Recurrent inflammatory stenosis of the M1 segment: diagnostic and therapeutic considerations

Abstract

Dear Sir: Recent advances of imaging technology have helped to identify stenoses of intracranial arteries as an important cause of cerebral ischemia [1]. It has been estimated that up to 10% of strokes are caused by intracranial occlusive disease. The introduction of intracranial angioplasty and stenting has added a new therapeutic option [2]. However the management of patients with a progressive middle cerebral artery stenosis can remain difficult even with a combination of medical and interventional treatment. A 60-year-old female patient of Indian origin presented in August 2008 with subarachnoid haemorrhage centred on the right Sylvian fissure. CT angiography revealed a tight stenosis of the proximal right middle cerebral artery (M1segment) as the sole abnormality. Subsequent intra-arterial DSA confirmed the presence of the stenosis and also showed distended lenticulostriate arteries on the right and an expansion in the extent of brain tissue supplied from the left ICA at the expense of the right MCA territory. The rupture of one of the friable collateral blood vessels was presumed to be the cause for the subarachnoid haemorrhage, rendering the stenosis symptomatic. As the patient had a history of coronary artery disease and hypercholesterolaemia, the stenosis was initially considered to be due to atherosclerosis. However, the patient subsequently developed transient episodes of left arm weakness and possible jaw claudication. MRI brain did not show any ischaemic lesions, but MRA showed new stenoses affecting the proximal left MCA and distal right internal carotid artery. Contrast-enhanced MRI demonstrated contrast enhancement in the wall of the right MCA. The combination of vessel wall enhancement and newly developed stenoses suggested cerebral vasculitis. Extensive investigation for a systemic vasculitis and CSF tests failed to show any abnormalities. Based on the imaging appearances and the patient’s recurrent symptoms, she was treated with steroids and cyclophosphamide, while her treatment for atheromatous disease was continued. The patient’s symptoms persisted after an initial course of high dose steroids, and a repeat MRA showed worsening of the MCA stenosis. Therefore an angioplasty of the M1 stenosis was performed under general anaesthesia 3 months (end of October 2008) after initial admission (Fig. 1a, b). The balloon (Gateway 2×8 mm) was inflated three times resulting in a significant improvement of the right hemispheric perfusion. There were no procedural complications, either clinically or on DWI MRI. After immunosuppressive treatment with cyclophosphamide for 6 months, a contrast-enhanced MRI showed improvement, though not a complete resolution of the vessel wall enhancement (Fig. 1c). The left middle cerebral artery stenosis had resolved. This improvement was regarded as supporting the presumed diagnosis of vasculitis with response to treatment. W. Kuker (*) : J. Downer Department of Neuroradiology, West Wing John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK e-mail: wilhelm.kuker@clneuro.ox.ac.uk