title: MRI of hemorrhagic renal cysts in polycystic kidney disease.
abstract: Nine patients with polycystic kidney disease were examined by MRI, CT, and sonography. MRI distinguished among simple cysts, cysts complicated by prior hemorrhage, and coexistent renal cell carcinoma. On T1-weighted spin-echo images, simple renal cysts appeared as round, homogeneous, low-signal regions with smooth outer margins and a distinct interface with remaining normal renal parenchyma or adjacent cysts. Hemorrhagic cysts were seen as homogeneous medium- to high-signal intensity regions, and about half of them correlated with hyperdense cysts by CT. In five cases, fluid-iron levels were evident by dependent high-intensity layering within the cysts. Renal cell carcinomas occasionally show high intensity because of hemorrhage, but intratumoral fluid-iron levels have not yet been described. These results suggest that MRI is useful in differentiating between simple cysts, hemorrhagic cysts, and neoplasms when CT and sonography are indeterminate.
mesh_terms: D000328:Adult; D002292:Carcinoma, Renal Cell / Q000175:diagnosis; D003560:Cysts / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006470:Hemorrhage / Q000175:diagnosis*; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D007690:Polycystic Kidney Diseases / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography