超急性期及急性期脑梗死全脑CT灌注和CT血管造影研究

A study of whole brain perfusion CT and CT angiography in hyperacute and acute cerebral infarction

目的评价全脑CT灌注成像加同步CT血管造影(CTA)对早期缺血性脑梗死的诊断价值.方法对20例缺血性卒中发作2～24 h病例分别行常规非强化CT(NCCT),CT全脑灌注成像(PWCT)及灌注后70 s的延时扫描(DCT),分别测量低灌注区中心,周边及健侧相对应区CT值,计算病变中央和对侧灌注血液容积(PBV),PWCT作为CTA源图像重建CTA,判断颅内大血管阻断或狭窄及分支缺损情况,灌注延时相了解侧支循环改变,PWCT用密度差法处理,1周至1个月后复查CT、MR确定最终梗死区面积,用SPSS软件统计分析.结果 20例缺血性卒中NCCT+PWCT+CTA未发现异常10例,其中临床及复查CT、MR证实短暂性脑缺血发作(TIA) 6例,腔隙性梗死4例,10例PWCT低灌注区中心﹑周边内侧与外侧和健侧对应区CT值比较差异具有统计学意义(P<0.01),而病灶中心﹑周边内和外之间差异无统计学意义(P>0.05),病变侧和健侧PBV值差异有统计学意义(P<0.05),所有最终梗死区面积较低灌注区增大,增大百分比与缺血时间呈中度负相关,R 2=0.42,CTA显示左大脑中动脉阻断2例,左大脑中动脉前、中分支缺如3例,NCCT、PWCT及CTA的敏感度分别为28.5%、71.4%和35.7%,延时相显示不对称充盈血管5例.结论 CT全脑灌注像加同步CTA对早期脑梗死的诊断不失为一种简便、省时和有效的方法,可明确低灌注区的存在及其大小、位置和相对应供血动脉的情况,对半暗带区也可作出一定程度的推测,可为临床早期溶栓治疗提供半定量的形态学依据.

Objective To evaluate the diagnostic value of whole-brain perfusion blood volume-weighted CT imaging (PWCT) and simultaneous CT angiography (CTA) on early stage of cerebral ischemic infarction. Methods Non-contrast CT (NCCT), CT perfusion-weighted imaging (PWCT) and delayed CT (DCT) were conducted on 20 cases of early ischemic infarction of whose onset time ranged from 2 to 24 hours. All cases were reexamined with CT or MRI one week to one month later. CT values and perfusion blood volume (PBV) of central and peripheral low perfusion areas as well as those of collateral side were measured. CTA was reconstructed with PWCT as source images to evaluate occlusion or stenosis of blood vessel, and DCT was used to detect the collateral circulation. Results Of the 20 cases, NCCT, PWCT and CTA were negative in 10 cases in which 6 were confirmed as Transient Ischemic Attack (TIA) on reexamined CT and clinical features, and the other 4 were confirmed as lacunar infarction. For the remaining 10 cases, a comparison was made with ANOVA between low perfusion area (central, peripheral inside and outside) and collateral side. The difference was significant (P<0.01). However, no significant difference was revealed in the central, peripheral inside and outside areas. PBV values were significant in low perfusion area and collateral side (P<0.05). The area of the final infarction was larger than that of the low perfusion area, and the percentage of enlargement exhibited medium negative correlation to the time of ischemia. CTA indicated that 2 cases suffered from left middle cerebral artery occlusion, meanwhile anterior and middle branches of MCA in the other 3 cases were not identified. The sensitivity of NCCT, PWCT and CTA were 28.5%, 71.4% and 35.7% respectively. DCT indicated that 5 cases had asymmetrical blood vessels. Conclusion The whole-brain perfusion-weighted CT imaging and simultaneous CT angiography (CTA) is proved to be a simple, timesaving and effective method for the diagnosis of early stage of ischemic infarction. This method can identify the existence, size, location and corresponding blood-supplying arteries of low perfusion area. It can also predict the existence of ischemic penumbra, providing semi-quantitative and morphological evidence for the clinical treatment of thrombolysis.