冠状动脉CTA个体化对比剂注射方案实现图像质量均一化的可行性研究

Feasibility study of individualized contrast medium injection protocol to achieve consistent image quality in coronary CT angiography

目的:探讨基于体表面积(BSA)的个体化对比剂注射方案在冠状动脉CT血管成像(CCTA)中的临床应用价值。方法:前瞻性将拟行CCTA检查的连续300例患者随机均分为实验组和对照组,两组采用相同的CCTA扫描方案及对比剂(350mg I/mL),实验组基于BSA制订个体化对比剂注射方案(Ⅰ期:对比剂10700BSA/350mL;Ⅱ期:对比剂1160BSA/350mL,生理盐水1160BSA×0.7/(350×0.3)mL;Ⅲ期:生理盐水30mL),对照组采用传统的固定碘负荷和注射流率的对比剂注射方案(Ⅰ期:对比剂60mL;Ⅱ期:对比剂30mL,生理盐水70mL;Ⅲ期:生理盐水30mL)。比较两组患者CCTA图像上升主动脉、左冠状动脉前降支及右冠状动脉近端的CT值和对比噪声比(CNR),以及两组内不同体重人群(<60、60～70和>70kg)血管强化程度的一致性。定量参数的比较采用独立样本t检验,分类变量的比较采用卡方检验,采用线性回归分析探讨体重与血管强化程度关系。结果:对照组和实验组中升主动脉的CT值分别为(483.26±76.79)和(477.98±69.15)HU;左冠状动脉前降支的CT值分别为(479.39±78.25)和(481.78±65.66)HU;右冠状动脉的CT值分别为(452.09±89.89)HU和(465.75±74.21)HU,3个指标的组间差异均无统计学意义(P>0.05)。对照组和实验组中前降支图像的CNR分别为46.94±20.07和44.07±18.18(P>0.05),右冠状动脉图像的CNR分别为50.75±10.34和49.80±17.06,差异均有统计学意义(P>0.05)。对照组中前降支和右冠状动脉的强化程度与体重呈线性负相关(r=-0.33和-0.19,P<0.01);实验组中前降支和右冠状动脉的强化程度与体重无统计学相关性(r=-0.09,P=0.280;r=-0.14,P=0.587)。两组中各体重亚组之间比较,对照组中前降支和右冠状动脉的CT值在各亚组间的差异均有统计学意义(P=0.003,P=0.021);实验组中前降支和右冠状动脉的CT值在亚组间的差异均无统计学意义(P=0.809,P=0.799)。结论:CCTA检查中采用基于体表面积的个体化对比剂注射方案可实现不同体重患者血管强化程度的均一性。

Objective: To discuss the feasibility of individualized contrast medium (CM) injection protocol tailored to body surface area (BSA) to achieve consistent and identical arterial enhancement in coronary CT angiography (CCTA). Methods: 300 consecutive patients who underwent CCTA examination were prospectively and randomly divided into experimental group and control group,150 in each.Same scan protocols including CM (350mg I/mL) for all the patients were strictly followed during CCTA scan except for the injection patterns of CM.Individualized CM injection protocols were adapted according to BSA value in the experimental group(phase Ⅰ:CM 10700BSA/350mL;phase Ⅱ:CM 1160BSA/350mL,normal saline 1160BSA×0.7/(350×0.3)mL;phase Ⅲ:normal saline 30mL);while the conventional protocol of using designated CM volume and injection rate was applied in the contrast group(phase Ⅰ:CM 60mL,phase Ⅱ:CM 30mL,normal saline 70mL,phaseⅢ:normal saline 30mL).The CT values of ascending aorta (AAo),proximal left anterior descending (LAD) and right coronary artery (RCA),and contrast-to-noise ratio (CNR) of LAD and RCA were measured and the intergroup difference were analyzed statistically.The vascular enhancement values of LAD and RCA in the three subgroups with different weight (<60,60~70 and >70kg) were compared between the two groups.Independent t -test was used for comparison of continuous variables,chi-square analysis was used for categorical variables,and the relationships between vascular enhancement and body weight were analyzed using linear regression analysis. Results: No statistically significant difference was found in CT values of AAo [(483.26±76.79)HU versus (477.98±69.15)HU],LAD [(479.39± 78.25)HU versus (481.78±65.66) HU] and RCA [(452.09±89.89)HU versus (465.75± 74.21)HU] between the control group and the experimental group (all P >0.05).And there was no statistical significant difference in CNR of LAD (46.94±20.07 versus 44.07±18.18) and RCA (50.75± 10.34 versus 49.80±17.06) between control group and experimental group (all P >0.05).However,correlation coefficient ( r value) between weight and enhancement of LAD and RCA was -0.33 and -0.19 (all P <0.01) in the contrast group,r value was -0.09 ( P =0.280) and -0.14 ( P =0.587) in the experimental group.In contrast group,statistically significant difference was found in CT value of LAD and RCA ( P =0.003,P =0.021) among the three subgroups and no significant difference in experimental group ( P =0.809,P =0.799). Conclusion: It is feasible to obtain consistent arterial enhancement and image quality in different patients for CCTA examinations with the individualized CM injection protocol tailored to BSA value.