| ObjectivesTo evaluate the imaging quality of high-resolution MR angiography and 3d-tof-mra in different degree of atherosclerotic stenosis of middle cerebral artery,and to compare whether there is difference between them.At the same time,the relationship between the number of acute cerebral infarction and the degree of stenosis and the characteristics of plaque in M1 segment of middle cerebral artery were compared.MethodsFrom January 2018 to December 2019,all patients with highresolution MR angiography of middle cerebral artery wall were collected from the 90 th Hospital of the joint service support force.All patients underwent conventional MRI including DWI(diffusion weighted imaging)and 3D-TOF-MRA,including 3d-tof-mra,DWI,2D black blood T1 WI and contrast enhanced 2D black blood T1 WI.According to the signal-tonoise ratio and vascular lumen display,the image quality is divided into three levels,and the imaging quality of 3d-tof-mra and highresolution vascular wall imaging sequence is compared.At the same time,the patients were divided into mild stenosis group(group A),moderate stenosis group(group B)and severe stenosis group(Group C)according to the degree of stenosis by high-resolution 2D black blood T1 WI sequence.The number of patients with acute cerebral infarction between the three groups was compared.At last,the patients were divided into two groups according to whether there was high signal in DWI image.Whether there was high signal in T1 WI and whether there was enhancement in middle cerebral artery plaque of the two groups were compared,and whether there was significant difference in plaque characteristics between the two groups was analyzed.SPSS 26.0 software was used for statistical analysis of all data.Chi square test was used for comparison of count data among groups.F test was used if the measurement data obeyed normal distribution and the variance was uniform.Rank sum test was used if the measurement data did not obeyed normal distribution or the variance was uneven.P < 0.05 has statistical significance.ResultsThere was significant difference in image quality between MRA group and high-resolution group(P = 0.007).The number of patients with acute cerebral infarction in mild stenosis group(group A),moderate stenosis group(group B)and severe stenosis group(Group C)was compared.There were significant differences between mild stenosis group and severe stenosis group,as well as between moderate stenosis group and severe stenosis group(P = 0.01).The proportion of patients with acute cerebral infarction in mild stenosis group was significantly lower than that in severe stenosis group,and that in moderate stenosis group was significantly lower than that in acute cerebral infarction The proportion of patients with severe stenosis was significantly smaller than that of patients with severe stenosis.There was no significant difference in the proportion of patients with acute cerebral infarction between mild stenosis group and moderate stenosis group.There was a significant difference in the number of enhanced plaques between the infarct group and the non infarct group.The proportion of enhanced plaques in the infarct group was significantly higher than that in the non infarct group(P < 0.001).There was no significant difference in T1 high signal between the two groups(P = 0.841).conclusions1.Compared with 3d-tof-mra,high-resolution MRA has significant advantages in the quality of vascular imaging.2.There is a certain correlation between the degree of vascular stenosis and the occurrence of acute cerebral infarction.At the same time,the enhancement characteristics of atherosclerotic plaques in the brain are also closely related to the occurrence of acute cerebral infarction,which should be paid attention to clinically.Objectives By using high-resolution MR vascular wall imaging and whole brain PWI perfusion imaging technology,the cerebral blood flow perfusion in the blood supply area of the middle cerebral artery on the affected side and the healthy side of the patients with different degrees of M1 atherosclerotic stenosis of the middle cerebral artery was compared and analyzed,and the relationship between the ratio of CBF on the affected side and the healthy side(defined as FFR)and the degree of stenosis of the middle cerebral artery was discussed Department,to provide help for the development of individualized treatment plan for patients.Methods From January 2018 to December 2019,all patients with clinical diagnosis of atherosclerosis,M1 segment stenosis of unilateral middle cerebral artery confirmed by MRA and without acute cerebral infarction were collected from the 90 th Hospital of the joint service support force.All patients underwent routine brain MRI including DWI and 3DTOF-MRA,high-resolution MR angiography of the middle cerebral artery and PWI of the whole brain.The scanning sequence includes 3d-tof-mra,axial DWI,2D black blood T1 WI,whole brain PWI and contrast enhanced 2D black blood T1 WI.Using 2D black blood T1 WI sequence to evaluate the stenosis degree of the middle cerebral artery in the affected side,less than 50% was mild stenosis,50%-69% was moderate stenosis,70%-99% was severe stenosis.The patients were divided into mild to moderate stenosis group(group A)and severe stenosis group(group B).The normal control group(Group C)was set up to post process the whole brain PWI perfusion image of the patients in each group.The blood supply area of the middle cerebral artery in the central layer of the semicircular circle above the lateral ventricle,the basal ganglia layer and the brainstem layer were selected as the area of interest,and FFR = the affected side of CBF/ On the healthy side of CBF,blood flow reserve fraction(FFR)was calculated,and whether there was significant difference between the three groups was analyzed.Results There were statistical differences in FFR values between experimental group A and experimental group B,and between experimental group B and control group,P < 0.05;between experimental group A and experimental group B,and between experimental group B and control group,P < 0.05.The cerebral blood flow reserve fraction of experimental group B was significantly lower than that of experimental group A and control group.Conclusions 1.There were significant differences in FFR between patients with mild and moderate middle cerebral artery stenosis and severe middle cerebral artery stenosis and between patients with severe middle cerebral artery stenosis and normal control group.The FFR value of patients with severe middle cerebral artery stenosis was significantly lower than that of patients with mild and moderate middle cerebral artery stenosis and normal control group.2.Patients with mild to moderate middle cerebral artery stenosis can maintain the perfusion level close to that of normal people by means of cerebral blood flow reserve,while patients with severe stenosis are more difficult to maintain the normal cerebral perfusion level.3.It is possible to measure noninvasive blood flow reserve fraction in cerebral circulatory system by using high-resolution MR angiography and MR perfusion imaging. |
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