Demonstration of the deposition of hemosiderin in the kidneys of patients with paroxysmal nocturnal hemoglobinuria by megnetic resonance imaging

Hemosiderinuria caused by intravascular hemolysis is a characteristic clinical feature of an acquired hemolytic disorder, paroxysmal nocturnal hemoglobinuria (PNH). We examined the deposition of hemosiderin (iron) in the kidneys of 6 patients with PNH using magnetic resonance imaging (MRI). Three patients with autoimmune hemolytic anemia (AIHA), a hemolytic disorder showing extravascular hemolysis, served as controls. In five of the six patients with PNH, a characteristic T2-weighted MRI of the kidneys, suggesting the deposition of iron (hemosiderin) predominantly in the renal cortex, was obtained. Hemosiderin-deposition was not revealed in the kidneys of any of the patients with AIHA. We conclude that MRI is a sensitive means of detecting hemosiderin deposited in the renal cortex of patients with PNH and that this feature is considerably specific for diseases showing intravascular hemolysis, as represented by PNH. (author)