Contrast Enhancement of the Anterior Eye Segment and Subarachnoid Space: Detection in the Normal State by Heavily T2-weighted 3D FLAIR

Abstract

Fluid-attenuated inversion recovery (FLAIR) has been reported more sensitive than T(1)-weighted images in detecting low concentration gadolinium-based contrast media (GBCM) in fluid, and heavily T(2)-weighted (hT(2)W) 3-dimensional (3D) FLAIR has recently been reported even more sensitive than conventional 3D FLAIR. We investigated whether high signal of the anterior eye segment (AES) and subarachnoid space (SAS) in various locations as well as cerebrospinal fluid (CSF) in cisterns and ventricles can be detected on hT(2)W 3D FLAIR images obtained 4 hours after intravenous administration of GBCM in subjects without eye and SAS diseases. Ten patients suspected of having Ménière's disease underwent hT(2)W 3D FLAIR 4 hours after intravenous administration of single-dose GBCM to evaluate endolymphatic hydrops. We evaluated signal intensity of AES, SAS surrounding the optic nerve, SAS in Meckel's cave, CSF in the internal auditory canal, CSF in the prepontine cistern, CSF in the lateral and fourth ventricles, and lymph fluid in the cochlea by comparison with non-contrast images obtained in a separate group of 5 patients. The signal intensity of each structure was normalized by that of the pontine parenchyma. We observed no signal difference in images of the pontine parenchyma obtained before and after enhancement. Significant signal difference was seen in all structures except the lateral and fourth ventricles. Four hours after intravenous injection, GBCM can be detected by hT(2)W 3D FLAIR in various fluid-containing spaces, such as the AES and various SAS and CSF spaces.