Dissecting aneurysms of the middle cerebral artery: neuroradiological and clinical features

Abstract

There are few reported cases of nontraumatic dissecting aneurysms of the middle cerebral artery (MCA), and their neuroradiological and clinical features have not been analysed. We looked at these aspects in a collaborative study. We reviewed 13 patients diagnosed as having a dissecting aneurysm of the MCA based on clinical signs and neuroradiological findings in 46 stroke centres between 1995 and 1999. There were four patients who presented with cerebral ischaemia, and nine who presented with bleeding. Of the former group, three were aged less than 15 years. Cerebral angiography showed extensive stenosis and a double lumen of the M1 portion in all four patients. High signal on T1-weighted images around the arterial flow void, due to intramural haematoma, was often seen in the second week. MR angiography showed findings corresponding those of intra-arterial angiography in all four cases. We saw an infarct on CT or MRI in territory of the perforating branches of the M1 segment in all four patients. In the patients presenting with bleeding, pure subarachnoid haemorrhage or a sylvian fissure haematoma was seen on initial CT, and the predominant angiographic finding was dilatation with stenosis, but the site of the lesions was not uniform. A double lumen or intimal flap was seen in about half the cases. Rebleeding occurred within 14 days of the onset in five of the nine patients, with a poor prognosis.

Two cases of spontaneous middle cerebral arterial dissection causing ischemic stroke

“…Spontaneous MCAD causing ischemic stroke is seldom reported. To our knowledge, there have been fewer than 20 cases, and these are often associated with internal carotid arterial dissection or trauma [1][2][3]. MCAD might be underdiagnosed; in our stroke database, of 940 patients with cerebral infarcts within the MCA distribution on diffusionweighted images, two patients (0.21%) were diagnosed as having MCAD.…”

“…Cervicocephalic arterial dissections usually involve the internal carotid and vertebral arteries, especially the extracranial portions. Middle cerebral arterial dissection (MCAD) is rare [1][2][3], and isolated spontaneous cases of MCAD are even seldom reported [2]. The clinical and radiological aspects of MCAD are poorly understood.…”

Structure and immunohistochemistry of the human lenticulostriate arteries

“…The small orifices of the LSAs can be easily occluded by a dissecting aneurysm or an atheromatous plaque of the MCA, or artery-to-artery embolism [4,19]. The orifice occlusion can also follow an MCA stent deployment [12].…”

Dilated Outer Diameter of the Dissected Artery: Acute Bilateral Anterior Cerebral Artery Dissection Evaluated by Repeat Magnetic Resonance Cisternography -Case Report-

“…Detection of double lumen or intimal flap at the affected artery are definitive but uncommon findings of arterial dissection. 2,[7][8][9] Pearl and string sign or string sign on angiography are accepted as suggestive findings for dissection. [7][8][9] Intramural hematoma on T 1 -weighted MR imaging is helpful to identify dissection in the early phase, 2,3,[7][8][9] but does not always appear in the acute phase.…”

“…2,[7][8][9] Pearl and string sign or string sign on angiography are accepted as suggestive findings for dissection. [7][8][9] Intramural hematoma on T 1 -weighted MR imaging is helpful to identify dissection in the early phase, 2,3,[7][8][9] but does not always appear in the acute phase. 2,3) Morphological changes of the dissected artery on serial angiography are reliable indicators of dissection, 2,8) but acute dissection cannot be established based only on the initial angiography.…”