Simultaneous assessment of regional adrenergic activity and perfusion with 123I-MIBG and 201Tl in congestive heart failure.

Simultaneous assessment of regional adrenergic activity and perfusion with 123I-meta-iodobenzylguanidine (123I-MIBG) and 201Tl in various organs was performed in 13 patients with congestive heart failure (CHF) and 13 subjects without heart failure. In order to reduce the crosstalk of 201Tl to the 123I energy window to less than 5%, a dose of 123I-MIBG more than five times greater than that of 201Tl was administered following 201Tl scintigraphy. Regional uptake of 201Tl (%dose) was significantly increased in the heart (left ventricle) and lung (both P < 0.01) in the patients with CHF. The increased global cardiac uptake could have been related to the enlarged left ventricle. The patterns of regional uptake of 123I-MIBG (% dose) at 15 min were similar to those of 201Tl, suggesting that early 123I-MIBG uptake could in part depend on regional perfusion in both groups. At 3 h, regional uptake of 123I-MIBG was significantly increased in the heart, lung and kidney (all P < 0.01) in the patients with CHF. The delayed 123I-MIBG uptake indicates the degree of neuronal accumulation of the tracer, and therefore reflects adrenergic activity. Interestingly, the cardiac 123I-MIBG (adrenergic activity) to 201Tl (unit of perfusion) ratio decreased significantly in the heart (P < 0.01) but increased significantly in the kidney (P < 0.01) in the patients with CHF compared with the control group. Cardiac 123I-MIBG washout was also significantly increased in the CHF patients. Moreover, the cardiac 123I-MIBG:201Tl ratio was negatively correlated with plasma norepinephrine concentration (r = -0.74, P < 0.01), but positively correlated with LVEF (r = 0.60, P < 0.01). These data suggest that there may be impairment of both the neuronal uptake function and the vesicular storage function in the failing heart, and an increment in neuronal uptake function in the kidneys in patients with CHF. We suggest that dual-tracer scintigraphy is a useful non-invasive method for the simultaneous assessment of adrenergic activity and perfusion in various organs in patients with heart failure.