title: Ring-shaped lateral ventricular nodules detected with brain MR imaging.
abstract: OBJECTIVE
  We evaluated the prevalence and imaging characteristics of ring-shaped lateral ventricular nodules (RSLVNs) detected by postcontrast brain magnetic resonance (MR) imaging.
  
  
  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 T₁-weighted (T₁WIs), T₂-weighted (T₂WIs), fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted (DWIs) images and characteristics of contrast enhancement.
  
  
  RESULTS
  In 5 patients, we found 6 RSLVNs (0.45%), 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 T₁WI, T₂WI, 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 imaging findings of a 0.45% prevalence of RSLVNs shows they are not so rare as previously reported. Except for configuration, 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 significance. However, their clear differentiation avoids unnecessary surgery.
authors.affiliation: Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan. reiko-nakajima@rad.twmu.ac.jp
authors.forename: Reiko
authors.initials: R
authors.lastname: Nakajima
authors.forename: Akira
authors.initials: A
authors.lastname: Uchino
authors.forename: Naoko
authors.initials: N
authors.lastname: Saito
authors.forename: Ryo
authors.initials: R
authors.lastname: Nishikawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002551:Cerebral Ventricle Neoplasms / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media