Nuclear Medicine. In: Fotter R, editor. Pediatric Uroradiology. Berlin: Springer Berlin Heidelberg; 2001. pp. 27-40. [DOI: 10.1007/978-3-642-56484-0_3]

Serum and urine cystatin C levels in children with post-pyelonephritic renal scarring: a pilot study

AIM

We aimed to investigate in children with a history of acute pyelonephritis the influence of unilateral post-pyelonephritic renal scarring detected by DMSA scan on serum (S(CysC)) and urine cystatin C (U(CysC)) as well as upon other traditional markers of renal damage.

METHODS

Children with DMSA proven pyelonephritis (n = 28) were grouped as either scar [+] (n = 19, unilateral renal scarring) or scar [-] (no scarring, n = 9). The scar [+] group was further divided into scar-1 (differential DMSA uptake, Delta(DMSA) </= 10%; n = 8) and scar-2 (Delta(DMSA) > 10%, n = 11) subgroups. S(CysC), serum creatinine, urine NAG, microalbumin, protein, fractional sodium excretion (FE(Na)), tubular phosphate reabsorption (TPR), and U(CysC/Cr) were evaluated in all patients.

RESULTS

Neither S(CysC) nor U(CysC) were affected by age, height, and weight. scar [+] versus scar [-] groups and scar-1 versus scar-2 subgroups were not different with regard to all studied parameters. S(CysC) did not increase in children with post-pyelonephritic unilateral renal scarring. However, 11 children with slightly increased (>0.95 mg/l) S(CysC) levels in scar [+] group tended to have higher Delta(DMSA), albeit not significantly. Furthermore, U(CysC/Cr) correlated well with urine microalbumin, NAG, and FE(Na) in all children and the scar [+] group (P < 0.05).

CONCLUSION

S(CysC) and U(CysC) did not differ among pediatric patients with and without unilateral post-pyelonephritic renal scarring. However, Delta(DMSA) uptake between the two kidneys tended to be raised in children with S(CysC) levels higher than the reference ranges. Additionally, U(CysC/Cr) exhibits parallelism with tubular functions.

Potential impact of pediatric MR urography on the imaging algorithm in patients with a functional single kidney

OBJECTIVE

The purpose of this study was to evaluate the potential of MR urography in the assessment of children with a suspected "functional single kidney."

SUBJECTS AND METHODS

Sixty patients (age range, 2.7 weeks to 15.7 years) who had been referred for assessment of a suspected functional single kidney underwent MR urography in addition to detailed sonography of the urinary tract and the currently indicated standard imaging. The results of the conventional imaging ((99m)Tc-dimer captosuccinic acid scintigraphy, voiding cystourethrography, and genitography) were compared with the results of sonography and MR urography; surgical findings served as the gold standard if available.

RESULTS

Twenty-six patients had a single kidney. The other diagnoses were six contralateral multicystic dysplastic kidneys, two normal ectopic kidneys, one crossfused double system, and 25 ectopic or dysplastic renal buds. Scintigraphy detected all normal kidneys, two ectopic kidneys, and two dysplastic renal buds. Detailed sonography missed two ectopic kidneys and two orthotopic dysplastic renal buds, but one additional renal bud that could not be confirmed on other imaging techniques (accuracy, 91.7%; sensitivity, 88.2%; specificity, 96.2%) was suspected. MR urography results were correct in all patients and verified in all 13 with surgical correlation.

CONCLUSION

MR urography allows a reliable assessment of renal and ureteral anatomy and of dysplastic or ectopic renal buds, even in non- or poorly functioning systems. MR urography therefore has the potential to replace the currently used excretory urography and scintigraphy. In patients with a suspected functional single kidney a detailed sonographic study and MR urography should be considered the diagnostic algorithm of choice.