Meng Ling-Chen, Wang Yu-Fen, Young Yi-Ho
Departments of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan.
Departments of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan.
Eur Arch Otorhinolaryngol. 2025 Mar;282(3):1201-1208. doi: 10.1007/s00405-024-09012-1. Epub 2024 Oct 5.
This study utilized Hydrops MRI in patients with cranial nerve (CN) VIII schwannoma to assess the concomitance with endolymphatic hydrops (EH), aiming to elucidate the mechanism of hydrops formation in these patients.
Twenty-six patients diagnosed as CN VIII schwannoma including vestibular schwannoma (VS) in 24 and intracochlear schwannoma (ICS) in 2 were enrolled. Fifteen patients received radiosurgery and 11 patients opted for a wait-and-scan approach. All patients underwent an inner ear test battery, followed by Hydrops MRI. Based on Hydrops MRI, 6 patients (23%) with positive EH were assigned to Group A, while the other 20 patients showing negative EH were assigned to Group B.
The abnormality rates of inner ear test battery in Group A ran from the audiometry (100%), cervical vestibular-evoked myogenic potential (cVEMP) test (83%), ocular VEMP (oVEMP) test (67%) to the caloric test (33%), exhibiting a significantly declining sequence. This declining sequence is consistent with the decreasing order in the prevalence of EH from the cochlea (83%), saccule (50%) to utricle (50%). However, Group B did not show such decreasing trend, indicating that Groups A and B did not share the common mechanism. The mean tumor size prior to radiosurgery was 1.91 ± 0.89 cm, which significantly reduced to 1.53 ± 0.60 cm at a mean interval of 6 years following radiosurgery. In contrast, tumor size remained unchanged in those opted for a wait-and-scan approach.
It is recommended to utilize Hydrops MRI for patients with CN VIII schwannoma during annual follow-up, particularly those experienced episodic vertigo and/or deteriorated hearing. The Hydrops MRI can not only monitor tumor size, but also detect the presence of EH, so as to guide treatment decision.
本研究对颅神经（CN）VIII 神经鞘瘤患者采用内淋巴积水磁共振成像（Hydrops MRI）评估其与内淋巴积水（EH）的并存情况，旨在阐明这些患者积水形成的机制。
纳入 26 例诊断为 CN VIII 神经鞘瘤的患者，其中 24 例为前庭神经鞘瘤（VS），2 例为耳蜗内神经鞘瘤（ICS）。15 例患者接受了放射外科治疗，11 例患者选择了等待观察并定期扫描的方法。所有患者均接受了一套内耳检查，随后进行 Hydrops MRI 检查。根据 Hydrops MRI 检查结果，6 例 EH 阳性患者（23%）被分配到 A 组，另外 20 例 EH 阴性患者被分配到 B 组。
A 组内耳检查的异常率从听力测定（100%）、颈前庭诱发肌源性电位（cVEMP）试验（83%）、眼 VEMP（oVEMP）试验（67%）到冷热试验（33%）呈显著下降顺序。这种下降顺序与 EH 在耳蜗（83%）、球囊（50%）到椭圆囊（50%）的患病率下降顺序一致。然而，B 组未显示出这种下降趋势，表明 A 组和 B 组没有共同的机制。放射外科治疗前肿瘤的平均大小为 1.91±0.89 cm，放射外科治疗后平均间隔 6 年时显著缩小至 1.53±0.60 cm。相比之下，选择等待观察并定期扫描方法的患者肿瘤大小保持不变。
建议对 CN VIII 神经鞘瘤患者在每年随访期间进行 Hydrops MRI 检查，尤其是那些有发作性眩晕和/或听力减退的患者。Hydrops MRI 不仅可以监测肿瘤大小，还可以检测 EH 的存在，从而指导治疗决策。
