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We present two cases of subclavian steel syndrome to give an impression of the wide spectrum of possible symptoms and of the commonly used imaging modalities in subclavian steal syndrome.
Case one is a 49-year-old female with periodic numbness in her left arm, followed by dizziness and nausea, occurring only while hanging laundry. MRI with angiography (fig 1A) and conventional angiography revealed a moderate proximal left subclavian artery stenosis (fig 2A–C), while Duplex ultrasound demonstrated the functional haemodynamic consequences (fig 1B–D) and the stenosis was eventually treated with a stenting procedure (fig 2D).
Case two is a 59-year-old male with chronic renal failure on haemodialysis presenting with acute left homonymous haemianopsia. His installed Cimino fistula was found enormously enlarged with calculated volume of total fistula flow 3945 ml/min. MRI of the brain demonstrated an acute ischaemic stroke of the occipital lobe (fig 3A, B). Further investigations showed a patent vertebrobasilar system, no subclavian artery stenosis and were negative for an embolic source (fig 3C, D). Ultrasonography of the brachiocephalic fistula revealed high haemodynamic demand (fig 4).1 Thus, the patient either suffered haemodynamic infarcts in two endbranches of the posterior cerebral artery or the oscillatory flow within the left vertebral artery caused clot formation leading to local embolic events.
While CT angiography and MR angiography both are suitable for detecting a subclavian artery stenosis,2,3 both techniques are less suitable for detecting dynamic and subtle changes in blood flow. However, cranial CT and MRI can provide more information about acute or chronic ischaemic events in the vertebrobasilar territory. Conventional angiography can determine the degree of a stenosis with greatest accuracy and demonstrate retrograde flow.
Ultrasound investigation disclosed important haemodynamic aspects of the disease that were not observed by MR angiography.
Competing interests: none.
Patient consent: Patient/guardian consent was obtained for publication.
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