摘要
目的比较双源CT 2.0与3.2螺距采集模式在主动脉造影及实质脏器中的图像质量和辐射剂量,以期选择最优扫描方案。方法前瞻性对40例怀疑主动脉疾病或随访患者行双源CT主动脉CTA检查。A组选用2.0螺距扫描模式,B组选用3.2螺距扫描,其他扫描参数相同。分别计算两组主动脉及实质脏器(肝脏、脾脏)平均CT值、背景噪声(SD)平均值、信噪比(SNR)、对比噪声比(CNR),并记录两组患者的辐射剂量、采集时间和扫描长度。应用SPSS 19.0软件对两组的图像质量和辐射剂量进行独立t检验。结果 (1)40例主动脉质量评分均在3分以上,A组主动脉质量评分为3.65±0.49,实质脏器评分为4.25±0.55,两者均高于B组(分别为3.20±0.41、3.85±0.37),差异均有统计学意义(t值分别为3.151、2.707;P值均<0.05)。(2)A组主动脉血管平均CT值为(411.47±117.82)HU,B组为(341.10±85.92)HU,两组间有显著差异(t=5.286,P<0.05);而A组实质脏器平均CT值[肝脏:(63.60±10.81)HU;脾脏:(103.65±26.48)HU]与B组[肝脏:(59.25±15.09)HU;脾脏:(98.70±22.28)HU]差异无明显统计学意义(t值分别为1.048、0.640;P值均>0.05)。A组主动脉血管区平均SD值为12.59±1.79,平均SNR为33.47±10.87,平均CNR为28.97±10.15,B组分别为14.61±2.49、24.05±7.78和20.52±7.19,差异均有统计学意义(t值分别为-7.202、7.711、7.437;P值均<0.05)。A组实质脏器平均SD值(肝脏:11.55±1.32;脾脏:15.60±2.30)低于B组(肝脏:12.45±1.19;脾脏:17.70±3.26);平均SNR(肝脏:5.61±1.35;脾脏:6.60±1.18)高于B组(肝脏:4.75±1.12;脾脏:5.62±1.07),差异均有统计学意义(t值分别为-2.267、-2.352、2.186、2.749;P值均<0.05)。(3)A组CT剂量指数[(4.55±0.71)m Gy]、剂量长度乘积[(280.25±47.10)m Gy/cm]和有效辐射剂量[(4.77±0.80)m Sv]与B组[(4.49±0.67)m Gy、(261.05±41.95)m Gy/cm、(4.44±0.71)m Sv]差异均无统计学意义(t值分别为0.282、-1.361、-1.367;P值均>0.05)。结论 2.0与3.2螺距扫描模式辐射剂量接近,但对实质脏器的显示更清晰,更适用于主动脉疾病的诊断。
Objective To investigate the influence of dual-source CT using 2.0-pitch and 3.2-pitch acquisition mode on the image quality and radiation dose in angiography of aorta and solid organs so as to determine the optimal scanning protocol. Methods Dual-source CT scanning of aorta was performed in 40 patients with suspected aortic disease. The patients were prospectively, randomly and equally divided into group A （ using 2.0-pitch scanning mode） and group B （ using 3.2-pitch scanning mode）. The mean CT values of aorta and solid organs （liver and spleen）, the mean background noise （SD）, the signal-to-noise ratio （SNR） and the contrast-to-noise ratio （CNR） of the two groups were separately calculated. The radiation dose, acquisition time, and scanning length were also recorded. The quantitative image quality parameters and radiation dose were statistically analyzed by using independent-sample student＇s t test with SPSS19.0 software. Results （ 1 ） The image quality score of aorta was 〉 3 in all 40 cases. In group A, the aortic quality score was 3.65 ± 0.49 and the quality score of solid organ was 4.25 ±0.55, both of which were higher than those in group B （3.20±0.41 and 3. 85±0.37 respectively）, the differences were statistically significant （t = 3. 151 and t = 2. 707; P 〈 0.5 ）. （2） The mean CT value of aorta in group A and group B was （411.47 ± 117.82） HU and （341.10± 85.92） HU respectively, the difference between the two groups was statistically significant （t = 5. 286, P 〈 0.05 ）. The mean CT value of the liver and spleen in group A was （63.60 ± 10.81 ） HU and （ 103.65 ± 26.48） HU respectively, which was （59.25 ± 15.09） HU and （98. 70± 22.28） HU respectively in group B, and the difference between the two groups was not significant （ t = 1. 048 and t = 0. 640 ; P 〉 0.05）. The mean SD, SNR and CNR of aortic area in group A were 12.59 ± 1.79, 53.47 ± 10.87 and 28.97 ± 10.15 respectively, and were 14.61 ± 2.49, 24.05 ± 7.78 and 20.52 ± 7.19 respectively in group B, the difference between the two groups was statistically significant （ t = - 7. 202, t = 7. 711 and t = 7. 437 respectively; P 〈 0.05 ）. The mean SD of liver and spleen in group A was 11.55 ± 1.32 and 15.60 ±2.30 respectively, which was lower than those in group B （ 12.45 ± 1.19 and 17.70 ±3.26 respectively）. The mean SNR of liver and spleen in group A （5.61 ± 1.35 and 6.60 ±1.18 respectively） was higher than those in group B （4.75 ±1.12 and 5.62 ± 1.07 respectively）, the difference between the two groups was statistically significant （t = -2. 267, t = -2. 352, t =2. 186 and t =2. 749 respectively; P 〈 0.05）. （3） The CTD, DLP and ED in group A were （d. 55 ±0.7l ） mGy, （80.25 ±47. 10） mGy/cm and （4.77 ± 0.80） mSv respectively, which were （4.49 ± 0.67） mGy, （261.05 ± 41.95） mGy/cm and （4.44 ± 0.71 ） mSv respectively in group B, and no statistically significant differences existed between the two groups （t =0. 282, t = - 1. 361 and t = - 1. 367 respectively ; P 〉 0.05 ）. Conclusion The radiation doses of 2.0-pitch and 3.2-pitch scanning mode are quite similar, but 2.0-pitch scanning mode can provide more clear images of solid organs and it is more suitable for the diagnosis of aortic disease than 3.2 pitch scanning.
出处
《临床放射学杂志》
CSCD
北大核心
2014年第12期1925-1930,共6页
Journal of Clinical Radiology
作者简介
通讯作者
