| Part 1 The quantitative MRI technique of intracranial artery blood flowObjective: To explore the reliability of applying the established cerebrovascular fluid model to measure intracranial arterial blood flow mechanics and optimize the imaging parameters,establish suitable dynamic scanning scheme for the measurement of intracranial arterial blood flow.This study could provide reliable experimental basis for clinical application.Methods: The cerebrovascular fluid model was placed in the center of the standard 8 channel head coil,using philips Achieva 3.0 T superconducting MRI scanner(Phillips Achieva 3.0 T TX).The imaging protocol: We applied the 2D Q-Flow sequence in positioning on 3 d TOF MRA images and choosed the slices that was perpendicular to the long axis of the lumen.The flow velocity were measured in different velocity of coding,flow direction and velocity,flow direction,Angle,levels,sizes of areas of interest,lumen velocity and pipe diameter.The original images were transmitted to Phillip5.0post-processing workstation,every cardiac cycle fluid signal intensity changes in value could be collected through PHILIPS Extended MR WorkSpace2.6.3.2 workstation Q-Flow analysis software.SAS V10 statistical software was applied for statistical analysis.Results: Flow phase contrast images could be found in 2D Q-Flow sequence,tube cavity fluid signal strength was changing with flowing rate and flowing velocity and the signal strength of tube cavity was increasing if the flowing rate was accelerated.Regardless of velocity direction,phase diagram images could display liquid flow direction correctly.There was no statistically significant difference between measured by different direction and the actual flow rate(t = 0.25,P=0.90>0.05).However,the velocity and the actual flow was statistically significant when different coding values(t=2.47,P=0.01<0.05).No correlation between the velocity and flow rate coding(P=0.92>0.05).The greater of the coding values,the greater difference between the the velocity and the real value.When Venc was equal to 90 cm/s,and the closest of the measured velocity and actual.There was no statistically significant difference between reverse flowing and the real value.The flowing velocity and the actual flow rate were positively correlated(correlation coefficient =0.98,P<0.0001).There was no statistically significant difference between the velocity the actual rate by same direction of liquid flow direction and velocity of coding or reverse(F = 3.62,P=0.0597 > 0.05).Regardless of the actual flow direction and velocity of code in the same direction or on the contrary,the velocity and the actual flow rate were no statistically significant difference.With the increase of measuring angles(angle range 0°~90°),the crosssectional area of the lumen was also increased gradually,the same as average error of the velocity and flow,and the velocity measurement error was higher than the flow.There was no statistically significant difference between the velocity and the actual rate in different slices.However,the velocity in the different place of the lumen and the actual rate was statistically significant difference flow rate.Conclusion: PC-MRA method of 2D Q-Flow sequence is an accurate and effective fluid quantitative research technology wirh high temporal resolution,good image quality for intracranial arterial blood flow mechanics.It may provide reliable experimental basis for the clinical application.But we should take attention in some factors affecting the accuracy of the measurement result in the application.Part 2 The quantitative MRI technique of intracranial artery in the general populationObjective: To explore the feasibility of MRA method of 2D Q-Flow sequence in measuring neck and primary intracranial vascular blood flow and velocity.It may provides the quantitative indicators for the further study of cerebrovascular disease about cerebral blood flow and other changes.Methods: A total of 98 cases of volunteers were recruited,(male were 45 cases,female were 53 cases,age ranged from 21 to 65 years).All volunteers were evaluated on a philips Achieva 3.0 T superconducting MRI scanner(Phillips Achieva 3.0 T TX)using standard 8 channel head coil and all the subjects were examed with routine MR examination in head.The imaging protocol included T2-weighted images(T2WI)in axial and sagittal,T1-weighted images(T1WI)in axial,fluid attenuated inversion recovery T2-weighted images(T2WI-FLAIR)in axial.MRA scanning range included internal carotid artery and intracranial segment of brain circulation,by using three dimensional time to fly.For quantitative detection of intracranial vascular cerebral blood flow,the 2D Q-flow sequence of PC method was adopted.A 3D TOF MRA scan was performed to obtain the vascular image location,and the 2D Q-flow scanning was performed vertically on the target vascular plane.The large blood vessels in the neck was perpendicular to the plane of ICA and 2D Q-Flow scanning including ICA,VA,the lower margin of the second cervical segment.The MCA could be scanned vertically in the oblique sagittal plane of the M1 segment,and the ACA was scanned vertically in A1 segment,and the PCA was obtained in the coronary scanning.3D TOF MRA images were transmitted to PHILIPS Extended MR WorkSpace 2.6.3.2workstation,the maximum density projection(MIP)method is adopted for three dimensional reconstruction in MRA original image.thus,we obtained vascular images of brain circulation.2D Q-Flow localization corresponding to the lumen diameter of blood vessels were measured.2D Q-Flow sequence images were transmitted to the workstation for images post-processing.cardiac cycle time-the velocity curve could be obtained.statistical software was applied for statistical analysis.Results: Left and right of the internal carotid artery(ICA)and vertebral artery(VA),the average flow and velocity had no significant statistical difference(P >0.05).Left and right of the brain arteries(ACA)flow velocity and flow were significantly different(P<0.05).Left and right sides of the middle cerebral artery(MCA)flow and velocity were significantly different(P< 0.05).Left and right sides of the posterior cerebral artery(PCA)flow and velocity had no significant difference(P>0.05).The flow and velocity of basilar artery(BA)in different slices had no significant difference(P>0.05).The average flow and velocity between different gender differences had no statistical significance(P>0.05)in bilateral internal carotid artery(ICA),vertebral artery(VA)and basilar artery(BA),anterior the cerebral artery(ACA),middle cerebral artery(MCA)and posterior cerebral artery(PCA).The blood vessels in different age groups(20 +,+ 30,40 +,+ 50,60 +)were are compared in pairs.We found that the average velocity in 20 +,30 +,40 +group had no statistical difference,the same as in the 30 +,40+,50 +,60 +group.But different results in 50 +,60+,20+ age group.The average flow and in different age groups(20 +,30+,40 +,50+,60 +)were are compared in pairs had no statistically significant.Conclusion: Q-Flow PC-MRA method is an accurate fluid quantitative and qualitative research technology.It provides a quantitative measurement method for the diagnosis and treatment of cerebrovascular disease.The average flow and velocity were increased with aging in intracranial arterial.There were statistical differences in the 20 + 50 +,60 + age group,the other different age groups had no statistical differences,the same result in different gender.Part 3 The quantitative MRI reasearch of cerebral blood flow change in transient ischemic attacks(TIA)patientsObjective: To evaluation the changes of cerebral blood flow and artery lesion distribution characteristics in by using MRA quantitative analysis techniques,it may provide more adequate imaging basis for the early diagnosis and treatment of TIA.Methods: A total of 106 cases of TIA patients were enrolled,(male were56 cases,female were 50 cases).All of them were underwent MRI examination within 72 h after the last symptom onset including DWI sequence to exclude acute cerebral infarction.The cerebral blood flow for quantitativedetection was measured by using PC method of 2D Q-Flow sequence,based on 3D TOF MRA scan for blood vessels as orientation,perpendicular to the line measuring target vessel level 2D Q-Flow scan.The images were transmitted to PHILIPS Extended MR Work Space 2.6.3.4 workstation for post-processing.2D Q-Flow localization corresponding to the lumen diameter of blood vessels were measured.Quantitative analysis was made in the cranial total,internal carotid artery and the area of vertebral artery,the average velocity,the average blood flow,and then the change of cerebral hemodynamic was compared.Results: The total cerebral blood flow of TIA group and normal control group were no significant statistical difference(P>0.05).The total blood flow decrease with increasing age that TIA group was much lower than the control group.TIA group of right internal carotid artery peak flow had significant difference compared with controls(P<0.05)that decreased comp-ared with control group.However,the same situation didn't happen in both of the left internal carotid artery and vertebral artery.Conclusion: Phase contrast magnetic resonance imaging has the pontenial to evaluate the change of cerebral blood flow in TIA patients.The decreasing in the total blood flow and the symptom onset of TIA is consistent.Phase contrast magnetic resonance imaging can provide the guidance to the diagnosis and prognosis of TIA. |
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