Multimodal Imaging Analysis for Brain Clearance: PET Imaging Based Clearance Slope, FASTT2 MRI‐based Parenchyma CSF fraction, and DTI‐based ALPS‐index

Glymphatic clearance is important to maintain brain health, which depends on two interconnected fluid systems: the novel glymphatic system and the traditional well‐characterized CSF system1. There are several imaging tools have been developed to evaluate the glymphatic function in the human brain, however each method providing only a limited perspective into glymphatic system2. A proper imaging tool should consider both circulation pathway of the bulk CSF flow, and a complex PVS network parallel to the microvascular structure. We developed and tested an imaging package including vCSF, CSFF, and DTI‐ALPS, to investigate the ventricular CSF turnover rate, perivascular CSF flow and brain parenchymal CSF fraction.