头颈部CTA中预测试的剂量优化研究——“三低”联合窄准直器宽度的应用效果  

Study of Dose Optimizing of Test-Bolus in Intracranial and Cervical CTA:The Effect of Joint Application of “ Three Lows”and Thinner Collimator

作　　者：梁永超 莫夏萍[1] 邓德茂 江雪源[1] 陈加军 韦兰珍[1] 廖海 段高雄[1] 兰志毅[1] 陈文福[1] 

机构地区：[1]广西中医药大学第一附属医院放射科南宁530023 [2]桂林医学院附属医院放射科

出　　处：《临床放射学杂志》2018年第1期143-147,共5页Journal of Clinical Radiology

摘　　要：目的探讨低管电压、低管电流及低对比剂剂量（三低）联合窄准直器宽度的预测试技术在头颈部CT血管成像（CTA）检查中的可行性。方法将拟行头颈部CTA检查的120例患者随机分成三组,每组40例,三组采用参数不同的小剂量预测试技术进行扫描延迟时间（DT）的确定。A组采用常规方法：管电压120 k V,管电流60m A,20 ml碘佛醇（320 mg I/ml）,准直器宽度和层厚5 mm;B、C组均采用：管电压80 k V,管电流20 m A,准直器宽度和层厚1.25 mm,但B组使用20 ml碘佛醇（320 mg I/ml）,C组则按患者体重（1 ml/kg）的10%作为预测试扫描的对比剂用量。记录三组预测试的达峰时间（T）、预测试扫描的人均碘用量（I）、剂量长度乘积（DLP）及有效剂量（ED）,测量、计算三组患者测试层面靶血管CT值、噪声（N）、信噪比（SNR）、对比噪声比（CNR）和最终原始图像中主动脉弓、大脑中动脉M1段的CT平均值（AA CTValue,M1CTValue）进行统计学分析。由两名高年资医师采用双盲法对三组患者头颈部动脉的显示情况及锁骨下静脉对比剂污染情况进行评分。结果三组预测的T、原始图像中主动脉弓及大脑中动脉M1段的平均CT值、图像质量的主观评分差异均无统计学意义（P〉0.05）,C组预测的T较A、B组的平均缩短约0.5 s;B、C组的DLP、ED[（2.87±0.54）m Gy·cm、（0.014±0.002）m Sv;（2.93±0.63）m Gy·cm、（0.014±0.003）m Sv]均低于A组的DLP、ED[（61.05±14.08）m Gy·cm、（0.305±0.07）m Sv],B、C组的平均ED仅约为A组的4.59%;C组预扫描的I低于A、B组的I,C组的I约为A、B组的31.50%,以上差异均具有统计学意义（P〈0.05）。结论 ＂三低＂联合窄准直器宽度的预测试技术应用于头颈部CTA检查是可行的,能大幅降低辐射剂量和对比剂用量。Objective To explore the feasibility and the effect of Test-Bolus with low tube voltage, low tube current , low dosage contrast medium（ CM ） （＂ Three-Lows＂） and thinner collimator in intracranial and cervical CT angiography （ CTA ）. Methods 120 patients with suspected craniocervical vascular disease randomly divided into three groups（40 ca- ses per group） underwent 64-MSCT with diffirent protocol of Test-Bolus for getting scan delay time （ DT ）. Group A using conventional methods ： kV = 120, mA = 60, CM = 20 ml, thickness = 5 mm; Group B and C ： kV = 80, mA = 20, thickness = 1.25 ram, CMs = 20 ml, CMc （ml） = weight （kg） ＊ l ml/kg ＊ 10%. Time to peak （T）, dosage of iodine per capita （I）, dose length product （DLP） ,effective dose （ED） were recorded. The peak CT value（PCTValue） of monitored arteries , background noise （N） ,signal to noise ratio （SNR） and contrast to noise ratio （CNR） of images of Test-Bolus and mean CT values of aortic arch, M1 segment of middle cerebral artery of final raw images （AA CTValue , M1 CTValue） were measured and assessed. Arterial displaying and interference from subclavian veins were further scored by two senior doctors. Results T,AA CTValue, M1CTValue, and image-quality-scores in three groups were not statistically different （P 〉 0.05 ） , T in group C is about 0.5s sooner compared with group A and B; DLP and ED in group B F （2.87 ±.54）mGy cm, （0. 014 ±.002）mSv] and group C [ （2.93 ± 0.63）mGy cm,（0.014 ±0.003）mSv] were both lower than group A [ （61.05 ± 14.08）mGy era, （0. 305 ± 0.07）mSv] ,ED in group B and group C were only about 4, 59% of that in group A （P 〈 0.05 ） ; I in group C was about 31.50% of that in group B and C （P 〈 0.05）. Conclusion The Test-Bolus with ＂Three Lows＂ and thinner collimator applied to intraeranial and cervical CTA is feasible for reducing the dosage of＂ CM and radiation dose greatly.

关 键 词：头颈部CTA “三低”联合窄准直器宽度预测试 辐射剂量 对比剂 

分 类 号：R816.1[医药卫生—放射医学]