Subependymal hyperintense layer on CISS sequence: An MRI study.

Abstract

The present study aimed to explore the subependymal layers overlying the cerebral ventricles using magnetic resonance imaging. A total of 69 outpatients underwent constructive interference in steady-state (CISS) sequence in thin-sliced, coronal, and sagittal sections. The subependymal layers were delineated as linear hyperintensities, coursing along the outer margins of the ventricular walls. On coronal images, the hyperintensities surrounding the anterior horn of the lateral ventricle were identified in 97% of patients, while those of the third ventricle were identified in 96% of patients. In the trigone and posterior horn of the lateral ventricle, the hyperintensities were delineated in all patients. On sagittal images, subependymal hyperintensities were identified in all. At the level of the anterior horn and third ventricle, the subependymal hyperintensities were found to communicate with the Virchow-Robin spaces (VRSs) in 68% and 65% of patients, respectively. At the level of the trigone and posterior horn of the lateral ventricle, the VRSs communicated with the subependymal hyperintensities in 83% of patients. Subependymal hyperintensity may represent an inflow passage of the VRSs that jointly contribute to efficient transependymal migration of the interstitial fluid into the ventricular cerebrospinal fluid.