The Value Of Arterial Spin Labeling And Susceptibility Weighted Imaging In The Prognosis Of Acute Cerebral Infarction

Objective:To research factors and clinical significance of focal perilesional hyperperfusion after acute ischaemic stroke,identified using arterial spin labelling(ASL).To research clinical significance of the distribution and degree of abnormal vein surrounding the infarcts on susceptibility weighted imaging(SWI).Furthermore,the imaging findings of the SWI and ASL were compared,and we want to determine here if their combined use in acute ischaemic stroke at 3T could bring new insight into the diagnosis and prognosis of stroke leading to eventual improved patient management.Materials and methods:In this study we included sixty-six acute cerebral infarction patients which occurred within 72 hours from onset to accept MR check.The conventional MRI(T1WI,T2 WI,DWI,FLAIR),MRA,SWI and 3D-ASL were performed on all subjects by using Siemens Skyra 3.0T MR imaging system.By using threshold of20%,we divided the patients into 3 groups according to the degree of the infarction and the surrounding area rCBF: hyperperfusion(ipsilateral and contralateral rCBF ratio>120%),and iso-perfusion(ipsilateral and contralateral rCBF ratio in the 80% to120%)and hypoperfusion(ipsilateral and contralateral rCBF ratio <80%).We defined high perfusion signal existed in the ASL images that surrounding the infarction area as Perilesional hyperperfusion(PLH).Sixty-six patients of acute cerebral infarction,according if high perfusion signal existed in the ASL images that surrounding the infarction core area,were divided into the PLH group and the control group.To calculated the relationship among PLH and infarction area,infarction site,the day of admission NIHSS scores,degree of responsibility stenosis vascular and recent prognosis using the statistics respectively.To observed the distribution and degree of abnormal vein surrounding the infarcts on SWI-mIP.To calculated the relationship among abnormal venous degree and infarction area,the day of admission NIHSS scores,degree of responsibility stenosis vascula and recent prognosis respectively.in addition,we analyzed the imaging findings of ASL and SWI image.To assess the relationship between the blood perfusion situation in periphery of acute cerebral infarction and degree of abnormal vein surrounding the infarcts,IP and degree of abnormal vein,as well as the blood perfusion status of periphery and in infarction and HT.Result:(1)Acute cerebral infarction lesions showed high signal intensity on DWI and low signal on ADC in all 66 patients,there were 19 cases with large infarctions area,15 cases with moderate area and 35 cases with small area.(2)In 53 out of 66 patienis had abnormal perfusion in infraction region,hyperperfusion in 3 patients,lower perfusion in 50 patients.In 31 out of 66 patienis had abnormal perfusion in peri-infarction region,hyperperfusion in 15 patients,lower perfusion in 16 patients.So PLH group had 15 cases(15/66,22.7%)and control group had 51 cases.The acute infarction area with PLH showed no statistical difference(P> 0.05).Analysis of infarct topography and PLH status demonstrated an association with cortical superior division MCA(P=0.035).PLH was associated with the day of admission NIHSS scores,degree of relevant artery stenosis,recent prognosis(P<0.05).(3)SWI demonstrated veins increase and dilatation in peri-infarcted region in30 patients.Vein distribution around the acute infarcts area was significant increase and dilatation in 13 patients and slight increase in 17 patient.In addition,SWI detected hemorrhage in 16 patients,Including infraction area in 5 patients and peri-infarction area in 11 patients.In 66 patients of acute cerebral infarction we found4 cases of arterial thrombosis.The correlation between the degree of abnormal vein and the day of admission NIHSS scores had no statistical significance(P>0.05).The degree of abnormal vein around acute infarcts region was associated with the acute infarct region,the degree of artery stenosis,recent prognosis(P<0.05).(4)In 12 out of 15 PLH group cases had no abnormal vein distribution aroud infarcts region,remaining 3 cases were in grade 1 change.There were 15 cases with ischemic penumbra(IP).In 11 out of 15 cases had grade 2 change of vein distribution aroud infarcts area,which generally consistent with the range of abnormal low perfusion in periphery of infarction region,identified using ASL.The blood perfusion situation in periphery of acute cerebral infarction had relationship with the degree of abnormal vein distribution aroud infarcts area(P<0.05).IP had relationship with the degree of abnormal vein distribution aroud infarcts area(P<0.05).Conclusion:(1)Our study revealed that ASL imaging can be used to capture post-ischaemic PLH patterns in acute cerebral infarction patients.PLH is associated with good collaterals or revascularization.PLH prompts small infarction area,mild neurologic deficits and good recent prognosis.The distribution of degree of artery stenosis is different in PLH group and the control group.(2)SWI image can show abnormal vien distribution of acute cerebral infarction.Displaying of abnormal veins distribution around the infarction indirectly reflects the state of the blood perfusion and cell metabolic state of ischemic brain tissue.Increasing significantly of abnormal veins distribution prompts severe degree of vascular stenosis,large infarction area,severe neurologic deficits and poor recent prognosis.(3)MRI imaging combined with ASL as well as SWI,can be more objective prompt hemodynamic information around the acute cerebral infarction region,can better evaluate the IP range and forecast HT through the infarction area and the surrounding perfusion state.They are without the contrast,strong repeatability and provide more information in patients condition,therapy and progronostic evaluation.