Multiple field strength in vivo T1 and T2 for cerebrospinal fluid protons

To estimate the feasibility of measuring in vivo CSF protein, oxygen, or other solutes through their effect on proton relaxation times, the T1 and T2 of CSF protons has been measured within the human lateral ventricles. T1 was measured at 6.25, 25.4, and 60.1 MHz with a two-point method. T2 was measured at 6.25 and 25.4 MHz using the CPMG sequence to acquire 8 echo images. The T1 was 4.3 s with no evidence of field dependence. The T2 was 2 s. Although these values approach those for water at the same temperature it is possible that the T1 is influenced by the normal oxygen concentration. Calculations based on the relaxivity of dissolved protein indicate that the use of these methods for the detection of elevated levels of CSF protein would be less sensitive than existing methods.