Title: [In vivo dynamic changes of inner ear guinea pigs with 9.4 T esla MRI].
Abstract: Objective: To observe the imaging characteristics of guinea pig cochlear structure using 9.4 Tesla magnetic resonance imaging system at different time intervals of contrast agent distribution in the inner ear. Methods: Form May 2015 to October 2015, five albino guinea pigs were injected with Gd-DTPA via the right internal jugular vein (3 ml/kg). Inner ears were scanned with 9.4T MRI. At the 10 th, 30 th, 60 th, 90 th and 120 th minutes post-Gd-DTPA, we took inner ear images to detect changes of endolymph and perilymph. Using Image J software, we acquired MRI gray value through the first, second, third and apical turn of cochlear at different time points. Analysis by one-way ANOVA was taken to analyze the resultsusing GraphPad Prism 5 software. Results: Only outlines of the cochlea and vestibule were visible before Gd-DTPA injection and there was no clear distinction between endolymph and perilymph. Cochlea vestibule on T1 weighted images was enhanced at the 10 th (the first turn of cochlear 8 203±819) after injection, and then imaging of each part of cochlea, including cochlea, vestibule, semicircular canal and even endolymph and perilymph, can be distinguished clearly, because they enhanced gradually at the 30 th(10 489±819), 60 th(13 965±591), and at 90 th(18 050±1 250) after injection. While at the 120 th(18 952±1 185) minute, imaging was not significantly enhanced than at the 90 th minute. The speed and volume of contrast agent spreaded into the various parts of the inner ear were different, and changes with distribution of contrast agent in each part of the inner ear showed a rising process in a certain period of time. The distribution of contrast agent in the inner ear had concentration gradient via basal turn higher and apical turn lower. Conclusions: Endolymph of inner ear can be distinguished from the perilymph using a 9.4T MRI system with Gd-DTPA, and the best observation timer was 90 minutes after intravenous injection of contrast agent. In summary, our study provides the clearly visualized imaging evidence of the changes of the lymphatic fluid, which may be useful for diagnosis of inner ear diseases such as Meniere's Disease.目的: 研究豚鼠耳蜗结构在9.4 T MRI系统中的成像特点。 方法: 2015年5—10月选用5只白化豚鼠在9.4 T MRI系统中进行内耳扫描,随后右侧颈内静脉注射钆喷酸葡胺(3 ml/kg),分别于注射后10、30、60、90和120 min进行内耳扫描。使用Image J软件对耳蜗的底转、第二转、第三转和顶转四个部位的不同时间点的MRI图像灰度值进行提取,绘制静脉注射造影剂后不同时间点耳蜗各部位MRI图像灰度变化曲线图,使用GraphPad Prism 5软件对结果行one-way ANOVA分析。 结果: 注射造影剂前,MRI仅能显示豚鼠耳蜗及前庭轮廓,不能辨别内、外淋巴液。注射造影剂后10 min(底转灰度值8 203±819)耳蜗前庭在T1像上即有增强,注射后30 min(底转灰度值10 489±819)和60 min(底转灰度值13 965±591)后耳蜗各阶显像逐渐增强,注射后90 min(底转灰度值18 050±1 250)时耳蜗、前庭、半规管均充分显影,可以清晰分辨出内外淋巴液,注射后120 min(底转灰度值18 952±1 185)时图像显影较90 min时无明显增强。造影剂进入内耳各部位的速度和量不等,在一定时间内,内耳各部位的造影剂分布变化均呈现持续上升的过程;造影剂在内耳各个部位的分布不均匀,耳蜗底转造影剂量最多,蜗顶最少,存在浓度梯度。 结论: 用钆喷酸葡胺增强的高分辨MRI系统可以清晰区分出豚鼠内外淋巴液,静脉注射钆造影剂后90 min为MRI内耳增强显影的最佳观察时间,使用钆造影剂的MRI成像为内淋巴积水的病理改变提供了影像学诊断依据。.
Publication Year: 2020
Publication Date: 2020-04-07
Language: en
Type: article
Indexed In: ['pubmed']
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Cited By Count: 1
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