Spotted Nephrogram Sign

A term of art referring to patchy perfusion of the renal parenchyma admixed with multiple foci of parenchymal infarction, fancifully likened to a spotted ‘big cat’—e.g., a leopard. The sign is seen by CT, MRI, angiography (aortography, arteriography) and caused by small vessel occlusion in systemic vasculitis—e.g., periarteritis nodosa—scleroderma, and rarely also severe nephrosclerosis