Ring-shaped Lateral Ventricular Nodules Detected with Brain MR Imaging

Abstract

Purpose: We evaluated the prevalence and imaging characteristics of ring-shaped lateral ventricular nodules (RSLVNs) detected by postcontrast brain magnetic resonance (MR) imaging.Materials and Methods: We retrospectively reviewed cranial MR images of 1,241 patients who underwent contrast-enhanced brain imaging between January 1, 2008 and March 31, 2011, excluded images of inadequate quality of 130 patients, and ultimately analyzed images of 1,111 patients (544 male, 567 female). We assessed location, shape, and signal intensity of RSLVNs on T 1 -weighted (T 1 WIs), T 2 -weighted (T 2 WIs), ‰uid-attenuated inversion recovery (FLAIR), and diŠusion-weighted (DWIs) images and characteristics of contrast enhancement.Results: In 5 patients, we found 6 RSLVNs (0.45z), four in the frontal horn and two in the roof of the body. Three RSLVNs were round, two were oval, and one was lobular on axial images. All 6 RSLVNs were isointense with adjacent brain parenchyma on T 1 WI, T 2 WI, and DWI but slightly hyperintense on FLAIR images; none showed enhancement on postcontrast MR imaging. Five nodules serially examined (range, 8 to 24 months) showed no interval changes.Conclusions: Our MR imagingˆndings of a 0.45z prevalence of RSLVNs shows they are not so rare as previously reported. Except for conˆguration, all nodules had similar intensity, and none showed contrast enhancement. Absence of changes during the follow-up period seemed to indicate that the nodules have no clinical signiˆcance. However, their clear diŠerentiation avoids unnecessary surgery.

A Case of Intracranial Subependymoma: Histopathological Confirmation of Ring-shaped Lateral Ventricular Nodule

“… 3 Nakajima et al also proposed that RSLVN may be a precursor to or variant of subependymoma because of the similar radiological and clinical findings. 2 Multiple RSLVNs also will not inconsistent with subependymoma, because a case of multiple subependymoma was reported previously. 3 However, a definitive conclusion has been difficult because subependymoma has not been described as having a ring-shaped appearance.…”

“…Subsequently, Nakajima et al reported a 0.45% prevalence of RSLVNs. 2 Although they noted RSLVNs might be benign lesions without rapid growth, histopathological confirmation has not been described. We report a case of RSLVN with histopathological examination of surgical specimens.…”