Quantification of myocardial blood flow with ¹¹C-hydroxyephedrine dynamic PET: comparison with ¹⁵O-H₂O PET

Background: ¹¹C-hydroxyephedrine (HED) PET has been used to evaluate the myocardial sympathetic nervous system (SNS). Here we sought to establish a simultaneous approach for quantifying both myocardial blood flow (MBF) and the SNS from a single HED PET scan. Methods: Ten controls and 13 patients with suspected cardiac disease were enrolled. The inflow rate of ¹¹C-HED (K1) was obtained using a one-tissue-compartment model. We compared this rate with the MBF derived from ¹⁵O-H₂O PET. In the controls, the relationship between K₁ from ¹¹C-HED PET and the MBF from ¹⁵O-H₂O PET was linked by the Renkin-Crone model. Results: The relationship between K₁ from ¹¹C-HED PET and the MBF from ¹⁵O-H₂O PET from the controls’ data was approximated as follows: K₁ = (1 − 0.891 * exp(− 0.146/MBF)) * MBF. In the validation set, the correlation coefficient demonstrated a significantly high relationship for both the whole left ventricle (r = 0.95, P < 0.001) and three coronary territories (left anterior descending artery: r = 0.96, left circumflex artery: r = 0.81, right coronary artery: r = 0.86; P < 0.001, respectively). Conclusion: ¹¹C-HED can simultaneously estimate MBF and sympathetic nervous function without requiring an additional MBF scan for assessing mismatch areas between MBF and SNS.