| 闫莉,邹奕轩,王静怡,付芳芳,王梅云.双低技术在肺动脉血管CT造影中的应用研究[J].中华放射医学与防护杂志,2023,43(4):301-306 |
| 双低技术在肺动脉血管CT造影中的应用研究 |
| Application of low tube voltage and reduced contrast medium in CT pulmonary angiography |
| 投稿时间：2022-07-13 |
| DOI：10.3760/cma.j.cn112271-20220713-00290 |
| 中文关键词: 肺动脉栓塞 低剂量 管电压 计算机体层成像 |
| 英文关键词:Pulmonary embolism Low dose Tube voltage Computed tomography |
| 基金项目:河南省科技公关项目(212102310689) |
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| 中文摘要: |
| 目的 探讨低剂量60 kV管电压技术联合低剂量对比剂应用于肺动脉CT血管造影(CTPA)的可行性。方法 纳入临床怀疑肺动脉栓塞要求行CTPA检查且体质量指数(BMI)< 25 kg/m2的门诊或住院患者60例,按照随机数字表法分为对照组(采用常规剂量方案:100 kV管电压,常规50 ml,速率为4.5 ml/s的对比剂注射方案)或试验组(采用低剂量方案:60 kV管电压,30 ml对比剂混合20 ml生理盐水,速率为4.5 ml/s的对比剂注射方案)各30例。测量肺动脉干、左右肺动脉和左右肺叶下动脉的HU值,计算信噪比(SNR)和对比噪声比(CNR),评价客观图像质量,并记录辐射剂量。主观图像质量由放射科医生根据总体图像质量及肺动脉增强均匀性用5分法进行评估。采用Mann-Whitney U检验比较两组的噪声、SNR、CNR及辐射剂量,采用χ2检验比较两组主观图像质量差异。结果 所有图像均满足临床诊断要求。试验组与对照组CTPA图像主观总体图像质量差异无统计学意义(P > 0.05),增强情况的评分差异无统计学意义(P > 0.05)。试验组与对照组在肺动脉干和左右下肺动脉的平均衰减值差异无统计学意义(P > 0.05),在左右肺动脉的平均衰减值差异有统计学意义(t=2.75、3.91,P＜ 0.05)。试验组与对照组的平均背景噪声差异无统计学意义(P > 0.05)。试验组在左肺动脉的CNR和右肺动脉的SNR与CNR较对照组高,差异有统计学意义(t=0.04、2.41、3.08,P < 0.05)。在试验组中,其他各肺动脉血管分支的SNR与CNR与对照组差异无统计学意义(P > 0.05)。在试验组中,CTPA检查的平均有效剂量为1.24 mSv,约为对照组的1/3,有统计学差异(t=21.65,P < 0.05)。结论 在BMI < 25 kg/m2的患者群体中,使用60 kV和低剂量对比剂用于CTPA检查是可行的,可在不影响图像质量的情况下降低辐射剂量和碘对比剂剂量。 |
| 英文摘要: |
| Objective To explore the feasibility of 60 kV tube voltage combined with reduced contrast medium in CT pulmonary angiography (CTPA).Methods Totally 60 outpatients and inpatients with a body mass index (BMI) of less than 25 kg/m2 who had suspected pulmonary embolism and were arranged for CTPA examination were enrolled in this study. They were divided into a control group and an test group according to the random number table method. A protocol with a conventional dose was adopted in the control group. This scheme consisted of 100 kV tube voltage and injection of 50 ml of contrast medium at the rate of 4.5 ml/s. A scheme with a low dose was employed in the experimental group. Specifically, this scheme involved 60 kV tube voltage scheme and injection of 30 ml of contrast medium mixed with 20 ml of normal saline at a rate of 4.5 ml/s. The objective image quality was assessed by measuring the Hounsfield units (HU) of five regions of interest (ROIs), i.e., pulmonary trunk, right and left pulmonary arteries, and right and left lower lobar arteries, and the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) were calculated. Moreover, the radiation doses were recorded. The subjective image quality was assessed by radiologists using a 5-point scale based on the overall image quality and the enhancement homogeneity of pulmonary arteries. The noise, SNR, CNR, and radiation dose of the two groups were compared using the Mann-Whitney U test, and the differences in the subjective image quality between the two groups were compared using the χ2 test.Results All images met the requirements for clinical diagnosis. The two groups did not show significant differences in the overall subjective quality of CTPA images and enhancement scores (P > 0.05), and in the average attenuation values of the pulmonary trunk and the left and right lower lobar arteries (P > 0.05), but exhibited statistical differences in the average attenuation values of the left and right pulmonary arteries (t = 2.75, 3.91, P＜ 0.05). There was no significant difference in the average background noise between the two groups (P > 0.05). The test group had higher CNR of the left pulmonary artery and higher SNR and CNR of the right pulmonary artery than the control group, with statistically significant differences (t = 0.04, 2.41, 3.08, P＜ 0.05). There was no significant difference in the SNR and CNR of other pulmonary artery branches between the two groups (P > 0.05). The test group had an average effective dose of 1.24 mSv for CTPA, which was about one-third of that of the control group, with statistically significant differences (t = 21.65,P< 0.05).Conclusions The scheme of 60 kV tube voltage and reduced contrast medium for CTPA is feasible for patients with BMI < 25 kg/m2. Using this scheme, the radiation and iodine dose can be reduced without affecting image quality. |
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