低剂量对比剂在64排螺旋CT主动脉成像中的探讨

目的探讨64排螺旋CT不同体重注射不同对比剂量在胸腹主动脉血管成像的中应用。方法临床可疑主动脉病变患者,知情同意后分A、B两组。A组20例:体重在60 kg以上注射60ml对比剂+40 ml生理盐水、B组20例:体重在60 kg以下按1 ml/kg对比注射+适量的生理盐水;两组均采用相同注射速率和浓度行对比剂浓度实时监控触发扫描,测量升主动脉、胸7(T7)及腰2(L2)水平降主动脉、主动脉分叉处CT值及血管横截面直径,并在扫描前测量患者的体重、身高、血压、心率。由两位影像诊断高级职称医师对重组主动脉及分支血管显示进行评价,并对血管强化程度、血管横截面直径、体重、身高、血压、心率数据进行统计学分析。结果两组在升主动脉、胸7(T7)及腰2(L2)水平降主动脉、主动脉分叉等处的平均CT值分别为:331.10 Hu、342.52 Hu、308.71 Hu、299.75 Hu和337.10 Hu、325.59 Hu、322.06 Hu、308.34 Hu,血管横截面平均直径为:37.40 mm、25.12mm、17.91 mm、15.50 mm和35.20mm、23.08 mm、12.37 mm、11.80 mm,体重为:72.50 kg、49.50 kg,身高为:175.70 cm、150.50 cm,血压为:130/78 mmHg、124/78 mmHg,心率76.5次/分、74.6次/分;两组间各点的平均CT值强化不具有统计学意义(P>0.05),重组血管清晰度及显示血管分支也无差异,各点的血管横截面平均直径具有统计学意义(P<0.05),体重、身高具有明显差异(P<0.01)、血压、心率各组不具有统计学意义(P>0.05)。结论 64层螺旋CT行主动脉MSCTA检查时,个性化因人而异不同体重注射不同对比剂量可获得良好的CTA图像,并满足诊断要求,为临床提供可靠的诊断依据,还降低了CIN潜在的风险。

Exploration on the use of low dose contrast medium in 64-slice CT imaging of the aorta

Objective The aim of this study was to explore the effect of different dosees of contrast medium（CM） according to different weight indexes in 64-slice CT imaging of the thoraco-abdominal aorta.Methods 40 suspicious patients for aortic disorders were divided into two groups.In the group A,20 patients with body weight 60 kg were injected 60 ml contrast medium and 40 ml physiological saline.In the group B,20 patients with body weight ≤ 60 kg were injected contrast medium in a dose of 1 ml/kg and an appropriate amount of physiological saline.Both groups were injected at the same speed and CM concentration.The body weight,height,blood pressure and heart rate were measured before CT scanning,and the patients received real-time monitoring and triggering scan to measure the CT values and diameters of the aortic intersecting surface at the levels of ascendening aorta,descendening aorta（T7,L2）,and aoric bifurcation.Two experienced senior imaging diagnostic doctors evaluated the CT images,and the measured data were statistically analyzed.Results the mean CT values of ascending aorta,thoracic aorta（T7）,lumbar aorta（L2） and aortic bifurcation were 331.10 Hu,342.52 Hu,308.71 Hu,299.75 Hu and 337.10 Hu,325.59 Hu,322.06 Hu,308.34 Hu,respectively.The mean diameter of the aorta at the four levels were 37.40 mm,25.12 mm,17.91 mm,15.50 mm and 35.20 mm,23.08 mm,12.37 mm,11.80 mm,respectively.The body weights were 72.50 kg and 49.50 kg,the heights were 175.70 cm and 150.50 cm,the systolic blood pressure were 130/78 mmHg and 124/78 mmHg,the heart rates were 76.5 beat/min and 74.6 beat/min,respectively.The intensified CT values of the two groups were not significantly different（P0.05）,the clarity of the recombined blood vessel branches were not significantly different.The mean diameters of different aortic segments were significantly different（P0.05）.The body weights and heights were significantly different（P0.01）.The blood pressure and heart rate were not significantly different in both groups.Conclusions In diagnosis of the aorta by 64-slice spiral computed tomography,the dosage of contrast medium should be provided individually according to different weight index meanwhile clear images can be obtained to meet with the diagnosis requirement and the potential risk of contrast-induced nephropathy can be lowered.