高分辨率三维真实重建反转恢复序列和三维液体衰减反转恢复序列评估内淋巴积水的对比研究

Visualization of endolymphatic hydrops after intratympanic injection of Gd-DTPA： a comparison of high resolution three dimensional-real inversion recovery and three dimensional fluid-attenuated inversion recovery with a variable flip angle sequence

目的比较高分辨率三维真实重建反转恢复（3D—real IR）序列和基于可变反转角技术的三维液体衰减反转恢复（3D—FLAIR—VFL）序列对内耳内淋巴积水的显示情况。方法对40例由我院耳科主任医师诊断为梅尼埃病或迟发性膜迷路积水的患者共52只耳行内耳轴面MR扫描。比较3D-FLAIR—VFL序列和3D—real IR序列图像的信噪比和对比噪声比，及对患侧内耳、患侧耳蜗底周、中周、顶周和前庭内淋巴积水的显示情况。使用配对t检验比较两种序列的信噪比和对比噪声比；使用配对χ^2检验比较两种序列对患侧内耳、患侧耳蜗底周、中周、顶周和前庭内淋巴积水的显示结果。结果3D—real IR序列的信噪比（28．06±12．71）高于3D—FLAIR-VFL序列（17．64±6．38），差异有统计学意义（t=6．37，P〈O．05）；3D-real IR序列的对比噪声比（33．79±13．52）也高于3D-FLAIR-VFL序列（15．40±6．04），差异也有统计学意义（t=11．11，P〈0．05）。52只患耳中，3D-FLAIR-VFL序列发现患侧内耳、患侧耳蜗底周、中周和顶周发生内淋巴积水的数量分别为41、33、37和10只，3D-realIR序列发现的数量分别为49、46、46和46只，3D-realIR序列对这些部位积水的检出率明显高于3D-FLAIR-VFL序列，差异均有统计学意义（P值分别为0．008，0．001，0．004和0．001，均〈0．05）。使用两种序列对前庭的评价结果一致，均发现39只内耳发生前庭内淋巴积水。结论与3D—FLAIR—VFL序列相比，高分辨率3D—real IR序列拥有更高的图像质量，及对耳蜗内淋巴积水更高的检出率。

Objective To compare the value of high resolution 3D-real inversion recovery（3D-real IR） and 3D fluid-attenuated inversion recovery with a variable flip angle （3D-Flair-VFL） sequence in the visualization of endolymphatic hydrops. Methods 52 ears in 40 patients with Meniere＇s disease or delayed endolymphatic hydrops were enrolled and performed by axial 3D-real IR and 3D-Flair MRI scans 24 hours after intratympanic injection of eight-fold diluted Gd-DTPA. Signal to noise ratio （SNR） and contrast-to-noise ratio （CNR） of the two sequences were calculated and compared by t test. Whether there were endolymphatic hydrops in the basal turn, middle turn, apical turn of the cochlear and vestibule was further evaluated. Results Both the SNR and CNR of 3D-real IR images were statistically higher than 3D-Flair images （SNR： 28.06± 12.71 vs. 17.64±6.38, P〈0.05; CNR： 33.79±13.52 vs. 15.40±6.04, P〈0.05）. Endolymphatic hydrops of the basal turn, second turn, apical turn of the cochlear and vestibule detected by 3D-Flair-VFL images were 33, 37, 10 and 41 cases, respectively, while by 3D-Flair-VFL images were 46, 46, 46 and 49 cases,respectively. There were significant differences between the two sequences in evaluating basal turn, second turn, apical turn of the cochlear except vestibule （P〈0.05）. Conclusion 3D-real IR images are clearer than 3D-Flair-VFL images and can display endolymphatic hydrops more precisely.