Perivascular CSF T2 Values compared to Sulcal and Lateral Ventricular CSF: a window into brain clearance pathways

Motivation: Earlier studies have measured CSF-T2 values in the sulci and ventricles of healthy subjects; however, these studies lacked sufficient resolution to assess the perivascular spaces (PVS). Goal(s): We obtained high-resolution multi-echo scans at 7T and compared PVS T2 values with those in the sulci and lateral ventricles. Approach: We hypothesized that T2 values in the PVS would be lower due to the presence of 'dirty' CSF closer to waste production sites. Six subjects were acquired with multi-echo 7T scans with long echo times, and T2 maps were created. Results: PVS had shorter T2 values than the sulci and lateral ventricles. Impact: The reduced T2 values observed in the PVS suggest the presence of 'dirty' CSF, supporting the idea that MR-visible PVS, primarily associated with arteries, may serve not only as channels for fresh CSF inflow but as mixing-sites of waste products.