双低技术在腹主动脉联合下肢动脉CTA中的可行性探讨

目的:比较腹主动脉联合下肢动脉CT成像中两种不同对比剂注射方案对对比剂剂量的影响。方法:搜集临床上怀疑腹主-下肢动脉疾病行CT血管成像(CTA)的患者50例,随机分为A、B组,对比剂(350 mg I/m L),A组:男16例,女9例,平均年龄(58.53±9.39)岁,平均体质量(67.86±11.65)kg,平均扫描范围(124.65±8.28)cm。B组:男17例,女8例,平均年龄(60.87±9.76)岁,平均体质量(66.23±12.42)kg,平均扫描范围(122.59±9.12)cm。A组注射流率4 m L/s,对比剂用量1.5 m L/kg。B组第1期5 m L/s注射20 m L,第2期3 m L/s注射剩余量;B组对比剂总量=1.5 m L/kg×体重-4 m L/s×(B方案对比剂注射时间-A方案对比剂注射时间)。对比剂注射完毕两组均以3 m L/s流率无缝隙注射生理盐水30 m L。两组均选择智能触发技术,监测平面为腹主动脉(右膈肌水平),阈值≥150 HU。对两组5个动脉段图像质量进行评分;测量5个动脉段CT值,记录两组对比剂剂量。均进行独立样本t检验。结果:A组5个动脉段图像质量评分、平均CT值分别为:4.76±0.44、(328.46±21.45)HU(腹主动脉段),4.20±0.58和(330.96±22.52)HU(髂动脉段),4.36±0.57、(327.16±23.65)HU(股动脉-腘动脉段),3.32±0.63、(296.53±20.43)HU(小腿动脉段),3.12±0.53、(257.26±21.21)HU(足背或足底动脉段);B组分别为:4.72±0.46、(329.75±23.12)HU(腹主动脉段),4.08±0.57、(331.63±24.64)HU(髂动脉段),4.16±0.55、(319.89±21.79)HU(股动脉-腘动脉段),3.24±0.66、(290.44±21.57)HU(小腿动脉段),3.28±0.46、(243.76±27.29)HU(足背或足底动脉段);B组均低于A组,差异均无统计学意义(P>0.05)。A、B组对比剂剂量分别为(93.79±13.68)m L和(74.61±14.76)m L,差异有统计学意义(P<0.05)。结论:对比剂流率5 m L/s+3 m L/s分期注射可在不影响图像质量的前提下降低腹主动脉联合下肢动脉CTA的对比剂用量。 

The Feasibilty of Double Lower Technique in Abdominal Aorta Combining Lower Extremity Arteries CT Angiography

objective: To compare the effects of two kinds of contrast medium injection projections on the contrast media dose in abdominal aorta combining lower extremity arteries CT angiography. Methods: 50 cases of patients who were suspected abdominal aorta-lower extremity arteries diseases and undergone CT angiography were divided into two groups(A and B) randomly, the contrast media dose was 350 mg I/m L. 16 males and 9 females in group A, the mean age was(58.53 ± 9.39), the mean body weight was(67.86 ± 11.65) kg and the mean scanning range was(124.65 ± 8.28) cm; 17 males and 8 females in group B, the mean age was(60.87 ± 9.76), the mean body weight was(66.23 ± 12.42) kg and the mean scanning range was(122.59 ± 9.12) cm. The injection rate in group A was 4m L/s and total dose was 1.5 m L/kg; in group B, the injection rate was 5 m L/s and total dose was 20 m L in the first step, and the others was injected with 3 m L/s in the second step, and the total dose in group B was equal to 1.5 m L/kg multiply weight and substract(4 m L/s multiply the time difference in two groups). The 30 m L normal saline was injected immediately after contrast medium injection in two groups, and injection rate was 3 m L/s. The intelligent touch scanning technique was used in two groups and the monitor plane was abdominal aorta(the level of right diaphragm), the ROI threshold value was ≥ 150 HU. Scored the five artery sections image quality, measured the CT values of five artery sections, recorded the contrast medium dose in two groups. The independent sample t test was used. Results: The image quality scores and CT values of five artery sections in group A was:(4.76 ± 0.44),(328.46 ± 21.45) HU(abdominal aorta section);(4.20 ± 0.58),(330.96 ± 22.52) HU(iliac artery section);(4.36 ± 0.57),(327.16 ± 23.65) HU(femoral artery-popliteal artery section);(3.32 ± 0.63),(296.53 ± 20.43) HU(crus artery section);(3.12 ± 0.53),(257.26 ± 21.21) HU(acrotarsium artery or planta artery); the data in group B was:(4.72 ± 0.46),(329.75±23.12) HU(abdominal aorta section);(4.08 ± 0.57),(331.63 ± 24.64) HU(iliac artery section);(4.16 ± 0.55),(319.89 ± 21.79) HU(femoral artery-popliteal artery section);(3.24 ± 0.66),(290.44 ± 21.57) HU(crus artery section);(3.28 ± 0.46),(243.76 ± 27.29) HU(acrotarsium artery or planta artery), the data in group B were all worse than that in group A, but there were no statistically significant difference; the contrast dose were(93.79 ± 13.68) m L and(74.61 ± 14.76) m L, there was statistically significant difference. Conclusion: It can obviously reduce the contrast medium dose of abdominal aorta combining lower extremity artery CT angiography that we use the 5 m L/s add 3 m L/s injection step in the premise of not affecting the image quality.