Simultaneous assessment of myocardial perfusion and adrenergic innervation in patients with heart failure by low-dose dual-isotope CZT SPECT imaging

Background: In patients with heart failure (HF) sequential imaging studies have demonstrated a relationship between myocardial perfusion and adrenergic innervation. We evaluated the feasibility of a simultaneous low-dose dual-isotope ¹²³I/^99mTc-acquisition protocol using a cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) camera.

Methods and results: Thirty-six patients with HF underwent simultaneous low-dose ¹²³I-metaiodobenzylguanidine (MIBG)/^99mTc-sestamibi gated CZT-SPECT cardiac imaging. Perfusion and innervation total defect sizes and perfusion/innervation mismatch size (defined by ¹²³I-MIBG defect size minus ^99mTc-sestamibi defect size) were expressed as percentages of the total left ventricular (LV) surface area. LV ejection fraction (EF) significantly correlated with perfusion defect size (P < .005), innervation defect size (P < .005), and early (P < .05) and late (P < .01) ¹²³I-MIBG heart-to-mediastinum (H/M) ratio. In addition, late H/M ratio was independently associated with reduced LVEF (P < .05). Although there was a significant relationship (P < .001) between perfusion and innervation defect size, innervation defect size was larger than perfusion defect size (P < .001). At multivariable linear regression analysis, ¹²³I-MIBG washout rate (WR) correlated with perfusion/innervation mismatch (P < .05).

Conclusions: In patients with HF, a simultaneous low-dose dual-isotope ¹²³I/^99mTc-acquisition protocol is feasible and could have important clinical implications.