Abstract

(15)O-H2O PET imaging is an accurate method to measure cerebral blood flow (CBF) but it requires an arterial input function (AIF). Historically, image-derived AIF estimation suffers from low temporal resolution, spill-in, and spill-over problems. Here, we optimized tracer dose on a time-of-flight PET/MR according to the acquisition-specific noise-equivalent count rate curve. An optimized dose of 850?MBq of (15)O-H2O was determined, which allowed sufficient counts to reconstruct a short time-frame PET angiogram (PETA) during the arterial phase. This PETA enabled the measurement of the extent of spill-over, while an MR angiogram was used to measure the true arterial volume for AIF estimation. A segment of the high cervical arteries outside the brain was chosen, where the measured spill-in effects were minimal. CBF studies were performed twice with separate [15O]-H2O injections in 10 healthy subjects, yielding values of 88?±?16, 44?±?9, and 58?±?11?mL/min/100?g for gray matter, white matter, and whole brain, with intra-subject CBF differences of 5.0?±?4.0%, 4.1?±?3.3%, and 4.5?±?3.7%, respectively. A third CBF measurement after the administration of 1?g of acetazolamide showed 35?±?23%, 29?±?20%, and 33?±?22% increase in gray matter, white matter, and whole brain, respectively. Based on these findings, the proposed noninvasive AIF method provides robust CBF measurement with (15)O-H2O PET.

View details for DOI 10.1177/0271678X17691784

View details for PubMedID 28155582