A novel imaging method for assessing vessel wall inflammation: Dynamic multi-bed PET parametric imaging

Objectives To develop a novel method for assessing near total body vascular wall inflammation over an extended field-of-view using dynamic multi-bed FDG PET.

Methods Whole-body parametric and standard uptake value (SUV) static PET images were obtained from 6 oncology patients. The parametric images were produced by dynamically scanning the patient over the heart for the first 6 minutes post FDG injection (24 frames), followed by six subsequent whole body scans. The total dynamic acquisition lasted less than 45 minutes and the collected data were analyzed using the Patlak method to produce Ki (influx) parametric images over the full whole-body scan range. The SUV images were acquired by performing a standard static whole-body scan beginning 1 hour post-injection of FDG. In both parametric and SUV images, the mean and maximum values of circular ROI at 10 different levels along the thoracic aorta were measured and the averages were calculated. For the SUVs, the measured values were corrected for lean body mass (SULmean and SULmax).

Results With static images, the average SULmean over 10 aorta regions was 1.23±0.27, and the average SULmax was 1.61±0.35. With parametric images, the average of the mean Patlak Ki was 0.77±0.57 and the average of the maximum was 1.60±0.85.

Conclusions Enabling minimization of background blood activity, the parametric Patlak Ki image is a novel method for quantitative assessment of inflammation in the walls of large portions of major vessels.