Discrimination of leptomeningeal carcinomatosis and meningeal inflammation/infection with internal acoustic canal enhancement

Purpose: The purpose of this study is to investigate whether the presence and pattern of enhancement at the internal acoustic canal (IAC) could help in discriminating between leptomeningeal carcinomatosis (LCa) and meningeal inflammation/infection (MMI). Methods: Magnetic resonance (MR) images of patients with leptomeningeal enhancement were retrospectively evaluated. MR images of the LCa group (n = 33), MMI group (n = 19) and control group (n = 33) were evaluated for the presence, type (moderate/prominent), and localization (unilateral/bilateral) of the IAC enhancement.
Results: The presence of IAC enhancement was significantly more common in patients with LCa (p < 0.001). In 73.7 % of patients with MMI, no contrast enhancement was observed in the IAC. In patients with contrast enhancement in the IAC, the risk of LCa in the etiology is 20 times greater than the risk of having MMI. Seventyfive percent of the IAC enhancement seen in LCa patients and 20 % of the IAC enhancements seen in MMI patients was bilateral. This difference was statistically significant (p = 0.029). Conclusion: Intense contrast enhancement of the IAC can be a marker for LCa.