| Objective:To explore the improved after the2small dose of contrast agent in pre test technique of64slice spiral CT in lower extremity arterial angiography feasibility.Methods:40patients with clinical suspicion of lower extremity arterial disease patients, were randomly divided into two groups:individual group and control group.20cases of the control group underwent CTA by bolus-tracking. And20cases of individual group, underwent CTA by Test-bolus, which used2small dose (contrast agent15ml, physiological saline30ml) test-bolus technique. According to the abdominal aorta (L3/4level) and bilateral anterior tibial artery or the posterior tibial artery (ankle level) dynamic scanning peak time to determine the CTA scan delay time and the scan duration. Each group of CTA images were Independent evaluated by two experienced senior attending physicians on the following four aspects:(1) visible farthest branch;(2) Clarity of vessels border;(3) vein interference;(4) CT value at4arterial segments (abdominal aorta-iliac artery, femoral artery-popliteal artery, crural artery segment, foot dorsal or plantar artery), and comparing the CTA image quality of2groups. Application of t inspection with arterial branch level, vascular edge, vein interference score and CT value in2groups.Results:In20cases of the individual group, success rate of abdominal aortic small dose pre-test is100%(20/20), peak time of abdominal aorta (TAO) is quite different, the time range is18.0～34.0s, and the average time is24.3±5.3s. And success rate of bilateral anterior tibial artery or the posterior tibial artery (ankle level) small dose pre test is98%(76/80), peak time of bilateral anterior tibial artery (TTI) is quite different, the time range is28.0～60.0s, and the average time is49.1±7.9s.16cases of left and right anterior tibial arterial peak time is inconsistency. The through time (Tt) of Abdominal aorta to anterior tibial artery is10～31.0s, average time is (18.84+5.5) s. It is individual differences in Tt, contrast the longest and the shortest is difference of2to3times. In the Individual group, calf arteries’visible farthest branch, clarity of vessels border, presence of venous contamination, CT value were3.4±0.8,2.7±0.5,0.2±0.4,219.5±10.638; in the control group, calf arteries’ visible farthest branch, clarity of vessels border, presence of venous contamination, CT value were2.9±1.0,2.4±0.8,0.8±0.5,187.9±14.027. In the Individual group, foot back arteries’visible farthest branch, clarity of vessels border, presence of venous contamination, CT value were3.2±0.8,2.6±0.5,0.3±0.4,187±14.027; In the control group, foot back arteries’visible farthest branch、clarity of vessels border presence of venous contamination、CT value were2.3±1.1,2.3±0.8,0.7±0.5,166.3±17.480. The two groups score were compared, individual group is better than control group, P<0.05. It is statistically significant. The venous interference score of Abdominal aorta-iliac artery section and femoral artery-popliteal artery section in two groups, individual group is0.0+0.0,0.0±0.0; control group is0.3±0.3,0.4±0.3; individual group is better than the control group, P<0.05. It is statistically significant.Conclusion:1. There are significant individual differences in the peak time of the abdominal aorta of individual group(TAo)、Tibialis anterior or posterior artery time to peak(TTI) and Abdominal aorta-the tibialis anterior/posterior artery transit time(Tt).2. Test-bolus could accurately specify the timing of the angiographic, to get better imaging of vascular than the Bolus-tracking. It is extremely important for clinical to provide preoperative evaluation and guide treatment... |
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