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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
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.
Other vascular neoplasms
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
Figure 4
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 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.
Imaging in pulsatile tinnitus
73