Skeletal muscle uptake of Tc 99m pyrophosphate in amyloidosis

Abstract

In a patient with amyloidosis involving the heart, kidneys, and skeletal muscles, a Tc 99m pyrophosphate “bone” scan demonstrated intense uptake of tracer by the skeletal muscles; but not by the heart or kidneys. Using the alizarin red stain, prominent calcium deposits were detected histologically in association with the skeletal muscle amyloid. These findings suggest that certain amyloid deposits will take up Tc 99m pyrophosphate, but only if sufficient amounts of calcium are associated with the amyloid.