CARDIAC AND PLEUROPULMONARY AL AMYLOID IMAGING WITH TC-99M LABELED APROTININ

Antiproteases are known to be present in amyloid deposits. We evaluate d the possibility of using an anti-serine protease (aprotinin) labelle d with technetium-99m (TcA), usually employed as a cortical renal trac er, for the imaging of amyloid deposits, Because of the known high upt ake of TcA by the kidneys, we limited our analysis to extra-abdominal amyloid localizations, We report the scintigraphic findings observed i n 24 patients with light chain amyloidosis (AL) and one with a heredit ary form who were known or suspected to have extra-abdominal involveme nt. Planar scans obtained 100 min after i.v. TcA administration showed myocardial accumulation in 11 patients, pleuropulmonary accumulation in nine, pericardial accumulation in two and localization in the neck region (thyroid, salivary glands and tongue) in eight. TcA scintigraph y was negative in five patients without clinical or laboratory evidenc e of extra-abdominal involvement, as well as in 12 control group patie nts with cardiac and renal diseases, These preliminary results indicat e TcA to be a low-cost, readily available radiopharmaceutical for imag ing of extra-abdominal involvement in AL type amyloidosis.