Late blood pool images after Tc-99m tetrofosmin injection in a patient with monoclonal gammopathy of uncertain significance and immunologic disorders.
The authors report a case of abnormal biodistribution of Tc-99m tetrofosmin in a patient with immunologic disorders who underwent rest-stress myocardial perfusion scintigraphy to assess the operative risk for surgery of possible relapse of adenocarcinoma of the left maxillary sinus. The patient had monoclonal gammopathy of uncertain significance with a serum electrophoretic pattern of both monoclonal immunoglobulin A and free kappa light chain components and a mild form of idiopathic immunohemolytic anemia. Two different images at rest after injection of Tc-99m tetrofosmin showed a typical blood-pool pattern with absence of detectable myocardial uptake. Other patients injected with the same batch of radiopharmaceutical showed myocardial uptake. A change of the molecular characteristics of tetrofosmin after the injection could not be a factor, because the values of the main chemical and physical parameters of the blood were in the normal range. Accordingly, the authors propose the hypothesis that the monoclonal immunoglobulin A or the free kappa light chains of this patient accidentally recognized one or more epitopes of the tetrofosmin molecule, binding it with high affinity and causing an abnormal biodistribution, characterized by late blood-pool imaging. No similar experiences have been described in the scientific literature.
Ceriani
L
L
Department of Nuclear Medicine, Ospedale di Circolo, Fondazione Macchi and University of Insubria, Varese, Italy. Mednuc@ospedale.varese.it
Giovanella
L
L
Garancini
S
S
D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds / Q000097:blood; D015609:Organotechnetium Compounds / Q000097:blood; D010265:Paraproteinemias / Q000000981:diagnostic imaging* / Q000276:immunology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000097:blood; D013997:Time Factors; D014018:Tissue Distribution
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin