Dynamic SPET parameters of ¹²³I-MIBG cardiac imaging

Early dynamic and late ¹²³I-MIBG SPET studies were performed to investigate several parameters used to distinguish the characteristics of various cardiac disorders. Forty-six individuals (34 non-diabetic, 12 diabetic) with or without heart disease were included in the study. Early dynamic and late static SPET images were acquired using a triple-headed gamma camera. After selecting mid-sections from vertical (VLA) and horizontal (HLA) long-axis images, regions of interest were created over the apex, whole heart and anterior, inferior, septal and lateral walls of the heart. Various uptake ratios at 3,11 and 19 min and 4 h after injection (HU3, HU11, HU19, DUP) and clearances (K_se: between HU3 and HU11; K_e: between HU11 and HU19; K_d: between HU19 and DUP) were calculated. There were significant differences among various cardiac pathologies on the delayed images. Cardiomyopathy patients showed the lowest uptake on the delayed images. When all segments in normal patients and all involved segments in myocardial infarcted patients were compared, there was significantly lower uptake of MIBG in infarcted segments at all time points. K_d showed the lowest value compared with and K_e. In cardiomyopathy patients, K_se, and K_d were significantly different from each other. Both K_se and K_e were significantly higher in cardiomyopathy patients than in normal patients. In conclusion, the results of this study are in line with published data and precise measurement of uptaK_e and clearance was possible when excluding background and blood pool activity.