Naganawa Shinji, Kawai Hisashi, Sone Michihiko, Ikeda Mitsuru
Department of Radiology, Nagoya University Graduate School of Medicine.
Magn Reson Med Sci. 2015;14(3):203-10. doi: 10.2463/mrms.2014-0112. Epub 2015 Mar 31.
Isolated vestibular-lateral semicircular canal dysplasia (LSCCD) is one of the most common anomalies of the inner ear. However, endolymphatic size in LSCCD is unknown. We measured the size of the endolymph in the vestibule of patients with LSCCD and compared it with that measured in patients without LSCCD.
We extracted 1102 magnetic resonance (MR) studies for the evaluation of endolymphatic hydrops (EH) from our database of radiology reports. Among these, we found 15 ears from 11 patients with LSCCD; 4 patients had bilateral abnormalities. Seven of the 15 ears demonstrated aplasia and 8 ears, hypoplasia of the lateral semicircular canal (LSCC). The control group consisted of 26 ears from 13 randomly selected patients without LSCCD. We measured the area of endolymph in the vestibule (ELA), total area of vestibular lymph fluid (TLA), and area of the central bony island (CBI) of the LSCC from axial MR images obtained after intratympanic or intravenous administration of gadolinium-based contrast material. The ratio of endolymphatic area to total lymphatic area (%EL) was defined as %EL = ELA/TLA × 100.We evaluated the correlation between %EL and the area of the CBI and compared age, %EL, degree of cochlear EH, hearing level, and presence of rotating vertigo among the 3 groups (aplasia, hypoplasia, control).
The mean %EL was 76.7% in the aplasia group, 50.0% in the hypoplasia group, and 27.8% in the control group (P < 0.001). There was a relatively strong linear correlation between the area of the CBI and %EL (r = -0.767). Patient age, mean hearing level, degree of cochlear EH, or presence of vertigo attacks did not differ significantly among the groups (P > 0.05).
The size of vestibular endolymph was larger in the groups with aplasia or hypoplasia than the control group. Thus, the current diagnostic cut-off value for significant vestibular EH (>50%) might not be appropriate for ears with LSCCD.
孤立性前庭-外侧半规管发育不全（LSCCD）是内耳最常见的异常之一。然而，LSCCD 中内淋巴的大小尚不清楚。我们测量了 LSCCD 患者前庭内淋巴的大小，并将其与无 LSCCD 患者的测量结果进行比较。
我们从放射学报告数据库中提取了 1102 份用于评估内淋巴积水（EH）的磁共振（MR）研究资料。其中，我们发现了 11 例 LSCCD 患者的 15 只耳朵；4 例患者为双侧异常。15 只耳朵中有 7 只表现为发育不全，8 只表现为外侧半规管（LSCC）发育不良。对照组由 13 例随机选择的无 LSCCD 患者的 26 只耳朵组成。我们通过鼓室内或静脉注射钆基对比剂后获得的轴向 MR 图像，测量了前庭内淋巴面积（ELA）、前庭淋巴液总面积（TLA）以及 LSCC 的中央骨岛面积（CBI）。内淋巴面积与总淋巴面积的比值（%EL）定义为%EL = ELA/TLA×100。我们评估了%EL 与 CBI 面积之间的相关性，并比较了三组（发育不全、发育不良、对照组）患者的年龄、%EL、耳蜗 EH 程度、听力水平以及旋转性眩晕的存在情况。
发育不全组的平均%EL 为 76.7%，发育不良组为 50.0%，对照组为 27.8%（P < 0.001）。CBI 面积与%EL 之间存在相对较强的线性相关性（r = -0.767）。各组之间患者年龄、平均听力水平、耳蜗 EH 程度或眩晕发作情况无显著差异（P > 0.05）。
发育不全或发育不良组的前庭内淋巴大小大于对照组。因此，目前显著前庭 EH（>50%） 的诊断临界值可能不适用于 LSCCD 患者的耳朵。
