HSC Section 8_April 2017

Imaging in pulsatile tinnitus

atherosclerosis, but CT or MR angiography may be effectively combined with skull-base imaging in the setting of PT. PT was the presenting symptom in 16 out of 136 consecutive cases of cervicocephalic (14 internal carotid and two vertebral) dissection. 15 On MRI dis- section manifests as a crescent of high T1- weighted signal intensity (mural haematoma), which narrows the signal void within the residual lumen ( Fig. 6 ). CTA may demonstrate an intimal flap and a double lumen, which should be viewed on a wide window width. 11 Fibromuscular dysplasia affects medium-sized vessels and is the second most common cause of extra-cranial carotid artery narrowing. 16 After is- chaemia, PT is the most common clinical presenta- tion and is the cause of PT in up to 6% of cases in the reported literature. 4,6 The characteristic string of beads angiographic pattern is the result of focal areas of stenosis and dilatation. Endolymphatic sac tumour is an aggressive vascu- lar tumour that arises from the distal (posterior) end of the endolymphatic sac ( Fig. 7 ). The tumour is rare but strongly associated with Von Hippel e- Lindau syndrome. 17 Clinical presentation includes PT, conductive and sensorineural hearing loss, fa- cial palsy, and vestibular dysfunction. 18 On MRI, areas of T1-weighted hyperintensity reflect blood Other vascular neoplasms

a series of 34 patients with PT using colour Doppler ultrasound and found a 12% incidence of carotid atherosclerosis. Duplex ultrasound is the tradi- tional non-invasive method of assessing carotid Lateral projection of an external carotid artery angiogram in a patient with glomus jugulare who presented with lower cranial nerve palsies and PT. Angiography shows the neuromeningeal branches of the ascending pharyngeal artery that supply the tumour arise directly from the occipital artery with a rapid in- tense tumour blush. Figure 4

Figure 5 Lateral projection in a woman with intracta- ble and objective PT with ‘‘normal’’ MRI/MRA who was advised to undergo conventional angiography to exclude a dAVF. There is a severe stenosis of the supraclinoid ca- rotid artery ipsilateral to the PT.

Figure 6 T1-weighted, fat-saturated, transverse MR image in a patient with ICA dissection, demonstrates an eccentric hyperintense rim of intramural haematoma (arrowhead) and narrowing of the vessel lumen.

73