[Functional-anatomic evaluation of dilated uropathies in children using combined MR-nephrography and MR-urography compared to renal scintigraphy]

Abstract

Purpose: To evaluate MR-tomographic assessment of split renal function and degree of obstruction compared to diuretic renal scintigraphy, and pathoanatomic imaging of the urinary tract as all in one exam.

Patients and methods: In a prospective study 62 children, aged 1 month to 9.5 years, mean 2.8 years, underwent diuretic renal scintigraphy and dynamic MR-Nephrography at the same day except for 7 patients with a time interval of 1 day. In all patients we did T2w (water-technique MR-Urography) additionally.

Results: Comparing split renal function we found a very close correlation in 54 out of 62 patients (correlation coefficient = 0.95). Due to technical failures 8 cases couldn't be calculated. Comparing degrees of obstruction there was an agreement in 57 out of 62 patients, 3 studies were gradually over-, 2 underestimated. All but one morphologic diagnoses in advance obtained by ultrasound and completed by other imaging modalities later on were confirmed MR-urographically. Though correctly imaged the functionless upper moiety in a renal duplication with ureterocele was misinterpreted at a first glance.

Conclusions: Combined MR-Nephrography and MR- Urography allows reliable assessment of split renal function and urinary excretion in children with obstructive uropathies compared to renal scintigraphy. T(2)w MR-Urography provides excellent depiction of dilated urinary tract. In near future MR-tomographic techniques will reduce or even replace scintigraphic and radiographic modalities in patients with urinary tract anomalies.