EVALUATION OF THE INTEGRITY OF THE BLOOD-BRAIN-BARRIER AFTER MENINGEAL TRAUMA

RATIONALE AND OBJECTIVES. The authors used magnetic resonance imaging (MRI) techniques to examine the effect of meningeal trauma produced by cisterna magna puncture on the integrity of the blood-cerebrospinal f luid barrier (BCB) in a rat model. METHODS. Intravenous gadolinium-DTP A (Gd-DTPA), a relaxation rate modifier which normally does not cross the BCB, was used as a probe to follow leakage of fluid across the BCB . After Gd-DTPA injection, cerebrospinal fluid (CSF) serial samples we re obtained through the needle used to create the experimental trauma. These samples were subsequently examined in vitro by MRI to obtain th eir T1 relaxation rates and assayed by mass spectrometry for gadoliniu m and elemental iron concentrations. RESULTS. The iron levels reflecte d the severity of puncture-related subarachnoid hemorrhage. Rats with ongoing meningeal damage showed significantly higher CSF levels of gad olinium and significantly higher CSF T1 relaxation rates than controls at all samples times over 1 hour after the puncture. Blood in the CSF could not explain these changes because the CSF iron levels did not s ignificantly differ from control levels. CONCLUSIONS. Intravenously ad ministered Gd-DTPA can gain access to the subarachnoid space through m inor defects in the BCB and cause significant increases in CSF T1 rela xation rates.