Department of Radiological Technology, Nagoya University Hospital.
Department of Radiology, Nagoya University Graduate School of Medicine.
Magn Reson Med Sci. 2023 Jul 1;22(3):335-344. doi: 10.2463/mrms.mp.2022-0017. Epub 2022 May 10.
To determine whether T2-contrast enhancement techniques can be used to diagnose endolymphatic hydrops, we compared fluid signal artifacts with and without T2-contrast enhancement techniques in 3D fluid-attenuated inversion recovery (3D-FLAIR).
We prepared a custom-made phantom consisting of eight tubes half-filled with saline. Images were obtained using four 3D-FLAIR: without T2-contrast enhancement (Normal), with non-selective T2-inversion recovery (T2-IR), and two with non-selective T2 preparation IR (T2-prep). Scans were performed with and without rice covering the phantom to simulate minimal and severe B0-inhomogeneity conditions. The average signal intensity (SI) values of eight saline tubes were compared between the four sequences and between each other. Comparisons were performed for all measurement slices and the central 10 slices. The images using T2-contrast enhancement technique were obtained from a volunteer and a patient suspected of Meniere's disease.
The Normal sequence SI for all slices was significantly lower than that for the other sequences, with smaller standard deviation (SD) and no outliers. Several outliers were detected in the other sequences. The SDs and outliers were larger without rice than with rice. When the central 10 slices with rice, the T2-IR had a significantly higher SI with more outliers compared with the Normal sequence. The T2-prep had no outliers and SIs that were comparable to those of the Normal sequence. However, without rice, the T2-IR and T2-prep sequences had significantly higher SIs with outliers and larger SDs compared to the Normal sequence. In the corresponding images, the Normal sequence achieved excellent fluid suppression, whereas the T2-IR and T2-prep sequences showed high-signal artifacts. Imperfect fluid suppressions were observed in the volunteer image and the endolymphatic hydrops on the post-gadolinium image differed in size and shape in the non-injected T2-IR in the patient image.
T2-contrast enhancement techniques should be used with caution in 3D-FLAIR for diagnosing endolymphatic hydrops.
通过比较三维液体衰减反转恢复（3D-FLAIR）序列中有无 T2 对比增强技术时的液体信号伪影，探讨 T2 对比增强技术是否可用于诊断内淋巴积水。
我们使用 4 种 3D-FLAIR 序列（未应用 T2 对比增强的常规序列、非选择性 T2 反转恢复序列、2 种非选择性 T2 预脉冲序列）制备一个包含 8 个半充满盐水管的定制化模型。在盐水管上覆盖大米模拟轻微和严重的 B0 不均匀性条件，完成有无大米条件下的扫描。比较 4 种序列及两两序列间盐水管的平均信号强度（SI）值。比较覆盖大米时的所有层面和中央 10 个层面，T2 对比增强技术的图像取自一位疑似梅尼埃病的志愿者和患者。
无大米覆盖时，所有层面的常规序列 SI 均显著低于其他序列，SI 标准差（SD）较小，无离群值；其他序列存在多个离群值，无大米覆盖时 SI 标准差及离群值大于有大米覆盖时。有大米覆盖时中央 10 个层面，T2-IR 序列 SI 明显高于常规序列，离群值更多；T2-prep 序列无离群值，SI 与常规序列相似。但无大米覆盖时，T2-IR 和 T2-prep 序列 SI 明显高于常规序列，且存在离群值和更大的 SD。相应图像中，常规序列可实现良好的液体抑制，而 T2-IR 和 T2-prep 序列显示高信号伪影。志愿者图像的液体抑制不完全，患者图像中未注射钆的 T2-IR 层面，内淋巴积水的大小和形状与增强后图像存在差异。
3D-FLAIR 诊断内淋巴积水时应谨慎应用 T2 对比增强技术。
