MR imaging appearance of infantile polycystic kidney disease

Clinical History

The patient was admitted with abdominal pain. On physical examination, bilateral renal enlargement was detected. Laboratory examination revealed no abnormal results. MR imaging was performed.

Imaging Findings

The patient was admitted with abdominal pain. On physical examination, bilateral renal enlargement was detected. Laboratory examination revealed no abnormal results.

Spin-echo T1-weighted magnetic resonance imaging (MRI) revealed bilateral renal enlargement. The kidneys kept their reniform shape, but there were humps. The renal parenchyma showed a homogeneous grainy appearance. The renal pelvis and calyces were normal (Fig. 1a). On gradient-echo T2-weighted imaging the kidneys displayed homogeneous hyperintense signals and the renal contours showed multiple humps (Fig. 1b). A linear radial enhancement pattern was seen in the cortex and medulla after injection of contrast medium (Fig. 1c).

Discussion

Infantile polycystic kidney disease is characterised pathologically by dilatation of the renal collecting tubules, hepatic cysts, and periportal fibrosis. Younger patients present predominantly with renal abnormality. It occurs in 6000 to 14000 live births. Perinatal disease will demonstrate massive renal enlargement, hypoplastic lungs and oligohydramnios. Death usually occurs as a result of renal failure and pulmonary hypoplasia. Older children will present with manifestations of portal hypertension. On sonography, massively enlarged echogenic kidneys with lack of corticomedullary differentiation are seen. Occasionally macroscopic cysts will be noted.

Enlargement of the kidneys with regular contours can also be seen on CT and MR imaging. The kidneys show increased signal intensity on T2-weighted MR images. Intravenous contrast injection may opacify long, radially oriented, and dilated collecting tubules on both CT and MR imaging (1). This produces opaque streaks, sometimes extending to the periphery of the kidney. These may be better seen on delayed films up 24-48 hours. Pelvocalyceal systems and ureters are not opacified in the severe form of the disease. With increased age, there is more likely to be liver and spleen enlargement. Renal enlargement and opacification of dilated ducts become less likely.

Differential Diagnosis List

Final Diagnosis

Infantile polycystic kidney disease

URL:	https://www.eurorad.org/case/1456
DOI:	10.1594/EURORAD/CASE.1456
ISSN:	1563-4086