Experiments And Imaging Studies Of High Blood Pressure Induced Reversible Posterior Encephalopathy Syndrome

Partâ… : Establishment of hypertension source RPES animal modelObjective To made a simple,easy handle and reproducible Reversible posteriorencephalopahy syndrome(RPES) model which consistent with the conditions of humanincidence of high blood pressure cause of this diseases. To make comparison analysisbetween the performance of pathology and imaging findings.Methods 30 New Zealand white rabbits were anesthetized and measured bloodpressure of the right hind leg mean arterial pressure which be calculated as the basis ofblood pressure. All rabbits randomly divided into 3 groups, group A and B were undergonethe surgery of narrowing left renal artery(about 1/2-2/3) to make renal hypertensionmodel. Group A been injected by inter-tartrate hydroxylamine(2.5mg / kg) every day afterone week. no other disposal for group B. Group C were taken intramuscular injection ofInter-tartrate hydroxylamine(2.5mg / kg)and intravenousmethylene blue inoculationfluid(5ml diluted)every day. All rabbits were scaned with conventional MRI sequencing ona regular basis (3 days / times) and brain tissue biopsy were taken at different period everygroup.Results One week later 6 cases in group A and 10 days later 4 cases in group C hadabnormal finding in the brain MRI-scan, the lesions were demonstrated as slightlyhypointensity on T1WI and hyperintensity on T2WI and remarkably hyperintensity onFLAIR and on DWI, pathology performance for the two groups confirmed of vasogenicbrain edema. The rabbits restored completely after one week.Conclusion By narrowing the left renal artery and intramuscular injection ofhydroxylamine, or intramuscular injection between re-tartaric acid hydrochloride injectioncan made animal models of RPES, It is easy to operate, the success rate is high and good repeatability. This model is consistent with the conditions of human incidence of highblood pressure cause of this diseases and has the three essential characteristics: (1)there is acorresponding clinical symptoms; (2)Imaging findings performance is similar withhumanity's RPES; (3)the rabbits restored completely after one week stopping the drug.Partâ…¡: Imaging and Pathology Control study between models ofAcute hypertensive-indued cerebral edema and RPESObjective To investigate the imaging and pathology performance diffirent betweenanimal models of acute brain injury of hypertension and models of RPES.Methods 20 New Zealand white rabbits were randomly divided into two groups,After anaesthetizing, group A were taken intravenous phenylephrine hydrochloride and theblood pressure were examined. When the blood pressure rose to the highest value, it beenmaintained for 30 minutes, then the ribbits been taken intravenous methylene blue injection5ml(diluted with normal saline) . Group B been injected by inter-tartratehydroxylamine(2.5mg / kg) and intravenous methylene blue 5ml (diluted with normalsaline)every day. Brain tissue of two groups were stained with methylene blue, ordinaryhematoxylin - eosin staining under light microscope observation.Results The methylene blue staining can found: brain tissue of rabbits from group Astained blue was more even, the brain, the cerebellum from group B had patchy blue dye,especially the behind brain organization stained significantly. Hematoxylin- eosin stainingunder light microscope observation of the experimental group was the performance of acutecerebral edema, edema in the group B were less than group A.Conclusion Intravenous infusion of phenylephrine hydrochloride for the sharpincreasing in blood pressure and maintaining the blood pressure at the highest for 30minutes Can successfully establish rabbits model of acute hypertension cerebral edema, andthe pathological and imaging changes were different from the model of RPES. Partâ…¢: The Imaging analysis in 95 cases of hypertensiveencephalopathyObjective To investigate the imaging features and diagnostic value of cranial CT andMRI in the patients with hypertensive encephalopathy.Methods The CT and MRI imaging of 65 cases of clinical diagnosis hypertensiveencephalopathy were reviewed retrospectively, including 60 cases of CT scan, 27 cases ofMRI scan(5 cases MRI scan alone). The basis of clinical symptoms of intracranialhypertension is divided into three groups: high intracranial pressure group,someneurological dysfunction and high intracranial pressure group,consciousness barriergroup. In each group, relationship between positive rate and the scope of the lesions in theimaging examination were investigated.Results Of 65 patients with clinical diagnosis of hypertensive encephalopathy, 45cases had abnormal finding in the cranial CT and MRI. 20 cases had no particular findingin cranial CT and MRI. 38 cases showed abnormal density in CT head scan and the topoccipital white matter changes were characterized by low-density. 19 cases had abnormalsignal in MRI head scan, The lesions mainly located in occipital white matter and weredemonstrated as slightly hypointensity on T1WI,hyperintensity on T2WI and remarkablyhyperintensity on FLAIR. The performance for 26 cases showed of the typical occipitaledema, 19 cases of diffuse edema, two cases of hemorrhage, and another two cases showedthat the formation of cerebral hernia.Conclusion Neuro-imaging characteristics of hypertensive encephalopathy showed ofsubcortical white matter edema. Cranial CT and MRI features of patients with HE canappear with no obvious change, typical edema in the parietal and occipital lobes and diffuseedema of the brain. Cranial CT and MRI scan has great significance for the diagnosis anddifferential diagnosis of HE as well as the assessment of the treatment efficacy. Partâ…ª: Imaging Findings and Diagnosis of Posterior ReversibleEncephalopathy SyndromeObjective To investigate the imaging features of reversible posterior cncephalopathysyndrome (RPES).Methods The clinical imaging data of 60 patients were analyzed retrospectively,including 18 patients with eclampsia or preeclampsia, the other with primary hypertension,renal hypertension, renal transplantation or bone marrow stem cells transplantation,systemic lupus crythematosus, cerebral angiography by use non-ionic contrast agent.Results The charactcristics of RPES on CT indicated low density in white matter theof parietal lobe and occipital lobe, but no enhancement on the contrast enhanced CT. MRIwas more sensitive than CT on determining lesions. The findings of CT showed that 16cases had low density in parietal, occipital and frontal lobe, 14 cases in parietal andoccipital lobe including 2 cases with bleeding in the lesions. Patients with widespreadlow-density of the parietal, occipital, frontal lobes, basal ganglia or cerebellum had poorprognosis, and reversible changes usually occurred in parietal lobe, occipital lobe, frontallobe and simple occipital lobe, Cases of preeclampsia and postpartum eclampsia, primaryhypertension, renal insufficiency and drug toxicity showed favourable prognosis, the othersstill adverse prognosis.Conclusion The imaging manifcstations and prognosis are different between RPEScaused by significantly higher blood pressure with no significant increase in bloodpressure. The decision of PRES about early diagnosis needs to consider the imagingcharacteristics, furthermore, such as clinical features, etiology and medication should alsobe comprehensively evaluated.