MRI评估原发性高血压和正常血压者延髓腹外侧神经血管接触的临床意义

Clinical significance of neurovascular contact of rostral ventrolateral medulla oblongata evaluated by using MRI in hypertension and normotensive subjects

目的MRI和MR断层血管成像（MRTA）评估在原发性高血压与正常血压健康自愿者，Ⅸ和Ⅹ颅神经进入脑干部延髓腹外侧（RVLM）神经血管接触和接触程度的临床意义。方法188例分为原发性高血压组（100例）和正常血压健康自愿组（88例）采用高分辨率的MRI和MRTA评估。由2名放射科医生在不知道研究对象高血压情况下阅片。神经血管接触程度分为3级：Ⅰ级轻微的血管接触，而范围短；Ⅱ级清楚可见血管与脑干连续接触，但没有明显的脑干变形；Ⅲ级血管接触，而延髓腹外侧变形和移位。结果原发性高血压组Ⅸ和Ⅹ颅神经进入脑干区RVLM神经血管接触52例（52．0％），正常血压健康自愿者组38例（43．2％），2组神经血管接触无统计学意义（χ^2=1．459，P=0．230），2组RVLM左侧或右侧接触率、接触程度（Ⅰ～Ⅲ级）和性别亦无统计学意义（χ^2=0．879，P=0．350；χ^2=0．238，P=0．628；χ^2=0．733，P=0．390）。结论在原发性高血压患者和正常血压健康自愿者神经血管接触同样常见。研究结果不支持神经血管接触与原发性高血压病因有关的假说。MR扫描层厚3mm检测神经血管接触，不是可信赖的最好的扫描方法。MRI不能帮助筛选没有症状的颅神经痛伴高血压延髓腹外侧神经血管接触。

Objective To evaluate the clinical usefulness of MR imaging （MRI） and MR tomography angiography （MRTA） in demonstrating the presence and degree of neurovascular contact of the rostral ventrolateral medulla oblongata （ RVLM ） in root entry zone of the 9th and 10th cranial nerves in patients with essential hypertension （EHT） and normotensive health volunteers （NTHV）. Methods Patients with EHT （ group 1, n = 100 ） and NTHV （ group 2, n = 88 ） underwent high-resolution （ axial and coronal） brain stem MRI and MRTA. Images were interpreted consensually by tow radiologists who were blinded to the patients hypertensive status. Neurovascular contact was graded as vessel contact without RVLM deformity （grade Ⅰ ） , clear vessel contact in continuity with the brain stem but without apparent associated deformity （ graded Ⅱ ） , and displacement contact of the RVLM （ graded Ⅲ ） . Results Neurovascular contact of RVLM was found in 52.0% （52/100） of EHT and in 43.2% （38/88） of NTHV （ χ^2 = 1. 459, P = 0. 230）. The compression rate （ grade Ⅰ- Ⅲ ） and affected side （ left or right） showed no statistically significant differences between the EHT and NTHV （ χ^2 = 0. 879, P = 0. 350; χ^2 = 0. 238, P = 0. 628 ; χ^2 = 0. 733, P = 0. 390 ）. Conclusion Neurovascular contact is not more frequently seen in patients with EHT than in normotensive contact subject. This result does no support the hypothesis that neurovascular contact at the RVLM is an etiology of EHT. Furthermore, thin-slice （3 mm） MRI may not be a reliable good screening method for detecting patients with neurovascular contact. Therefore, MRI cannot aid patient selection among hypertension patients lacking symptomatic cranial neuralgias.