Application Of CT Screening In Pre-infarction Period

Objective:Through one-stop CT screening, including CT plain scan, CT perfusion, CTA and plaques assessment, on the patients diagnosed with the ischemic stroke, find out the patients in the early phase of the cerebral infarction and separately do the assessment from the morphological and hemodynamic aspects so as to provide the theory basis for early clinical intervention treatment.Materials and methods:Collect the cases of patients diagnosed with the cerebrovascular disease from September,2010to March,2012and use the Siemens sensation64row helical CT scanner manufactured by the Germany Siemens on all cases to do the head and neck CT plain scan, CT brain perfusion imaging and CT angiography imaging screening. Exclusive criteria:the non-acute cerebral infarction; Hemorrhagic cerebrovascular disease; known vascular lesions and cases having accepted the intravascular fibrinolytic therapy before the screening. Inclusive criteria: TIA; cases with cerebral ischemia symptoms or without neural function defect; cerebral ischemia symptoms together with three tenors or coronary heart disease; acute cerebral infarction divided into TIA group and acute cerebral infarction group. Transfer data to Syngo workstation for analysis; use the perfusion analysis software on cases of the infarction group to determine hypoperfusion areas, and combining with the CT images, define two regions of interest(ROI) on the parameter graph time to peak, TTP、.infarction core of low CBF and cerebral blood volume CBV time to start,TTSmean transit time, MTT、,2.ischemic penumbra(IP)of low CBF and normal CBV). Calculate the absolute values of ROI parameter and with their corresponding ratios to the contralateral mirror image measurement. All CTA scanning data of98patients were transmitted to the workstation after the smooth reconstruction. Assess wall plaques on horizontal surface images, and apply the Curved Planar Reformation (CPR) and Maximum Intensity Projection (MIP) to observing the vascular shape on the whole. Use Volume Reconstruction (VR) to reconstruct the third and fourth classes of arterial branches in the front, middle and back of the brain. Calculate the stenosis rate in accordance with the North American Symptomatic Carotid Endarterectomy Trial (NASCET).All the data, through the SPSS11.0statistical software processing, take P<0.01as the verification standard.Results:1.CT flat and results of the175regular CT flat for Saul, Saul after screening CT flat with CTPI standard128cases.2.CTPI results CTPI has not seen the obvious abnormity30cases, abnormal in98cases, divided into TIA group53and acute cerebral infarction group of45; TIA group53patients with clinical attacks under three times in9patients, and pour the parameters are statistically significant TTS, attacks more than3patients44cases, TTS, TTP have a statistics meaning;53patients with clinical manifestations in TIA correlation with the abnormal performance, the TTP was significantly longer in40cases, obviously an extension of the MTT32cases, rCBF chart is found to have low infusion of performance in22, rCBV chart is found to have low infusion of performance28cases.45cases of acute cerebral infarction patients in4of excessive perfusion;38cases of low perfusion;3cases not found significant perfusion is unusual,38cases of infarction area in patients with low perfusion26patients can be obviously IP (infarction volume cm35～8cm3),45cases of acute cerebral infarction patients, whether in the IP core infarction rCBV, rCBF relative value of absolute value and has significant difference (P<0.01). The core of the rCBF all infarction ratio<0.23, rCBV ratio<0.56; IP rCBF>0.29ratio, rCBV ratio>0.67, rCBF ratio>0.39, rCBV ratio>0.99all showed a normal brain tissue.3.CTA resultsTIA group highly narrow internal carotid artery17of teams, moderate narrow13of teams, mild narrow44of teams, and vascular no narrow. Atherosclerosis with soft patch in11, and calcification plaques of35patients. Unilateral vertebral artery atherosclerosis mild narrow8teams.32cases of intracranial arteries that have different degrees of narrow, of which the anterior cerebral arteries A1period of narrow in16, the brain artery M1section27cases narrow, M2period of narrow4cases, MCA merger before the brain artery stenosis in15cases, posterior cerebral artery stenosis in5patients. Vertebral artery with basal artery mild narrow3branch. Acute cerebral infarction internal carotid artery is highly narrow group nine, moderately narrow31teams, mild narrow24teams, and vascular no narrow. Plaques analysis for performance, calcified plaque17cases, soft patch27cases, intracranial arteries,28cases in different degree of narrow, the anterior cerebral arteries A1section6patients with narrow, MCA M1period of narrow22cases, M2period of narrow in7cases, MCA merger before the brain artery stenosis4cases, posterior cerebral artery stenosis in4. Vertebral artery with basal artery mild narrow in1. The internal carotid artery and brain artery stenosis degree and brain tissue perfusion abnormal changes of the correlation analysis4.The internal carotid artery stenosis138cigarettes, intracranial artery stenosis60place, narrow degree and CBV and CBF are unrelated.5.Carotid Artery Atherosclerotic Plaque analysis90plaques were detected, patients, TIA:of which35were calcified plaques.7were soft plaques and4were mixed plaques. Acute cerebral infarction:of which17were calcified plaques.19were soft plaques and8were mixed plaques.6located at the Aortic arch,18at the common carotid artery。51at the bifurcation of the carotid artery and15at the internslcarotid artery. Conclusion:1.The plain CT scan with convenient and efficient examination can rule out the non-ischemia cranial vascular disease; however, it has relatively low detection rate for the patient with cerebral infarction in earlier stage.2.CTPI can conduct a relative good evaluation for brain tissue blood flow state for the patients with cerebral infarction in earlier stage. Among them, TTS is the relatively sensitive parameter for patients with the outbreak of TIA less than3times/month; TTS and TTP are the relatively sensitive parameters for patients with the outbreak of TIA more than3times/month. The infarction cores of acute cerebral infarction, and IP have significant difference in both the relative value and absolute value of rCBV and rCBF.3.As a relative non-invasive vessel examination, CTA can well display the narrowed parts, range and degree in the head and neck where may have angiostenosis, rule out other Vascular diseases and offer a forceful objective basis to determine the vessel scleratheroma cerebrovascular disease. This study analyzes the correlation of parameter of the internal carotid artery stenosis and cerebral perfusion, and proves that there is no correlation between the degree of internal carotid artery stenosis and the singular degree of cerebral perfusion, i.e., the degree of arteriostenosis is not proportional to the degree of brain tissue ischemia.4.Through the CT value of plaque and analysis of its stability, we find that the unstable plaque is one of the risk factors resulting in TIA and acute cerebral infarction.5. For the one-stop CT screening for the patients with the cerebral infarction in earlier stage, the custom screening scheme should be made according to the clinical manifestation, the number of outbreaks and CT scan performance.