等渗低浓度碘对比剂对兔脑CT灌注参数的影响

目的 探讨采用等渗低浓度碘对比剂碘克沙醇(270 mgI/ml)对兔脑CT灌注参数的影响。方法 将50只健康成年雄性新西兰大白兔随机均分为A组(碘海醇350 mgI/ml)和B组(碘克沙醇270 mgI/ml)。对两组实验兔行256层螺旋CT脑灌注扫描,由2名阅片者于CT图像后处理工作站获取脑灌注的脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)、达峰时间(TTP)、毛细血管通透率和灌注参数图,分析上矢状窦CT值、CNR和脑组织的SNR,按照4分法评价各组图像质量,采用两独立样本t检验和Mann-Whitney U检验对两组结果进行统计学分析。结果 共36只兔脑CT灌注扫描成功,A组20只,B组16只。两组兔CT脑灌注的灌注参数值CBF、CBV、MTT、TTP差异均无统计学意义(P均>0.05),A组的毛细血管通透率高于B组,差异有统计学意义(P<0.05),两组的上矢状窦CT值和CNR、脑组织的SNR差异均无统计学意义(P>0.05),两组的图像质量主观评分差异无统计学意义(P>0.05),2名阅片者对图像评价的一致性良好(Kappa=0.419,P<0.01)。结论 在相同扫描参数条件下,采用低浓度对比剂兔脑CT灌注成像与常规浓度对比剂相比,图像质量和灌注参数(除毛细血管通透率)均不受影响。

Influence of low-concentration iso-osmolar iodixanol on rabbit CT brain perfusion parameters

Objective To evaluate the influence of low-concentration iso-osmolar iodixanol (270 mgI/ml) on the rabbit CT brain perfusion parameters. Methods A total of 50 male New Zealand white rabbits with 25 assigned to A group (iohexol 350) and 25 assigned to B group (iodixanol 270) underwent brain perfusion imaging on a 256-slice MDCT scanner. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and permeability were recorded and parametric evaluated on image post-processing workstation by 2 radiologists. CT attenuation and CNR of superior sagittal sinus, SNR of brain parenchyma of each protocal were acquired and evaluated. Image quality were graded (scale:1-4) and compared among 2 groups. Statistical analysis were performed with independent sample t test and Mann-Whitney U test. Results A total of 36 rabbits brain CT perfusion scanning was successful, A group of 20, B group of 16. Permeability was higher in A group compared to B group (P<0.05), while there were no significant differences of CBF, CBV, MTT and TTP between the two groups (all P>0.05). The differences of CT values and CNR of superior sagittal sinus, SNR of brain parenchyma were not statistically significant between two groups (P>0.05). There was no difference in image quality scores of two groups (P>0.05). The two readers kept good constistency (Kappa=0.419, P<0.01). Conclusion In the same conditions of the scan, compared with conventional concentration of contrast agent, image quality and perfusion parameters (except capillary permeability rate) are not affected using low concentration of contrast agent in rabbit brain CT perfusion imaging.