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.