Assessment of a novel ¹⁸F-labeled myocardial PET tracer in normal and ischemic models of rats

Purpose: ¹⁸F-HX-01 is a fluorine 18-labeled berberine derivative designed as a new positron emission tomography (PET) myocardial perfusion imaging (MPI) agent. Here we report an abstract about the usefulness of this novel tracer in the model of normal and ischemic rats.

Methods: Healthy rats (n=3) and rats with transient (3-min, n=3) or permanent (n=3) left descending coronary artery occlusion were made for the assessment by a dedicated micro-PET/CT. All the above animals underwent a dynamic PET scan, besides, SUVmean was used as quantitative parameter. Volume of interests (VOI) were drawn in PET images on the following organs: myocardium, lung, infarct region, liver and blood pool, and the relative organ time-activity curves (TACs) were automatically generated.

Results: Dynamic Micro PET imaging in normal rats showed high initial heart uptake (5 min, SUVmean 3.75) and persistent retention without obvious wash-out for 2 h. The liver had higher initial activity (5 min, SUVmean 5) with rapid wash out at 10 to 30 min after IV injection. Other organs had low activity (Fig. 1A). In model of ischemic rats or rats with myocardial infarction, the induced defects were well identified (Fig. 1B and 1C). Dynamic Micro PET imaging with ¹⁸F-HX-01 showed a clear and sustained cardiac uptake in rats with minimal lung interference and rapid liver clearance. The uptake of the heart to non-target organs (lung and liver) were also higher as a result of sustained high cardiac activity, low lung activity, and rapid liver activity clearance. TACs were as follows (Fig. 1D-1F).

Conclusions: Current study demonstrated that ¹⁸F-HX-01 cardiac PET imaging in rats shows confidence and certainty in distinguishing normal myocardium from myocardial ischemia and infarction. Further assessment is still needed in stress-rest protocols and to investigate its quantitative value in lager animals. Fig.1 Typical dynamic Micro PET images of ¹⁸F-HX-01 in normal rat (A), rat with transient ischemic (B) and myocardial infarction (C). Corresponding PET-derived time-activity curves (TACs) of the major organs in normal rat (D), rat with transient ischemic (E) and myocardial infarction (F).

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