[Common carotid artery thrombosis--clinical and radiological evaluation]

Common carotid artery thrombosis (CCAT) is not common. We studied 4 patients with CCAT to clarify the clinical and radiological features of this disorder. Case 1 had only episodes of TIA. Case 2 was diagnosed by chance as having CCAT at the time of admission due to cerebellar infarction. On the contrary, Cases 3 and 4 were admitted because of disturbance of consciousness and hemiparesis. Case 4 died soon after his stroke because of complications. We evaluated cases 1, 2 and 3 using head CT, head MRI, neck MRI, MR angiography, SPECT and cerebral angiography. Case 4, who was evaluated with head CT and cerebral angiography, was autopsied to confirm the occlusion of the common carotid artery. The clinical severity of CCAT varies from asymptomatic to severe, because each differs in the time taken for complete occlusion of the common carotid artery; the development of collateral circulation; and hemodynamics of the brain. As for the collaterals their contribution is variable; for example, the thyrocervical and other arteries function as the bypass. We can diagnose CCAT easily and noninvasively using MR angiography and neck MRI based on disappearance of the flow void in the common carotid artery or internal carotid artery. On physical examination, it is important to detect faded pulsation of the superficial temporal artery that is ipsilateral to the occluded common carotid artery.