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Reprinted by permission of Clin Radiol. 2009; 64(3):319-328.

Clinical Radiology (2009) 64 , 319 e 328

PICTORIAL REVIEW

Imaging in pulsatile tinnitus G. Madani a , * , S.E.J. Connor b

a Radiology Department, St Mary’s Hospital, London, UK, and b Neuroradiology Department, King’s College Hospital, London, UK

Received 11 January 2008; received in revised form 17 July 2008; accepted 1 August 2008

Tinnitus may be continuous or pulsatile. Vascular lesions are the most frequent radiologically demonstrable cause of pulsatile tinnitus. These include congenital vascular anomalies (which may be arterial or venous), vascular tumours, and a variety of acquired vasculopathies. The choice of imaging depends on the clinical findings. If a mass is present at otoscopy, thin-section computed tomography (CT) is indicated. In the otoscopically normal patient, there is a range of possible imaging approaches. However, combined CT angiography and venography is particularly useful. ª 2008 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

radiological investigation of non-PT is low and thin-section, T2-weighted magnetic resonance im- aging (MRI) sequences are generally used for screening. 3 Thus knowledge of the nature of the tinnitus (PT versus non-PT) is essential. There is a wide variation in the reported in- cidence of structural abnormalities in patients with PT ranging from 44 e 91% ( Table 1 ). 4 e 9 This is likely to reflect variations in the study populations, expertise, and methods of investigation. Paragan- gliomas, dural arteriovenous fistulae (dAVFs), idio- pathic intracranial hypertension (IIH), venous anatomical variations, and atheromatous arterial disease represent the most frequent causes. 4 e 9 An underlying cause is usually identified in patients with objective tinnitus ( Table 1 ). 4 e 9 This review focuses on the radiological imaging of PT. The choice and focus of imaging for PT is guided by the clinical findings. The presence of a visible intratympanic or retrotympanic mass and the sus- picion of arterial [reduced by pressure on the ipsilateral internal carotid artery (ICA)] or venous (reduced by pressure on the ipsilateral jugular vein) aetiologies are particularly important.

Introduction

Tinnitus is the perception of an auditory sensation, most frequently a ringing sound, in the absence of an external stimulus. Tinnitus may be classified as pulsatile (PT) or continuous. PT is usually related to vascular causes and is pulse-synchronous (coinciding with the patient’s heartbeat). It may be subjective (heard only by the patient) or objective (also audible to the examiner). The prevalence of persistent tinnitus (lasting more than 5 min) in the UK adult population is around 10%; half of these patients find the symp- tom moderately or severely annoying. 1 PT is much less common than non-PT, affecting approximately 4% of patients with tinnitus. 2 PT may not require radiological investigation; cases may be transient, related to drugs, systemic processes (e.g. hyper- tension, anaemia, pregnancy), or other conditions, such as migraine. Radiological investigation aims to find treatable causes of tinnitus. In the setting of non-PT, the main entity to exclude is a cerebellopontine cis- tern mass lesion. In the absence of additional audiological findings, the diagnostic yield of * Guarantor and correspondent: G. Madani, Radiology Depart- ment, St Mary’s Hospital, Imperial College NHS trust, Praed Street, London W2 1NY, UK. Tel.: þ 44-2078861116; fax: þ 44- 2078872281. E-mail address: gittamadani@yahoo.com (G. Madani).

Radiological investigation

If a mass is seen at otoscopy, then a thin-section computed tomography (CT) of the petrous tempo- ral bones is needed to assess the middle ear.

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