Transverse relaxation of cerebrospinal fluid depends on glucose concentration

Purpose: To evaluate the biophysical processes that generate specific T-2 values and their relationship to specific cerebrospinal fluid (CSF) content. Materials and methods: CSF T-2, were measured ex vivo (14.1 T) from isolated CSF collected from human, rat and non-human primate. CSF T-2s were also measured in vivo at different field strength in human (3 and 7 T) and rodent (1, 4.7, 9,4 and 11.7 T) using different pulse sequences. Then, relaxivities of CSF constituents were measured, in vitro, to determine the major molecule responsible for shortening CSF T-2 (2 s) compared to saline T-2 (3 s). The impact of this major molecule on CSF T-2 was then validated in rodent, in vivo, by the simultaneous measurement of the major molecule concentration and CSF T-2. Results: Ex vivo CSF T-2 was about 2.0 sat 14.1 T for all species. In vivo human CSF T-2 approached ex vivo values at 3 T (2.0 s) but was significantly shorter at 7 T (0.9 s). In vivo rodent CSF T-2 decreased with increasing magnetic field and T-2 values similar to the in vitro ones were reached at 1 T (1.6 s). Glucose had the largest contribution of shortening CSF 12 in vitro. This result was validated in rodent in vivo, showing that an acute change in CSF glucose by infusion of glucose into the blood, can be monitored via changes in CSF T-2 values. Conclusion: This study opens the possibility of monitoring glucose regulation of CSF at the resolution of MRI by quantitating T-2. (C) 2017 Published by Elsevier Inc.