Indium-111-antimyosin scintigraphy in the early detection of heart damage after anthracycline therapy in children

Purpose: To determine the value of indium-111-antimyosin (¹¹¹In-AM) scintigraphy in the early detection of myocardial damage in children treated with doxorubicin. Patients and Methods: Twelve planar scintigrams were made of eight patients (seven children and one young adult; mean age, 12 years). Three scans were obtained before doxorubicin therapy in three patients, and nine scans were obtained during doxorubicin therapy in seven patients. The heart-to-lung ratio (HLR) was calculated. Left ventricular function was assessed echocardiography before and during therapy by measuring the fractional shortening (FS). Results: The HLR of the three baseline scans was below 1.5, within the normal range for adults. Six of the seven patients whose scans were obtained during chemotherapy had abnormal HLR values (> 1.5). One patient had severe myocyte damage and showed un early increase in the HLR (2.3) after a cumulative doxorubicin dose of 150 mg/m². The FS measured echocardiography was normal throughout therapy, and the final cumulative dose of doxorubicin was 450 mg/m². This patient developed fatal clinical heart failure 3 months after completion of chemotherapy. In one patient, who was pretreated with the cardiaprotective agent dexrazoxane, the HLR remained within normal limits during therapy. Conclusion: ¹¹¹In-AM scintigraphy seems to be suitable to detect early myocardial damage after a cumulative doxorubicin dose of 150 mg/m² in children and may be useful for identifying children who are at increased risk of developing cardiac sequelae.