| BackgroundAt present,cerebrovascular disease is one of the three major causes of human death,among which the incidence of acute ischemic stroke is the highest.After the occurrence of acute cerebral infarction,hemorrhage occurs in the infarct area or the infarct blood supply area,which is called hemorrhagic transformation(HT).According to domestic and foreign research reports,the incidence of hemorrhagic transformation in patients with cerebral infarction is very high,up to 10%～40%.The peak period of hemorrhagic transformation is36 hours to 2 weeks after cerebral infarction.At present,CT and MRI are commonly used in the diagnosis of hemorrhagic transformation,but there are still some cases of hemorrhagic transformation which are not aggravated.Susceptibility weighted imaging(SWI)is a 3D gradient echo technology,which has the characteristics of flow compensation,high resolution,and can be reconstructed by thin layer.It elies on magnetic susceptibility difference imaging between tissues,which is sensitive to blood metabolites and iron ions.Itis of great significance in the early diagnosis of micro bleeding and bleeding.In addition,SWI is also sensitive to the display of small veins.Therefore,this paper uses susceptibility weighted imaging detection method to analyze its application value in hemorrhagic transformation,and analyzes the related risk factors of hemorrhagic transformation in acute cerebral infarction.ObjectivesTo investigate the diagnostic value of susceptibility weighted imaging(SWI)in hemorrhagic transformation in patients with first-episode acute cerebral infarction(ACI)and analyze the related risk factors.MethodsA total of 285 patients with first-episode acute cerebral infarction admitted to the Department of Neurology of Yanshi people’s Hospital from January 2017 to December2019 were selected.According to the inclusion criteria and exclusion criteria,120 patients were finally enrolled in the study.After the symptoms appeared,they were admitted to the hospital for routine CT scan to exclude cerebral hemorrhage,and then MRI,DWI and SWI examinations were completed within 48 hours,Then according to the patient’s condition changes at any time or 2 weeks after reexamination of head CT,MRI,SWI examination.Three months after the onset of the disease,the patient went to the hospital for reexamination/telephone follow-up,recorded the m Rs(modified Rankin scale)score of the patient,and made the following research and analysis.The main observation contents were as follows:(1)to observe the imaging manifestations of bleeding transformation of the first acute cerebral infarction on CT,MRI and SWI:the location,size,density(signal)and surrounding conditions of the acute cerebral infarction,and analyze the sensitivity of CT,MRI and SWI sequence images in the detection of HT in patients with first-episode acute cerebral infarction;(2)The SWI images of patients with first-episode acute cerebral infarction were analyzed to show the number of cases and number of cerebral microbleeds,and the correlation with HT was analyzed;(3)The number of venous vessels in acute cerebral infarction area reflects the level of local cerebral oxygen metabolism rate and the speed of local cerebral blood flow.This paper will observe the display of small veins in acute cerebral infarction focus area by SWI,and analyze the relationship between the display of small veins in cerebral infarction area and HT.(4)The clinical data,imaging features and biochemical indicators of HT patients and non HT patients were compared and analyzed.The risk factors of HT were summarized through statistical analysis.(5)The relationship between HT,peri infarct drainage vein dilation and prognosis in large infarct group.Spss22.0 software was used for statistical analysis.Statistical data were analyzed by X~2 test.Kruskal Wallis H-rank sum test was used for statistical analysis.Results(1)120 patients were confirmed by imaging examination,56 cases had hemorrhagic transformation,and 64 cases had no hemorrhagic transformation.(2)The sensitivity of CT,MRI and SWI in detecting HT was 75%(42/56),64.3%(36/56)and 100%(56/56),respectively.Compared with CT and MRI,SWI could well display all HT lesions,and SWI sequence showed a larger range of HT than CT and MRI.(3)In this study,among 120 patients with first-episode acute cerebral infarction,49patients with first-episode acute cerebral infarction had microbleeding lesions in the brain parenchyma in the first SWI examination,of which 16 cases were moderate to severe,12cases had HT,accounting for 75%;Among 33 cases of mild microbleeds,20 cases had HT,accounting for 60.6%;Among 71 cases without microbleeds,24 cases had HT,accounting for 33.8%;The difference between the two groups was statistically significant(P<0.05).(4)According to SWI’s display of draining veins in infarct area and its relationship with HT,the obvious rate of small veins in infarct area of 68 patients in HT group and non HT group was 71.4%(25/35)and 15.2%(5/33),the difference between the two groups was statistically significant(P<0.05).(5)In 81 patients with massive cerebral infarction,the prognosis of HT group and non HT group was poor,36/46(78.3%)and 14/35(40%)respectively,the difference was statistically significant(P<0.05).Among 81 patients with massive cerebral infarction,21/26(80.8%)and 19/34(55.9%)had poor prognosis in peri infarct drainage vein dilation group and no change group,respectively(P<0.05).(6)There was no significant difference between HT group and non HT group in increased total cholesterol,decreased high density lipoprotein,increased low density lipoprotein and antiplatelet aggregation therapy(P>0.05),there were significant differences in infarct size,diabetes history,hypertension history,hypertriglyceride,atrial fibrillation and thrombolytic therapy between the two groups(P<0.05)Conclusions(1)SWI is superior to CT andconventional MRI in the detection rate of HT in patients with first-episode acute cerebral infarction;Patients with acute cerebral infarction combined with moderate to severe microbleeds in brain parenchyma and massive cerebral infarction are more likely to have hemorrhagic transformation;In SWI sequence images,patients with acute cerebral infarction who showed obvious venules in infarct area were more likely to have HT;Hemorrhagic transformation and obvious expansion of veins around the infarct are related to poor prognosis in patients with massive cerebral infarction.(2)From the analysis of individual differences,diabetes history,hypertension history,high triglyceride atrial fibrillation history,thrombolytic therapy are the risk factors of HT. |
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