DEMONSTRATION OF THE DEPOSITION OF HEMOSIDERIN IN THE KIDNEYS OF PATIENTS WITH PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA BY MAGNETIC-RESONANCE-IMAGING

Hemosiderinuria caused by intravascular hemolysis is a characteristic clinical feature of an acquired hemolytic disorder, paroxysmal nocturn al hemoglobinuria (PNH). We examined the deposition of hemosiderin (ir on) in the kidneys of 6 patients with PNH using magnetic resonance ima ging (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 M RI of the kidneys, suggesting the deposition of iron (hemosiderin) pre dominantly in the renal cortex, was obtained. Hemosiderin-deposition w as not revealed in the kidneys of any of the patients with AIHA. We co nclude that MRI is a sensitive means of detecting hemosiderin deposite d in the renal cortex of patients with PNH and that this feature is co nsiderably specific for diseases showing intravascular hemolysis, as r epresented by PNH.