The Relationship Of The Transient Ischemic Attack (TIA) And The Carotid Athrosclerosis With Ultrasound

Transient ischemic attack (TIA) is a common and frequently encounter- ed disease. To recognize the etiopathogenisis, enhance the diagnositic treatment and comprehend the relationship between the diseased region and clinical symptom, we can prevent the occurrence of TIA effectually. Commonly the disease of the carotid artery system and the vertebra-basal artery system can both cause the TIA, thus,the process of carotid artery is the mean reason of cerebral ischemic. At present, the MRA and the ultrasonograpy are the mean examination with no insult. With the development of ultrasound techniques, ultrasonography is widely used in the diagnosis of vascular disease, especially the research of carotid athrosclerosis. The scholar in the world usually pay more attention to the carotid athrosclerosis stenosis and the indication of the operation,thus pay less attention to the relationship between the TIA and other blood vessels such as subclavical artery and vertebra-basal artery. Accordingly, we know the test of vessel structure and hemodynamic feature by ultrasonograpy will have important significanne for the etiology and therapeutics of TIA.In this investigation, the TIA group is consisted of 57 cases , among which 36 for male, for 21 female, from 35 to 85 years old, average is 60 ;and the control group is of 78 people, among which 48 for male, 30 for female, from 42 to 78 years old, average is 56. Ultrasonography of the carotid artery was conducted on two groups, examination items includes intima-media thickness (IMT), degree of stenosis, the location of plaque, and the feature of plaque. And we yield the conclusions as follow:(1)Intima-media thickness(IMT): the numerus of TIA group is higher than that of control group remarkably. Normally the vessel wall of the carotid artery presents tow parallel patterns, one is the intima that is tenuity and slick, the other is externa composed of connective tissue, is lighter than the intima. Between them is the stratum medium, which is in low echo-level.The normal vessel wall is uniformity, the thickness of the intima is about 0.1～0.9mm.Once angiosclerosis happened, fatty deposits under the intima, thicken the IMT obviously, so thickening of the IMT could reflex athrosclerosis in early period.(2)predilection site of carotid athrosclerosis plaque is the bulbus caroticus and the beginning of the subclavical artery. The reason of this phenomenon is the blood flow through the furcation and the angulation of the vessel causes vortex. That damages the intima and makes the high-density chylomicron and lipoprotein gather in these coarse regions, such as the furcation of carotid artery and bulbus caroticus. If the athrosclerosis causes the the furcation of artery elongate and distend, make the angulation change, the lamina flow turn, as for the eddy current damage the artery further and the process of athrosclerosis speeds up. Athrosclerosis is the most promoting agent.for the occurrence of thrombus. It make effective on the intimia that is thoroughly exposed, adhere the platelet on the intimia, and make the content release and aggregate, then form the embolism.Otherwise, the whirl velocity and the pressure of bulbus caroticus can damage the platelet,finally form the mural thrombosis or increase the plaques in the intimia, then, the thrombus fall off, block the blood vessels in cranium, cause cerebrovascular disease.(3)The athrosclerosis with different quality can cause different nervous system symptom. In thegroup of TIA, there are 38 cases with athrosclerosis in all 54 cases. Applanatus plaque is most of all, the ulcer plaque is lest. Compared with control group, disparity is significant. The anisotropic and low level echo plaque of TIA group is more than those in the control group. disparity has statistical significance. The plaque in the vertebral artery is less, only one case, non in the control group. It may be concerned with narrow caliber of the vertebral artery. Accordingly the character of echo, there are four types of plaque, they are applanatus, soft, hard and ulcer plaques, we also can divide plaques as stable and unstable plaques. There are fibrous layer covering on the stable plaques, retrogressive changes less happen. Its surface is smooth, retrogression is completed, even stegnosis is severe, the disease symptom is less occuring. The unstable plaque has uneven structure. Much lipid is piled up outside cells, less smooth muscle and collagen exists, hemorrhage and tissue necrosis happens in the plaque, it is able to form ulcer,often cause the damage of nervous system. The unstable plaque is the dangerous factor of the cerebrovascular disease, thus the stable plaque is much safer. The outcome of this investigation also illustrates the phenomenon.We arrive at the conclusion as follow: the thickening of IMT could reflex the athrosclerosis in the early period, it has important significance for the study of athrosclerosis.The carotid athrosclerosis often emerges in the cross of the blood vessel, bulbus caroticus is the most common place. then is the beginning of subclavical artery.Different carotid athrosclerosis plaque has different influence on the TIA. Low level echo and unstable plaques is the mean risk factors of ischemic cerebrovascular disease, thus, high-level echo and stable plaques is less risk.Carotid athrosclerosis has close relationship with TIA,the study of the carotid athrosclerosis has important significance for the diagnosis and the prognosis of TIA.Color doppler technique has its own quality in the testing of carotid athrosclerosis.