Measurement of cardiovascular function using a novel view-sharing PET reconstruction method and tracer kinetic...

Recent advancements in PET instrumentation have made the non-invasive assessment of cardiovascular function in small animals a reality. The majority of small animal PET systems use stationary detector gantries, thus affording high temporal resolution imaging of cardiac function. Systems designed to maximize spatial resolution and detection sensitivity employing rotating gantry designs are suboptimal when high temporal resolution imaging is needed. To overcome this limitation, the current work developed a novel view-sharing data analysis scheme suitable for dynamic cardiac PET imaging using ¹⁸F-NaF as the tracer and tracer kinetic model analysis. This scheme was tested in a rat model of cardiovascular function where the relationship between direct transonic flow measures of cardiac output were highly correlated (f(x) = 1.0216x - 24.233, R = 0.9158, p < 0.001) with the new model. Similarly, derived measures of stroke volume were also highly correlated (f(x) = 0.9655x - 0.0428, R = 0.9453, p < 0.001) with the current approach. Administration of xylazine caused a statistically significant increase in stroke volume (0.32 ± 0.07 ml, p = 0.003, n = 4) and a significant decrease in both heart rate (-155 ± 7.1 beats/min, p < 0.001, n = 4) and cardiac output (-75.9 ± 23.0 ml/kg min, p = 0.01, n = 4). These findings suggest that the new sinogram binning and kinetic modeling methods produce reliable cardiac function measures suitable for longitudinal monitoring of cardiovascular function.