PDF

Int J Med Sci 2025; 22(4):897-902. doi:10.7150/ijms.100216 This issue Cite

Research Paper

Accuracy of Sonographic Renal Pelvic Diameter in Assessment of Renal Function among Patients with Ureteropelvic Junction Obstruction using Scintigraphy as a Gold Standard

Mahasin G. Hassan¹ , Tasneem S.A. Elmahdi², Moudi Alotaibi¹, Enas Fallatah³, Faten A. Nasser³

1. Department of Radiological Sciences, College of Health and Rehabilitation Sciences, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
2. Department of Diagnostic Radiologic Technology, Faculty of Applied Medical Sciences, Taibah University, Al-Madinah Al-Munawara, Saudi Arabia
3. Department of Radiology, Madina Maternity and Children Hospital, Al-Madina Al Munawara, Saudi Arabia.

✉ Corresponding author: Mahasin G. Hassan, Department of Radiological Sciences, College of Health and Rehabilitation Sciences, Princess Nourah bint Abdulrahman University, PO Box 84428, Riyadh 11472, Saudi Arabia; E-mail: mghassanedu.sa. ORCID http://orcid.org/ 0000-0002-9965-8915. More

Abstract

Objectives: The study aimed to assess the diagnostic accuracy of sonographic renal pelvic diameter (RPD) in pediatric patients with ureteropelvic junction obstruction (UPJO) and its potential as a solo diagnostic tool. The study also looked for a clinically meaningful cutoff point in sonographic RPD, with the goal of optimizing sensitivity and specificity for discriminating between normal and impaired renal function in UPJO cases.

Materials and methods: The study, which took place at a maternity and child hospital, involved 75 children under the age of three who had been diagnosed with UPJO. Data was collected from 2020 to 2022 using both ultrasonography and renal scintigraphy, with cases diagnosed using only one modality being excluded.

Results: The analysis included descriptive and t-tests. The results demonstrated a significant difference in sonographic RPD between pediatric patients with normal and impaired renal function and with large and normal renal diameters. The average renal pelvis diameter was found to be 2.2 ±1.9 cm. The sensitivity and specificity of sonographic RPD for predicting impaired renal function in UPJO vary significantly across multiple cutoff points, underlining RPD's diagnostic potential.

Conclusion: The study concluded that combining two modalities (ultrasound and scintigraphy) improves results when the renal pelvic diameter surpasses 1 cm.

Keywords: accuracy, renal pelvic diameter, renal function, ureteropelvic junction obstruction

Introduction

In recent years, ureteropelvic junction obstruction (UPJO) has become more frequently detected due to the increased sensitivity of ultrasound scans. The prevalence is high among neonates with hydronephrosis. UPJO is one of the most common causes of congenital urinary tract obstruction [1].

Usually, the result of UPJO is hydronephrosis. The critical point is that untreated conditions will lead to a loss of kidney function [2]. The retention and stasis of urine, with insufficient clearance of bacteria from the urinary tract, is a significant factor for most urinary pathogens [3]. One of the most common causes of renal failure in infants and children is obstructive nephropathy due to congenital hydronephrosis secondary to UPJO [4,5].

Renal pelvis diameter (RPD) is a significant indicator of serious conditions antenatally. Ultrasound is the chosen modality for assessing the renal pelvis in fetuses, neonates, and children [6]. Ultrasound can measure the anteroposterior (AP) diameter at the maximal dilatation area of the intrarenal transverse plane [7]. Among children, RPD differs according to age. It increases gradually from 3.1 mm in newborns to 5.5 mm at 18 years old [8]. Measurements between 7 and 10 mm may indicate renal failure [9]. The most effective diagnostic tools for investigating children with upper tract renal obstruction include ultrasonography and nuclear medicine [10,11]. Ultrasonography is safe, noninvasive, easily accessible, and repeatable without radiation exposure [12], while renal scintigraphy provides information about renal perfusion and function [13].

Management and treatment decisions depend on the condition of the obstruction. Scans are repeated at different intervals, drainage is performed for patients with normal renal function, and surgery, such as pyeloplasty, is performed for impaired renal function [2,4,14]. Most cases are resolved spontaneously 30 months after birth [15].

Glomerular Filtration Rate (GFR) measured by DTPA (diethylenetriamine pentaacetic acid) scan, and Effective Renal Plasma Flow (ERPF) measured by MAG3 (mercaptoacetyltriglycine) scan is used to assess the renal function. DTPA scan is mainly used to measure GFR directly, specifically targeting glomerular filtration. In contrast, MAG3 is predominantly used to evaluate effective renal plasma flow and tubular function rather than for direct GFR measurement. In clinical settings, these methods often complement each other. Research indicates that while DTPA is more suitable for direct GFR assessment, MAG3 can effectively estimate renal function, especially in tubular function and renal perfusion. Although each scan has its primary focus, both provide valuable insights into renal function [16, 17].

This study assessed the accuracy of RPD in renal function assessment with the gold standard, renal scintigraphy. The presence of a significant cutoff point for RPD could lead to a reduction in unnecessary imaging studies.

Materials and Methods

Research design

The study was a cross-sectional research design employing a quantitative research approach.

Sample

The study included children younger than three years old diagnosed with UPJO and scanned using ultrasonography and renal scintigraphy, either by nuclear gamma camera scanning or positron emission tomography (PET). The study included all cases between 2020 and 2022, with a total of 75 cases using a convenience sampling method. Any case with vesicoureteral reflux, hydroureter, ureterovesical junction obstruction, posterior urethral valves and diagnosed with one modality (ultrasonography or scintigraphy) was excluded. The time interval between the ultrasound and scintigraphy was an average of two days.

Data collection and analysis

This study retrospectively collected data from patients' records from the Picture Archiving and Communication System (PACS). All patients were well-hydrated for ultrasonography and scintigraphy. Renal ultrasonography was performed by trained sonographers using a GE Voluson E10 ultrasound machine. Renal ultrasound exams were performed by four sonographers, each with three years of experience in pediatric sonographic scanning. All sonographers worked under the supervision of five radiologists. Scanning was usually performed when patients were supine, using linear ultrasound transducers with an operating frequency of 5-10 MHz. The following images were acquired for both kidneys: longitudinal view: lateral, mid (with color Doppler) and medial, and transverse view of the upper, mid (with color Doppler), and lower renal levels. RPD was measured in the transverse section at the innermost maximum dilated part of the renal pelvis.

For renal scintigraphy, 29 patients were scanned using Philips - ADAC SKY Light nuclear gamma camera scanning, and 46 were scanned using Philips PET. The radiopharmaceutical drug used for nuclear scanning was 99mTc-DTPA (diethylenetriaminepentaacetic acid). For PET, the radiopharmaceutical drug used was 99mTc-MAG3 (mercaptoacetyltriglycine). The GFR and ERPF cut-offs used in the study reflect the renal function of the hydronephrotic kidney. The following parameters were assessed: site of obstruction (RT or LT kidney), rate of tracer (accumulation and washout), and renal function (either by measuring GFR or ERPF).

The hospital implements quality control measures to ensure adherence to the standardized protocol in renal scintigraphy. Two radiologists with more than five years of experience evaluated all images in this study. Moreover, the same protocol was used for all patients. A unified reporting format for documenting renal pelvis measurements was used for all patients. The hospital follows international standards for function interpretation. The GFR was considered normal when it was 28 ±26 mL/min/1.73m² for patients less than one year old, 43 ±28 mL/min/1.73m² for patients between 1-2.5 years old, and 72 ±40 mL/min/1.73m² for patients older than 2.5 years. ERPF measurement was based on Schlegel's method and classified as normal or abnormal. Schlegel criteria for younger children is considered normal when it varies between 200 to 600 mL/min/1.73m².

A data collection sheet that included all study variables was used to obtain data in patient records stored in PACS. The data sheet contains three parts. The first concerns demographic data (gender and age of the patient) and the cause of obstruction (congenital or acquired). The second part is related to sonographic RPD measurement. Data related to the classification of hydronephrosis was not available. The third part is related to the following renal scintigraphy parameters: site of obstruction (RT or LT kidney), rate of tracer (accumulation and washout; slow, rapid, or normal), and renal function (either by measuring GFR in nuclear scanning or ERPF in PET). The analysis was version 28 of the Statistical Analysis for Social Sciences for Windows (IBM Corp., Armonk, N.Y., USA).

Ethical considerations

The study was approved by the Institutional Review Board (IRB) at Princess Nourah bint Abdulrahman University (no. 23-0126) and King Salman bin Abdulaziz Medical City (no. 22-072). There was no need for a consent form. The volunteer data were coded (patients' names were not mentioned) and used only for this study.

Results

Descriptive statistics

This study included 75 patients with UPJO with a mean age of 0.9 ± 1 years, the majority of whom were male (n=54; 72%), and the cause was congenital in most of the patients (n=73; 97.3%). Using ultrasound, the mean renal pelvis diameter was estimated to be 2.2 ± 1.9 cm, ranging between 0.1 cm and 10 cm. There was a very wide range in renal pelvic diameter measurements, 0.1cm to 10cm. However, these data were collected retrospectively from patient files, and the indications for what constitutes a normal renal pelvic diameter were not found.

Renal scintigraphy revealed that obstruction occurred in the left kidney in 33 (44%) patients and the right kidney in 42 (56%) patients. The rate of tracer accumulation was mainly rapid (n= 57; 76%), while washout was slow (n=63; 84%). Kidney size was enlarged in 38 (50.7%) of patients, while abnormal function was detected in 38 (50.7%) of patients.

Inferential statistics

An Independent Sample's t-test was used to examine the RPD mean difference between the normal and abnormal renal function groups. The difference was considered significant (Table 1).

The mean RPD for individuals with normal renal function was significantly lower than the mean RPD for patients with abnormal renal function. A p-value less than 0.05 indicated that there is a statistically significant difference in mean RPD between patients with normal and impaired renal function. The observed difference in mean RPD values was not only statistically significant, but it may also have clinical significance, indicating that RPD can be used as a potential diagnostic marker to differentiate between normal and abnormal renal function in pediatric UPJO cases. The result suggested that abnormal renal function was associated with an elevated RPD in UPJO patients.

Regression

This regression analysis (Table 2) examines the relationship between renal pelvic diameter (RPD) and abnormal renal function at three different cut-off points (1, 1.5, and 2). The results show that RPD is significantly associated with abnormal renal function at cut-off values of 1 and 2, with odds ratios of 4.3 and 2.7, respectively, indicating that larger RPDs substantially increase the likelihood of abnormal renal function. The relationship is strongest at cut-off 1, where the odds of abnormal function are over four times higher. However, at a cut-off of 1.5, the association is not statistically significant, suggesting it may not be as effective in predicting abnormal renal function.

The summary table (Table 3) shows how each cut-off for renal pelvic diameter (RPD) affects the ability to predict abnormal renal function (RFN). The main observation is that there is a trade-off between sensitivity and specificity as the cut-off increases.

• Cut-off 1.0 has the highest sensitivity (92.1%), meaning it is most effective in identifying cases of abnormal renal function. However, it has the lowest specificity (27.0%), indicating a high rate of false positives. This makes it a good threshold for minimizing missed abnormal cases but may lead to over-predicting abnormal renal function in patients with normal RPD.
• Cut-off 1.5 strikes a moderate balance, with a lower sensitivity (71.1%) and a moderate specificity (45.9%). The PPV (57.4%) and NPV (60.7%) are close, meaning it offers a more balanced prediction between true positive and true negative results, though neither is particularly high.
• Cut-off 2.0 has the highest specificity (73.0%), indicating it is best at identifying normal renal function (i.e., fewer false positives), but the lowest sensitivity (50.0%), meaning it misses a substantial portion of abnormal cases. The PPV is also the highest (65.5%), meaning that when it predicts abnormal function, it's more likely to be correct. However, its lower NPV (58.7%) means it is less reliable in predicting normal renal function.

Discussion

Ultrasound is the most suitable method for urine tract examination, particularly for renal investigations [18]. In detecting hydronephrosis, ultrasound has an overall diagnostic accuracy of 85.2% [19], and ultrasound has four classifications of hydronephrosis according to the Society of Fetal Urology (SFU) hydronephrosis grading system [20].

In renal failure (RF) cases, ultrasound has high accuracy in detecting obstructions [21], and it can differentiate acute from chronic RF [13]. The ultrasound image showed reduced renal size, parenchyma thinning, and hyper-echogenicity in chronic RF. However, the exact diagnosis of the underlying chronic disease is not generally possible with ultrasound only [22]. Renal scintigraphy remains the gold standard for assessment of split renal function [13]. The radiotracers provide renal functional measures, such as glomerular filtration rate, effective renal plasma flow, tubular function, and renal blood flow [23]. The study was conducted among children under three years old since UPJO never progressed after age two, and all subsequent procedures were performed until age three [24].

The study revealed that most UPJO cases were congenital. This aligns with the literature stating that congenital causes are the most common etiology [2]. Similar to what has been found in previous studies, the results show that cases are more common in males than in females [25, 26, 27]. Unfortunately, to date, there is no known justification for this difference. The study showed that all cases were unilateral, and no bilateral cases were among children under three years old. The literature has established that the left side is more affected than the right [2] and that congenital anomalies are high on the same side [28]. The prevalence of the disorder in this study is high on the right side, which needs more studies to be confirmed and justified [29].

The standard deviations for RPD were quite large, even in the abnormal function group (2.7+2.1), indicating that several RPD values were measuring less than 1 cm. It's possible that some of these lower RPD values resulted from a previous issue, such as a febrile urinary tract infection (UTI). Febrile UTI is a prevalent infection in children that can lead to renal scarring and may result in long-term issues, such as chronic kidney disease [30]. Additional studies could clarify the connection between RPD measurements and functional outcomes. It would be beneficial to examine the patients' histories of UTIs or other insults to understand the observed data better.

Different studies have disclosed the relationship between renal size and function. Ziauddeen et al. found that fetal kidney volume was related to minor increases in the estimated glomerular filtration rate (eGFR) in mid-childhood [31]. Jovanović et al. proved that renal size in chronic kidney disease (CKD) patients is associated substantially with renal function [32]. However, it is important to note that nuclear medicine or magnetic resonance urography assesses many cases of hydronephrosis without functional compromise, and hydronephrosis does not necessarily indicate abnormal renal function.

This study shows that the RPD mean difference between the normal and abnormal renal function groups is considerable. RPD was higher among patients with abnormal renal function. The findings reveal a significant association between RPD and abnormal renal function at the 1 cm and 2 cm cut-off values, with odds ratios of 4.3 and 2.7, respectively. This suggests that larger RPDs significantly raise the probability of experiencing abnormal renal function.

The cutoff value of 1 cm will help us include the largest number of cases with abnormal renal function. It had a higher sensitivity equal to 92.1%. This threshold effectively minimizes missed abnormal cases but may result in over-predicting abnormal renal function in patients with normal RPD. Patients with RPD of 1cm or less are likely to have a normal function, assuming the contralateral kidney is also normal because this corresponds to relatively mild hydronephrosis.

The cutoff value of 2 cm had a higher specificity of 73% (have fewer false positives), which will help exclude the largest number of cases with normal renal function. At this threshold, there is a strong likelihood of accurate predictions of abnormal function, while the lower NPV suggests reduced reliability in confirming normal renal function. A cut-off of 2 cm misses a few cases with hypofunction but will be more specific. The study performed by Botros et al. confirmed these results. Their study found that APD was significantly correlated with renal function and is an effective parameter for surgical decisions [33].

In the context of evaluating the accuracy of sonographic renal pelvic diameter in assessing renal function among patients with ureteropelvic junction obstruction, the use of biomarkers holds significant promise. For example, Paraboschi et al. have demonstrated the potential of urinary biomarkers in detecting damage associated with pelvic-ureteric junction obstruction, offering a non-invasive complement to traditional imaging methods [34]. Similarly, Madsen highlighted the utility of urinary biomarkers in assessing hydronephrosis, suggesting that these biomarkers can provide valuable insights into renal function and damage [35]. Incorporating these biomarkers could enhance the accuracy and overall diagnostic capability in assessing renal conditions beyond what sonographic measurements alone can offer.

The study's limitations included using two different protocols for renal scintigraphy, two different parameters to assess renal function, a small sample size, and the study's retrospective nature. To improve accuracy, using one protocol for renal scintigraphy, increasing the sample size, and conducting a prospective study could be beneficial. The possibility of other contributing variables, e.g., febrile UTI, is one of the study's limitations.

Conclusion

Careful sonographic RPD had a high diagnostic value for renal function. The combination of two modalities (ultrasound and renal scintigraphy) increases the accuracy of results when RPD exceeds 1 cm and helps in therapeutic decision-making. Only 8% of patients with APRPD <1cm are likely to have decreased function and thus can safely be monitored with renal sonogram only in most cases. This will lead to a reduction in unnecessary imaging studies. Despite these results, clinical decisions should be made cautiously, considering the limitations of ultrasound, since overdiagnosis or underdiagnosis can lead to severe clinical consequences (such as unnecessary treatments). In the future, a prospective study overcoming the limitations of this study will improve and verify the study's results.

Funding

The authors extend their appreciation to the Deputyship for Research & Innovation, Ministry of Education in Saudi Arabia for funding this research work through the project number RI-44-0881.

Competing Interests

The authors have declared that no competing interest exists.

References

1. Jackson L, Woodward M, Coward RJ. The molecular biology of pelvi-ureteric junction obstruction. Pediatr Nephrol. 2018;33(4):553-571

2. Ureteropelvic Junction Obstruction. StatPearls Website. https://www.statpearls.com/point-of-care/30820. Updated October 7, 2023. Accessed December 30. 2023

3. Albarrak M, Alzomor O, Almaghrabi R, Alsubaie S, Alghamdi F, Bajouda A, Nojoom M, Faqeehi H, Rubeea SA, Alnafeesah R, Dolgum S, ALghoshimi M, AlHajjar S, AlShahrani D. Diagnosis and Management of Community-acquired Urinary Tract Infection in Infants and Children: Clinical Guidelines Endorsed by the Saudi Pediatric Infectious Diseases Society (SPIDS). Int J Pediatr Adolesc Med. 2021;8(2):55-67

4. Ather MH, Jafri AH, Sulaiman MN. Diagnostic accuracy of ultrasonography compared to unenhanced CT for stone and obstruction in patients with renal failure. BMC Med Imaging. 2004;4(1):2

5. Granata A, Floccari F, Insalaco M, Clementi A, Di Lullo L, D'Amelio A, Zamboli P, Logias F, Romano M, Fiorini F. L'ecografia nelle infezioni del rene [Ultrasound assessment in renal infections]. G Ital Nefrol. 2012;9(57):47-S57

6. Neonatal Hydronephrosis. Radiopaedia Website. https://radiopaedia.org/articles/neonatal-hydronephrosis. Updated on Jan 3 2023. Accessed December 30. 2023

7. Hodhod A, Eid H, Capolicchio JP, Petrella F, Sadri I, El-Sherbiny M, Jednak R, Lacroix C. How can we measure the renal pelvic anteroposterior diameter in postnatal isolated hydronephrosis? Journal of Pediatric Urology. 2023;19(1):75-82

8. Establishing a Reference Range for the Renal Pelvis Anterior-Posterior Diameter in Children Ages 0-18 Years. Societies for Pediatric Urology Website. https://spuonline.org/abstracts/2014/MP10.cgi. Published May 16, 2014. Accessed August 7. 2023

9. Kari JA, Habiballah S, Alsaedi SA, Alsaggaf H, Al-dabbagh A, AbulHamail A, Marzouki A, Eldeek B. Incidence and outcomes of antenatally detected congenital hydronephrosis. Annals of Saudi Medicine. 2013;33(3):260-4

10. Capello SA, Kogan BA, Giorgi LJ Jr, Kaufman RP Jr. Prenatal ultrasound has led to earlier detection and repair of ureteropelvic junction obstruction. J Urol. 2005;174(4 Pt 1):1425-1428

11. Wiener JS, Emmert GK, Mesrobian HG, Whitehurst AW, Smith LR, King LR. Are modern imaging techniques over diagnosing ureteropelvic junction obstruction? J Urol. 1995;154(2 Pt 2):659-661

12. Brown T, Mandell J, Lebowitz RL. Neonatal hydronephrosis in the era of sonography. AJR. 1987;148(5):959-63

13. Riccabona M. Renal Failure in Neonates, Infants, and Children: The Role of Ultrasound. Ultrasound Clinics. Elsevier saunders. 2006;1:457-469

14. Scalabre A, Clément Y, Guillière F, Ayciriex S, Gaillard S, Demède D, Bouty A, Lanteri P, Mure PY. Early detection of ureteropelvic junction obstruction in neonates with prenatal diagnosis of renal pelvis dilatation using 1H NMR urinary metabolomics. Sci Rep. 2022;12(1):13406

15. Vandervoort K, Lasky S, Sethna C, Frank R, Vento S, Choi-Rosen J, Goilav B, Trachtman H. Hydronephrosis in Infants and Children: Natural History and Risk Factors for Persistence in Children Followed by a Medical Service. Clin Med Pediatr. 2009;3:63-70

16. Claudio M, Michela M, & Luca T. Comparison of GFR measurement with [99mTc]-DTPA and clinical methods based on creatinine measurement in patients over 80 years old. Journal of Clinical Nephrology. 2022;6(3):086-090

17. Arroyo A. J. Effective renal plasma flow determination using technetium-99m MAG3: Comparison of two camera techniques with the Tauxe method. Journal of Nuclear Medicine Technology. 1993;21(3):162-166

18. Shu B, Feng X, Martynov I, Lacher M, Mayer S. Pediatric Minimally Invasive Surgery—A Bibliometric Study on 30 Years of Research Activity. Children. 2022;9(8):1264

19. Dalla-Palma L, Bazzocchi M, Pozzi-Mucelli RS, Stacul F, Rossi M, Agostini R. Ultrasonography in the diagnosis of hydronephrosis in patients with normal renal function. Urol Radio. 1983;5:221-226

20. Onen A. Grading of Hydronephrosis: An Ongoing Challenge. Front Pediatr. 2020;8:458

21. Arafa NM, Fathi MM, Safwat M, Moro H, Torky H, Kenawi M, Abdel-Wahab M. Accuracy of ultrasound in the diagnosis of nonfunctioning kidneys. J Urol. 1982;128(6):1165-1169

22. Buturović-Ponikvar J, Visnar-Perovic A. Ultrasonography in chronic renal failure. Eur J Radiol. 2003;46(2):115-22

23. Werner RA, Pomper MG, Buck AK, Rowe SP, Higuchi T. SPECT and PET Radiotracers in Renal Imaging. Semin Nucl Med. 2022;52(4):406-418

24. Abadir N, Schmidt M, Laube GF, Weitz M. Imaging in children with unilateral ureteropelvic junction obstruction: time to reduce investigations? Eur J Pediatr. 2017;176(9):1173-1179

25. Ayyat F, Al Jishi M. Ureteropelvic Junction Obstruction in Paediatrics. Urol Ann. 2016;8(2):102-108

26. Snyder HM, Lebowitz RL, Colodny AH, Bauer SB, Retik AB. Ureteropelvic Junction Obstruction in Children. Urologic Clinics of North America. 1980;7(2):273-290

27. UPJ Obstruction. What Is It, Treatment, Surgery & Recovery. Cleveland Clinic Website. https://my.clevelandclinic.org/health/diseases/16596-ureteropelvic-junction-obstruction. Updated October 6 2020. Accessed December 30. 2023

28. Houat A, Guimarães C, Takahashi M, Rodi G, Gasparetto T, Blasbalg R, Velloni F, Congenital Anomalies of the Upper Urinary Tract. A Comprehensive Review. RadioGraphics. 2021;41(2):462-486

29. Schreuder MF. Unilateral anomalies of kidney development: why is left not right? Kidney Int. 2011;80(7):740-745

30. Horsager TH, Hagstrøm S, Skals R, Winding L. Renal scars in children with febrile urinary tract infection - Looking for associated factors. J Pediatr Urol. 2022;18(5):682.e1-682.e9

31. Ziauddeen N, Jeffrey RF, Waiblinger D, Fraser SD, Alwan NA, Yuen HM, Azad R, Mason D, Wright J, Coward RJ, Roderick PJ. Role of fetal kidney size on kidney function in childhood: the born in Bradford cohort renal study. BMC nephrology. 2023;24(1):41

32. Jovanović D, Gasic B, Pavlovic S, Naumovic R. Correlation of kidney size with kidney function and anthropometric parameters in healthy subjects and patients with chronic kidney diseases. Renal Failure. 2013;35(6):896-900

33. Botros S, Ali A, Shawky N. Transverse Comparisons Between Ultrasound and Radionuclide Parameters in Children with Pelvi-Ureteric Junction Obstruction. Egypt. J. Hosp. Med. 2018;72(5):4543-4550

34. Paraboschi I, Mantica G, Dalton NR, Turner C, Garriboli M. Urinary biomarkers in pelvic-ureteric junction obstruction: a systematic review. Transl Androl Urol. 2020Apr;9(2):722-742

35. Madsen MG. Urinary biomarkers in hydronephrosis. Dan Med J. 2013Feb;60(2):B4582

Author contact

Corresponding author: Mahasin G. Hassan, Department of Radiological Sciences, College of Health and Rehabilitation Sciences, Princess Nourah bint Abdulrahman University, PO Box 84428, Riyadh 11472, Saudi Arabia; E-mail: mghassanedu.sa. ORCID http://orcid.org/ 0000-0002-9965-8915.

Received 2024-8-21
Accepted 2025-1-1
Published 2025-1-21

Citation styles

©2025 Ivyspring International Publisher. Terms of use