Vascular compression of rostral medulla oblongata: prospective MR imaging study in hypertensive and normotensive subjects.

PURPOSE: To prospectively evaluate prevalence of neurovascular contacts (NVCs) at the rostral medulla oblongata in normotensive and hypertensive subjects.

MATERIALS AND METHODS: Forty-three patients with severe essential hypertension and 45 normotensive subjects were matched for age, sex, and body mass index. Magnetic resonance (MR) imaging included transverse and coronal T2-weighted turbo spin-echo (section thickness, 3.0 mm), transverse three-dimensional (3D) time-of-flight MR angiographic (section thickness, 0.8 mm), and 3D constructive interference in steady state (CISS) (section thickness, 1.0 mm) sequences. All MR images were reviewed by two radiologists who were blinded to the hypertensive status of subjects. Presence and degree of NVC at rostral medulla and left/right rostral ventrolateral medulla (RVLM) were evaluated together with conspicuity of anatomic structures on MR images. Differences in prevalence of NVC among normotensive and hypertensive subjects were tested for statistical significance (P <.05) by using nonparametric tests.

RESULTS: Among hypertensive patients, 34 (79%) of 43 showed NVC of rostral medulla at any location, and 14 (33%) of 43 had NVC at the left RVLM. In controls (normotensive subjects), 35 (78%) of 45 showed NVC of rostral medulla, and 17 (38%) of 45 had NVC at left RVLM. Prevalence of NVC was not significantly different between both groups at any location of rostral medulla. Compared with T2-weighted turbo spin-echo and 3D time-of-flight MR imaging sequences, 3D CISS offered better contrast resolution of neural and vascular structures and superior delineation of outer vascular contours.

CONCLUSION: Vascular compression of the rostral medulla oblongata is a frequent finding in both hypertensive and normotensive subjects. Results of this study do not support NVC at left RVLM as an etiologic factor in essential hypertension.