Measurement of cerebrospinal fluid oxygen partial pressure in humans using MRI

Fluid‐attenuated inversion recovery (FLAIR) images obtained during the administration of supplemental oxygen demonstrate a hyperintense signal within the cerebrospinal fluid (CSF) that is likely caused by T 1 changes induced by paramagnetic molecular oxygen. Previous studies demonstrated a linear relationship between the longitudinal relaxation rate ( R 1 = 1/ T 1 ) and oxygen content, which permits quantification of the CSF oxygen partial pressure ( P csf O 2 ). In the current study, CSF T 1 was measured at 1.5 T in the lateral ventricles, third ventricle, cortical sulci, and basilar cisterns of eight normal subjects breathing room air or 100% oxygen. Phantom studies performed with artificial CSF enabled absolute P csf O 2 quantitation. Regional P csf O 2 differences on room air were observed, from 65 ± 27 mmHg in the basilar cisterns to 130 ± 49 mmHg in the third ventricle. During 100% oxygen, P csf O 2 increases of 155 ± 45 and 124 ± 34 mmHg were measured in the basilar cisterns and cortical sulci, respectively, with no change observed in the lateral or third ventricles. P csf O 2 measurements in humans breathing room air or 100% oxygen using a T 1 method are comparable to results from invasive human and animal studies. Similar approaches could be applied to noninvasively monitor oxygenation in many acellular, low‐protein body fluids. Magn Reson Med 54:113–121, 2005. © 2005 Wiley‐Liss, Inc.