Evaluation value of functional magnetic resonance urography on unilateral renal function in children with hydronephrosis

Abstract

Objective To assess the value of functional magnetic resonance urography (fMRU) for the unilateral renal function in children with hydronephrosis. Methods Fourteen children with congenital hydronephrosis (unilateral hydronephrosis in 12 cases, bilateral hydronephrosis in 2 cases) examined by fMRU in Beijing Children′s Hospital, Capital Medical University, were enrolled.In 7 patients of them, diuretic renal scintigraphy (DRS) was performed within 10 days before fMRU examination.The following parameters in fMRU, as renal parenchymal volume, volumetric differential renal function (vDRF), Patlak, Patlak differential renal function (pDRF), index of glomerular filtration rate (GFR) and differential renal function based on index of GFR (gDRF), were calculated and analyzed.Statistical analysis was performed by using SPSS 13.0. Results In 7 cases whose fMRU and DRS were examined, the indexes of GFR obtained from fMRU and GFR from DRS were well correlated (r=0.892, P<0.001) in 14 kidneys.The gDRF determined by 2 methods on the left kidneys[the average was(46.80±19.20)% and(45.18±20.29)%, respectively] had no significant difference (t=0.051 6, P=0.624), which was also highly correlated (r=0.912, P=0.004). In 12 cases with unilateral hydronephrosis, vDRF, pDRF, index of GFR and gDRF in hydronephrotic side[(43.54±9.61)%, (42.80±10.83)%, (38.56±29.23) mL/min, (38.37±13.61)%] were all less than those in the contralateral side[(56.46±9.61)%, (57.19±10.83)%, (57.02±26.22) mL/min, (61.63±13.61)%](t=2.326, 2.300, 2.422, 2.960; P=0.040, 0.042, 0.034, 0.013). However, there was no statistical difference in both renal parenchymal volume and Patlak between the hydronephrotic and the contralateral side kidneys(t=1.765, 1.450; P=0.105, 0.175). Conclusions fMRU is a very valuable examination method in evaluating single kidney function in children with congenital hydronephrosis, and able to demonstrate that gDRF, indexes of GFR, vDRF and pDRF decrease in the hydronephrotic kidney. Key words: Magnetic resonance urography; Hydronephrosis; Glomerular filtration rate; Child