Rollins N, Booth T, Shapiro K
Department of Radiology, Children's Medical Center, Dallas, TX 75235, USA.
Childs Nerv Syst. 2000 Sep;16(9):569-75; discussion 575-7. doi: 10.1007/PL00007299.
Foramen magnum and jugular foramen stenosis, well-known problems in achondroplasia, may result in brain stem compression and venous outflow obstruction, respectively. We studied a series of children with achondroplasia using gated cine phase contrast (PC) CSF flow studies to evaluate CSF dynamics across the foramen magnum and MR venography (MRV) to depict obstructed venous drainage.
Ten patients (9 months to 11 years, mean 2.85 years) were referred for possible brain stem compression. MRI included routine sequences, cine PC with velocity encoding (VENC) = 5 cm/s, and MRV. Six patients, including the asymptomatic patient, had brain stem compression without tonsillar herniation; two had tonsillar herniation; and two had neither brain stem compression nor tonsillar herniation. Abnormal tonsillar movement was seen only with tonsillar herniation. MRV showed steno-occlusive disease of the internal jugular vein (IJV) in nine patients, sigmoid sinus in four, and absent or hypoplastic transverse sinus in seven. Veno-occlusive disease was not progressive. No patient had massive hydrocephalus, although larger ventricles were associated with more profuse venous collateral formation and more severe degrees of IJV stenosis. Three patients have undergone CSF diversion.
MR imaging may be useful in defining the pathophysiology of brain stem compression and hydrocephalus in achondroplasia.
枕骨大孔和颈静脉孔狭窄是软骨发育不全中众所周知的问题，可能分别导致脑干受压和静脉回流受阻。我们对一系列软骨发育不全患儿进行了门控电影相位对比(PC)脑脊液流动研究，以评估枕骨大孔处的脑脊液动力学，并进行磁共振静脉血管造影(MRV)以描绘静脉引流受阻情况。
10例患者（9个月至11岁，平均2.85岁）因可能存在脑干受压而前来就诊。MRI检查包括常规序列、速度编码(VENC)=5cm/s的电影PC以及MRV。6例患者，包括无症状患者，存在脑干受压但无扁桃体疝；2例有扁桃体疝；2例既无脑干受压也无扁桃体疝。仅在有扁桃体疝的情况下可见异常的扁桃体运动。MRV显示9例患者颈内静脉(IJV)存在狭窄闭塞性病变，4例患者乙状窦存在病变，7例患者横窦缺如或发育不全。静脉闭塞性疾病没有进展。尽管脑室较大与更丰富的静脉侧支形成和更严重的IJV狭窄相关，但没有患者出现大量脑积水。3例患者接受了脑脊液分流术。
磁共振成像可能有助于明确软骨发育不全中脑干受压和脑积水的病理生理机制。
