Stroke Brain Edema - Non-invasive Detection Mechanism And Treatment Of Exploration

Background and ObjectivesBrain edema is the most important complication of the patients with cerebral disease, and associated with high mortality. Accurate evaluation of the edema severity and correct management on time are associated with rescuing success of the critical patient. Current methods such as CT and MRI are expensive and unconvenient, therefore, It's necessary to explore a new method of monitoring brain edema, which can provide rapid, noninvasive, convenient monitoring edema at bedside for a long period, to contribute to clinical evaluation and treatment of brain edema.Biological electric impedance analysis applied to body component measurement, is a rapid, unexpensive and safe method developed in recently, and has become a hot spot of investigation. Up to now, there are few noninvasive studies of BEI measurement of brain. We designed a noninvasive brain edema measurement system according to BEI measure principle. The Cerebral EI(CEI) of stroke patients was measured by using this measurement system to reflect the dynamic changes of the brain edema after stroke.The results were compared with the lesion showed by CT to establish a new method of measuring brain edema which could provide noninvasive and real-time measurement at bedside.Methods①we designed a noninvasive cerebral impedance measure system, and confirmed its feasibility. ②The CEI of 100 normal volunteers, initially definited the range of normal value. ③The CEI of 24 patients with hypertensive intracerebral hemorrhage was measured continuously, which was compared with the volume of hematoma and edema showed by CT. ④The CEI of.50 patients with cerebral infarction, (19 of which onset time <24h)was measured, and the relationship between the changes of CEI and the volume of lesion showed by CT/MRI was analyzed.Results1． The low frequency current from noninvasive measure system could penetrate the cranium with poor electroconductivity, and could reflect the change of water content in brain tissue.2． The left and right side of CEI were almost symmetric at different frequency (P>0.05). Age,sex and measuring time did not obviously affect the CEI.3． The CEI of hematoma side was initially low and followed by high level. The rate of CEI change of hematoma side within 24h had negative correlation with the volume of hematom(r=－0.8953,P<0.01), however, the rate of CEI change of hematoma side had positive correlation with the volume of perihematomal tissue edema(r=0.8811,P<0.01).4． The CEI of infarct side were higher than contralateral. The rate of CEI change of infarct side(<24h) had positive correlation with the volume of volume ischemic lesion showed by DWI(r=0.6845, p<0.05)。Conclusions1． The CEI is a stable physical parameter for reflecting the electrical character of human brain tissue, and could be measured noninvasivly.2． Noninvasive CEI measurement could sensitively reflect the change of hematoma and perihematomal tissue edema, which contribute to clinical evaluation and treatment of cerebral hemorrhage.3． Noninvasive CEI measurement could reflect intracelluar edema early(<24 hours) after cerebral infarction, which contribute to prompt clinical judgement of the nature of lesion.