Small high-signal lesions posterior to the intracranial vertebral artery incidentally identified by 3D FLAIR: retrospective study of 127 patients

概要

Purpose
　A small, benign high-signal lesion (HSL) posterior to the intracranial vertebral artery (VA) at the foramen magnum is a new entity revealed by a 3D flu id-attenuated inversion-recovery (FLAIR) sequence. However, this entity has not been sufficiently investigated. We aimed to investigate the magnetic resonance (MR) imaging findings of HSLs posterior to the intracranial VA that were incidentally detected by 3D FLAIR.

Methods
　We retrospectively evaluated 3717 patients using a 3-T MR unit. Analyses for HSL images included the number of lesions per patient, lesion size, contact with VA, and contact with spinal accessory nerve (SAN). Other MR images were also evaluated to determine the presence of HSLs. For patients with HSLs detected by 3D FLAIR, the signal intensities were also evaluated on the corresponding 3D Tl-weighted images (T1 WIs) and 2D T2-weighted images(T2WIs). When postcontrast studies were performed, HSLs were assessed for presence or absence of contrast enhancement. When follow-up MR imaging