[Renal dynamics: comparison between diuretic renogram and magnetic resonance imaging]

This study aimed to establish a comparison between the data obtained in the renal functional study through magnetic resonance using gadolinium with diuretic (furosemide) charge (MR-Gd/F), on the one hand, and the parameters obtained with the classical diuretic renogram (DR) (differential renal function -DRF- and renographic curve -RC-), on the other hand.

10 patients were studied, 6 male and 4 female, aged between 1 month and 6 year-old. All the patients were submitted to a MR-Gd/F and a DR. In both cases, furosemide was used as overload. The pathologies observed included syndrome of the pyeloureteral junction, polar vessel, ureter valve, ectopic ureter, duplex kidney, renal dysplasia, renal ectasy, pelvic kidney and horseshoe kidney. The percentage of gadolinium uptake was compared versus the DRF, and the MR curve was compared versus the RC. Surgical treatment was required in 5 cases and an expectancy behaviour was taken in 3 cases. Among the operated patients, the diagnosis accurry was confirmed by the surgery and the pathological study.

A 80% consistency was found between the gadolinium uptake and the DRF. There was a 90% correlation between the MR-Gd/F curve and the RC. In two cases, the MR-Gd/F required to modify the surgical criterion -previously based on the DR- and an expectancy behaviour was taken. In 90% of the operated cases, the diagnostic assumption obtained through the MR-Gd/F coincided with the surgical and pathological findings, whereas there was a coincidence in just 60% of the cases studied through the DR (p > 0.0008).

The MR offers a real time study: anatomical, vascular and functional. Good correlation between DR and MR with respect to: (% DRF,%Gd MR and diuretic curve). The MR demonstrates greater precision in diagnosis.The MR allows recognition of non obstructive polar vessels that can then be conservatively managed.