Naganawa S, Koshikawa T, Iwayama E, Fukatsu H, Ishiguchi T, Ishigaki T, Ikeda M, Nakashima T, Ichinose N
Department of Radiology, Nagoya University School of Medicine, Japan.
AJNR Am J Neuroradiol. 2000 Oct;21(9):1664-9.
In enlarged endolymphatic duct (EED) and sac (EES) syndrome, deformity of the EED and EES is congenital; however, hearing loss is acquired. To investigate the pathophysiology of progressive sensorineural hearing loss in EED and EES syndrome, we measured the volume of the EED and EES, the diameter of the EED and EES, the area of the cochlear modiolus, and the signal intensity of the EES and compared our findings against degree of hearing loss.
Thin-section MR images of 33 ears in 17 patients with EED and EES syndrome were studied. All studies were obtained on a 1.5-T MR unit using a quadrature surface phased-array coil. Heavily T2-weighted 3D fast asymmetric spin-echo images were obtained with a voxel size of 0.3 x 0.3 x 0.8 mm without zero-fill interpolation. Two radiologists traced the areas of the EED and EES manually, and the volume was calculated. The area of the cochlear modiolus, diameter of the EED and EES, and signal intensity of the EES were also measured by drawing regions of interest manually. The signal intensity ratio of EES/CSF was calculated. These measured values were compared against audiographic data, and the degree of linear correlation was determined.
The volume of the EED and EES, the area of the modiolus, the diameter of the EED and EES, and the signal intensity of the EES did not show significant correlation with degree of hearing loss.
These findings suggest that there is a microscopic area of damage or fragility in the inner ear not visible even with thin-section heavily T2-weighted MR imaging.
在扩大内淋巴管（EED）和内淋巴囊（EES）综合征中，EED和EES的畸形是先天性的；然而，听力损失是后天获得的。为了研究EED和EES综合征中进行性感音神经性听力损失的病理生理学，我们测量了EED和EES的体积、EED和EES的直径、蜗轴面积以及EES的信号强度，并将我们的研究结果与听力损失程度进行了比较。
对17例EED和EES综合征患者的33只耳朵进行了薄层MR图像研究。所有研究均在1.5-T MR设备上使用正交表面相控阵线圈获得。使用体素大小为0.3×0.3×0.8 mm的重T2加权3D快速不对称自旋回波图像，不进行零填充插值。两名放射科医生手动描绘EED和EES的区域，并计算体积。蜗轴面积、EED和EES的直径以及EES的信号强度也通过手动绘制感兴趣区域进行测量。计算EES/脑脊液的信号强度比。将这些测量值与听力图数据进行比较，并确定线性相关程度。
EED和EES的体积、蜗轴面积、EED和EES的直径以及EES的信号强度与听力损失程度均无显著相关性。
这些发现表明，即使使用薄层重T2加权MR成像，内耳中仍存在一个微观损伤或脆弱区域，肉眼无法看到。
