and body mass index. Renal size increases and then decreases with aging, and significant variations of renal size exist among different ethnicities. Our work provides a reliable reference range for renal size in the Chinese population, and valid relationships between renal dimensions and other parameters.

Renal artery involvement in acute aortic dissection: Prevalence and impact on renal atrophy in non-interventional treatment patients

BACKGROUND

To evaluate the frequency of renal artery dissection (RAD) and renal hypoperfusion in aortic dissection (AD) and its effect on subsequent renal atrophy in patients who did not undergo therapeutic intervention.

METHODS

Initial CT data of 155 patients with acute AD (Stanford type A = 88, B = 67) were retrospectively analyzed. The false lumen statuses were patent (n = 94), partially thrombosed (n = 25), and completely thrombosed (n = 36) (also called as intramural hematoma (IMH)). Follow-up CT images of the surviving 122 patients (6-62.6 months, median, 28.9 months) were reviewed for analysis of sequential changes in renal volume. A regional decrease of ≧20 Hounsfield units in the renal cortex was defined as a renal hypo-enhancement sign (RHS). Simplified CT estimations of renal volume and estimated glomerular filtration rates (eGFR) were calculated. The generalized estimating equations (GEE) method was used to predict renal atrophy.

RESULTS

Fifty of the 122 patients presented with 59 RAD in the current study, and a positive RHS was noted in 33.9% (20/59) of these involved kidneys. GEE analysis showed hypertension, surgical treatment for AD, presence of RAD, and positive RHS as significant risk factors for renal atrophy. Patients with RHS had the most severe form of renal atrophy. The severity of renal atrophy was mildly correlated with GFR change (γ2 = 0.044, p < 0.001).

CONCLUSION

Renal atrophy in AD was predicted by the CT findings of RAD and RHS. The severity of renal atrophy was weakly reflected by eGFR.

Renal ultrasound and Doppler parameters as markers of renal function and histopathological damage in children with chronic kidney disease

AIM

Doppler ultrasonography can be used to assess the progression of vascular (arterial sclerosis) and parenchymal (glomerular sclerosis and crescents) renal damage. The aim of this study was to evaluate the significance of some sonographic and Doppler parameters as non-invasive markers of glomerular filtration rate (GFR) and renal histopathological damage in children.

METHODS

A cohort of 84 children were enrolled in a case-control study (42 with CKD stages 2-5 and 42 healthy children). GFR was assessed using new improved equation using serum creatinine and cystatin C. Sonar guided renal specimen was obtained and evaluated for the severity of global sclerosis (GS), segmental sclerosis (SS), tubular atrophy (TA), interstitial fibrosis (IF), arterial sclerosis (AS) and arteriolar hyalinosis (AH). The following sonographic and Doppler parameters were assessed in both patients and control group: resistivity index (RI), pulsatility index (PI), atrophic index (AI), mean renal volume, mean renal density, time average velocity (TAV) and body surface area related volume perfusion (BSARVP).

RESULTS

There was significant difference in renal density (P < 0.001), RI (P < 0.001), PI (P = 0.021), TAV (P < 0.001) and BSARVP (P < 0.001) between patients and control group. The cutoff value of RI was 63.5% (sensitivity 83% and specificity 64%). Multivariate analysis revealed that renal density and RI were significant predictors of worsening of estimated GFR (eGFR) in CKD patients.

CONCLUSION

Any increase in the RI and PI values must arouse alarm to the possibility of advancing renal damage. Moreover, RI and PI could fairly predict the degree of glomerular sclerosis and interstitial fibrosis.

Sex and gender differences in chronic kidney disease: progression to end-stage renal disease and haemodialysis

Sex and gender differences are of fundamental importance in most diseases, including chronic kidney disease (CKD). Men and women with CKD differ with regard to the underlying pathophysiology of the disease and its complications, present different symptoms and signs, respond differently to therapy and tolerate/cope with the disease differently. Yet an approach using gender in the prevention and treatment of CKD, implementation of clinical practice guidelines and in research has been largely neglected. The present review highlights some sex- and gender-specific evidence in the field of CKD, starting with a critical appraisal of the lack of inclusion of women in randomized clinical trials in nephrology, and thereafter revisits sex/gender differences in kidney pathophysiology, kidney disease progression, outcomes and management of haemodialysis care. In each case we critically consider whether apparent discrepancies are likely to be explained by biological or psycho-socioeconomic factors. In some cases (a few), these findings have resulted in the discovery of disease pathways and/or therapeutic opportunities for improvement. In most cases, they have been reported as merely anecdotal findings. The aim of the present review is to expose some of the stimulating hypotheses arising from these observations as a preamble for stricter approaches using gender for the prevention and treatment of CKD and its complications.

Relation between Kidney Length and Cardiovascular and Renal Risk in High-Risk Patients

BACKGROUND AND OBJECTIVES

Kidney length is often measured during routine abdominal ultrasonography and may be of use to identify patients at high vascular and renal risk. We aimed to explore patient characteristics related to kidney length, from which reference values were derived, and evaluate the relationship between kidney length and the risk of cardiovascular events and ESRD in high-risk patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The study population consisted of 10,251 patients with clinical manifest arterial disease or vascular risk factors included in the Second Manifestations of ARTerial disease (SMART) Study cohort between 1996 and 2014. Linear regression was used to explore patient characteristics of kidney length. The relationship between kidney length and cardiovascular events (myocardial infarction, stroke, and cardiovascular mortality), all-cause mortality, and ESRD was analyzed using Cox regression. Kidney length was analyzed in tertiles, using the second tertile as the reference category.

RESULTS

Kidney length was strongly correlated with body surface area (2.04 mm; 95% confidence interval [95% CI], 1.95 to 2.13 per 0.1 m2 increase) and eGFR (1.62 mm; 95% CI, 1.52 to 1.73 per 10 ml/min per 1.73 m2 increase). During the median follow-up of 6.3 years, 1317 patients experienced a cardiovascular event, including 711 myocardial infarctions, 369 strokes, and 735 vascular cause deaths. A total of 1462 patients died of any cause and 52 patients developed ESRD. Irrespective of eGFR, patients in the third tertile of kidney length (11.7-16.1 cm) were at higher risk of cardiovascular mortality (hazard ratio, 1.33; 95% CI, 1.05 to 1.67) and cardiovascular events (hazard ratio, 1.28; 95% CI, 1.09 to 1.50). Patients in the first tertile of kidney length (7.8-10.8 cm) were not at higher risk of cardiovascular adverse events.

CONCLUSIONS

Large kidney length is related to higher risk of cardiovascular events and mortality in high-risk patients, irrespective of eGFR. Kidney length may serve as a clinical marker to further identify patients at high cardiovascular risk.

Role of ultrasonographic chronic kidney disease score in the assessment of chronic kidney disease

PURPOSE

Ultrasonography (US) is an inexpensive, noninvasive and easy imaging procedure to comment on the kidney disease. Data are limited about the relation between estimated glomerular filtration rate (e-GFR) and all 3 renal US parameters, including kidney length, parenchymal thickness and parenchymal echogenicity, in chronic kidney disease (CKD). In this study, we aimed to investigate the association between e-GFR and ultrasonographic CKD score calculated via these ultrasonographic parameters.

METHODS

One hundred and twenty patients with stage 1-5 CKD were enrolled in this study. The glomerular filtration rate was estimated by the Chronic Kidney Disease Epidemiology Collaboration equation. US was performed by the same radiologist who was blinded to patients' histories and laboratory results. US parameters including kidney length, parenchymal thickness and parenchymal echogenicity were obtained from both kidneys. All 3 parameters were scored for each kidney, separately. The sum of the average scores of these parameters was used to calculate ultrasonographic CKD score.

RESULTS

The mean age of patients was 63.34 ± 14.19 years. Mean kidney length, parenchymal thickness, ultrasonographic CKD score and median parenchymal echogenicity were found as 96.2 ± 12.3, 10.97 ± 2.59 mm, 6.28 ± 2.52 and 1.0 (0-3.5), respectively. e-GFR was positively correlated with kidney length (r = 0.343, p < 0.001), parenchymal thickness (r = 0.37, p < 0.001) and negatively correlated with CKD score (r = -0.587, p < 0.001) and parenchymal echogenicity (r = -0.683, p < 0.001). Receiver operating characteristic curve analysis for distinction of e-GFR lower than 60 mL/min showed that the ultrasonographic CKD score higher than 4.75 was the best parameter with the sensitivity of 81% and positive predictivity of 92% (AUC, 0.829; 95% CI, 0.74-0.92; p < 0.001).

CONCLUSION

We found correlation between e-GFR and ultrasonographic CKD score via using all ultrasonographic parameters. Also, our study showed that ultrasonographic CKD score can be useful for distinction of CKD stage 3-5 from stage 1 and 2. We suggested that the ultrasonographic CKD score provided more objective data in the assessment of CKD.

Variations in renal morphometry: A hospital-based Indian study

Introduction:

The currently available standard renal nomograms for comparison of renal dimensions in India are based on the measurements made in the Western population. The objectives of our study were to identify variations in renal morphometric parameters in subjects with no known renal disease in a hospital-based Indian population and to find out any correlation between renal volumes with split renal functions and body mass index (BMI).

Materials and Methods:

One hundred and fifty-one subjects undergoing contrast-enhanced computerized tomography (CT) scan for various purposes, including donor nephrectomy, from June 2012 to August 2014 were included in the study. The renal and ureteral dimensions were assessed from the contrast-enhanced CT scan images of these patients.

Results:

The mean length, width, thickness and volume of the left kidney were 11.02 ± 1.13 cm, 5.21 ± 0.75 cm, 4.65 ± 0.84 cm and 138.22 ± 29.81 mL, respectively, and those for the right kidney were 10.86 ± 1.12 cm, 5.13 ± 0.77 cm, 4.73 ± 0.95 cm and 137.54 ± 34.48 mL, respectively. The mean length of the left ureter was 23.51 ± 1.48 cm and that of the right ureter was 23.24 ± 1.93 cm. The mean volume of the kidneys in males and females was also different. The volume of the kidney did not statically correlate with the split glomerular filtration rate ((P = 0.12) and BMI (P = 0.52)).

Conclusions:

Our study revealed that there exist differences in various morphometric parameters of the kidney and ureter in different subsets of the Indian population attending our hospital as compared with the standard values quoted in the world literature.

Sonographic measurement of renal size in patients undergoing chronic hemodialysis: Correlation with residual renal function

Previous studies have reported that renal size may change when the function is compromised. However, it is not known whether sonographically measured renal size reflects the residual renal function (RRF) in patients undergoing chronic hemodialysis. A total of 140 patients undergoing chronic hemodialysis (≥3 months) were investigated in the present study. The patients were divided into two groups according to the daily urine volume: Individuals with RRF (RRF+ group; ≥200 ml; n=65) and without RRF (RRF− group; <200 ml; n=75). Renal sizes were measured using sonography and renal volumes were calculated with the ellipsoid formula. Univariable and multivariable stepwise forward logistic regression analyses were performed to examine the correlation between the presence of RRF and various variables. The results indicated that there were statistically significant differences (P<0.001) between the RRF+ and RRF− groups with regard to renal length, width, thickness and volume of the left (length, 7.9±1.2 vs. 6.8±1.2 cm; volume, 60.0±26.7 vs. 40.2±18.1 ml, respectively) and right (length, 7.6±1.2 vs. 6.7±1.2 cm; volume, 50.2±26.5 vs. 33.9±15.3 ml, respectively) sides of the kidney. Multivariable stepwise forward logistic regression analyses showed that the mean renal length or volume and hemodialysis duration were independent predictors of the presence of RRF. Therefore, renal size assessment by ultrasonography may be useful for RRF evaluation in patients undergoing chronic hemodialysis.

Estimating glomerular filtration rate in older people

We aimed at reviewing age-related changes in kidney structure and function, methods for estimating kidney function, and impact of reduced kidney function on geriatric outcomes, as well as the reliability and applicability of equations for estimating glomerular filtration rate (eGFR) in older patients. CKD is associated with different comorbidities and adverse outcomes such as disability and premature death in older populations. Creatinine clearance and other methods for estimating kidney function are not easy to apply in older subjects. Thus, an accurate and reliable method for calculating eGFR would be highly desirable for early detection and management of CKD in this vulnerable population. Equations based on serum creatinine, age, race, and gender have been widely used. However, these equations have their own limitations, and no equation seems better than the other ones in older people. New equations specifically developed for use in older populations, especially those based on serum cystatin C, hold promises. However, further studies are needed to definitely accept them as the reference method to estimate kidney function in older patients in the clinical setting.

Clinicopathological assessment of the nephron number

Recent studies have demonstrated much larger variability in the total number of nephrons in normal populations than previously suspected. In addition, it has been suggested that individuals with a low nephron number may have an increased lifetime risk of hypertension or renal insufficiency, emphasizing the importance of evaluating the nephron number in each individual. In view of the fact that all previous reports of the nephron number were based on analyses of autopsy kidneys, the identification of surrogate markers detectable in living subjects is needed in order to enhance understanding of the clinical significance of this parameter. In this review, we summarize the clinicopathological factors and findings indicating a reduction in the nephron number, focusing particularly on those found at the time of a preserved renal function.

Renal relevant radiology: radiologic imaging in autosomal dominant polycystic kidney disease

Autosomal-dominant polycystic kidney disease is a systemic disorder and the most common hereditary renal disease, which is characterized by cyst growth, progressive renal enlargement, and development of renal failure. The cystic nature of autosomal dominant polycystic kidney disease and its renal and extrarenal complications (kidney stones, cyst hemorrhage, intracerebral aneurysm, liver cysts, cardiac valve abnormalities, etc.) give radiologic imaging studies a central role in the management of these patients. This article reviews the indications, comparative use, and limitation of various imaging modalities (ultrasonography, magnetic resonance imaging, computerized tomography scan, Positron emission tomography scan, and renal scintigraphy) for the diagnosis and management of complications in autosomal dominant polycystic kidney disease. Finally, this work provides evidence for the value of total kidney volume to predict disease progression in autosomal dominant polycystic kidney disease.

Correlation of Doppler parameters with renal pathology: A study of 992 patients

Ultrasound examination is a non-invasive diagnostic technique that is used on patients with suspected or established renal disease. The purpose of this study was to determine the role of intrarenal Doppler ultrasonography in the assessment of the renal pathology of patients with chronic kidney disease (CKD), as shown by kidney biopsy. This retrospective analysis enrolled 992 consecutive patients with CKD who underwent intrarenal Doppler ultrasonography and a kidney biopsy at the Departments of Nephrology of three hospitals between January 2006 and December 2010. Doppler parameters, including the peak systolic velocity (PSV), end-diastolic velocity and resistive index (RI) of the interlobar arteries, were compared with the renal biopsy findings. The RI of the interlobar arteries was correlated with the estimated glomerular filtration rate and the histological damage scores, demonstrating the most evident correlation with the tubulointerstitial damage (TI) score among the three histological components. The PSV of the interlobar arteries increased as the CKD stage progressed and correlated with a number of the renal histological changes, including the glomerulosclerosis and TI scores. The RI and PSV of the interlobar artery are correlated with the histopathological pattern in CKD. Thus, the RI and PSV of the interlobar artery may be potential indicators for monitoring the progression of renal damage.

Renal relevant radiology: use of ultrasonography in patients with AKI

As judged by the American College of Radiology Appropriateness Criteria, renal Doppler ultrasonography is the most appropriate imaging test in the evaluation of AKI and has the highest level of recommendation. Unfortunately, nephrologists are rarely specifically trained in ultrasonography technique and interpretation, and important clinical information obtained from renal ultrasonography may not be appreciated. In this review, the strengths and limitations of grayscale ultrasonography in the evaluation of patients with AKI will be discussed with attention to its use for (1) assessment of intrinsic causes of AKI, (2) distinguishing acute from chronic kidney diseases, and (3) detection of obstruction. The use of Doppler imaging and the resistive index in patients with AKI will be reviewed with attention to its use for (1) predicting the development of AKI, (2) predicting the prognosis of AKI, and (3) distinguishing prerenal azotemia from intrinsic AKI. Finally, pediatric considerations in the use of ultrasonography in AKI will be reviewed.

Estimating renal function to reduce the risk of adverse drug reactions

The aging process is characterized by relevant changes in pharmacokinetics. Renal function is known to decline with aging. However, as a result of reduced muscle mass, older individuals frequently have a depressed glomerular filtration rate (GFR) despite normal serum creatinine, and such a concealed renal insufficiency may impact significantly on the clearance of hydrosoluble drugs, as well as the risk of adverse drug reactions (ADRs) from hydrosoluble drugs. The assessment of renal function should thus be a mandatory item in the global examination of patient characteristics. Equations for estimating GFR have become very popular in recent years. However, different equations may yield significantly different estimated glomerular filtration rate (eGFR) values, which have important implications in dosing drugs cleared by the kidney. Current knowledge suggests that eGFR based on the Chronic Kidney Disease-Epidemiological Collaboration (CKD-EPI) study equation outperformed eGFR based on the Modification of Diet in Renal Disease (MDRD) study equation and creatinine clearance estimate based on the Cockcroft-Gault formula as a predictor of ADRs from kidney cleared drugs. More recently, the combined creatinine-cystatin C equation was shown to perform better than equations based on either of these markers alone in diagnosing CKD, even in older patients. However, its accuracy in predicting ADRs and usefulness in drug dosing is still to be investigated.

Correlation of ultrasonographic parameters with serum creatinine in chronic kidney disease

OBJECTIVE

The purpose of our study is to correlate renal echogenicity with serum creatinine in order to determine the significance of renal echogenicity when it comes to identifying the progression of chronic kidney disease (CKD) and for the sonographic grading of CKD.

MATERIALS AND METHODS

Sixty patients above 30 years of age who had been diagnosed with CKD according to the guidelines of the National Kidney Foundation were included in the study. Patients on kidney replacement therapy or with fatty liver findings on ultrasonography were excluded. Ultrasounds of kidneys were performed by two radiologists who were blind to the patients' serum creatinine levels. Renal cortical echogenicity was compared with serum creatinine. Statistical analysis was performed using one-way ANOVA followed by Scheffe's test. The relationship between serum creatinine and sonographic features was assessed by correlation coefficient analysis. A P value less than 0.05 was considered statistically significant.

RESULTS

Mean serum creatinine was 2.80 mg/dl for Grade 1 (range: 0.9-9.2 mg/dl), 3.69 mg/dl for Grade 2 (range: 1.2-10.3 mg/dl), 3.86 mg/dl for Grade 3 (range: 1.1-6.5 mg/dl), and 7.90 mg/dl for Grade 4 (range: 3.1-11.4 mg/dl). The grades being determined by cortical echogenicity on imaging A statistically significant, positive correlation was observed between serum creatinine and grading based on cortical echogenicity (P = 0.004).

CONCLUSION

Renal echogenicity and its grading correlates better with serum creatinine in CKD than other sonographic parameters such as longitudinal size, parenchymal thickness, and cortical thickness. Hence, renal echogenicity is a better parameter than serum creatinine for estimating renal function in CKD, and has the added advantage of irreversibility.

Reference values for renal size obtained from MAG3 scintigraphy

PURPOSE

The purposes of this study were to establish reference values for renal size determined from 99mTc-MAG3 renal scintigraphy and to derive regression equations to predict normal limits.

METHODS

The study population consisted of 106 subjects evaluated for kidney donation who underwent 99mTc-MAG3 renal scintigraphy. Renal length, width, and area were determined from the pixel length and area of whole-kidney regions of interest and correlated with patient sex, height, weight, body mass index, and body surface area (BSA). Reference values were obtained based on estimation of the lower and upper percentiles via quantile regression.

RESULTS

The mean (SD) left and right kidney lengths was 12.2 (1.0) and 12.1 (1.0) in male and 11.9 (0.9) and 11.8 (0.9) in female patients, respectively. Sex was not a significant factor in the quantile regression models. Regression equations defining the lower and upper limits of renal length (cm) and area (cm) are as follows: left kidney length (5th percentile), 8.2+1.3×BSA; left kidney length (95th percentile), 9.1+2.3×BSA; right kidney length (5th percentile), 8.8+1.0×BSA; right kidney length (95th percentile), 11.1+1.4×BSA; left kidney area (5th percentile), 32.5+9.6×BSA; left kidney area (95th percentile), 12.6+31.7×BSA; right kidney area (5th percentile), 16.1+18.5×BSA; right kidney area (95th percentile), 32.6+22.2×BSA.

CONCLUSIONS

Regression equations have been developed, which define the upper and lower limits of renal size from 99mTc-MAG3 images and may assist in the detection of unsuspected bilateral increases or decreases in renal size.

The resistive index is a marker of renal function, pathology, prognosis, and responsiveness to steroid therapy in chronic kidney disease patients

To evaluate the significance of the renal resistive index (RI) as a noninvasive marker of renal histological damage and a prognostic indicator, we examined RI by Doppler ultrasonography in 202 chronic kidney disease (CKD) patients who underwent renal biopsy. RI increased as the CKD stage progressed and correlated with age, systolic blood pressure, estimated glomerular filtration rate (eGFR), and renal histological changes, including glomerulosclerosis, arteriolosclerosis, and tubulointerstitial damage. Prognostic evaluation with a median follow-up period of 38.5 months revealed that patients with RI ≥ 0.7 (high RI group, n = 39) had significantly poorer renal survival than those with RI < 0.65 (normal RI group, n = 120) and 0.65 ≤ RI < 0.7 (high-normal RI group, n = 43). The patients in the high-normal RI group showed good response to steroids. However, in the high RI group, steroid therapy did not significantly improve renal survival. Of the clinical indices studied, RI ≥ 0.7, hypertension, proteinuria, and low eGFR at diagnosis were independent risk factors for worsening renal dysfunction. In conclusion, RI in CKD patients was considered as a marker of renal function, histological damage, and renal prognosis, and a possible determinant of indication for steroids.

The morphometric development and arterial vascularization of bovine fetal kidneys in the prenatal period

This study presents a morphometric developmental analysis of bovine kidneys and a demonstration of intrarenal arterial vascularization in the prenatal period. A total of 40 Holstein bovine fetuses constituted the material of the study. The fetuses were divided into three groups, according to the gestational stages they belonged to early, mid- and late stages, such that each group comprised 10 fetuses. Sixty kidneys and their renal arteries were evaluated using morphometric measurements. Furthermore, 10 bovine fetuses were injected with cast solution to demonstrate the intrarenal arteries. Data obtained in the present study were statistically analyzed. Although the right and left kidneys did not significantly differ from each other, significant differences existed between the different gestational stages (P<0.05). The kidney parameters, including length, width and thickness, were positively correlated with both the right and left kidneys as well as with gestational age. Four types of intrarenal arterial segmentation were demonstrated. Type I was observed in 10 kidneys (50%), type II in four kidneys (20%) as well as type III, and type IV in only two kidneys (10%). In the most frequent arterial segmentation type (type I), the renal artery divided into three segmental arteries, which supplied the cranial polar, medial and caudal polar regions of the kidney, after stemming from the abdominal aorta. Furthermore, cases of double and multiple renal arteries were also observed.

Normal values for renal parenchymal volume and kidney length as measured by non-enhanced multidetector spiral computed tomography

BACKGROUND

Renal parenchymal volume (RPV) is considered an important index for clinical decisions. However, normal values have not been established, which hinders the clinical application of RPV.

PURPOSE

To test the accuracy and reproducibility of RPV and to investigate the normal values of RPV and kidney length as measured by non-enhanced multidetector computed tomography (CT).

MATERIAL AND METHODS

An animal model study was performed to test the accuracy and repeatability of RPV measured by CT. RPV of porcine kidneys was measured by water displacement (actual values) and non-enhanced multidetector CT. Individual RPV and kidney length were measured by non-enhanced CT in patients with no clinical history of renal disease (n = 722). Patient height, age, weight, body surface area (BSA), and body mass index (BMI) were assessed before each patient's CT examination was performed.

RESULTS

RPV obtained by the CT method was within 2% of the RPV determined by the water displacement method. The normal values of RPV (M ± 1.96 standard deviation [SD]) were 145.72 ± 54.37 mL for men and 132.46 ± 41.94 mL for women. The normal values of kidney length (M ± 1.96 SD) were 10.27 ± 1.98 cm for men and 9.93 ± 1.58 cm for women. RPV did not significantly correlate with BSA or weight in women, but correlated significantly with height and age in both men and women. Of the assessed factors age, weight, height, BSA, and BMI, age, and height were the independent factors that best reflected RPV, in both men and women.

CONCLUSION

The present animal study results showed that non-enhanced multidetector CT findings accurately reflect the RPV. The subsequent study performed in humans showed that the RPV of the presently sampled Chinese population was lower than the commonly quoted reference values obtained from Western populations.

Determinants and functional significance of renal parenchymal volume in adults

BACKGROUND AND OBJECTIVES

The significance of renal parenchymal volume and the factors that influence it are poorly understood.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Renal parenchymal volume (RPV) was measured on contrast-enhanced CT scans after exclusion of sinus fat and vessels in 224 healthy subjects evaluated as kidney donors and in a separate cohort of 22 severely obese individuals before and after 6 months of weight loss. GFR was measured by iohexol clearance in 76 of the transplant donors. RPV was correlated with age, GFR, and various anthropometric parameters.

RESULTS

In potential transplant donors, RPV correlated with body surface area (BSA; r = 0.68) and was 7% larger in men but did not vary with age or race. Gender and body size were independent determinants of RPV. RPV correlated well with GFR (r = 0.62) and accounted for almost all of the variability in a model of GFR that included age, race, gender, and body surface area. GFR correlated more strongly with RPV than with creatinine-based equations. The same relationship between RPV and BSA was observed in obesity, and RPV decreased with weight loss.

CONCLUSIONS

In healthy adults younger than 65 years, renal parenchymal volume is governed by body size and gender but not age or race and is strongly correlated with GFR. This indicates that renal parenchymal volume varies to meet metabolic demand and is closely linked to renal function.

Reduced kidney size in adult offspring of Balkan endemic nephropathy patients and controls: a prospective study

INTRODUCTION

Reduced kidney size has been proposed as a criterion for clinical diagnosis of Balkan endemic nephropathy (BEN). Some studies suggest that smaller kidneys are found in advanced stages of BEN, whereas others reported them in earlier stages. To investigate the clinical course of kidney sizes in the offspring of BEN and non-BEN parents, we followed up a cohort of adult offspring over 5 years. We hypothesized that parental history affects kidney dimensions.

METHODS

Four repeated ultrasound measurements of kidney length and cortex width were conducted in 121 offspring of BEN and 98 offspring of non-BEN parents. Repeated measurements were analyzed using mixed models adjusting for gender and time-dependent information on other kidney diseases, diabetes, age, height and year of follow-up.

RESULTS

A reduction of kidney length was associated with maternal BEN (-4 mm, P = 0.001). We detected a parallel decline in kidney length in the various offspring groups. However, kidney cortex width was significantly smaller when both parents or the mother had BEN and offspring age > or =60 years (-1.88 mm, P = 0.0003; -1.03 mm, P = 0.05). In the 5th year of follow-up, 37 participants developed BEN (14 confirmed, 23 suspected). Kidney cortex width at baseline was smaller in offspring who developed BEN (P = 0.0001).

CONCLUSIONS

The development of kidney dimensions depends on the parental BEN status and offspring age. In BEN offspring, ultrasound measurements of the kidney cortex width seem to have a prognostic value.

Relation between total renal volume and renal function: Usefulness of 3D sonographic measurements with a matrix array transducer

OBJECTIVE

The aims of this study were to evaluate the reproducibility of 3D sonography with a matrix array transducer as a means of measuring renal volume and to investigate correlations between renal volume and renal function.

SUBJECTS AND METHODS

One hundred twenty subjects (20 consecutively registered patients with one of the five stages of chronic renal disease and 20 healthy volunteers [stage 0 renal function]) were enrolled. Individual renal volume was determined by two independent observers using 2D sonographic and 3D matrix array transducer sonographic data. The reproducibility of volume measurement was evaluated for both of these methods. After total renal volume was normalized to body surface area, correlations between normalized total renal volume and estimated glomerular filtration rate (GFR) were evaluated. Differences in normalized total renal volume related to stage of renal function also were evaluated.

RESULTS

The reproducibility of 3D sonographic measurements obtained with a matrix array transducer was greater than that of 2D sonographic measurements. The correlation between normalized total renal volume obtained with matrix array transducer 3D sonography and estimated GFR for two observers (r = 0.809 and 0.813; p < 0.001) was better than that between normalized total renal volume obtained with 2D sonography and estimated GFR (r = 0.696 and 0.715; p < 0.001). The mean normalized total renal volumes obtained with matrix array transducer 3D sonography in stages 0 and 1 were significantly larger than those in other stages (p < 0.001). The mean normalized total renal volume in stage 5 disease was significantly smaller than the volumes in the other stages (p < 0.001).

CONCLUSION

Three-dimensional sonography with a matrix array transducer is a reliable means of measuring renal volume during evaluations of patients with reduced renal function.

Renal atrophy secondary to chemoradiotherapy of abdominal malignancies

PURPOSE

To identify factors predictive of renal atrophy after chemoradiotherapy of gastrointestinal malignancies.

METHODS AND MATERIALS

Patients who received chemotherapy and abdominal radiotherapy (RT) between 2002 and 2008 were identified for this study evaluating change in kidney size and function after RT. Imaging and biochemical data were obtained before and after RT in 6-month intervals. Kidney size was defined by craniocaudal measurement on CT images. The primarily irradiated kidney (PK) was defined as the kidney that received the greater mean kidney dose. Receiver operating characteristic (ROC) curves were generated to predict risk for renal atrophy.

RESULTS

Of 130 patients, median age was 64 years, and 51.5% were male. Most primary disease sites were pancreas and periampullary tumors (77.7%). Median follow-up was 9.4 months. Creatinine clearance declined 20.89%, and size of the PK decreased 4.67% 1 year after completion of chemoradiation. Compensatory hypertrophy of the non-PK was not seen. Percentage volumes of the PK receiving ≥10 Gy (V(10)), 15 Gy (V(15)), and 20 Gy (V(20)) were significantly associated with renal atrophy 1 year after RT (p = 0.0030, 0.0029, and 0.0028, respectively). Areas under the ROC curves for V(10), V(15), and V(20) to predict >5% decrease in PK size were 0.760, 0.760, and 0.762, respectively.

CONCLUSIONS

Significant detriments in PK size and renal function were seen after abdominal RT. The V(10), V(15), and V(20) were predictive of risk for PK atrophy 1 year after RT. Analyses suggest the association of lower-dose renal irradiation with subsequent development of renal atrophy.