Wang Feng, Lyu Huiying, Zhao Menglong, Sha Yan, Zhang Fang, Cheng Yushu, Huang Wenhu, Tang Wenlin, Xie Youzhou, Lu Ping
*Department of Radiology †Department of Otolaryngology, Eye and ENT Hospital, Fudan University ‡Siemens Ltd., Shanghai, China.
Otol Neurotol. 2017 Apr;38(4):585-590. doi: 10.1097/MAO.0000000000001331.
We assessed whether the three-dimensional fluid-attenuated inversion-recovery (3-D FLAIR) and three-dimensional inversion-recovery with real reconstruction (3-D real IR) sequences can be used to detect cochlea endolymphatic hydrops (EHs) in guinea pigs using 3 Tesla magnetic resonance imaging (3T MRI). The results of 3-D real IR imaging were compared with histopathological outcomes.
Fourteen healthy men and women albino guinea pigs were used in this study. Their right ears received procedures that promoted EHs, and their left ears were used as untreated controls. High-resolution 3T MRI, combined with the intratympanic injection of gadolinium (Gd) in both ears, was performed 8 to 12 weeks after surgery. Both sides of the cochlea midmodiolar sections were observed under a light microscope and saved as the histopathological images. The signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) between the T2-weighted 3-D FLAIR and T2-weighted 3-D real IR sequences were compared. The appearance of EHs in the basal, second, third, and apical turns of the cochlea was further evaluated using 3-D FLAIR, 3-D real IR, and the histopathological images. Moreover, the maximum scala media area ratios (SMRs) on the histopathological sections were compared with the grading of the EHs on the 3-D real IR sequence with regard to each turn of the cochlea.
Significant differences were found between the 3-D FLAIR and 3-D-real IR sequences with regard to the SNRs and CNRs (p < 0.05): the 3-D FLAIR sequence exhibited higher SNRs (SNRROI: 347.95 ± 105.01; SNRB: 103.28 ± 17.61) compared with the 3-D real IR sequence (SNRROI: 86.71 ± 30.11; SNRB: 11.11 ± 3.45), whereas the 3-D real IR sequence showed higher CNRs (2.78 ± 0.58) compared with the 3-D FLAIR sequence (2.18 ± 0.55). Various degrees of EHs were observed in each turn of the cochlea in the experimental ears on the basis of the histopathological images. Thirteen, 10, 4, and 0 EHs were observed in the basal, second, third, and apical turns of the cochlear using 3-D FLAIR images, respectively, whereas 14, 14, 14, and 13 EHs were found using 3-D real IR images, respectively. Significant differences were found between the two sequences when evaluating the second, third, and apical turns of the cochlear but not with regard to the basal turn (p < 0.05). The SMRs were proportional to the extent of the EHs on 3-D real IR imaging in each turn of the cochlea.
3-D real IR images are clearer than 3-D FLAIR images, and they can display cochlea EHs more precisely using 3T MRI in guinea pigs. The extent of the EHs on 3-D real IR imaging was more consistent with the histopathological observations in each turn of the cochlea.
我们评估了三维液体衰减反转恢复（3-D FLAIR）序列和三维真实重建反转恢复（3-D real IR）序列能否用于通过3特斯拉磁共振成像（3T MRI）检测豚鼠的耳蜗内淋巴积水（EHs）。将3-D real IR成像的结果与组织病理学结果进行比较。
本研究使用了14只健康的白化豚鼠（雌雄均有）。对它们的右耳进行促进EHs形成的操作，左耳作为未处理的对照。术后8至12周进行高分辨率3T MRI检查，并在双耳鼓室内注射钆（Gd）。在光学显微镜下观察耳蜗中膜切片的两侧，并保存为组织病理学图像。比较T2加权3-D FLAIR序列和T2加权3-D real IR序列之间的信噪比（SNRs）和对比噪声比（CNRs）。使用3-D FLAIR、3-D real IR和组织病理学图像进一步评估耳蜗基底转、第二转、第三转和顶转中EHs的表现。此外，将组织病理学切片上的最大中阶面积比（SMRs）与3-D real IR序列上耳蜗各转的EHs分级进行比较。
在SNRs和CNRs方面，3-D FLAIR序列与3-D real IR序列之间存在显著差异（p<0.05）：与3-D real IR序列（SNRROI：86.71±30.11；SNRB：11.11±3.45）相比，3-D FLAIR序列表现出更高的SNRs（SNRROI：347.95±105.01；SNRB：103.28±17.61），而3-D real IR序列显示出比3-D FLAIR序列更高的CNRs（2.78±0.58）（2.18±0.55）。根据组织病理学图像，在实验耳的耳蜗各转中观察到了不同程度的EHs。使用3-D FLAIR图像在耳蜗基底转、第二转、第三转和顶转中分别观察到13例、10例、4例和0例EHs，而使用3-D real IR图像分别发现14例、14例、14例和13例EHs。在评估耳蜗第二转、第三转和顶转时，两个序列之间存在显著差异，但在基底转方面没有差异（p<0.05）。在耳蜗的每一转中，SMRs与3-D real IR成像上EHs的程度成正比。
3-D real IR图像比3-D FLAIR图像更清晰，并且在豚鼠中使用3T MRI时，它们能够更精确地显示耳蜗EHs。3-D real IR成像上EHs的程度与耳蜗各转的组织病理学观察结果更一致。
