双低剂量 CT尿路成像临床可行性研究

摘要

Objective To investigate the feasible clinical scheme of the double low-dose ( low-dose contrast agent and low X-ray radiation ) CT urography .Methods Eighty patients undergoing CT urography were randomly divided into four groups(groups A,B,C,D),with 20 cases in each group.The fixed tube current method was performed in group A with tube voltage of 120 KV and 150 mAs.The automatic tube current modulation method was performed in groups B ,C, D with tube voltage of 120 KV and SD of 10 HU,15 HU,20 HU.Groups A and B were given iohexol (300 mgI/ml), 1.3 ml/kg,while groups C and D were given ioversol (320 mgI/ml),0.8 ml/kg.The original thin slice images were transferred to the Vitrea workstation for post processing ,while the axial images and reformatted images were sent to the NFPACS.The CT dose index(CTDIvol),the amount of iodine contrast agent(g),body mass index and kidney levels mAs in each group were recorded .The image quality was analyzed .Results The image scores showed the significant differences among four groups(P<0.05).Group A had similar image quality with group B.The scores of group A and group B were 5, of group C and group D were (4.43 ±0.50) and (3.63 ±0.49),respectively.There were significant differences in CTDIvol among 4 groups(P<0.05).The radiation dose of groups B,C,D were lower than that of group A for 55%,72%and 80%, respectively.Iodine contrast agent dosage of group C and group D decreased by 33%.Conclusion The automatic tube current modulation method can effectively reduce the radiation dose .Group B scanning conditions can be used as a routine scan scheme to reduce radiation dose .The radiation dose and the amount of iodine contrast agent of group C and group D decrease significantly ,but the image quality meets the diagnostic requirements ,they can be used as an optimal double low-dose scanning method for CT urography .%目的：探讨低剂量对比剂和低X线辐射量CT尿路成像在临床上是否可行。方法80例需要CT尿路成像检查的患者，按就诊顺序随机分成4组，每组20例。 A组采用固定管电流法，120 KV，150 mAs；B、C、D组均采用自动管电流调制法，管电压120 KV，SD值10 HU、15 HU、20 HU；A、B组碘海醇（300 mgI/ml）1．3 ml/kg，C、D组碘佛醇（320 mgI/ml）0．8 ml/kg。将原始薄层图像在东芝16排CT Vitrea工作站上进行后处理，将轴位图像和重组图像传送至NFPACS上。分别记录每组病例的CT容积剂量指数（CTDIvol）、对比剂碘用量（g），体重指数和双肾层面的毫安秒。评价图像质量。结果4组之间图像评分差异有统计学意义（P＜0．05），其中A组和B组图像质量相等，评分均为5分，C组为（4．43±0．50）分、D组（3．63±0．49）分。4组CTDIvol比较，差异有统计学意义（ P＜0．05），3组辐射剂量比A组分别降低约55％、72％和80％。 C组、D组对比剂碘用量下降约33％。结论自动管电流调制法可以有效降低辐射剂量值，B组扫描条件可以作为常规扫描方案，以降低辐射剂量。 C组和D组的辐射剂量和对比剂碘用量明显减少，但图像质量可以满足诊断需要，可以作为CT尿路成像的双低剂量优化扫描方法。