Noninvasive identification of anthracycline cardiotoxicity. Comparison of 123I-MIBG and 123I-BMIPP imaging

To test the feasibility of myocardial 123I-MIBG and 123I-BMIPP imaging for the early detection of anthracycline cardiotoxicity, 13 patients who had received anthracycline anticancer chemotherapeutic agents were studied. Two-dimensional echocardiography and myocardial imaging with both 123I-MIBG and 123I-BMIPP were performed in 13 patients treated with anthracycline (group A) and 10 normal control subjects (group C). Anterior myocardial images were obtained 15 minutes and 3 hours after the injection of isotopes. The heart-to-mediastinum ratio (H/M ratio) was used to quantify cardiac 123I-MIBG and 123I-BMIPP uptake. The left ventricular shortening fraction (%SF) and the ratio of peak mitral flow velocity in early diastole to that at the time of atrial systole (E/A ratio) were measured by echocardiography. The H/M ratio of 123I-MIBG was lower in group A than in group C (1.5±0.2 vs. 1.9±0.2, p<0.01). The patients in group A had faster clearance of 123I-MIBG from the myocardium than those in group C (27±10% vs. 22±4%, p<0.05). However, the H/M ratio and clearance of 123I-BMIPP were similar between the two groups (H/M ratio: 2.1±0.2 vs. 2.0±0.2, clearance: 24±6% vs 26±6%). The %SF (37±8% vs. 36±7%) and E/A ratio (1.4±0.4 vs. 1.6±0.3) were comparable in groups A and C. The present findings indicated that myocardial imaging with 123I-MIBG could detect myocardial damage in patients treated with anthracycline in the early stage when cardiac systolic and diastolic function was still preserved. Early detection of anthracycline cardiotoxicity by 123I-MIBG would reduce the incidence and severity of heart failure. (author)