面神经静脉畸形的高分辨率CT及MRI特征分析

Imaging characteristics analysis of high resolution CT and MRI of facial nerve venous malformation

目的分析面神经静脉畸形(FNVM)的高分辨率CT及MRI特征性表现。方法回顾性收集2016年1月至2020年12月上海交通大学医学院附属第九人民医院经病理证实的23例FNVM患者。所有患者均行术前颞骨HRCT及平扫、扩散加权成像(DWI)和动态增强MRI(DCE-MRI)。观察病灶位置、病灶形态、信号特点、DCE-MRI强化方式,分析时间-信号强度曲线(TIC)类型,并测量表观扩散系数(ADC)。结果23例FNVM病灶位于膝状神经节19例、乳突段1例、内听道3例。19例以面神经膝状神经节为病灶中心的患者中,HRCT表现为蜂窝状骨质改变13例、表现为光滑的膨胀性骨质改变6例。位于乳突段的病灶HRCT亦表现为蜂窝状骨质改变。3例位于内听道的病灶中,有2例可见点片状高密度新骨形成,另1例出现骨壁吸收破坏。所有23例病灶MRI均表现为形态不规则的结节,T_(1)WI呈等信号14例、低信号8例、高信号1例,脂肪抑制T_(2)WI呈高信号15例、等信号8例,增强后均呈明显的不均匀强化,ADC值为(1.18±0.20)×10^(-3) mm^(2)/s,DCE-MRI见特征性的“点到面”充填式强化方式,TIC曲线呈Ⅰ型(持续上升型)。结论FNVM的HRCT和MRI影像表现具有一定的特征性,蜂窝状骨质改变和“点到面”充填式强化方式为较有特征性的影像学征象。

Objective To analyze imaging features on high resolution CT(HRCT)and MRI of facial nerve venous malformation(FNVM).Methods A total of 23 patients with pathologically confirmed FNVM were retrospectively included from January 2016 to December 2020 in the Shanghai Ninth People′s Hospital,Shanghai Jiao Tong University School of Medicine.All patients underwent preoperative temporal bone HRCT,non-contrast MRI,diffusion weighted imaging(DWI)and dynamic contrast enhanced MRI(DCE-MRI).The location,morphology,and signal intensity of the lesions,as well as the enhancement pattern on DCE-MRI were reviewed.The time-intensity curve(TIC)was analyzed and the apparent diffusion coefficient(ADC)was measured.Results The locations of FNVM lesions were geniculate ganglion(n=19),mastoid segment(n=1)and internal auditory canal(n=3).Among 19 cases in geniculate ganglion,HRCT showed honeycomb-like bone change(n=13)or expansive bone destruction with sharp border(n=6).The case located in mastoid segment also presented as honeycomb-like changes.The other 3 cases in internal auditory canal presented with patchy hyperdensity bone change(n=2)or resorptive bone destruction(n=1).All 23 lesions demonstrated as irregular nodules with obviously heterogeneous enhancement on MRI.The lesions showed isointensity(n=14),hypointensity(n=8)or hyperintensity(n=1)on T_(1)WI,and hyperintensity(n=15)or isointensity(n=8)on fat-suppression T_(2)WI.The ADC values of the lesions were(1.18±0.20)×10^(-3) mm^(2)/s.A characteristic"point-to-plane"progressive enhancement pattern displayed on DCE-MRI,with typeⅠTIC(persistent pattern)presented.Conclusion The imaging characteristics of FNVM are honeycomb-like bone changes on HRCT and"point-to-plane"progressive enhancement pattern on DCE-MRI.