15O-Water PET Arrival Time Correlation with MR ASL Mean Arterial Time

Motivation: Arterial Transit Time (ATT) is an important hemodynamic biomarker for cerebrovascular diseases such as stroke and although 15O-water PET is considered the gold standard CBF imaging modality, its capabilities in measuring transit time has not been demonstrated. Goal(s): To map tracer arrival time in 15O-water PET exams. Approach: Reconstructed short frames during the early PET acquisition with consistent image quality and used a 5D noise filtering method to measure time-activity-curve and then PET-arrival-time for each voxel. Results: PET-arrival-time can map perfusion related abnormalities apparent in simultaneously acquired ASL-ATTImpact: Even though 15O-water PET is considered the gold standard CBF imaging modality, it lacks measuring an important hemodynamic biomarker, arterial-transit-time. By using MR-priors, we measured the PET-arrival-time on PET/MR and showed it correlates well with MATT measured by ASL simultaneously.