Willinsky R A
University of Toronto, Ont.
Can Assoc Radiol J. 1992 Apr;43(2):93-9.
The causes of tinnitus can be grouped according to whether the noise is continuous or pulsatile, whether it is subjective or objective and whether there is a retrotympanic mass. Imaging algorithms can be based on these symptoms and signs. For patients with nonpulsatile tinnitus and a normal drum, magnetic resonance imaging is preferred if a retrocochlear lesion is suspected, whereas high-resolution computed tomography (HRCT) is recommended if a cochlear abnormality is likely. If a chronic inflammation in the middle ear is suspected, HRCT is the study of choice to differentiate cholesteatoma from chronic otitis media. If the bruit is objective and the tympanic membrane normal, selective cerebral angiography should be the initial investigation, because most such patients have an acquired vascular abnormality, usually a dural arteriovenous fistula. If there is pulsatile tinnitus and a retrotympanic mass, HRCT should be the first examination because this technique allows differentiation of a vascular variation, such as an aberrant carotid artery or jugular dehiscence, from a paraganglioma.
耳鸣的病因可根据噪音是持续性还是搏动性、是主观性还是客观性以及是否存在鼓室后肿物进行分类。成像算法可基于这些症状和体征。对于非搏动性耳鸣且鼓膜正常的患者，如果怀疑有蜗后病变，首选磁共振成像；而如果可能存在耳蜗异常，则推荐高分辨率计算机断层扫描（HRCT）。如果怀疑中耳有慢性炎症，HRCT是区分胆脂瘤与慢性中耳炎的首选检查。如果耳鸣是客观性的且鼓膜正常，选择性脑血管造影应作为初始检查，因为大多数此类患者有后天性血管异常，通常是硬脑膜动静脉瘘。如果存在搏动性耳鸣和鼓室后肿物，HRCT应作为首选检查，因为该技术能够区分血管变异，如异常颈动脉或颈静脉裂孔，与副神经节瘤。
