Venous lacunae presenting with unusual upward protrusion: an anatomic study using high-resolution magnetic resonance imaging.

ABSTRACT

PURPOSE: This study aims to investigate the distribution and anatomic features of venous lacuna presenting with unusual upward protrusion (VLUUP) using high-resolution magnetic resonance (MR) imaging. METHODS: This retrospective study included 59 consecutive outpatients who underwent MR imaging with gadolinium. Acquired imaging data were transferred to a workstation for analysis. RESULTS: The 30 male and 29 female subjects were aged from 10 to 76 years. A total of 46 VLUUPs located parasagittally were identified in 36 of the 59 patients, 24 on the right, and 22 on the left; 29 patients had one VLUUP, 4 patients had two, and 3 patients had three. Most VLUUPs (93 %) were distributed in the posterior third of the frontal region and the remainder (7 %) in the middle third. There were no VLUUP found in the anterior third of the frontal region or the parietal or occipital regions. The mean longitudinal and lateral dimensions of the VLUUPs and distance from the midline to the medial margin of the VLUUP were 9.7 mm (3.1-27.6), 6.9 mm (3.1-11.5), and 14.3 mm (1.6-43.5), respectively. CONCLUSIONS: The VLUUPs carry a higher risk of injury when making a bony window in or involving the parasagittal posterior frontal region. High-resolution MR imaging is useful for delineating the VLUUPs.