双源CT分次注射法低辐射CT泌尿道造影的可行性研究

Split-bolus CT urography with low voltage scan and iterative reconstruction in dual-source:feasibility and dose reduction

目的探讨双源CT分次注射法联合迭代算法CT泌尿道造影的辐射剂量、图像质量。方法对58例初诊为泌尿道疾病而准备行CTU检查的患者随机分为两组。A组(对照组),采用常规扫描方式(120k V电压,平扫、皮质期、髓质期和排泄期扫描),滤波反投影法重建,B组为实验组,采用分次注射法,低电压扫描迭代算法重建,分析两组的辐射剂量、图像质量。结果共55例患者顺利完成检查(A组27例、B组28例),两组的平均总辐射剂量分为(27.18±5.26)m Sv和(3.85±0.91)m Sv,差别有明显统计学意义(t=-27.30;P=0.00),B组辐射剂量下降85.84%;A、B两组图像质量主观评分分别为(4.62±0.71)分和(4.35±1.15)分,差别无统计学意义(Z=-0.75;P=0.52);图像质量客观评分SNR和CNR分别为(115.33±18.12,123.25±21.03)和(105.45±19.25,109.96±21.55),差别无统计学意义(t=1.38,P=0.17;t=2.10,P=0.10)。结论双源CT分次注射法联合低电压扫描迭代重建CTU检查可大幅度降低该检查的辐射剂量,但图像质量未受明显影响。

Objective To evaluate the image quality, dose reduction of Split-bolus CT Urography （CTU） with low voltage scan and sinogram affirmed iterative reconstruction （SAFIR）. Methods A total of 58 consecutive patients with confirmed or sus- pected urinary system diseases needed CTU examination were divided into two groups. Group A was experiment group, with con- vention scan （120 kV） with one time injection used. Group B was control group, by low voltage scan （80 kV）, SAFIR algorithm with Split-Bolus injection. The radiation dose arid image quality were compared in two groups. Results The total 55 patients completed CTU examination successfully（27 cases in group A and 28 cases in group B）. The average radiation dose in group B reduced by 85.84% than group A, with （3.85 ±0, 91 ） arid （27.18 ±5.26） mSv separately. The statistic difference was signifi- cant （ t = -27.30; P = 0, 00）. Subjective image qtality score was （4.62 ± 0.71 ） and （4.35± 1.15） in group A and B sepa- rately, with no significant statistical difference （ Z = -0, 75 P = 0, 52）. SNR and CNR of objective image quality in group A and B were （ 115.33 ± 18.12, 123.25 ± 21. 03） and （ 105, 45 ±19.25, 109.96 ± 21.55） separately, with no significant difference in SNR and CNR （ t = 1.38, P = 0. !7; t = 2, 10, P =-0. !0）. Conelllsion Split-bolus CTU combined with SAFIR algorithm method can reduce the radiation dose significartly, but the image quality is unaffected obviously.