自身对照内耳外淋巴钆造影3D-FLAIR成像评估膜迷路积水

Endolymphatic hydrops evaluation by self-control 3D-FLAIR MRI of perilymphangiography with gadolinium

目的采用经鼓膜穿刺鼓室内注入对比剂Gd-DTPA后行MR扫描的方法,探讨内耳外淋巴钆造影三维液体衰减反转恢复(3D-FLAIR)成像量化评估膜迷路积水程度的可行性,以及梅尼埃病(MD)时对比剂在耳蜗底转和前庭处的分布特点。方法对66例经临床确诊的单侧MD患者双侧耳均经鼓膜穿刺鼓室内注入Gd-DTPA稀释液,24 h后行内耳3D-FLAIR MR扫描和内耳3D MR水成像(MRH)。选定耳蜗层面和前庭层面,分别测量内耳3D MRH图像上双侧耳蜗底转宽度(d耳蜗)和前庭面积(f前庭),以及内耳3D-FLAIR图像上双侧耳蜗底转外淋巴显影宽度(D耳蜗)、前庭外淋巴显影范围(S前庭)和前庭外淋巴与同层面脑干的信号强度比(SIR前庭)。通过上述数值计算出3D-FLAIR图像耳蜗底转宽度系数R耳蜗(患侧D耳蜗/健侧D耳蜗)、前庭范围系数R前庭(患侧S前庭/健侧S前庭)和前庭/脑干信号系数R SIR(患侧SIR前庭/健侧SIR前庭),比较R前庭与R SIR之间、R耳蜗与R前庭之间有无相关性及相关程度。结果66例单侧MD患者的患侧与健侧的D耳蜗分别是(1.29±0.65)mm和(2.03±0.27)mm、S前庭分别是(5.09±4.59)mm^2和(12.70±2.46)mm^2、SIR前庭分别是(0.48±0.54)和(1.25±0.64),比较差异均有统计学意义(t=8.476、t=10.615、t=7.339,P<0.05),且患侧数值明显低于健侧。R前庭与R SIR呈高度正相关(r=0.890,P<0.01),R耳蜗与R前庭呈低度正相关(r=0.315,P<0.05)。结论基于相应层面内耳3D MRH,内耳外淋巴钆造影3D-FLAIR成像可活体显示膜迷路积水并量化评估积水程度,为MD的诊断与治疗提供影像学依据。MD膜迷路积水时,对比剂在前庭外淋巴的分布范围和分布浓度均明显减少,而对比剂在耳蜗底转与前庭外淋巴的分布范围相关性不明显,提示两处的膜迷路积水程度可能是不均衡的。

Objective After intratympanic gadolinium administration through the tympanic membrane,three dimensional fluid attenuated inversion recovery magnetic resonance imaging(3D-FLAIR MRI)was performed to explore the feasibility of endolymphatic visualization and quantitative evaluation of labyrinthine hydrops,and to probe the gadolinium distribution of cochlear basal turn and vestibule in Meniere's disease.Methods Twenty-four hours after bilateral intratympanic gadolinium administration through the tympanic membrance,66 patients with unilateral Meniere's disease diagnosed clinically underwent 3D-FLAIR and 3D magnetic resonance hydrography(MRH)imaging at a 3.0 Tesla MRI system.The cochlear and vestibular slices were determined.The width of cochlear basal turn(d cochlea)and the area of vestibule(f vestibule)were measured respectively on 3D MRH.The perilymphatic width of cochlear basal turn(D cochlea),the enhanced range of vestibular perilymph(S vestibule)and the signal intensity ratio between the vestibule and the brain stem(SIR vestibule)were measured respectively on 3D-FLAIR MRI.The width coefficient(R cochlea)of cochlear basal turn(affected side Dcochlea/healthy side Dcochlea),the range coefficient(R vestibule)of vestibule(affected side S vestibule/healthy side S vestibule)and the signal coefficient(R SIR)of vestibule and brain stem(affected side SIR vestibule/healthy side SIR vestibule)were work out on 3D-FLAIR MRI.The correlation between R vestibule and R SIR,R cochlea and R vestibule were explored.Results For the affected side and the healthy side,D cochlea were(1.29±0.65)mm and(2.03±0.27)mm,S vestibule were(5.09±4.59)mm^2 and(12.70±2.46)mm^2,SIR vestibule were(0.48±0.54)and(1.25±0.64)in 66 patients,which were significantly different(t=8.476,t=10.615,t=7.339,P<0.05).Above measurments of the affected side were significantly lower than those of the healthy side.There were high-level positive correlation between R vestibule and R SIR(r=0.890,P<0.01),and low-level positive correlation between R cochlea and R vestibule(r=0.315,P<0.05).Conclusion According to 3D MRH,3D-FLAIR MRI of perilymphangiography with gadolinium can in vivo show and quantify endolymphatic hydrops,thus providing radiographic evidence for the diagnosis of Meniere's disease.Distribution and concentration of gadolinium of vestibular perilymph both decreased significantly in Meniere's disease.There was no significant correlation between cochlear basal turn and vestibule for gadolinium distribution,indicating unbalanced labyrinthine hydrops in cochlea and vestibule.