【摘要】 目的探讨256层螺旋CT高级迭代重组技术(iDose4)在低辐射剂量肺动脉成像应用中的价值。方法将需接受肺动脉CTA检查、身体质量指数(BMI)18.5~24.0的患者60例,随机分成常规组与低剂量组,每组各30例。常规组扫描管电压120 k V,管电流250 m As,低剂量组扫描管电压80 k V,管电流100 m As,其余扫描参数两组一致。常规组用传统的滤波反投影重组算法(FBP),低剂量组采用迭代重组算法。由2名高级职称的放射科医师以统一标准对各组图像质量进行主观评价。测量、计算肺动脉CT值均数和对比噪声比(CNR)进行客观评价,并计算扫描的辐射剂量指标:平均容积CT辐射量指数(CTDIvol)、辐射量长度乘积(DLP)和有效辐射量(ED)。对两组图像质量主客观评价结果及辐射剂量进行统计学分析。结果两组图像质量主观评价比较无显著差异(P>0.05),常规组肺动脉CT值均数(388.43±35.27)HU,低剂量组肺动脉CT值均数(450.33±55.63)HU,差异具统计学意义(P<0.05);CNR分别是35.68±11.18、34.98±10.96,差异无统计学意义(P>0.05)。CTDIvol分别为16.90 m Gy、2.00 m Gy,DLP分别为(578.33±14.58)m Gy.cm、(93.77±5.92)m Gy.cm,ED分别为(8.10±0.20)m Sv、(1.31±0.08)m Sv,两组各辐射剂量指标的差异均有统计学意义(P<0.05)。结论 256层螺旋CT低剂量扫描结合迭代重建iDose4技术应用在肺动脉成像中,可保证图像质量同时大幅降低辐射剂量,值得临床推广应用。更多还原

【Abstract】 Objective To explore the application values of 256-slice spiral CT with advanced iterative reconstruction( idose4) and low dose in pulmonary artery imaging. Methods Sixty-six patients whose body mass indexes were from 18.5 to 24. 0kg / m2 accepted pulmonary artery CTA because the patients had clinical needs. All patients were divided into routine and low dose group according to randomization and each group included 30 cases. The tube voltage 120 kv,tube current250 m As were used in the routine group and tube voltage 80 kv,tube current 100 m As were used in low dose group. Other parameters were the same in both groups. The reconstructing method in the routine group was traditional filtered back projection( FBP) and one in low dose was iterative reconstruction( idose4). Tow senior radiologists subjectively evaluated the imaging qualities according to equal standards. The mean of the CT value in pulmonary artery,contrast noise ratio( CNR)served as objectively evaluated indexes. The average volume CT radiating index( CTDIvol),radiating dose length product( DLP),effective dose( ED) served as indexes to evaluate scanning dose. The above data was statistically analyzed. Results The qualities between the routine group and the low dose group had no evident difference by subjective evaluation( P> 0. 05). The mean CT value of the pulmonary artery in routine group was( 388. 43 ± 35. 27) HU and in the low dose group was( 450. 33 ± 55. 63) HU; they had statistical significance( P < 0. 05). CNR of routine and low dose group were respectively 35. 68 ± 11. 18 and 34. 98 ± 10. 96 that had no statistical significance( P > 0. 05). CTDIvol of both groups were respectively 16. 90 m Gy and 2. 00 m Gy,DLP were respectively( 578. 33 ± 14. 58) m Gy. cm and( 93. 77 ± 5. 92) m Gy.cm,ED were( 8. 10 ± 0. 20) m Sv and( 1. 31 ± 0. 08) m Sv respectively. The differences of all the indexes in radiation dose in both groups had statistical significance( P < 0. 05). Conclusion 256-slice spiral CT with advanced iterative reconstruction( idose4) and low dose in pulmonary artery imaging was able to maintain imaging quality as well as decrease greatly the radiation dose so that it was worth being applied.更多还原