Appearance of Autosomal Recessive Polycystic Kidney Disease in Magnetic Resonance Imaging and RARE-MR-urography

Purpose: To describe the appearance of autosomal recessive polycystic kidney disease (ARPKD) on MRI and RARE-MR urography.

Materials And Methods: Seven boys and one girl (aged 3 months to 14 years, median 2.5 years) were evaluated. Images were obtained with 0.23-T and 1.5-T MR systems using T1-weighted (T1-W) spin-echo, T2-weighted (T2-W) turbo-spin-echo and RARE-MR-urography sequences. Signal intensities, morphological appearance of the affected kidneys and, specifically, the picture of the urinary tract on RARE-MR-urography were evaluated.

Results: All children showed kidney enlargement, reniform but humpy kidney shape, homogeneously grainy renal parenchyma, normal renal pelvis and normal calyces. Signal intensity was hyperintense in T2-W images in all cases. In six cases (n = 7), T1-W images were hypointense. On RARE-MR urography a hyperintense, linear radial pattern was seen in the cortex and medulla which represents the characteristic microcystic dilatation of collecting ducts in ARPKD. Three boys and the girl presented with a few circumscribed small subcapsular cysts.

Conclusions: In order to confirm the diagnosis of ARPKD, RARE-MR urography seems to be a non-invasive imaging tool that shows directly the microcystic dilated water-filled collecting ducts.