The effect of intravenous gadolinium on the magnetic resonance appearance of cerebrospinal fluid.

The authors determined whether a sufficient amount of intravenously administered gadolinium enters the cerebrospinal fluid (CSF) to visibly shorten the T1 relaxation time. Transfer of intravenously administered contrast media into the CSF has been previously documented for iodinated contrast materials; however, the change in computed tomography density is not sufficient to have a clinically useful myelographic effect. Visible shortening of the T1 of CSF on gadolinium-enhanced magnetic resonance imaging of the spine may have clinical use. Twelve dogs were given gadolinium, and CSF was sampled at intervals over a 6-hour period. The T1 values of the CSF samples were quantitated and plotted against time. The average decrease in T1 was 23% at 60 minutes, which is nearly the peak effect. The increased signal intensity was visible at clinical window settings at 60 minutes. It is possible that this may be clinically useful for certain types of examinations. Importantly, this should be recognized as a normal appearance, and not necessarily a sign of pathology.