Case control MR-CISS and 3D TOF MRA imaging study of medullary compression and hypertension in hemifacial spasm.

The association between ventro-lateral medulla (VLM) compression and hypertension has not been compared between hemifacial spasm (HFS) and healthy controls using advanced magnetic resonance imaging (MRI) techniques specific for detecting neurovascular compression. We conducted a MR-constructive interference in a steady state (CISS) and Magnetic Resonance Angiography (MRA) imaging study of VLM compression in hypertensive HFS patients and hypertensive controls compared with healthy controls without hypertension. A total of 125 subjects, including 45 HFS, 51 healthy controls, and 29 hypertensive controls were included. When compared with healthy controls, there was a higher prevalence of VLM compression in hypertensive HFS (82.2% vs. 41.2%, P < 0.001, odds ratio = 6.61, 95% CI 2.37-19.48), and hypertensive controls (72.4% vs. 41.2%, P = 0.007, odds ratio = 3.75, 95% CI 1.42-9.89). Although the prevalence in hypertensive HFS was higher compared to controls with hypertension, this was not significant (82.2% vs. 72.4%). Compared to healthy controls, there was an increasing proportion of higher compression scores on the right (P = 0.001) and left (P = 0.038) (chi square for trend) in hypertensive HFS and hypertensive controls. Kruskal-Wallis test revealed that the mean right compression score on the right (P = 0.003), left (P = 0.026) and the mean bilateral compression score (P < 0.0001) was higher in hypertensive HFS and hypertensive controls compared to healthy controls. MR-CISS and MRA imaging revealed a greater likelihood of VLM compression in hypertensive HFS and hypertensive controls compared to healthy controls. Our case control study provides further support that VLM compression is associated with hypertension in HFS.