家兔脑出血模型头颅CT值变化规律初步探讨

目的:通过立体定向技术注射家兔自体动脉血到达脑基底节区的方法,构建家兔脑出血模型,分析不同时间段注射血液后头颅CT值的演变规律,探讨脑出血后头颅CT混合征形成的可能机制。方法:健康家兔70只,根据注入脑组织血液成分的不同分为全血组(50只)、血浆组(10只)和血清组(10只);对于全血组,根据注血间隔时间的不同又分为5个亚组,分别为A亚组(间隔1 h)、B亚组(间隔2 h)、C亚组(间隔3 h)、D亚组(间隔4 h)、E亚组(间隔5 h),每组10只,首次注射自体动脉血形成血肿后分别在不同时间段内再次注射相同成分的血液到血肿周边形成二次血肿;对于血清组和血浆组,于注射全血形成血肿后同时间段内向血肿周边或对侧分别注射自体血血清或血浆,造模完成后立即行头颅CT,记录家兔头颅CT不同区域的CT值,对比注射不同血液成分CT值的变化和同一血液成分间隔不同时间CT值的变化规律。结果:全血组经不同时间段向颅内注血可形成高低不同密度的血肿病灶,其低密度部位CT值高于脑组织与脑脊液,类似混合征表现;血清和血浆组亦可形成高低密度,但低密度部位与脑脊液CT值相近,不易区分,不符合混合征征象。结论:二次出血可能是脑出血头颅CT混合征的形成原因,而低密度区可能是首发出血,高密度区则可能是新发出血。

Preliminary Study on Variation Pattern of CT Values in Rabbits with Cerebral Hemorrhage

To establish a rabbit model of intracerebral hemorrhage by injecting autologous arterial blood into the basal ganglia region of rabbits by stereotactic technique, then analyze the evolution of CT values after injection of blood at different time periods in order to explore the possible mechanism of the formation of blend sign. Methods: Seventy healthy rabbits were divided into whole blood group (n=50), plasma group (n= 10), and serum group (n=10) according to the different blood components injected into the brain. The whole blood group was divided into 5 subgroups with 10 rabbits per subgroup according to time interval between injections: subgroup A (1 h gap), subgroup B (2 h gap), subgroup C (3 h gap), subgroup D (4 h gap), and subgroup E (5 h gap). After the first injection of autologous arterial blood to form a hematoma, the same component of blood was injected again at different intervals into the periphery of the hematoma to form a secondary hematoma; for rabbits in the serum group and plasma group, after hematoma was formed by injection of whole blood, within the same period of time, serum or plasma was injected at positions contralateral or ipsilateral to the first hematoma. Head CT scan was performed immediately following generation of model, and CT value of different cerebral regions was recorded. The CT value of groups injected with different blood components was compared, and the CT value variation pattern between groups injected with the same components at different time intervals was assessed. Results: In the whole blood group, injection of blood at different time intervals resulted in hematoma lesions of different densities. The CT value at the low-density site was higher than that of brain tissue and cerebrospinal fluid and was similar to the blend sign. The high and low densities were also formed in the serum and plasma groups, but the low-density sites showed similar CT values as that of cerebrospinal fluid; it was not easily distinguishable and did not meet the criteria of blend sign. Conclusion: Secondary hemorrhage may be the cause of brain CT blend sign in intracerebral hemorrhage. Low-density areas may indicate initial bleeding while high-density areas may be secondary bleeding