| 1. OBJECTIVE:We aimed to evaluate the cerebrospinal fluid (CSF) flow within cerebral aqueduct in hypertension patients and healthy human beings with phase-contrast cine MRI (PCC MRI). To analyze the systolic mean velocity,diastolic mean velocity,systolic peak velocity and diastolic peak velocity of CSF, establishing the preliminary reference standards of systolic mean velocity、diastolic mean velocity、 systolic peak velocity and diastolic peak velocity and distinguishing the differences between hypertension patients and healthy human beings.2. PATIENTS AND METHODS:2.1 Research objects(1) The hypertension group:60 patients were all in accordance with the hypertension standard suggested in the "Hypertension Prevention and Cure Guideline of China". The heart rate is 60-100times/min. The physical examination found no other diseases.26 patients were male and 24 patients were female, ranging from 20 to 73 years old with a mean age of 53.6±12.7 years old. The course of disease ranged from 2-10 years with an average value of 5.1 years.(2) The Control group:60 healthy volunteers were in accordance with the normal standard suggested in the "Hypertension Prevention and Cure Guideline of China".The heart rate is 60-100 times/min.The physical examination found no other diseases.26 cases were male and 24 cases were female, ranging from 20 to 71 years old with a mean age of 46.4±13.7 years old. All of the above received both conventional MRI and PCC MRI.2.2 The measurement of blood pressurePatients’blood pressure was measured immediately after the examination finished.2.3 Conventional MRI examinationsAll examinations were performed on Philips Achieva 3.0T MRI scanner, using standard head coil as emission and reception coil. All the patients underwent conventional axial T1-weighted image, axial T2-weighted image, fluid attenuated inversion recovery (FLAIR), and sagittal T2-weighted image.2.4 Phase-contrast cine MRI examinationsAll examinations were performed on Philips Achieva 3.0T MRI scanner, using standard head coil as the emission and reception coil and using a peripheral-pulse unit (PPU) signal with retrospective triggering. The scans were obtained in the sagittal position (sagittal T2WI) and perpendicular to CSF flow direction at the cerebral aqueduct(ampulla).TR、TE, the minimum;deviation angle,15°; field of view,15×15 cm; matrix,256×179; slice thickness,4.0mm; velocity encoding was determined as 12 cm/s; number of cardiac phases=16; flow encode directions, foot-head;using flow respiratory compensation.The scanning time for each patient was approximately 5 minutes.2.5 Data and image analysis48 images were obtained per cardiac cycle.1-16 are QFlow images; 17-32 are amplitude images; 33-48 are phase images.Qualitative analysis:To make the aqueduct outline clear by adjusting the window width and window. Both the amplitude images and phase images can be played continuously by running the film (Cine) model,which can display CSF flow velocity and direction in the aqueduct during one cardiac cycle.The amplitude images display CSF flow velocity within the aqueduct by showing black and white gray scale. When the velocity is faster, the signal is higher; and when the velocity is slower, the signal is lower.The signal is only related to the velocity, but has no relationship with the direction of CSF flow.This research shows that the velocity of both the control group and the hypertension group are not constant, but periodical changes related to the cardiac cycle.Differ from the amplitude images, the phase images show direction of CSF flow. The direction of velocity coding is foot-head (FH) in our study. During systole, CSF flowing from foot to head, showing low signal; during diastole, CSF flowing from head to foot, showing high signal.The phase images show the direction of the CSF within the aqueduct changing rhythmically in one cardiac cycle both in two groups.Quantitative analysis:To make the aqueduct shows clearly by adjusting window width and window level on axial QFlow images.And chose the maximum area of the aqueduct to draw ROI by two radiologists respectively, then the computer automatic analysis the images. Systolic mean velocity、diastolic mean velocity、systolic peak velocity and diastolic peak velocity can be obtioned in a cardiac cycle. Both the groups can obtion two forms of results which contained datas and graphics.CSF flow curve:The curve was calculated by R-R interal as X-axis and by CSF velocity as Y-axis.2.6 Statistical analysisAll results are reported as the mean±standard deviation. Statistical analyses w ere performed using SPSS 13.0 (SPSS Inc., Chicago, IL, USA). The data among thr ee groups were statistically analyzed by using a One-way ANOVA and the campari ons between three groups were performed by q test. Comparisons between two grou ps were performed using unpaired Student’s t-test. The confidence interval was set a t 95%(p<0.05).RESULT1. Details about hypertension group (table2) 2. Conventional MRI showed no obvious abnormity both in normal control group and hypertension group.3. PCC MRI results(1) CSF within the aqueduct is bidirectional motion associating with cardiac cycle both in hypertension group and control group;(2) The systolic mean velocity, diastolic mean velocity, systolic peak velocity and diastolic peak velocity in the aqueduct of the control group are (-0.385±0.181) cm/s, (0.303±0.141) cm/s, (-0.676±0.305) cm/s and (0.570±0.208) cm/s respectively; The systolic mean velocity, diastolic mean velocity, systolic peak velocity and diastolic peak velocity in the aqueduct of the hypertension group are (-0.617±0.219) cm/s, (0.504±0.224) cm/s, (-0.964±0.333) cm/s and (0.806±0.284) cm/s respectively. The systolic mean velocity, diastolic mean velocity, systolic peak velocity and diastolic peak velocity of the two groups were noted statistical significance(P<0.05);(3) The systolic mean velocity, diastolic mean velocity, systolic peak velocity and diastolic peak velocity of group pulse pressure ≥60mmHg were faster than the other with statistical significance(P<0.05);(4) The systolic mean velocity, diastolic mean velocity, systolic peak velocity and diastolic peak velocity of group with systolic pressure ≥160mmHg were faster than the other two groups.There were statistical difference in group with systolic pressure ≥160mmHg and group with systolic pressure<140mmHg(P<0.05).The systolic mean velocity, diastolic mean velocity, systolic peak velocity and diastolic peak velocity of group with 140mmHg≤pulse pressure<160mmHg were faster than group with systolic pressure<140mmHg, but without statistical difference(P>0.05);(5) There were statistical differences in group with diastolic pressure<90mmHg, group with 90 ≤diastolic pressure<100 and group with diastolic pressure≥100. And there were statistical difference comparing in pairs (P<0.05).The systolic mean velocity, diastolic mean velocity, systolic peak velocity and diastolic peak velocity increased with the higher diastolic blood pressure;(6) The systolic mean velocity, diastolic mean velocity, systolic peak velocity and diastolic peak velocity of 0<disease course<5 years group and disease course> 5 years group were noted no statistical significances(P>0.05), but systolic mean velocity,diastolic mean velocity,systolic peak velocity and diastolic peak velocity of disease course> 5 years group were faster than 0<disease course<5 years group. At present, we can not exclude the effect of disease course to the systolic mean velocity,diastolic mean velocity,systolic peak velocity and diastolic peak velocity and further research is needed.4. CONCLUSION:(1)CSF within the aqueduct is bidirectional motion associating with cardiac cycle both in hypertension patients and healthy human beings;(2)CSF hydrodynamics of the hypertension patients are higher than healthy human beings;(3)There was a tendency that as the pulse pressure increased, CSF hydrodynamics became higher;(4)There was a tendency that as the systolic blood pressure increased, CSF hydrodynamics became higher;(5)There was a tendency that as the diastolic blood pressure increased, CSF hydrodynamics became higher;(6)At present, we can not exclude the effect of disease course to CSF hydrodynamics and further research is needed;(7)This study established the preliminary reference standards of the systolic mean velocity、diastolic mean velocity、systolic peak velocity and diastolic peak velocity and distinguished the differences between hypertension group and control group. |
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