MRI 3D ASL,APT And SWI Study On The Relationship Between Regional Perfusion And Metabolic Status In Patients With Subacute Cerebral Infarction

PurposeThis study used arterial spin labeling?ASL?imaging,amide proton transfer?APT?imaging and susceptibility weighted imaging?SWI?to quantitatively evaluate the changes in blood perfusion,p H and oxygen metabolism in infarct core?IC?and ischemic penumbra?IP?tissues of patients with subacute cerebral infarction in unilateral middle cerebral artery blood supply and analyzed their correlations.Materials and MethodsThis study was a prospective study and was reviewed and approved by the Ethics Committee of the First Affiliated Hospital of Dalian Medical University.The study subjects were divided into subacute infarction group and control group.A total of 23patients in the infarction group were hospitalized in the department of neurology from April to November 2019,including 14 males and 9 females?64.00±10.71yrs?;15 patients in the control group,including 9 males and 6 females?64.4±7.77yrs?.The clinical and laboratory data of all patients were recorded,and the National Institute of Health stroke scale?NIHSS?scores at admission and discharge were evaluated by a neurologist.In this study,routine MRI sequences and DWI,3D-p CASL?with 1.5 s and 2.5 s of post-labelling delay?,SWI,APT were performed using the Philips Ingenia CX 3.0T MRI scanner with 32-channel head coil.APT and ASL image post-processing were performed using the workstation?Intelli Space Portal,ISP?provided by the vendor.The relative cerebral blood flow?r CBF?and APTw images automatically obtained at the workstation are fused with the DWI images.The DWI high-signal area is defined as the IC,the CBF-DWI mismatch area is defined as the IP_CBF and the APT-DWI mismatch area is defined as the IP_APT.3D ROI was used to semi-automatically outline each layer of the lesion area on the IC and IP to obtain the 3D r CBF_lesion value and 3D APTw_lesion values,including the maximum(APTw_max)?minimum(APTw_min)and mean(APTw_mean).Calculate the difference between the maximum and minimum values(APTw_max-APTw_min),defined as APTw_max-min.Manually delineate the areas consistent with the IC and IP areas on the healthy hemisphere,and obtain the r CBF_normal and APTw_normal values of the local brain area.Calculate the ratio of relative cerebral blood flow(rr CBF=r CBF_lesion/r CBF_normal)in IC and IP area.Comparing the IC,the 3D APTw values of the corresponding areas on both sides were measured on the APT images of the control group.The scanned SWI image can be automatically reconstructed to obtain a phase image?PI?and a minimum density image(SWI_{Min IP}).The SWI image data was transmitted to a personal computer in DICOM format and the post-processing was performed using signal processing in nuclear magnetic resonance?SPIN?software.Combined with DWI and SWI_{Min IP}images,the phase difference value of the vein around the lesion was measured on PI,and expressed by?value?unit:spin?.Data analysis was performed using the statistical package for social science?SPSS?version 22.0.All the APTw values were consistent with the normal distribution using the One-Sample K-S test.Therefore,the measurement data were expressed as mean±standard deviation.The age and APTw values of the infarction group and the control group were compared using independent sample t test;the gender differences between the two groups were tested by the chi-square test;the paired sample t test was used to compare the APTw values of the infarct side and the contralateral side,as well as the APTw values of the IC and IP;Pearson correlation analysis was performed on the APTw values in the IC and IP of the infarction group and CBF values,??_lesion,IC or IP volume,time from symptom onset to MRI scan,and NIHSS scores.Pearson correlation analysis was performed on parameters and??_lesion of infarction group.P<0.05 was considered statistically significant.Results1.Changes of CBF and APTw in IC of subacute cerebral infarctionIn the IC,the rr CBF_1.5 values=0.64±0.58,rr CBF_2.5=0.78±0.58,meaning that r CBF were lower than those on the contralateral side.There were no significant difference in the APTw values between the IC of the infarction group,the contralateral side and the control?P>0.05?.2.Changes of CBF and APTw in IP of subacute cerebral infarctionIn the IP,the rr CBF_1.5 values=0.74±0.43;rr CBF_2.5=0.84±0.28,meaning that r CBF were lower than those on the contralateral side.Compared with the contralateral side,the APTw_max?APTw_max-min values in the IP decreased at PLD 1.5,the APTw_minvalue increased and the APTw_max-min value decreased at PLD 2.5?P<0.05?;Compared with the IC area,the APTw_max?APTw_min?APTw_max-min values of the IP increased,and the differences were statistically significant?P<0.05?.3.Comparison between IP_CBF volume and IP_APT volumeIP_CBF1.5 volume,IP_APT,IP_CBF2.5volume,volume gradually decreased,but only the volume of IP_CBF1.5 and IP_CBF2.5 were statistically significant?P<0.05?.4.Comparison of infarct and contralateral venous phase difference????in the infarction groupThe phase difference between the veins belonging to the middle cerebral artery blood supply area on the infarct side is significantly higher than that on the healthy side(??_lesion=424.65±25.73?spin?,??_normal=330.72±14.93?spin?,t=4.494,P<0.001).5.Correlation between APTw values and rr CBF value,ADC value,volumes,??_lesionin the infarction groupAPTw_min in the IC had a moderate positive correlation with its rr CBF value(r_1.5=0.507,P=0.014;r_2.5=0.520,P=0.011);APTw_mean had a moderate positive correlation with rr CBF_2.5?r=0.471,P=0.023?;APTw_mean value and ADC value had a moderate positive correlation?r=0.433,P=0.039?;there was no significant correlation between each APTw value and IC volume as well as??lesions?P>0.05?.APTw_max?APTw_mean?APTw_max-min values in the IP had moderate negative correlation with rr CBF_1.5?r=-0.453,P=0.030;r=-0.432,P=0.040;r=-0.460,P=0.027?;there was no significant correlation between each APTw value and IP_CBF volume?P>0.05?;APTw_max and APTw_max-min values had moderate correlation with?_lesion?r=0.450,P=0.031;r=0.428,P=0.041?.6.The relationship between CBF,APT and SWI changes in subacute cerebral infarction and clinical and laboratory indicatorsThere was no significant correlation between APTw values in IC and IP and blood glucose,total cholesterol,triglyceride,HDL,LDL,HCY content,admission blood pressure,diabetes history,hypertension history,stroke history,smoking and drinking?P>0.05?.NIHSS_discharge scores had positive correlation with IC volume?r=0.694,P<0.001?and APTw_max?r=0.473,P=0.023?in the IC;?NIHSS scores had negative correlation with IC volume?r=-0.715,P=0.011?and???r=0.425,P=0.043?and a positive correlation with rr CBF_1.5 in the IC?r=0.493,P=0.017?.Conclusion1.There is a clear decrease in cerebral blood flow perfusion and hypoxic changes in the IC area of the subacute infarction,but the acid-base metabolism changes are not significant;The changes between the three are interrelated,the latter is related to the dispersion state of water molecules,which to some extent can affect the patient's condition changes?NIHSS score?.2.There is also a decrease in cerebral blood flow perfusion and hypoxia changes in the IP of the subacute infarction,and there are clear changes in acid-base metabolism locally;the latter changes are affected by local blood flow perfusion.3.For subacute cerebral infarction,the IP volume defined by the APT-DWI mismatched area is similar to that defined by the CBF-DWI,and the IC volume is closely related to the disease outcome.