兔急性脑梗塞可逆／不可逆性损伤区的ADC演变规律研究

【目的】观察急性脑梗塞可逆（RDR）／不可逆性损伤区（IDR）的表观弥散系数（ADC）演变规律，探讨ADC界定RDR／IDR的价值。【方法】健康家兔40只，其中35只行大脑中动脉闭塞（MCAO）术，术后按0．5、1、3、6、9、12和24h时间点分组，每组5只；对照组5只。使用GE signa Highspeed MR/i 1．5T超导MRI仪，完成弥散加权成像及灌注加权成像检查，测定可逆损伤区（RDR）、不可逆性损伤区（IDR）及其镜像区的ADC及相对表观弥散系数（rADC）值。统计分析使用配对t检验。【结果】在MCAO后0．5—24h，IDR的ADC及rADC值均低于镜像区（P〈0．05）；在0．5-3h，IDR的ADC及rADC下降明显；在6—12h，保持较恒定的状态；24h时，出现升高。RDR镜像区的ADC及rADC值，在MCAO后0．5—3h，与镜像区相比无显著性差异（P〉0．05）。在6—9h，RDR的ADC及rADC值低于其镜像区（P〈0．05）。在MCAO后各时间点，IDR的ADC及rADC与RDR比较均有显著性差异（P〈0．01）。【结论】ADC及rADC可作为判断梗塞区脑组织存活状态的可靠指标。

Study on the evolving process of the apparent diffusion coefficient of reversibly and irreversibly damaged region in acute cerebral infarction in rabbit

Objective] To investigate the evolving process of the apparent diffusion coefficient （ADC） of reversibly and irreversibly damaged region in acute cerebral infarction and explore its value of defining the reversibly damaged region （RDR） /irreversibly damaged region （IDR）. Methods] A total of 40 rabbits were used. Middle cerebral artery occulusion （MCAO） was performed on 35 rabbits and then divided into 7 groups according to the time after operation （0.5, 1, 3, 6, 9, 12 and 24h postoperatively, 5 rabbits for each group）. 5 rabbits didnot receive operation served as control group, Diffusion-weighted imaging and perfusion- weighted imaging were performed with GE Signa Highspeed MR/i 1.5T superconductive MRI system, and accepted the apparent diffusion coefficient （ADC） and relative apparent diffusion coefficient （rADC） value in the RDR, IDR and its mirror region, statistical analysis Paired t-test was used for. Results] 0.5 to 24 hours after MCAO, the ADC and rADC values in the IDR were below the mirror region （ P 〈 0.05）, 0.5 to 3 h, dropped significantly; 6 to 12 h, maintained a constant state; 24 h increased. The ADC and rADC values in the RDR in the 0.5 to 3 h after MCAO when compared with the mirror region there were no significant difference （ P 〉 0.05）. In 6 to 9 hours, the ADC and rADC values were below its mirror region （ P 〈 0.05）. At each time point after MCAO, the ADC and rADC in the IDR when compared with the RDR there was a significant difference （ P 〈 0.01）. Conclusions] ADC and rADC can he used as a reliable indicator for defining the survival state of the brain in infarct region.