多排CT灌注成像对大鼠超急性期脑梗死的诊断价值

Diagnostic value of multi-slice CT perfusion imaging to hyperacute cerebral infarction in rats

目的:探讨多排CT灌注成像(CTPI)技术对大鼠超急性期脑梗死的诊断价值。方法:雄性SD大鼠50 只,随机分为对照组10只,实验组40只。实验组按大脑中动脉栓塞(MCAO)后0.5h、1h、2h、3h、6h均分为5个 时点,每个时点8只;对照组也分为5个时点,每个时点2只。2组采用GELightSpeed16排CT机于MCAO后各时 点行灌注扫描,分别计算脑血流量(CBF)图、脑血容量(CBV)图、平均通过时间(MTT)图。在三色的功能图像上画 取双侧对称性兴趣区(ROI),获得病灶侧与对侧脑组织的血流动力学参数值,计算CBF的绝对值和相对值。比较 CBF、CBV、MTT成像结果与TTC染色结果并分析2者间的相关性。结果:对照组各参数图均未见异常灌注区,TTC 染色显示双侧大脑半球对称性红染。实验组各参数图均可见缺血梗死区域。MACO后各时点CBV图中的低灌注 体积与CBF图核心区体积之间差异无统计学意义(P>0.05)。TTC染色梗死体积与CBF核心区、CBV异常灌注区 体积均呈正相关较低(r=0.960,P<0.01;r=0.911,P<0.01);TTC染色梗死体积与MTT异常灌注区体积相关性 较低(r=0.800,P<0.01)。结论:16排CTPI可早期发现梗死病变,能全面显示并可量化梗死和缺血半暗带的部 位、范围和程度,为临床诊断和治疗提供个性化信息。

Aim: To evaluate the ability of multi-slice CT perfusion imaging(CTPI) to detect hyperacute infarction in rats. Methods: A toal of 50 SD rats were randomly divided into control group(n=10) and ischemic group(n=40).The ischemic greup was undergone middle cerebral artery occlusion(MCAO) and subdivided into five time points (n=8) according to 0.5 h,1 h,2 h,3 h,and 6 h interval after the onset of occlusion. The control group was subdivided into five time points(n=2) similar to the ischemic group. CT perfusion imaging was performed by GE Lightspeed 16 slice CT scanner at each occluding time point. The cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) of bilateral symmetric regions of interest from 3-color functional maps were calculated, including absolute and relative values. The results were compared with TTC stain findings,and the relationship between them was analyzed. Results: Neither abnormal findings nor pathologic changes were found in control group. Infarction and ischemic changes could be displayed clearly according to each functional map. No significant difference existed between the volume of hypoperfusion areas on CBV maps and obvious hypoperfusion areas on CBF maps (P>0.05). TTC stain showed the infarction areas pale correlationship of obvious hypoperfusion regions on CBF maps, hypoperfusion areas on CBV maps with TTC pale staining areas( r=0.960,P<0.01;r=0.911,P<0.01). While there was no obvious correlationship between abnormal regions on MTT maps and TTC pale staining areas(r=0.800,P<0.01). Conclusion: The 16 slice CT perfusion imaging can detect early and display the location, extent, and degree of infarction and ischemic penumbra in all aspects, and can provide much more individual information for the clinical diagnosis and therapy.