Fluid signal suppression characteristics of 3D-FLAIR with a T2 selective inversion pulse in the skull base
Shinji Naganawa, Yutaka Kato, Tadao Yoshida, Michihiko Sone
Abstract
Meningeal lymphatics have been visualized in animals and humans by the administration of an exogenous tracer 1 , 2 . In a recent study, Albayram et al. 3 reported that dural lymphatic structures along the venous sinuses in dorsal regions and along the cranial nerves in ventral regions of the human brain can be visualized by non-contrast enhanced 3D T2-Fluid Attenuated Inversion Recovery (3D-FLAIR) magnetic resonance (MR) imaging, which relies on the intrinsic signals from protein-rich lymphatic fluid. While attempts to depict the meningeal lymphatic system in humans without the use of contrast agents are to be applauded, there are some concerns regarding the MR images of the ventral dural lymphatic system in Fig. 4 in the article by Albayram et al. 3 . Depending on the type of inversion pulse used, 3D-FLAIR images may show insufficient signal suppression of cerebrospinal fluid in the skull base 4 , and some of the skull base dural lymphatics visible in their figure may be an artifact.